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Annual Dialysis Data Report 2015, JSDT Renal Data Registry

Abstracts

The annual survey of Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) was conducted for 4380 dialysis facilities at the end of 2015, among which 4321 facilities (98.7%) responded. The response rate of the 2015 survey was comparable with the past, even though it was the first year after the new anonymization method. The number of chronic dialysis patients in Japan continues to increase every year; it has reached 324,986 at the end of 2015. The mean age was 67.86 years. At the end of 2015, the prevalence rate was 2592 patients per million population. Diabetic nephropathy was the most common primary disease among the prevalent dialysis patients (38.4%), followed by chronic glomerulonephritis (29.8%) and nephrosclerosis (9.5%). The rate of diabetic nephropathy and nephrosclerosis has been increasing year by year, whereas that of chronic glomerulonephritis was declining. The number of incident dialysis patients during 2015 was 39,462; it has remained stable since 2008. The average age was 69.20 years, and diabetic nephropathy (43.7%) was the most common cause in the incident dialysis patients. These patients caused by diabetes did not change in number for the last several years. Meanwhile, 31,608 patients died in 2015; the crude mortality rate was 9.6%. The patients treated by hemodiafiltration (HDF) have been increasing rapidly from the revision of medical reimbursement for HDF therapy in 2012. It has attained 53,776 patients at the end of 2015, which were 10,493 greater than that in 2014. In particular, the number of online HDF patients increased about ten times 2012. The number of peritoneal dialysis (PD) patients was 9322 in 2015, which was slightly increased than 2014. Twenty percent of PD patients treated in the combination of hemodialysis (HD) or HDF therapy. Five hundred seventy-two patients underwent home HD therapy at the end of 2015; it increased by 43 from 2014.

Further JRDR data analyses could clarify the relationships between various dialysis modalities, patient care, and clinical outcomes; furthermore, it could also make it possible to establish clinical practice guidelines or medical reimbursement revisions based on the evidence.

Trial registration

JRDR was approved by the ethical committee of JSDT and has been registered in the “University hospital Medical Information Network (UMIN) Clinical Trials Registry” as an approved number of UMIN000018641 since 2015.

Part I. JRDR 2015 Annual Data Report; General Remarks

Introduction

Japanese Society for Dialysis Therapy (JSDT) has conducted a survey (JSDT Renal Data Registry: JRDR) on the status of chronic dialysis therapy in Japan at the end of every year since 1968, covering almost all dialysis facilities throughout the country [1, 2]. Despite the fact that this survey is conducted without providing any compensation to participating facilities, its response rate represents a largely complete and unbiased survey of the status of chronic dialysis in Japan, making it quite rare in the world. In publishing our results, we would like to take this opportunity to express our sincere gratitude to everyone at the participating dialysis facilities for taking part in the survey in addition to their routine clinical practice.

JRDR had previously featured two types of reports: prompt (unfixed) data reported at the annual meeting held every June and defined (fixed) data wherein previous data were subsequently screened. The prompt data were distributed at the annual meeting in “An Overview of Regular Dialysis Treatment in Japan, the Illustrated Report”. The defined data are presented in “An Overview of Regular Dialysis Treatment in Japan, the CD-ROM Report” and were distributed at the end of the year to all facilities that were JSDT members or participated in the survey. The annual JRDR report, which was published every January in the Journal of Japanese Society for Dialysis (in Japanese), also consists of the defined data. In various cases, the prompt data from the illustrated report were overwhelmingly cited by numbers. The decade of the 2010s has been predicted to include a reduction in the pace of increase in the number of dialysis patients, reaching the point where this number would decrease within a few years [3]. This meant that sometimes defined data would indicate that the rate was still increasing even if it had decreased in the prompt data, which could cause serious confusion. Thus, the use of prompt data for the illustrated reports was discontinued in the 2014 survey, and the illustrated report and CD-ROM were prepared from the defined data instead [4]. The illustrated report is now distributed at the end of the year to each dialysis facility with the CD-ROM included in its back cover.

In December 2014, the Ethical Guidelines for Medical and Health Research Involving Human Subjects was issued by the Ministry of Health, Labour, and Welfare and the Ministry of Education, Culture, Sports, Science, and Technology, demanding that all academic societies strictly follow ethical considerations and protect personal information in epidemiological research [5]. Even JSDT changed its survey methods based on these guidelines, starting with enhanced anonymization from its 2015 year-end survey to ensure the protection of personal information. The specific changes made to their survey methods can be found on the members-only pages of the JSDT homepage (http: //www.jsdt.or.jp/). Furthermore, all survey methods were reviewed in March 2015 by the ethics committee (JSDT Ethics Committee Approval No. 1) to uphold ethical validity, fairness, and transparency of surveys. The reviewed survey methods were then entered into the UMIN Clinical Trials Registry (UMIN-CTR) for availability to the public (UMIN000018641), and the review results were batched together for posting on the JSDT homepage. Enhanced anonymization consisted of a system wherein patient information was converted into a random string of alphanumeric characters using a special algorithm, and the correspondence tables for retrieving the real names of patients were held by each dialysis facility; hence, even the JSDT headquarters could not retrieve patient information. The 2015 year-end survey represented the first year of complete anonymization using this system, and although participating facilities were asked to handle more work than usual, the response rate was almost same as in other years. We were reminded of the sincere attitude towards dialysis treatment of all those involved in dialysis treatment in Japan, as well as their trust and expectations towards JSDT.

Survey methods

Sending and collecting questionnaires

The JRDR survey is performed by two types of questionnaires: facility questionnaires that include questions, such as the number of dialysis beds, staff, and patients, and patient questionnaires that include questions, such as dialysis prescriptions, laboratory findings, and outcome indices of individual dialysis patients. In the 2015 year-end JRDR survey, two USBs were mailed to dialysis facilities nationwide in December 2015. One USB contained facility and patient questionnaires prepared in MS Excel, whereas the other USB contained the correspondence tables needed to anonymize patient information and recover real names. The patient questionnaires contained patient information recorded in previous years using the anonymization methods, which were then updated by dialysis facilities to include data on patient survival, death, transfers, and other outcomes. Furthermore, new patients were registered, and the correspondence table USB was used to anonymize the information once all patients were entered. Once anonymized, patient information on questionnaires including their name, sex, and date of birth were converted into a string of alphanumeric characters of random fixed length. Subsequently, each dialysis facility only returned the questionnaire USB to the JSDT administrative offices after confirming that patient personal information was completely anonymized. As described above, anonymization was enhanced with the 2015 JRDR survey, abolishing the paper-based survey methods used before 2014. Paper-based surveys are now only used for certain facilities. The initial deadline was January 31, 2016, but facilities that had not responded were urged to participate, and they were eventually incorporated into the 2015 year-end data with a June 30 deadline.

Survey items

The following items were asked in the 2015 JRDR survey. As described above, the 2015 survey was the first after enhanced anonymization; hence, new topical survey items were not incorporated, and the contents were similar to the 2014 year-end survey. In addition, all survey items before 2014 are included on the member pages of the JSDT homepage (http: //www.jsdt.or.jp/)).

  • Facility survey

    1. 1.

      Overview and scope of facilities

      • Name and contact numbers (TEL, FAX) of facility, as well as the year and month when the facility started providing dialysis treatment

      • Dialysis capabilities: Capacity for simultaneous hemodialysis (HD) treatments, maximum capacity for HD treatments, and number of bedside consoles

      • Number of workers involved in dialysis treatment (e.g., doctors, nurses, clinical engineers, nutritionists, case workers)

      • Number of medical dialysis specialists qualified by JSDT

    2. 2.

      Patient dynamics

      • Number of prevalent dialysis patients at the end of 2015 (number of patients by treatment modality, inpatient/outpatient)

      • Number of dialysis patients undergoing nighttime dialysis in 2015

      • Number of incident dialysis patients in 2015 (number of incident HDF and peritoneal dialysis (PD) patients)

      • Number of deceased patients during 2015

    3. 3.

      Dialysis fluid quality control

      • Use of endotoxin retentive filter (ETRF)

      • Dialysis fluid sampling status and sampling site of dialysis fluid during testing

      • Frequency for measuring endotoxin (ET) concentration in dialysis fluid and ET concentration in dialysis fluid

      • Frequency for measuring total viable microbial count (TVC) in dialysis fluid, sampling volume for TVC, cultivation medium for TVC, and TVC in dialysis fluid

  • Patient survey

    1. 1.

      Patient personal information

      • Sex, date of birth, year and month of start of dialysis, year and month of transfer from another hospital, primary disease, residence (prefecture), dialysis modality, month of transfer (destination facility code), outcome category, outcome date (transfer, death, dropout, or transplantation) (destination facility code), month of death, cause of death, dates of changes, change codes, status of combined therapies involving PD with HD or hemodiafiltration (HDF), etc., PD experience, and number of kidney transplants

    2. 2.

      HD/HDF therapy conditions

      • Frequency of dialysis session per week, dialysis time per session, and blood flow rate

      • HDF: dilution methods, substitution fluid volume per session

      • Body height, pre- and post-dialysis body weight, pre-dialysis systolic blood pressure, pre-dialysis diastolic blood pressure, and pre-dialysis pulse rate

    3. 3.

      Laboratory findings

      • Pre- and post-dialysis serum urea nitrogen (UN), pre- and post-dialysis serum creatinine concentration, pre-dialysis serum albumin concentration, pre-dialysis serum C-reactive protein (CRP) concentration, pre-dialysis serum calcium concentration, pre-dialysis serum phosphorus concentration, serum parathyroid hormone (PTH) assay method, PTH level (intact or whole PTH), pre-dialysis hemoglobin concentration, serum total cholesterol concentration (total cholesterol), and serum high-density lipoprotein cholesterol concentration (HDL-C)

    4. 4.

      Outcome factors

      • Antihypertensive drug use, smoking, history of diabetes, history of myocardial infarction, history of cerebral hemorrhage, history of cerebral infarction, limb amputation, history of proximal femur fracture, history of encapsulating peritoneal sclerosis (EPS)

    5. 5.

      Peritoneal dialysis (PD) survey

      • Therapeutic history: Current PD dialysis vintage, number of months in which PD was performed in 2015

      • Peritoneal function: Implementation of peritoneal equilibration test (PET), 4-h creatinine concentration dialysate/plasma ratio in PET (PET Cr D/P ratio)

      • Dialysis prescription: Type of PD fluid, volume of PD fluid per day, PD treatment time per day, daily urine volume, mean fluid removal volume per day, Kt/V by residual kidney function (residual kidney Kt/V), Kt/V by PD (PD Kt/V)

      • Dialysis method: Use of automated peritoneal dialysis (APD) machine, changing maneuver of PD fluid

      • Infectious disease: Numbers of peritonitis during 2015 (peritonitis frequency), numbers of exit-site infections during 2015

Methods for publicizing survey results and overview of this report

As described in the introduction, JRDR survey results could be reported by preparing an illustrated report and an annual report based on the defined data from the 2014 survey. The annual report was posted every January in the Journal of Japanese Society for Dialysis (in Japanese), and a translated version was posted approximately 6 months later in the Therapeutic Apheresis and Dialysis (TAD). In copies of the TAD, survey results were mostly reported in tables due to page limitations, and the illustrated report provides graphic explanations. The JSDT website makes downloading PDFs of TAD papers and the illustrated reports possible and, furthermore, MS-PowerPoint presentations with illustrations [6], but it was the illustrated reports that overwhelmingly receive the most use in general. In contrast, several foreign countries have been demanding that the results of the JRDR survey be published in a form that people around the world may easily use. In the 2016 business plan, the JRDR Committee proceeded with preparations to make PDFs of English language versions of the annual report, English translations of MS-PowerPoint presentations, and MS Excel files with tables in English available on the JSDT website to let the rest of the world know the state of dialysis therapy in Japan and the expertise available. When this was done, the posting destination was changed from the TAD to the journal Renal Replacement Therapy (RRT), which joined a new English language JSDT journal (now preparing the 2014 year-end survey report). In changing the publication methods for survey results, the form of illustrated, Japanese language, and English language reports had to be streamlined as much as possible to simplify the effort required to prepare reports in Japanese and translate them into English. This report was published by this process, and although it was written, based on tables and drawings used in the illustrated report, the issue of how to maintain uniformity in areas such as the order of recording is still being sorted out. Hence, there might still be some inconvenience for readers, and thus, we apologize. We report the survey results and discussion in “JRDR Annual Data Report (ADR) 2015” in the Part II as described below.

Contents of JRDR 2015 ADR

Chapter 1: Basic demographics

  1. 1.

    Facility dynamics

  2. 2.

    Number of dialysis patients

  3. 3.

    Distribution of dialysis patients by treatment modality and prefecture

  4. 4.

    Mean age, sex, and dialysis vintage

  5. 5.

    Primary diseases

  6. 6.

    Causes of death

  7. 7.

    Crude death rate and survival rate

Chapter 2: Current status of dialysis fluid quality management

  1. 1.

    Overview of dialysis fluid quality

  2. 2.

    Dialysis fluid ET testing

  3. 3.

    Dialysis fluid viable microbial testing

  4. 4.

    Present status of ETRF installation

  5. 5.

    Overall dialysis fluid quality

Chapter 3: Current status of hemodiafiltration (HDF)

  1. 1.

    HDF patient dynamics

  2. 2.

    Types and annual changes of HDF treatment modality

  3. 3.

    HDF prescriptions

  4. 4.

    Urea kinetics, nutrition, and inflammation in HDF patients

  5. 5.

    Management for anemia and CKD-MBD in HDF patients

Chapter 4: Current status of peritoneal dialysis (PD)

  1. 1.

    PD patient dynamics

  2. 2.

    Present status of PD + HDF combined therapy

  3. 3.

    PD prescriptions

  4. 4.

    Residual kidney function (urine volume and residual kidney Kt/V)

  5. 5.

    Peritoneal function (ultrafiltration volume and PD Kt/V)

  6. 6.

    Peritoneal equilibration test (PET) and dialysate/plasma creatinine (D/P Cr) ratio

  7. 7.

    Exit-site infection (ESI) and peritonitis

  8. 8.

    History of encapsulating peritoneal sclerosis (EPS)

Chapter 5: Current status of elderly dialysis patients

  1. 1.

    Present status of elderly dialysis patients

  2. 2.

    Hemodynamics, dialysis prescriptions and urea kinetics in elderly dialysis patients

  3. 3.

    Nutrition and inflammation in elderly dialysis patients

  4. 4.

    Management for anemia and CKD-MBD in elderly dialysis patients

Chapter 6: Current status of diabetic dialysis patients

  1. 1.

    Present status of diabetic dialysis patients

  2. 2.

    Hemodynamics, dialysis prescriptions, and urea kinetics in diabetic dialysis patients

  3. 3.

    Nutrition and inflammation in diabetic dialysis patients

  4. 4.

    Management for anemia and CKD-MBD in diabetic dialysis patients

  5. 5.

    Annual changes in diabetic dialysis patients dynamics

Part II. JRDR 2015 Annual Data Report: results and discussion

Chapter 1: Basic demographics

Facility dynamics

The 2015 JRDR survey was conducted at 4380 facilities nationwide, and the 4321 facilities has responded. The number of responding facilities had been increasing over the past 10 years, but a nine-center reduction (0.2 point reduction) from the previous year was observed in the 2015 survey. There was a concern that the enhanced anonymization and the abolition of paper-based survey had resulted in a decreased response rate and an undervaluation of dialysis facility and patient counts. However, the response rate for facility survey was 98.7%, whereas the facility response rate for patient survey was 94.6% of the total; thus, there was hardly any change from the previous year. Thus, a decrease in the number of facilities responding to questionnaires does not necessarily mean a substantial decrease in the number of dialysis facilities. However, recently, the slowing rate of increase in dialysis patients was observed, and thus, future trends have become a matter of attention (Tables 1 and 2). The 4321 facilities had 133,538 bedside consoles (a 1983 increase from the previous year), a simultaneous HD treatment capacity of 131,514, and a maximum capacity for HD treatments of 438,391. Compared with the end of 2014, these represented increases of 1.5, 1.3, and 1.4%, respectively (Table 2).

Table 1 Summary of chronic dialysis therapy in Japan, 2015
Table 2 Changes in the number of bedside consoles, 1980–2015

Number of dialysis patients

Based on the facility survey, the total number of patients receiving chronic dialysis therapy at the end of 2015 was 324,986, which represents the prevalence of chronic kidney disease patients undergoing dialysis therapy. The number of dialysis patients increased by approximately 10,000 people annually through 2005, but this rate has been slowing in recent years. At the end of 2014, the number had increased by 6010 from the previous year, and at the end of 2015, it had increased by 4538 people (Fig. 1, Table 3). (In the figure, the decrease in the number of patients at the end of 1989 is apparently the effect of the exceptionally low 86% questionnaire response rate that year [2]).

Fig. 1
figure1

Changes in the number of prevalent dialysis patients, 1968–2015. The low response rate in 1989 caused a dip in patient numbers

Table 3 Prevalent, incident, and deceased dialysis patient counts and adjusted rates, 1983–2015

In 2012, Nakai et al. [3] predicted the number of future dialysis patients, stating that the number would decrease from a peak of approximately 348,000 in 2021. The number of dialysis patients per million of the population (pmp) would be 2592.4 persons, an increase of 75.1 people from the previous year, meaning there would be one dialysis patient for every 385.7 Japanese citizens (Table 3) [7]. The population of Japan has been on the decline since 2011; thus, the percentage of the population has increased year by year. Incidentally, the highest number of dialysis patients pmp in the world is in Taiwan, with Japan following a close second [8]. In contrast, the number of incident dialysis patients represents the incidence of chronic kidney disease patients undergoing dialysis therapy, and although the number of incident dialysis patients before 2008 showed an increasing trend, it began to exhibit a decrease in 2009. Since then, faint fluctuations in the number of patients have been observed, but the rate has remained largely constant. However, the number of incident dialysis patients in 2015 increased 1135 persons from the previous year to 39,462, exceeding 39,000 persons for the first time (Fig. 2, Table 3). In contrast, the annual number of deceased patients has consistently increased through 2011. However, since then the rate has remained mostly constant. The number of deceased 2015 prevalent patients increased to 31,068, an increase of 361 persons from 2014, exceeding 31,000 persons for the first time (Fig. 2, Table 3).

Fig. 2
figure2

Incident and deceased dialysis patient counts, 1983–2015

Distribution of dialysis patients by treatment modality and prefecture

Tabulation in the 2015 JRDR survey was switched to a method focusing upon treatment modality, such as HDF, which showed a rapid increase in use recently. The percentages held by each therapeutic method are 79.5% for HD, 17.0% for HDF, 0.0% for hemofiltration (HF), 0.4% for hemoadsorption dialysis, 2.9% for PD, and 0.2% for home hemodialysis (HHD) (Table 1). The percentage of total home dialysis therapy in Japan including PD and HHD was 3.1%, which was the lowest in the developed world [8]. HDF therapy, particularly online HDF, had dramatically increased in use since the 2012 revision of the medical payment system, and the total number of patients using HDF at the end of 2015 was 55,333 persons. A total of 9322 patients were treated by PD, which represented a slight increase from 9255 in 2014. Twenty percent of all PD patients were on the combination therapy with HDF, a percentage which has remained largely constant for the past 5 years. A total of 572 patients were on HHD, which was a 43-person increase from 2014. This represented a large rate of increase, but the percentage of all therapies was still small. Thirty-three thousand three hundred seventy patients were treated in nighttime dialysis at the end of 2015, which represented a decrease from 41,271 persons in 2014. The number of nighttime dialysis patients was approximately 41,000 to 42,000 persons for several years. However, it is possible that either it actually decreased in 2015 or changes in how the number of nighttime dialysis patients are entered in the 2015 survey, and furthermore, the addition of “Dialysis for a given period of time recognized by insurance as starting after 5:00 p.m. or ending after 9:00 p.m.” as the definition of nighttime dialysis in annotated response fields had an influence; thus, future trends require attentive observation. The total number of incident dialysis patients was 39,462 persons, of whom 94.4% began HDF or similar therapies, and 5.6% began PD. Changes in how incident HDF as well as incident PD cases were entered may have influenced the tabulated values.

Before 2014, the number of chronic dialysis patients by prefecture was presented categorized into daytime dialysis, nighttime dialysis, HHD, and PD, but the tabulation method was changed to details on the treatment modality from the 2015 JRDR survey. The number of dialysis patients in prefectures is governed by fundamental population differences, and those differences remain large on the order of the patient number in pmp. The mean in Japan is 2592.4 pmp, but greatly differs depending on the region from 1963.7 pmp (Akita Prefecture) to 3712.8 pmp (Tokushima Prefecture). Similarly, regional differences in the percentages of each treatment modality were found, and the percentage of HDF representing all dialysis patients has a nationwide mean of 17.0%, although major differences ranging from 6.6% (Miyazaki Prefecture) to 41.5% (Shimane Prefecture) were found. The percentage of PD patients also similarly has a nationwide mean of 2.9%, but major differences ranging from 0.7% (Saga Prefecture) to 7.3% (Kagawa Prefecture) (Table 4) were found.

Table 4 Prevalent dialysis patient counts, by modality and prefecture, 2015

Mean age, sex, and dialysis vintage

The ages and sexes of chronic dialysis patients continues to change over time; hence, patients need to be divided into 2015 incident dialysis patients and prevalent dialysis patients, through which trends were identified over time. The number of patients who were entered into the patient survey table and initiated dialysis in 2015 with confirmed age and sex was 36,792. This is equal to 93.2%, or 2670 persons less than the 39,462 persons recorded into the facility survey. There were 25,004 males and 11,788 females, and similarly to the previous year, there were approximately twice as many males as females. The mean age of all incident dialysis patients was 69.20 years, representing a 0.16-year increase compared with the 69.04 year mean age at the end of 2014. The mean age was 68.37 years for men and 70.95 years for women, which compared with the previous year represented a 0.23-year and 0.04-year increase, respectively. If incident patients are categorized into 5-year age groups (Fig. 3, Table 5), then the age groups with the highest percentages were men aged between 65 and 69 years and women aged between 80 and 84 years. Very elderly patients 75 years or older accounted for 45.8% of females and 36.6% of males. In contrast, the total number of 2015 prevalent patients with sex and age recorded into patient questionnaires was 313,212 persons, equal to 96.4% or 11,774 persons less than the 324,986 persons in facility questionnaires. The mean age of prevalent patients was 67.86 years, or a 0.32-year increase from the previous year. The mean age of males was 67.07 years, which meant a 0.32-year increase, and the mean age of females was 69.28 years, representing a 0.34-year increase (Fig. 4, Table 6). The age group with the highest percentage was males and females aged 65 to 69 years. As shown in the annual changes in the mean age of incident and prevalent patients, both groups exhibited an increase linearly. However, in recent years, this increase has been slowing (Fig. 5, Table 7).

Fig. 3
figure3

Incident dialysis patient distribution, by age and sex, 2015

Table 5 Incident dialysis patient distribution, by age and sex, 2015
Fig. 4
figure4

Prevalent dialysis patient distribution, by age and sex, 2015

Table 6 Prevalent dialysis patient distribution, by age and sex, 2015
Fig. 5
figure5

Average age of incident and prevalent dialysis patients, 1983–2015

Table 7 Mean age of incident and prevalent dialysis patients, 1983–2015

As indicated in the changes over time in the number of prevalent patients in each survey year by age, the number of patients less than 65 years showed signs of increasing by the end of 2011, but this became a decreasing trend from the end of 2012 against the background of increasing age among incident patients. The number of patients younger than 65 years at the end of 2015 was 109,195, a decrease of 3264 persons compared with the end of 2014. In other words, the increase in the number of chronic dialysis patients in Japan was due to the increase in the number of patients aged 65 years or older. Furthermore, an increase was observed in the percentage of the very elderly aged 75 years or older, resulting in 5560 dialysis patients aged 90 years or older (Fig. 6, Table 8).

Fig. 6
figure6

Prevalent dialysis patient distribution, by age, 1982–2015

Table 8 Prevalent dialysis patient distribution, by age, 1982–2015

The dialysis vintages of 2015 prevalent patients were evaluated in a 5-year-segment (Fig. 7, Table 9), then patients with a dialysis vintage of less than 5 years accounted for 47.3% of the total. Twenty-five thousand three hundred ninety-one patients had a dialysis vintage of 20 years or longer, which represents an increase of 561 persons or 8.1% of the total compared with the previous year. Six hundred seventeen persons had a dialysis vintage of longer than 40 years, it was 0.2% of all dialysis patients. The longest dialysis vintage was 47 years and 6 months. Regardless of dialysis vintage, the absolute number of males tended to be higher than females, a difference that became smaller the longer the dialysis vintage is. At less than 5 years, the male percentage was 67.5%, but it decreased to 51.4% in patients with dialysis vintages of 30 to 34 years. However, the percentage of male patients with dialysis vintages of 35 to 39 years and 40 years or longer increased again to 53.2 and 55.3%, respectively. Chronic dialysis therapy was first covered by insurance in Japan in 1967, and it is believed this had an effect. The percentage of patients with vintages less than 5 years has gradually decreased, whereas patients with long vintages have been increasing. Patients with dialysis vintages of 10 years or longer have now reached 27.8%. Patients with vintages of 20 years or longer did not reach 1.0% in 1992, but reached 8.1% by the end of 2015 (Fig. 8, Table 10).

Fig. 7
figure7

Prevalent dialysis patient distribution, by sex and dialysis vintage, 2015

Table 9 Prevalent dialysis patient distribution, by sex and dialysis vintage, 2015
Fig. 8
figure8

Prevalent dialysis patient distribution, by dialysis vintage, 1988–2015

Table 10 Prevalent dialysis patient distribution, by dialysis vintage, 1988–2015

Primary diseases

The primary diseases of chronic dialysis patients have continued to change over time; hence, incident dialysis patients and 2015 prevalent patients need to be divided for the study. We shall discuss this point while comparing the two groups.

The most frequent primary disease among the 2015 incident dialysis patients was diabetic nephropathy, chronic glomerulonephritis, and nephrosclerosis at 43.7, 16.9, and 14.2%, respectively; however, 12.2% had an unknown primary disease. The mean age at incidence was 67.29, 68.77, and 75.33 years for diabetic nephropathy, chronic glomerulonephritis, and nephrosclerosis, respectively (Table 11). The most frequent primary disease for 2015 prevalent patients was diabetic nephropathy, chronic glomerulonephritis, and nephrosclerosis at 38.4, 29.8, and 9.5%, respectively; however, 9.5% had an unknown primary disease (Table 12). The mean age was 66.90, 67.52, and 74.25 years for chronic glomerulonephritis, diabetic nephropathy, and nephrosclerosis, respectively. Both incident and prevalent dialysis patients showed a high mean age for nephrosclerosis and a low mean age for kidney diseases due to congenital abnormalities.

Table 11 Incident dialysis patient distribution, by primary disease, 2015
Table 12 Prevalent dialysis patient distribution, by primary disease, 2015

The annual changes in primary diseases of incident dialysis patients showed that diabetic nephropathy was supplanted by chronic glomerulonephritis in 1998, which then became the most prevalent primary disease. Subsequently, the percentage of diabetic nephropathy exhibited an increasing trend, but then remained largely constant these past several years. The percentage of chronic glomerulonephritis has continued to decrease. In contrast, the percentage of nephrosclerosis and unknown primary disease has continued to increase (Fig. 9, Table 13).

Fig. 9
figure9

Incident dialysis patient distribution, by primary disease, 1983–2015. Abbreviations: PKD, polycystic kidney disease; RPGN, rapidly progressive glomerulonephritis

Table 13 Incident dialysis patient distribution, by primary disease, 1983–2015

As the main primary disease among prevalent patients changed, diabetic nephropathy continuously increased and supplanted chronic glomerulonephritis in the 2011 survey as the most frequent primary disease. Thereafter, it has continuously increased, but the rate of increase seems to ebb slightly (Fig. 10, Table 14). Chronic glomerulonephritis is decreasing linearly, whereas nephrosclerosis and unknown primary diseases are continuously increasing. Otherwise, the numbers for polycystic kidney disease, chronic pyelonephritis, SLE nephritis, and rapidly progressive glomerulonephritis, for example, have remained constant as similar to previous years.

Fig. 10
figure10

Prevalent dialysis patient distribution, by primary disease, 1983–2015. Abbreviations: PKD, polycystic kidney disease; RPGN, rapidly progressive glomerulonephritis

Table 14 Prevalent dialysis patient distribution, by primary disease, 1983–2015

Causes of death

We compared the causes of death for all 2015 incident dialysis patients and 2015 prevalent dialysis patients overall. The highest causes of death in 2015 incident dialysis patients by sex were infectious disease (25.2%), heart failure (23.5%), malignant tumor (12.3%), and others (10.2%) in males and heart failure (27.3%), infectious disease (27.1%), others (11.8%), and malignant tumor (8.1%) in females. This ranking for males was the same as that at the end of 2014, but there was a 1.1-point decrease in infectious disease, a 0.4-point decrease in malignancy, and a 0.7-point increase in heart failure. This ranking for females has had heart failure as the most prevalent cause since 2010, and it increased by 1.8 points compared with that at the end of 2014. Overall, infectious disease was the most prevalent mortality factor at 25.8%, followed by heart failure (24.7%) as the second, and malignant tumor (10.9%) as the third (Fig. 11, Table 15). In the 2015 facility survey, 31,068 deaths were reported, but in the patient survey, the number of patients with cause of death and sex recorded was 29,064 persons, which was equal to 93.5% of the 31,068 deceased. Male mortality factors from the highest to the lowest were heart failure (24.8%), infectious disease (22.6%), malignancy (10.6%), and cerebrovascular disease (6.3%). Among females, the ranked list was heart failure (28.1%), infectious disease (20.9%), cerebrovascular disease (7.2%), and malignancy (7.0%). The ranked list among all deceased patients was heart failure (26.0%), infectious disease (22.0%), malignant tumor (9.3%), and cerebrovascular disease (6.6%).

Fig. 11
figure11

Incident dialysis patient distribution, by cause of death and sex, 2015

Table 15 Incident patient distribution, by cause of death and sex, 2015

No change was observed in the order of any mortality factors by sex since 2014. The percentage of cardiovascular disease combining heart failure, cerebrovascular disease, and myocardial infarction was 35.7% among males, 39.0% among females, and 36.8% of the total (Fig. 12, Table 16).

Fig. 12
figure12

Deceased dialysis patient distribution, by cause of death and sex, 2015

Table 16 Deceased dialysis patient distribution, by cause of death and sex, 2015

Comparing mortality factors by age group (Fig. 13, Table 17), the ages at death among incident patients in 2015 increased, and deaths due to heart failure, infectious disease, and cachexia/uremia also increased. Particularly, among those aged 85 years or older, deaths from infectious disease reached 30.0%. This was largely the same trend seen in all mortality factors by age group for 2015 (Fig. 14, Table 18).

Fig. 13
figure13

Incident dialysis patient distribution, by cause of death and age, 2015

Table 17 Incident dialysis patient distribution, by cause of death and age, 2015
Fig. 14
figure14

Deceased dialysis patient distribution, by causes of death and age, 2015

Table 18 Deceased patient distribution, by causes of death and age, 2015

Regarding the changes over time in the cause of death among patients who died during the incident year, heart failure was the most prevalent mortality factor in the 1990s, but infectious disease gradually rose to reach a percentage nearly the same as heart failure since mid-2000, and even exceeded heart failure. In 2015 as well, infectious disease was the most prevalent factor (25.8%), followed by heart failure as the second (24.7%). The order from the third most prevalent factor did not change: malignant tumor (10.9%), cerebrovascular disease (5.7%), and myocardial infarction (2.8%). Over the long term, death by cerebrovascular disease or myocardial infarction tended to decrease, whereas death due to infectious disease or malignancy tended to increase (Fig. 15, Table 19).

Fig. 15
figure15

Causes of death during the incident year, 1990–2015

Table 19 Causes of death during the incident year, 1990–2015

As for overall dialysis patients’ changes in cause of death over time, death by infectious disease has consistently increased since 1993. Although its rate of increase slowed until last year, this year it again increased by 1.1%. Cerebrovascular disease has been consistently on a gradual decrease since 1994. Recently, myocardial infarction-related deaths have been on a gradually decreasing trend from a peak of 8.4% in 1997. The deaths from malignant tumor have gradually increased starting from 5.8% at the end of 1987, but have remained roughly level since reaching approximately 9.0% in 2004. Categorizing deaths due to heart failure, cerebrovascular disease, and myocardial infarction as cardiovascular deaths, they represented 54.8% of the total in 1988, and then decreased at a largely fixed pace, reaching 36.0% in 2009 (Fig. 16, Table 20). Furthermore, the cause of death category codes in this survey have been greatly revised at two points, the 2003 and the 2010 JRDR survey (see the 2010 JRDR report for details of the revisions [9]).

Fig. 16
figure16

Major causes of death, 1983–2015

Table 20 Major causes of death, 1983–2015

Crude death rate and survival rate

We calculated the annual crude death rate from patient dynamics in the facility survey. Because incident patients increased in age and included greater numbers of those with diabetic nephropathy and those with poor prognosis due to nephrosclerosis or other factors, the crude death rate tended to worsen annually. The lowest crude death rate was 7.9% in 1989, a year with a low questionnaire response rate. However, the rate exceeded 9.0% as 9.7% in 1992 and has remained approximately 9.2% to 9.8% since then, reaching 9.6% in 2015 (Table 21).

Table 21 Annual crude death rate, 1983–2015

At of the end of 2015, the survival rate was 89.9% for 1-year survival of 35,864 patients who initiated dialysis in 2014, 60.8% for five-year survival of patients who initiated dialysis in 2010, 35.9% for 10-year survival of patients who initiated dialysis in 2005, 23.5% for 15-year survival of patients who initiated dialysis in 2000, 15.4% for 20-year survival of patients who initiated dialysis in 1995, and 11.8% for 25-year survival of patients who initiated dialysis in 1990. Concerning the individual changes in survival rate over time, the short-term prognosis for 1- and 5-year vintage dialysis patients continuously improved, even though the number of elderly diabetic patients increased (Fig. 17, Additional file 1: Table S1).

Fig. 17
figure17

1-, 5-, 10-, 15-, 20-, 25-, and 30-year survival rate, 1983–2014

Chapter 2: current status of dialysis fluid quality management

Overview of dialysis fluid quality

In the JRDR survey, a survey was started from the end of 2006 on microbiological quality of dialysis fluid and its management. Based on the results, the JSDT standard for dialysis fluid microbial quality was revised in 2008 [10]. In this standard, dialysis fluid microbial quality should be evaluated based on both ET concentration and total viable microbial count (TVC). These both should be evaluated more frequently than once monthly. At least two bedside consoles should be tested in every month, and all consoles were tested a minimum of once annually. The required minimum quality used in dialysis therapy was defined as “standard dialysis fluid” with a dialysis fluid ET concentration < 0.05 EU/mL, and TVC < 100 cfu/mL. “Ultra-pure dialysis fluid (UPD)” is defined as having a dialysis fluid ET concentration < 0.001 EU/mL (less than the detectable limit), and TVC < 0.1 cfu/mL. JSDT recommended the use of UPD for all dialysis therapies. At the time these standards were adopted, as well as in 2016, they were the strictest criteria in the world. Furthermore, in the 2010 revision of the medical payment system, dialysis fluid quality was newly added, and thus, dialysis fluid quality control dramatically improved from the 2010 survey [9]. In 2015, dialysis fluid ET concentration and dialysis patient prognosis were analyzed using the JRDR data, and the patient group that was being treated at facilities with a dialysis fluid ET concentration < 0.001 EU/mL reportedly had a clearly higher 1-year survival rate than the patient group undergoing treatment at facilities with a concentration of 0.100 EU/mL or higher [11]. The dialysis fluid quality and its control were evaluated in 4303 facilities which had one or more bedside consoles in the 2015 survey.

Dialysis fluid ET testing

Dialysis fluid ET concentration is recommended to be measured by limulus tests in the JSDT standard [9]. In Japan, these ET assay systems are available at a relatively low cost and are widely used in most dialysis facilities. However, this situation is quite unique in the world. In a total of 4303, facilities had one or more bedside consoles, wherein 4233 facilities (98.4%) responded with their dialysis fluid ET assay frequency. These include 3424 facilities (80.9%) satisfying the once monthly or more rule in the standard (Fig. 18, Table 22). The data for dialysis fluid ET concentrations were obtained from 4109 facilities (95.5%). Among them, 3268 facilities (79.5%) attained ET concentration of the < 0.001 EU/mL guaranteed by UPD and 3986 facilities (97.1%) reached ET < 0.050 EU/mL guaranteed by standard dialysis fluid (Fig. 19, Table 22). As for the changes over time in dialysis fluid ET concentration testing frequency, the results were 33.1% in 2008 when water quality standards were enacted [11], which then stepped up to 70.6% in 2010 when water quality management has started being reimbursed and thereafter has gradually increased [8] (Fig. 20, Table 23). Regarding annual changes in dialysis fluid ET concentration, both the level guaranteed by UPD and the level guaranteed by standard dialysis fluid have changed over time (Fig. 21, Table 24). The decrease in dialysis fluid ET concentration in 2008 is due to the switch in dialysis fluid ET concentration units from EU/L to EU/mL based on international rules, and many incorrect entries were found.

Fig. 18
figure18

Facility distribution, by endotoxin measurement frequency, 2015

Table 22 Facility distribution, by endotoxin measurement frequency and concentration, 2015
Fig. 19
figure19

Facility distribution, by endotoxin concentration, 2015

Fig. 20
figure20

Facility distribution, by endotoxin measurement frequency, 2006–2015

Table 23 Facility distribution, by endotoxin measurement frequency, 2006–2015
Fig. 21
figure21

Facility distribution, by endotoxin concentration, 2006–2015

Table 24 Facility distribution, by endotoxin concentration, 2006–2015

Dialysis fluid viable microbial testing

Dialysis fluid viable microbial testing was performed by TVC, the number of colonies after the 7-day cultivation at 17 to 23 °C using a heterotrophic agar plate medium [9]. A total of 4212 facilities (97.9%) responded with their dialysis fluid TVC assay frequency, which included 3189 facilities (75.7%) satisfying the once monthly or more rule in the JSDT standard (Fig. 22, Table 25). A total of 3966 facilities (92.2%) responded with their dialysis fluid TVC, with 2905 facilities (73.2%) reaching the < 0.1 cfu/mL guaranteed by the UPD and 3940 facilities (99.4%) reaching the < 100 cfu/mL guaranteed by the standard dialysis fluid (Fig. 23, Table 25).

Fig. 22
figure22

Facility distribution, by TVC measurement frequency, 2015. Abbreviation: TVC, total viable microbial count

Fig. 23
figure23

Facility distribution, by TVC, 2015. Abbreviation: TVC, total viable microbial count

Table 25 Facility distribution, by microbial measurement frequency and TVC

TVC testing frequency increased annually, and although it increased in 2010 similar to the ET assay, its frequency was always slightly lower than ET (Fig. 24, Table 26). The changes over time in dialysis fluid TVC indicated that the level guaranteed by UPD and the level guaranteed by standard dialysis fluid have increased over time, which is similar to dialysis fluid ET concentration (Fig. 25, Table 27).

Fig. 24
figure24

Facility distribution, by TVC measurement frequency, 2006–2015. Abbreviation: TVC, total viable microbial count

Table 26 Facility distribution, by TVC measurement frequency, 2006–2015
Fig. 25
figure25

Facility distribution, by TVC, 2006–2015. Abbreviation: TVC, total viable microbial count

Table 27 Facility distribution, by TVC, 2006–2015

As described above, the JSDT standard recommend the use of a certified bacterial culture medium such as R2A, TGEA, or one with similar sensitivity [9]. In general, in methods using an agar plate medium, such as R2A or TGEA, a 0.5-mL sample size is the limit to guarantee a 100 cfu/mL standard dialysis fluid. On the other hand, to guarantee the UPD standard of < 0.1 cfu/mL, a minimum of 10 mL or more of dialysis fluid must be sampled and cultured after being strained through a membrane filter. Thus, the JRDR survey examined the sampling volume of dialysis fluid as well as the type of culture medium used. In the 2015 survey, 3879 of 4303 facilities (90.1%) responded regarding the medium for TVC (Fig. 26, Table 28), 56.4% and 30.4% of facilities used R2A and TGEA, respectively. Thus, 86.8% of facilities satisfied quality standards. Of 4303 facilities, 3986 (92.6%) responded regarding the sampling volume. In the 2015 survey, 79.2% of facilities sampled 10 mL or more dialysis fluid for the UPD guarantee (Fig. 27, Table 28). The trend of the types of medium used for TVC indicates that the numbers of facilities using TEGA are increasing, while the facilities using R2A are decreasing. In total, an overall increase in satisfying the standard has been observed (Fig. 28, Table 29). The sampling volume for TVC assay guaranteeing UPD has been gradually increasing (Fig. 29, Table 30).

Fig. 26
figure26

Facility distribution, by cultivation medium, 2015. (1). R2A, Reasoner’s No. 2 agar. (2) TGEA, tryptone glucose extract agar. (3) TSA, trypticase soy agar

Table 28 Facility distribution on TVC measurement, by cultivation medium and sampling volume, 2015
Fig. 27
figure27

Facility distribution, by sampling volume for TVC measurement, 2015. Abbreviation: TVC, total viable microbial count

Fig. 28
figure28

Facility distribution, by cultivation medium, 2006–2015. (1) R2A, Reasoner’s No. 2 agar. (2) TGEA, tryptone glucose extract agar. (3) TSA, trypticase soy agar

Table 29 Facility distribution, by cultivation medium, 2006–2015
Fig. 29
figure29

Facility distribution, by sample volume for TVC measurement, 2006–2015. Abbreviation: TVC, total viable microbial count

Table 30 Facility distribution, by sampling volume for TVC measurement, 2006–2015

Present status of ETRF installation

Installation of an ETRF is indispensable for maintaining dialysis fluid quality within UPD level, and JSDT established the standard for the management of ETRF [12]. Of 4303 facilities with one or more bedside consoles, 4294 facilities (99.8%) responded regarding ETRF installation. Among them, 4172 facilities (97.2%) installed ETRF in one or more bedside consoles (Table 31). Of 133,538 bedside consoles in 4303 facilities, 121,014 consoles (90.6%) had an ETRF installed (Table 32). The usage of ETRF at sampling has strong impacts on the results of ET concentration and TVC. The percentages of the facilities satisfying UPD standard in “Use” of ETRF were higher than those in “None-use” (Figs. 30 and 31, Tables 33 and 34). One process of ETRF can theoretically attain the UPD standard of both ET concentration and TVC, unless the contamination of dialysis fluid immediately before ETRF is extremely severe. However, even when an ETRF was installed, neither a 19.1% ET concentration nor a 24.8% TVC satisfied the UPD standard. These results suggest that the spread of ETRF has contributed to the improvement of dialysis fluid quality and that there are issues in the handling of ETRF to achieve UPD [12].

Table 31 Facility counts, by ETRF installation, 2015
Table 32 Bedside console counts, by ETRF installation, 2015
Fig. 30
figure30

Facility distribution, by ETRF installation during sampling endotoxin concentration, 2015. Abbreviation: ETRF, endotoxin retentive filter

Fig. 31
figure31

Facility distribution, by ETRF installation during sampling TVC, 2015. Abbreviation: ETRF, endotoxin retentive filter

Table 33 Facility distribution, by ETRF installation during sampling endotoxin concentration, 2015
Table 34 Facility distribution, by ETRF installation during sampling and TVC, 2015

Overall dialysis fluid quality

The JSDT standard requires facilities to satisfy both dialysis fluid ET concentration and TVC simultaneously within UPD or dialysis fluid standard, in order to maintain the microbiological quality of dialysis fluid [9]. Of 4303 facilities, 3959 (92.0%) responded about both their dialysis fluid ET concentration and TVC. These included 2704 facilities (68.3%) that achieved UPD and 3833 facilities (96.8%) that achieved a standard dialysis fluid (Fig. 32, Table 35). Figure 33 shows the annual changes in the achievement rate of UPD and standard dialysis fluid computed from facilities that responded with both ET concentration and TVC, which has improved since 2009 (Fig. 33, Table 36).

Fig. 32
figure32

Facility distribution, by TVC and endotoxin concentration, 2015. Abbreviation: TVC, total viable microbial count

Table 35 Facility distribution, by TVC and endotoxin concentration, 2015
Fig. 33
figure33

Facility distribution, in achievement of UPD and standard dialysis fluid, 2009–2015. Abbreviation: UPD, ultrapure dialysis fluid

Table 36 Facility distribution, in achievement of UPD and standard dialysis fluid, 2009–2015

Chapter 3: Current status of HDF

HDF patient dynamics

Hemodiafiltration (HDF) includes several variations as online HDF, offline HDF, push/pull HDF, acetate-free biofiltration (AFBF), and intermittent infusion hemodiafiltration (IHDF). The patients treated by HDF in Japan rapidly increased year by year and reached 53,776 by the end of 2015, accounting for 17.8% of all HD/HDF patients (Fig. 34, Table 37). Of 53,776 HDF patients, 34,316 (63.8%) were males and 19,460 (36.2%) were females (Fig. 35, Table 38). The mean age was 64.8 years for males and 66.9 years for females; the age category with the greatest percentage being ages 65 to 69 years. These distributions and trends resembled those of HD patients (Fig. 3), and HDF therapy was being performed for various ages. Concerning the main primary disease in HDF patients, diabetic nephropathy and chronic glomerulonephritis accounted for 34.1 and 35.2%, respectively. Comparing HD patients, the percentage of diabetic nephropathy was low, and the percentage of chronic glomerulonephritis was high (Fig. 36, Table 39). The distribution of dialysis vintages was largely the same as that for HD patients (Fig. 6) (Fig. 37, Table 40). Males tended to be more numerous in each age category, although the number of male and female patients was largely the same for dialysis vintages of 25 years or longer.

Fig. 34
figure34

Prevalent dialysis patient distribution, by HDF modality, 2009–2015. Abbreviations: HDF, hemodiafiltration; AFBF, acetate-free biofiltration; IHDF, intermittent infusion hemodiafiltration

Table 37 Prevalent patient distribution, by HDF modality, 2009–2015
Fig. 35
figure35

HDF patient distribution, by age and sex, 2015

Table 38 HDF patient distribution, by age and sex, 2015
Fig. 36
figure36

Dialysis patient distribution, by HDF/HD and primary disease, 2015. Abbreviation: PKD, polycystic kidney disease

Table 39 Dialysis patient distribution, by HDF/HD and primary disease, 2015
Fig. 37
figure37

HDF patient distribution, by sex and dialysis vintage, 2015

Table 40 HDF Patient distribution, by sex and dialysis vintage, 2015

Types and annual changes of HDF treatment modality

The most numerous HDF patients were online HDF patients at 44,527 persons (82.8% of HDF patients). Most of all HDF patients were for offline HDF before 2011, but the majority became online HDF since 2012 and has significantly increased (Fig. 34, Table 37). In contrast, the number of offline HDF patients has been decreasing year by year. IHDF was added to survey items from 2015 and has been identified as accounting for 6.6% of all HDF. The percentage of HDF therapy, both online and offline, increased as dialysis vintage lengthened, and the percentage of HD showed a decreasing trend (Fig. 38, Table 41). IHDF represented about 1% of all treatment modalities throughout all groups. Other than that, the percentage of PD decreased as dialysis vintage lengthened, whereas hemoadsorption dialysis showed a trend wherein its percentage increased by the same degree that dialysis vintage lengthened.

Fig. 38
figure38

Dialysis patient distribution, by dialysis modality and dialysis vintage, 2015. Abbreviations: HDF, hemodiafiltration; AFBF, acetate-free biofiltration; IHDF, intermittent infusion hemodiafiltration

Table 41 Dialysis patient distribution, by dialysis modality and dialysis vintage, 2015

HDF prescriptions

Regarding the dilution method, most of online HDF involved pre-dilution, whereas offline HDF and AFBF mostly involved post-dilution (Fig. 39, Table 42). HDF dialysis prescriptions were illustrated four ways: by method (online, offline) × by dilution method (pre-dilution, post-dilution). The combination with the largest number of patients was online/pre-dilution with 35,994 persons, and the smallest was offline/pre-dilution with 484 persons. First, comparing the blood flow rate that for online HDF tended to be higher than that for offline HDF, and no clear difference was found between pre- and post-dilution (Fig. 40, Table 43). The blood flow rate for the online HDF/pre-dilution combination was the highest, with a mean of 229 mL/min. Fifty percent of more patients were found to have a blood flow rate of 220 mL/min or higher, whereas 8.8% had a blood flow rate of 300 mL/min or higher. There was no clear difference between the combinations in terms of dialysis time (Fig. 41, Table 44).

Fig. 39
figure39

HDF patient distribution, by HDF modality and dilution mode, 2015

Table 42 Patient distribution, by HDF modality and dilution mode, 2015
Fig. 40
figure40

HDF patient distribution, by dilution mode and blood flow rate, 2015

Table 43 HDF patient distribution, by dilution mode and blood flow rate, 2015
Fig. 41
figure41

HDF patient distribution, by dilution mode and dialysis time, 2015

Table 44 HDF patient distribution, by dilution mode and dialysis time, 2015

The online HDF/pre-dilution combination had the highest substitution volume, with a mean of 40.1 L (per session), whereas online/post-dilution combination had 10.0 L (Fig. 42, Table 45). Offline HDF had substitution volumes of 10.6 and 8.1 L with pre-dilution and post-dilution, respectively. On about the annual changes in substitution volume, the number of patients with online HDF/pre-dilution tended to increase yearly, although no changes in the substitution volume were observed (Fig. 43, Table 46). Online HDF/post-dilution also did not largely change over time. In contrast, the number of offline HDF/pre-dilution patients decreased in 2015, although the substitution volume showed a slight increasing trend yearly. The number of patients with offline HDF/post-dilution tended to decrease, but the substitution volume slightly increased.

Fig. 42
figure42

Mean substitution volume, by online/offline and dilution mode, 2015

Table 45 Mean substitution volume, by online/offline and dilution mode, 2015
Fig. 43
figure43

Trend of substitutional fluid volume per single session (L), 2012–2015

Table 46 The trend of substitutional fluid volume per single session (L), 2012–2015

Urea kinetics, nutrition, and inflammation in HDF patients

Urea kinetics, nutritional, and inflammation status were compared between HD and HDF patients (by each dilution method). When we compared urea kinetics using single pool Kt/V urea (Kt/Vsp), the Kt/Vsp for online HDF/pre- and post-dilution and offline HDF/post-dilution combinations tended to be higher than that for HD. Offline HDF/pre-dilution Kt/Vsp was largely the same as for HD (Fig. 44, Table 47). Subsequently, we compared normalized protein catabolic rate (nPCR), serum albumin concentration, creatinine concentration, and % creatinine generation rate (%CGR) as an evaluation of nutritional status. No clear difference was found between HDF and HD for nPCR and albumin concentration. Creatinine concentration was higher for online HDF/pre- and post-dilution than with HD, and largely the same as with HD for offline HDF/pre- and post-dilution. %CGR was higher for online HDF/pre- and post-dilution than for HD (Fig. 45, Table 47).

Fig. 44
figure44

Kt/Vsp, by dialysis modality and sex, 2015

Table 47 Comparisons of HD, online HDF, and offline HDF, (1), 2015
Fig. 45
figure45

Comparisons, by dialysis modality and sex, 2015

We compared serum CRP concentration as an inflammation index (Fig. 45, Table 48). Compared with HD, the concentration tended to be low with online HDF/pre-dilution, and showed a high trend with offline HDF/pre- and post-dilution.

Table 48 Comparisons of HD, online HDF, and offline HDF, (2), 2015

Management for anemia and CKD-MBD in HDF patients

We evaluated the management for anemia and CKD-MBD markers in HDF patients compared with HD patients. Hemoglobin concentration showed a slightly high trend with online HDF/pre- and post-dilution. Phosphorus concentration and intact PTH levels for online HDF/pre- and post-dilution were somewhat high compared to HD. Corrected calcium concentration was slightly high with online HDF/post-dilution and offline HDF/pre- and post-dilution (Fig. 45, Table 48).

Chapter 4: Current status of peritoneal dialysis (PD)

PD patient dynamics

There were 9322 PD patients at the end of 2015. The variations of PD therapy were PD only, an combination with HD once weekly, twice weekly, thrice weekly, and some other combinations; and the number of patients in each modality was 7460 persons, 1576 persons, 185 persons, 30 persons, and 71 persons, respectively (Table 49). The total number of PD patients had been gradually decreasing since 2009 (Fig. 46). However, we should understand that a total number of PD patients in JRDR did not always reflect the real number of PD patients in Japan. The JRDR survey only targeted facilities performing HD; hence, PD patients treated at other facilities are not included. We started a survey of the number of incident PD patients since 2015, and have found 2197 patients.

Table 49 Prevalent PD patient counts, by the combination of HD, 2015
Fig. 46
figure46

Prevalent and incident PD patient counts, 2009–2015

A total of 8846 PD patients responded to patient questionnaires, including 5728 (64.8%) males and 3118 (35.2%) females, with mean ages of 62.8 years and 62.7 years for males and females, respectively. The age distribution showed a normal distribution, peaking with the 65- to 74-year age category, which was the same trend with HD patients (Fig. 3) (Fig. 47, Table 50). The PD vintage distribution showed that less than 2 years accounted for 43.9% of the total and 8.4% were 8 years or longer (Fig. 48, Table 51). Diabetic nephropathy was the primary disease in 31.9% of PD patients, which was very close to the 32.4% for chronic glomerulonephritis. Comparing HD patients, the percentage of diabetic nephropathy showed a lower prevalence (Fig. 49, Table 52).

Fig. 47
figure47

Prevalent PD patient distribution, by age and sex, 2015

Table 50 Prevalent PD patient distribution, by age and sex, 2015
Fig. 48
figure48

Prevalent PD patient distribution, by PD vintage and sex, 2015

Table 51 Prevalent PD patient distribution, by PD vintage and sex, 2015
Fig. 49
figure49

Prevalent dialysis patient distribution, by PD or HD and primary disease, 2015. Abbreviation: PKD, polycystic kidney disease

Table 52 Prevalent patient distribution, by PD or HD and primary disease, 2015

Present status of PD + HD combined therapy

The percentage of the patients undergoing PD only was 80.3% of the total, the percentages of PD only and PD + HD combined therapy both revealed no changes over time (Fig. 50, Table 53). The percentage of the patients undergoing a combination of PD and HD were increased as PD history got longer (Fig. 51, Table 54). The highest frequency of HD combinations was once weekly, and when PD history reached 8 years or longer, 50% or more of PD patients had a combination with HD.

Fig. 50
figure50

Prevalent PD patient distribution, by PD + HDF combination frequency, 2009–2015

Table 53 Prevalent patient distribution, by PD + HD combination frequency, 2009–2015
Fig. 51
figure51

Prevalent PD patient distribution, by PD vintage and PD + HD combination frequency, 2015

Table 54 Prevalent patient distribution, by PD vintage and PD + HD combination frequency, 2015

PD prescriptions

The mean volume of PD fluid per day was 6.71 and 5.98 L for males and females, respectively. The volume was found to decrease as age increased (Fig. 52, Table 55) and increased as PD vintage got longer (Fig. 53, Table 56). When we examined the PD treatment times, there was hardly any difference between sexes with 17.8 and 17.6 h for males and females, respectively, and no clear difference was found by age (Fig. 54, Table 57). In contrast, a trend was found in which PD treatment time became longer as PD vintage got longer. In particular, PD patients receiving 24-h treatment made up 76.3% of the total when PD vintage was 8 years or longer (Fig. 55, Table 58). The percentage of the patients using the automated peritoneal dialysis (APD) was 44.9% of all patients undergoing PD alone (Table 59). As for replacement of PD dialysis fluid, most used bag replacement machines utilizing ultraviolet light (52.4%), followed by those using completely manual methods (30.2%), and those using thermal sterile connecting devices (14.8%) (Table 60).

Fig. 52
figure52

PD fluid volume, by age and sex, 2015

Table 55 PD dialysis fluid volume, by age and sex, 2015
Fig. 53
figure53

Prevalent PD patient distribution, by PD vintage and PD fluid volume, 2015

Table 56 Prevalent patient distribution, by PD vintage and PD fluid volume, 2015
Fig. 54
figure54

PD treatment time, by age and sex, 2015

Table 57 PD treatment time, by age and sex, 2015
Fig. 55
figure55

Prevalent PD patient distribution, by PD vintage and PD treatment time, 2015

Table 58 Prevalent patient distribution, by PD vintage and PD treatment time, 2015
Table 59 Prevalent PD patient counts, by APD machine use, 2015
Table 60 Prevalent PD patient counts, by PD fluid changing maneuver, 2015

Residual kidney function (urine volume and residual kidney Kt/V)

We evaluated the residual kidney function in patients undergoing PD alone by urine volume and residual kidney Kt/V. The mean urine volume per day was 774 and 643 mL for men and women, respectively; thus, a higher tendency was found among males (Fig. 56, Table 61). The difference was unclear for age, but as PD vintage got longer, urine volume showed a decreasing trend. When PD vintage was 8 years or longer, 55.2% had a urine volume < 100 mL (Fig. 57, Table 62). The mean residual kidney Kt/V was 0.68 and 0.64 for males and females, respectively (Fig. 58, Table 63). The difference was unclear for age, but the residual kidney Kt/V also showed a decreasing trend as PD vintage got longer similar to urine volume. Particularly, we found 89.4% to have a residual kidney Kt/V < 0.4 if PD vintage was 8 years or longer (Fig. 59, Table 64).

Fig. 56
figure56

Urine volume, by age and sex, 2015

Table 61 Urine volume, by age and sex, 2015
Fig. 57
figure57

Prevalent PD patient distribution, by PD vintage and urine volume, 2015

Table 62 Prevalent PD patient distribution, by PD vintage and urine volume, 2015
Fig. 58
figure58

Residual renal Kt/V, by age and sex, 2015

Table 63 Residual renal Kt/V, by age and sex, 2015
Fig. 59
figure59

Prevalent PD patient distribution, PD vintage and residual renal Kt/V, 2015

Table 64 Patient distribution, PD vintage and residual renal Kt/V, 2015

Peritoneal function (ultrafiltration volume and PD Kt/V)

We evaluated peritoneal function in patients undergoing PD alone by fluid removal volume and PD Kt/V. Mean ultrafiltration volume was 641 and 628 mL for males and females, respectively (Fig. 60, Table 65). The difference was unclear for age, but ultrafiltration volume showed an increasing trend as PD vintage got longer (Fig. 61, Table 66). In patients with a PD vintage of 8 years or longer, 55.6% had an ultrafiltration volume of 800 mL or more. The mean PD Kt/V was 1.20 and 1.37 for males and females, respectively; thus, we found a high trend in females (Fig. 62, Table 67). In terms of age, the < 45 years category was somewhat higher than other age categories. PD Kt/V also showed an increasing trend as PD vintage got longer. We found that 61.1% had a PD Kt/V of 1.6 or more if PD vintage was 8 years or longer (Fig. 63, Table 68).

Fig. 60
figure60

Ultrafiltration volume, by age and sex, 2015

Table 65 Ultrafiltration volume, by age and sex, 2015
Fig. 61
figure61

Prevalent PD patient distribution, by PD vintage and ultrafiltration volume, 2015

Table 66 Prevalent PD patient distribution, by PD vintage and ultrafiltration volume, 2015
Fig. 62
figure62

PD Kt/V, by age and sex, 2015

Table 67 PD Kt/V, by age and sex, 2015
Fig. 63
figure63

Prevalent PD patient distribution, by PD vintage and PD Kt/V, 2015

Table 68 Prevalent PD patient distribution, by PD vintage and PD Kt/V, 2015

PET and D/P Cr ratio

The testing rate for peritoneal equilibration test (PET) in patients undergoing PD alone was 45.3% and that for Fast PET only was 20.1%, and the untested rate was 34.6% (Table 69). The mean (dialysate/plasma creatinine) D/P Cr ratio was 0.68 and 0.64 for males and females, respectively, and thus was slightly high among males (Fig. 64, Table 70). D/P Cr ratio showed an increasing trend as age increased. Almost no consistent trend was seen in D/P Cr ratio by PD vintage, but the ratio was 0.64 if PD vintage was 6 years or longer, and the ratio decreased slightly to 0.62 if it was 8 years or longer (Fig. 65, Table 71). Concerning the D/P Cr ratio by primary disease, it was highest at 0.70 with diabetic nephropathy, followed by 0.68 with nephrosclerosis (Fig. 66, Table 72).

Table 69 History of PET, 2015
Fig. 64
figure64

D/P Cr ratio, by age and sex, 2015. Abbreviation: D/P Cr ratio, dialysate/plasma creatinine ratio

Table 70 D/P Cr ratio, by age and sex, 2015
Fig. 65
figure65

Prevalent PD patient distribution, by PD vintage and D/P Cr ratio, 2015. Abbreviation: D/P Cr ratio, dialysate/plasma creatinine ratio

Table 71 Patient distribution, by PD vintage and D/P Cr ratio, 2015
Fig. 66
figure66

D/P Cr ratio, by primary disease, 2015. Abbreviation: D/P Cr ratio, dialysate/plasma creatinine ratio

Table 72 Prevalent PD patient distribution, by primary disease and D/P Cr ratio, 2015

ESI and peritonitis

The patient rate of exit-site infection (ESI) or peritonitis onset was evaluated as the following formula in patients undergoing PD alone. ESI was found in 20.2% of PD patients who responded, and peritonitis was seen in 14.4%. The overall patient ESI incidence rate was 0.40 counts per patient year, and the peritonitis incidence rate was 0.24. (Fig. 67, Table 73).

Fig. 67
figure67

Prevalent PD patient distribution, by onset of ESI and peritonitis, 2015. Abbreviation: ESI, exit-site infection

Table 73 Patient’s ESI and peritonitis rate, 2015

ESI incidence rate (counts/person/year) = ESI episodes in 2015 in all subjects ÷ total months on PD in 2015 in all patients × 12

Peritonitis incidence rate (counts/person/year) = peritonitis episodes in 2015 in all subjects ÷ total months on PD in 2015 in all patients × 12

The peritonitis incidence rate in male PD patients was 0.27, slightly greater than the 0.20 in females. We found an increasing trend in the incidence rate of the older age group (Figs. 68 and 69, Tables 74 and 75). In addition, no consistent trend was found between peritonitis onset and PD vintage (Fig. 70, Table 76). As for primary disease, the peritonitis incidence rate was high in nephrosclerosis (0.26) and diabetic nephropathy (0.27) (Fig. 71, Table 77).

Fig. 68
figure68

Patient’s peritonitis rate, by sex, 2015

Fig. 69
figure69

Patient’s peritonitis rate, by age, 2015

Table 74 Patient’s peritonitis rate, by sex, 2015
Table 75 Patient’s peritonitis rate, by age, 2015
Fig. 70
figure70

Patient’s peritonitis rate, by PD vintage, 2015

Table 76 Patient’s peritonitis rate, by PD vintage, 2015
Fig. 71
figure71

Patient’s peritonitis rate, by primary disease, 2015

Table 77 Patient’s peritonitis rate, by primary disease, 2015

History of EPS

The history of encapsulating peritoneal sclerosis (EPS) was observed in 678 (5.2%) patients out of 13,033 patients who were currently undergoing PD or had once underwent PD. This included 86.6% with a history of steroid administration and 79.5% with a history of surgical treatment (Table 78). The breakdown of these 678 patients was 413 males (60.9%) and 265 females (39.1%) (Fig. 72, Table 79). The age distribution largely resembled that for all PD patients (Fig. 47). In terms of relationship to dialysis vintage, 494 patients (72.9%) had a vintage of 8 years or longer, and the incidence rate was significantly high in this category (Fig. 73, Table 80). Regarding primary disease, a significantly high rate was found in 374 patients (55.2%) with chronic glomerulonephritis (Fig. 74, Table 81).

Table 78 Patient with EPS history distribution, by treatment for EPS, 2015
Fig. 72
figure72

Patient with EPS history distribution, by age and sex. Abbreviation: EPS, encapsulating peritoneal sclerosis

Table 79 Patient with EPS history distribution, by age and sex, 2015
Fig. 73
figure73

Patient with EPS history distribution, by dialysis vintage and sex, 2015. Abbreviation: EPS, encapsulating peritoneal sclerosis

Table 80 Patient with EPS history distribution, by dialysis vintage and sex, 2015
Fig. 74
figure74

Patient with EPS history distribution, by primary disease, 2015. Abbreviations: EPS, encapsulating peritoneal sclerosis; PKD, polycystic kidney disease

Table 81 Patient with EPS history distribution, by primary disease and sex, 2015

Chapter 5: Current status of elderly dialysis patients

Present status of elderly dialysis patients

We defined dialysis patients who were 75 years or older as “elderly dialysis patients,” and compared categories that were < 60 years, and 60 to 74 years in age. The number of patients in each group was 71,270 patients as < 60 years, 141,634 patients aged 60 to 74 years, and 100,308 patients as 75 years or older. In regard to the male-to-female ratio, males dominated in all age categories, but as age increased, the percentage of females also increased; hence, females accounted 40.8% of elderly dialysis patients (Fig. 75, Table 82). In terms of dialysis vintage, the elderly dialysis patients had the shortest dialysis vintage at 5.71 years, while 54.8% had a vintage of < 5 years and 80.3% had a vintage < 10 years (Fig. 76, Table 83). As for the primary disease among elderly dialysis patients, the percentage of nephrosclerosis was high (16.6%) compared with that among other age groups, whereas the percentages of diabetic nephropathy (34.3%) and chronic glomerulonephritis (26.5%) were low (Fig. 77, Table 84). In past histories of elderly dialysis patients, although the percentages of myocardial infarction, cerebral infarction, and proximal femur fracture were high, no difference was found for cerebral hemorrhage or limb amputation (Fig. 78). Otherwise, history of kidney transplants, history of PD, and smoking were significantly lower than all the other groups (Fig. 79).

Fig. 75
figure75

Prevalent dialysis patient distribution, by age and sex, 2015

Table 82 Prevalent dialysis patient distribution, by age and sex, 2015
Fig. 76
figure76

Prevalent dialysis patient distribution, by age and dialysis vintage, 2015

Table 83 Prevalent dialysis patient distribution, by age and dialysis vintage, 2015
Fig. 77
figure77

Prevalent dialysis patient distribution, by age and primary disease, 2015. Abbreviations: RPGN: rapidly progressive glomerulonephritis; PKD, polycystic kidney disease

Table 84 Prevalent dialysis patient distribution, by age and primary disease, 2015
Fig. 78
figure78

Prevalent dialysis patient distribution, by comorbidity and age, 2015

Fig. 79
figure79

Prevalent dialysis patient distribution, by history of kidney transplantation and peritoneal dialysis, smoking status and age, 2015

Hemodynamics, dialysis prescriptions, and urea kinetics in elderly dialysis patients

The mean blood pressure and pulse rate of elderly dialysis patients were 149/72 mmHg and 72 bpm, respectively. Both blood pressure and pulse showed a decreasing trend as age increased (Fig. 80, Table 85). Particularly, in a comparison of blood pressure, the decrease in diastolic blood pressure was pronounced compared with systolic blood pressure, suggesting that the pulse pressure increases with aging. We compared Kt/Vsp as an index of dialysis efficiency, but no clear difference was found by age (Fig. 81, Table 86). The mean dialysis time in elderly dialysis patients was 3.85 h, which was shorter than in other groups, with 27.2% at < 4 h. (Fig. 82, Table 87) The mean blood flow rate among elderly dialysis patients was 195 mL/min, which was the lowest among different groups, wherein 36.0% had a blood flow rate < 200 mL/min (Fig. 83, Table 88).

Fig. 80
figure80

Blood pressure and pulse rate, by age, 2015

Table 85 Blood pressure and pulse rate, by age, 2015
Fig. 81
figure81

Kt/Vsp, by sex and age, 2015

Table 86 Kt/Vsp, by age and sex, 2015
Fig. 82
figure82

Prevalent dialysis patient distribution, by age and dialysis time, 2015

Table 87 Prevalent patient distribution, by age and dialysis time, 2015
Fig. 83
figure83

Prevalent dialysis patient distribution, by age and blood flow rate, 2015

Table 88 Prevalent dialysis patient distribution, by age and blood flow rate, 2015

Nutrition and inflammation in elderly dialysis patients

Serum albumin concentration, creatinine concentration, %CGR, and nPCR all decreased as age increased and were lowest in elderly dialysis patients (Fig. 84, Table 89). Among these, no difference was found between men and women for albumin concentration and %CGR, but males tended to be high in creatinine concentration, and females showed a high trend for nPCR. Serum CRP concentration increased with age, and among different groups, the elderly group was the highest. Between sexes, males showed a slightly high trend.

Fig. 84
figure84

Nutrition and inflammation indices, by sex and age, 2015

Table 89 Nutrition and inflammation indices, by sex and age, 2015

Management for anemia and CKD-MBD in elderly dialysis patients

Hemoglobin concentration showed a tendency to decrease as age increased. The mean hemoglobin concentration in elderly dialysis patients was lowest at 10.6 g/dL (Fig. 85, Table 90), wherein 27.2% of elderly dialysis patients had < 10 g/dL. Serum phosphorus concentration and intact PTH concentration also showed a decreasing trend as age increased (Figs. 86 and 87, Tables 91 and 92). The mean phosphorus concentration in elderly dialysis patients was 4.9 mg/dL, and the intact PTH concentration was 162 pg/mL, which were the lowest values between different groups. Hypophosphatemia (< 3.5 mg/dL) and hypoparathyroidism (< 60 pg/mL), less than reference values in the CKD-MBD guidelines, were found in 12.9 and 20.2% of elderly dialysis patients, respectively. In contrast, no difference was found in corrected calcium concentration between groups (Fig. 88, Table 93).

Fig. 85
figure85

Prevalent dialysis patient distribution, by age and hemoglobin concentration, 2015

Table 90 Prevalent dialysis patient distribution, by age and hemoglobin concentration, 2015
Fig. 86
figure86

Prevalent dialysis patient distribution, by age and phosphorus concentration, 2015

Fig. 87
figure87

Prevalent dialysis patient distribution, by age and intact PTH concentration, 2015

Table 91 Prevalent dialysis patient distribution, by age and phosphorus concentration, 2015
Table 92 Prevalent dialysis patient distribution, by age and intact PTH concentration, 2015
Fig. 88
figure88

Prevalent dialysis patient distribution, by age and corrected calcium concentration, 2015

Table 93 Prevalent dialysis patient distribution, by age and corrected calcium concentration, 2015

Chapter 6: Current status of diabetic dialysis patients

Present status of diabetic dialysis patients

“Diabetic dialysis patients” was defined as patients for whom diabetic nephropathy was the primary disease or who had a history of diabetes. Of 271,337 dialysis patients who responded, 144,870 were diabetic dialysis patients, accounting for 53.4% of the total. The diabetes prevalence was slightly higher in males as 57.5% than females as 45.8% (Fig. 89, Table 94). The diabetes prevalence become higher as the patients got older: 40% in the patient category older than 30 years old and 56.5% in the category older than 60 years and younger than 75 years (Fig. 90, Table 95). In addition, diabetes prevalence decreased as dialysis vintage got longer, and when dialysis vintage reached 25 years or longer, the percentage of diabetic dialysis patients was < 10% (Fig. 91, Table 96). The percentages of past history of myocardial infarction, cerebral infarction, and limb amputation were clearly higher among diabetic dialysis patients (Fig. 92). In contrast, no clear difference was found in cerebral hemorrhage and proximal femur fracture whether diabetes was present. Otherwise, no significant difference was found in past history of kidney transplants and PD among diabetic dialysis patients, whereas smokers were relatively numerous (Fig. 93).

Fig. 89
figure89

Prevalent dialysis patient distribution, by sex and presence of diabetes, 2015

Table 94 Prevalent dialysis patient distribution, by sex and presence of diabetes, 2015
Fig. 90
figure90

Patient distribution, by age and presence of diabetes, 2015

Table 95 Patient distribution, by age and presence of diabetes, 2015
Fig. 91
figure91

Prevalent dialysis patient distribution, by dialysis vintage and presence of diabetes, 2015

Table 96 Prevalent dialysis patient distribution, by dialysis vintage and presence of diabetes, 2015
Fig. 92
figure92

Prevalent dialysis patient distribution, by major past history and presence of diabetes, 2015

Fig. 93
figure93

Prevalent dialysis patient distribution, by history of kidney transplantation and peritoneal dialysis, smoking status and presence of diabetes, 2015

Hemodynamics, dialysis prescriptions, and urea kinetics in diabetic dialysis patients

The mean systolic blood pressure in diabetic dialysis patients was 156 mmHg, which was high compared with 147 mmHg in the non-diabetic group. However, diastolic blood pressure showed no difference between patients and was 78 mmHg for all. Pulse rate was 75 and 74 bpm, respectively; thus, practically no difference was found between groups (Fig. 94, Table 97). When we compared Kt/Vsp as an index of dialysis efficiency, both male and female diabetic dialysis patients showed a low trend (Fig. 95, Table 98). Comparing dialysis prescriptions, no difference was found in dialysis time and blood flow rate between groups, and distributions were also largely the same (Figs. 96 and 97, Tables 99 and 100). Although no major differences were found in dialysis prescriptions between groups, certain differences were found in hemodynamics and urea kinetics.

Fig. 94
figure94

Blood pressure and pulse rate, by presence of diabetes, 2015

Table 97 Blood pressure and pulse rate, by presence of diabetes, 2015
Fig. 95
figure95

Kt/Vsp, by sex and presence of diabetes, 2015

Table 98 Kt/Vsp, by presence of diabetes and sex, 2015
Fig. 96
figure96

Prevalent dialysis patient distribution, by presence of diabetes and dialysis time, 2015

Fig. 97
figure97

Prevalent dialysis patient distribution, by presence of diabetes and blood flow rate, 2015

Table 99 Prevalent dialysis patient distribution, by presence of diabetes and dialysis time, 2015
Table 100 Prevalent dialysis patient distribution, by presence of diabetes and blood flow rate, 2015

Nutrition and inflammation in diabetic dialysis patients

We compared indices for diabetic dialysis patient nutrition and inflammation to those of patients without diabetes. Albumin concentration in diabetic patients was the same as that in non-diabetic patients, whether male or female. In contrast, creatinine concentration, %CGR, and nPCR showed a low trend for both males and females among diabetic dialysis patients. CRP concentration showed a high trend among diabetic patients that was more prominent among females (Fig. 98, Table 101).

Fig. 98
figure98

Nutrition and inflammation indices, by sex and presence of diabetes, 2015

Table 101 Nutrition and inflammation indices, by sex and presence of diabetes, 2015

Management for anemia and CKD-MBD in diabetic dialysis patients

The mean hemoglobin concentration in diabetic dialysis patients was 10.7 g/dL, which was largely equal to the 10.8 g/dL in non-diabetic patients (Fig. 99, Table 102). The serum phosphorus concentration was 5.2 and 5.3 mg/dL for dialysis patients with and without diabetes, revealing almost no difference (Fig. 100, Table 103). Furthermore, the corrected calcium concentration also showed no difference, with a mean of 9.1 and 9.2 mg/dL, respectively (Fig. 101, Table 104). Intact PTH concentration was 189 pg/mL for non-diabetic patients, whereas it was slightly lower for diabetic dialysis patients at 169 pg/mL (Fig. 102, Table 105).

Fig. 99
figure99

Prevalent dialysis patient distribution, by presence of diabetes and hemoglobin concentration, 2015

Table 102 Prevalent dialysis patient distribution, by presence of diabetes and hemoglobin concentration, 2015
Fig. 100
figure100

Prevalent dialysis patient distribution, by presence of diabetes and phosphorus concentration, 2015

Table 103 Prevalent dialysis patient distribution, by presence of diabetes and phosphorus concentration, 2015
Fig. 101
figure101

Prevalent dialysis patient distribution, by presence of diabetes and corrected calcium concentration, 2015

Table 104 Prevalent dialysis patient distribution, by presence of diabetes and corrected calcium concentration, 2015
Fig. 102
figure102

Prevalent dialysis patient distribution, by presence of diabetes and intact PTH concentration, 2015

Table 105 Prevalent dialysis patient distribution, by presence of diabetes and intact PTH concentration, 2015

Annual changes in diabetic dialysis patient dynamics

A survey of diabetes prevalence was started from 2013 (In the 2013 survey, patients with diabetes were defined as having a history of diabetes, or having used three types of diabetes therapeutics. Primary disease was not considered). The dynamics of diabetic dialysis patients from 2013 to 2015 are shown in the figure (Fig. 103, Table 106). The number of diabetic dialysis patients, both males and females, showed an increasing trend over time. This was more pronounced among males, but hardly any difference was found overall in the male-to-female ratio. A slight difference was found relative to age with an increasing trend seen from 67.5 to 67.8 years and thereafter to 68.0 years. Differences relative to dialysis vintage were also found, which gradually got longer from 4.87 to 4.92 and 5.03 years (Fig. 104, Table 107, Fig. 105, Table 108).

Fig. 103
figure103

Diabetic dialysis patient distribution, by sex, 2013–2015

Table 106 Diabetic dialysis patient distribution, by sex, 2013–2015
Fig. 104
figure104

Diabetic dialysis patient distribution, by age, 2013–2015

Table 107 Diabetic dialysis patient distribution, by age, 2013–2015
Fig. 105
figure105

Diabetic dialysis patient distribution, by dialysis vintage, 2013–2015

Table 108 Diabetic dialysis patient distribution, by dialysis vintage, 2013–2015

Conclusions

In a summary of 2015 JRDR survey, chronic dialysis patients and dialysis facilities had been still increasing but the increasing rates had been gradually slowing in Japan. The average ages of incident and prevalent dialysis patients had been also glowing as up to 70 years old. Most of dialysis patients had been treated by in-center dialysis, and PD patient count had been slightly decreased. The combination therapy with PD and HDF is one of the unique points of the Japanese PD style, even if they start the combination therapy just after the dialysis initiation. The percentage of home dialysis defined as PD and HHD was quite as low as 3.0% of all dialysis patients, and Japan was one of the lowest countries in the penetration of home dialysis. A well-balanced dialysis modality choice might be needed in the future when home cares for elder dialysis patients would be needed. Online HDF had been rapidly increasing more and more just after the revision of medical reimbursement for online HDF in 2012, and the percentage of all convective therapy was 17% of all dialysis patients. The Japanese style online HDF is very unique compared with the worldwide standard method, so the evidence of it should be established in Japan. Further JRDR data analyses could clarify the relationships between various dialysis modalities, patient care, and clinical outcomes; furthermore, it could also make it possible to establish clinical practice guidelines or medical reimbursement revisions based on the evidence.

Abbreviations

AFBF:

Acetate-free biofiltration

APD:

Automated peritoneal dialysis

CRP:

C-reactive protein

D/P Cr ratio:

Dialysate/plasma creatinine ratio

EPS:

Encapsulating peritoneal sclerosis

ESI:

Exit-site infection

ETRF:

Endotoxin retentive filter

HD:

Hemodialysis

HDF:

Hemodiafiltration

HDL-C:

High-density lipoprotein cholesterol concentration

HHD:

Home hemodialysis

JRDR:

JSDT Renal Data Registry

JSDT:

Japanese Society for Dialysis Therapy

Kt/V :

Index for standardized dialysis dose defined as follows: K is the urea clearance, t is the dialysis time, V is the body fluid volume

PD:

Peritoneal dialysis

PET:

Peritoneal equilibration test

PIH:

Pregnancy-induced hypertension

PKD:

Polycystic kidney disease

pmp:

Per million of the population

PTH:

Parathyroid hormone

RPGN:

Rapidly progressive glomerulonephritis

TVC:

Total viable microbial count

UMIN:

University hospital Medical Information Network

UMIN-CTR:

the UMIN Clinical Trials Registry

UN:

urea N

USB:

Universal serial bus

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Acknowledgements

We owe the completion of this survey to the efforts of the members of the subcommittee of the District Cooperative Committee members mentioned as followings and the staff members of the dialysis facilities who participated in the survey and responded to the questionnaires. We would like to express our deepest gratitude to all these people.

District Cooperative Committee: Noritomo Itami, Tetsuya Kawata, Chikara Oyama, Koji Seino, Toshinobu Sato, Shigeru Sato, Minoru Ito, Masaaki Nakayama, Atsushi Ueda, Takashi Yagisawa, Tetsuo Ando, Tomonari Ogawa, Hiroo Kumagai, Makoto Ogura, Takahiro Mochizuki, Ryoichi Ando, Kazuyoshi Okada, Tetsuya Kashiwagi, Chieko Hamada, Yugo Shibagaki, Nobuhito Hirawa, Junichiro Kazama, Yoichi Ishida, Hitoshi Yokoyama, Ryoichi Miyazaki, Mizuya Fukasawa, Masaki Nagasawa, Teppei Matsuoka, Akihiko Kato, Noriko Mori, Yasuhiko Ito, Hirotake Kasuga, Sukenari Koyabu, Takashi Udu, Tetsuya Hashimoto, Masaaki Inaba, Terumasa Hayashi, Tomoyuki Yamakawa, Shinichi Nishi, Akira Fujimori, Tatsuo Yoneda, Shigeo Negi, Akihisa Nakaoka, Takafumi Ito, Hitoshi Sugiyama, Takao Masaki, Yutaka Nitta, Hirofumi Hashimoto, Masato Yamanaka, Masaharu Kan, Kazumichi Ota, Masahito Tamura, Koji Mitsuiki, Yuji Ikeda, Masaharu Nishikido, Akira Miyata, Tadashi Tomo, Shoichi Fujimoto, Tsuyoshi Nosaki, and Yoshinori Oshiro.

This article is translated from Japanese, originally published as “Annual dialysis data report 2015, JSDT Registry” in the Journal of the Japanese Society for Dialysis Therapy, 2017; 50: 1-62 with permission from Japanese Society for Dialysis Therapy. The original work is at “https://www.jstage.jst.go.jp/article/jsdt/50/1/50_1/_pdf”

Funding

There are no funding for the current study.

All efforts and costs for the 2015 JRDR survey and making the ADR were totally given by the JSDT.

Availability of data and materials

  • When anyone wants to use the data and materials from the current manuscript without modifications, all data and materials are freely available, stating “the data are from the annual dialysis data report 2015 of JSDT renal data tregistry”.

  • When anyone wants to use the data and materials from the current manuscript with modifications, any re-calculations or something, they have to state the following sentence in their publication. “The data reported here have been provided by the annual dialysis data report 2015 of JSDT renal data tregistry. The interpretation and reporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the JSDT.”

Author information

IM was the director of CRDR in 2015 and directed all of the 2015 JRDR survey. IM and MT finalized the results of the survey and made this manuscript. SO and AW designed the survey sheets and made a special program mounted in MS Excel worksheet for the convenience of self-assessment for the dialysis quality of each dialysis facility. SN, NK, KT, SG, and TH had the responsibilities on the data analysis. JM had the responsibility on the ethical aspect of the JRDR survey. KN was the president of JSDT in 2015, and checked all the results from the 2015 JRDR survey and approved them to be published. All authors read and approved the final manuscript.

Correspondence to Ikuto Masakane.

Ethics declarations

Ethics approval and consent to participate

  1. 1.

    The JSDT registry was approved by the ethical committee of JSDT; the approval no. is 1.

  2. 2.

    The aims of JSDT Renal Data Registry (JRDR) were well explained for the participated dialysis patients through the dialysis facilities.

  3. 3.

    It does not always need to get the documented approval form from the patients because all the collected data were the existing ones and there were no new interventions.

  4. 4.

    The original data had been totally anonymized, so there are no risks for deteriorating the privacy of the dialysis facilities and the patients.

  5. 5.

    The data presented in the current manuscript does not contain any images, videos, voice recording which might have a risk for identifying an individual.

Consent for publication

Not applicable

Competing interests

The authors declare that they have no competing interests.

Additional file

Additional file 1:

Table S1. Cumulative survival rates by incident year, 1983–2014. (XLSX 20 kb)

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Keywords

  • Elder dialysis patients
  • Diabetic nephropathy
  • Ultrapure dialysis fluid
  • Online hemodiafiltration
  • Combination of PD and HD