Fig. 1

The general description of dialysis facilities that responded to the questionnaire survey. The regions of dialysis facilities that responded to the questionnaire survey are shown in Fig. 1a. We divided them into 10 regions from north to south, i.e., Hokkaido, Tohoku, Kanto except Tokyo, Tokyo, Tokai, Koshinetsu/Hokuriku, Kinki, Chugoku, Shikoku, and Kyushu/Okinawa. We received similar rate of responses from each region. The number of dialysis patients in these facilities is shown in Fig. 1b