|Source: USRDS Atlas 2011|
- In 2009, 290,661 patients in Japan were on dialysis. An increase of 7240 patients (2.6%) compared with that of 2008.
- The crude death rate of dialysis patients from the end of 2008 to the end of 2009 was 9.6%.
- The mean age of the new patients introduced into dialysis, 67.3 years
- The mean age of the entire Japanese dialysis patient population, 65.8 years.
- Primary diseases such as diabetic nephropathy and chronic glomerulonephritis for new dialysis patients, showed a percentage of 44.5% and 21.9%, respectively.
- Among the patients treated by facility dialysis, 95.4% of patients were treated three times a week, and the average time required for one treatment was 3.92 ± 0.53 (SD) hours.
- The number of patients using a polysulfone membrane dialyzer was the largest (50.7%) and the average membrane area was 1.63 ± 0.35 m.
- Nearly 90% of patients had a functioning arteriovenous fistula and 7.1% an AV graft graft.
- The US crude mortality (see Fig), while falling is two-fold higher than that in Japan (In 2006, 20.1% of U.S. dialysis patients died), but the rate is falling.
- The higher mortality does not seem to be explained by frequency of dialysis: ≈95% of Japanese patients on three- times a week dialysis, whereas ≈98% of US patients on three times dialysis.
- The average time on dialysis of the US dialysis population is age dependent: ≈65% on >4 hrs of dialysis but a only approximately 55% of older patients on >4 hrs of dialysis.
- The age and the prevalence of diabetes was similar between the US and the Japanese.
- There is a markedly higher rate of fistula usage in Japan as compared to the US.
- The Japanese use highly purified water, but the use of the "ultrapure water" only really began when the Japanese standards were revised in 2008. ("ultrapure" dialysate is commonly defined as having a bacterial count less than 100 CFU/L and an endotoxin content less than 0.03 EU/mL measured by the Limulus amebocyte lysate assay).
- The use of home dialysis is higher in the US than Japan, although low in both. (In the US the rate of home dialysis has gone from 6% in 1985 to 0.1% in 2009).
The bottom-line? There are a number of differences in dialysis practice that alone or together could explain the difference in mortality. While the very low transplantation rate in Japan, i.e. selection bias, might be a part of the explanation, it does not explain the two-fold higher mortality rate in the US. InJapan, like the US, there is a highly prevalent diabetic population on dialysis with an average age in the 60s that similarly dialyzes 3 times a week in center. It's either better dialysis or some other factor, but not just differences in transplant rates, nor is it because the Japanese are very selective in who they treat on dialysis.