Age distribution and yearly changes in the incidence of ESRD in Japan

Background: Although several treatment and screening methods have been tried, the incidence of patients with end-stage renal disease (ESRD) on renal replacement therapy (RRT) continues to increase worldwide. By making a detailed analysis of the major primary renal diseases, we found there have been some favorable effects in the incidence rate of ESRD recently in Japan. Methods: A total of 339,478 patients in Japan and 909,591 patients in the United States started RRT between 1983 and 1999. We compared trends of average age and incidence rate in each age group with major primary renal diseases and in racial groups after adjusting for general population aging by using a linear regression analysis. Results: All trends in ESRD incidence rates among Japanese, US total, US white, and US black patients showed significant increases (P < 0.001). A significant positive linear relationship between year and mean age at start of RRT also was observed (P < 0.001). After adjustment for general population aging, the mean age increment in Japanese patients with glomerulonephritis was increased significantly, and the proportion of Japanese patients who had glomerulonephritis and were younger than 45 years was decreased, but this decrement was not observed in US patients with glomerulonephritis. Conclusion: The reduced number of new patients with ESRD with glomerulonephritis might be caused by early detection and early referral to nephrologists as a result of the Japanese urinalysis-screening program. To reduce the ESRD population, it will be necessary to establish more effective treatment methods to delay exacerbation of progressive renal diseases.