Trends in incidence of end-stage renal disease in Japan, 1983-2000: age-adjusted and age-specific rates by gender and cause.

BACKGROUND: Trends in age-adjusted or age-specific incidence rates of end-stage renal disease (ESRD) have never been examined in Japan, a major ESRD epidemic area. METHODS: A nationwide registry has provided the number of ESRD patients commencing maintenance renal replacement therapy for time period from 1983 to 2000. We computed gender- and age-specific incidence rates of ESRD over 2-year periods, in total or by cause. Age-adjusted incidence rates were calculated using the 1985 Model Population of Japan as the standard. RESULTS: Causes of ESRD in 1999-2000 were, in order of decreasing frequency, diabetic nephropathy, chronic glomerulonephritis, unknown causes, nephrosclerosis and polycystic kidney disease in men, and chronic glomerulonephritis, diabetic nephropathy, unknown causes, nephrosclerosis and polycystic kidney disease in women. The age-adjusted all-cause incidence of ESRD increased until 1995-1996, but has since levelled off in both genders. The age-adjusted rate for diabetic nephropathy has been rapidly increasing, while that for chronic glomerulonephritis has decreased since 1995-1996. The former rate exceeded the latter in 1997-1998 in men. All-cause ESRD has rapidly increased in the eighties age group, whereas the increase slowed down in younger age groups in the late 1990s. The rate for diabetic nephropathy has linearly risen in almost every age group in men, whereas it began to level off in women aged 40-59 years at about 1995. For chronic glomerulonephritis, the rate had already started to decline in the mid-1980s in those aged <45 years. The rate of nephrosclerosis has been increasing independently of age. CONCLUSIONS: The present study shows changes in the epidemiological features of the incidence of ESRD in Japan from 1983 to 2000.