Black Americans experience a disproportionate burden of ESRD compared with whites. Whether this is caused by the increased prevalence of chronic renal insufficiency (CRI) among blacks or by their increased progression from CRI to ESRD was investigated. A birth cohort analysis was performed using data from the Third National Health and Nutrition Examination Survey and the United States Renal Data System. It was assumed that those who developed ESRD in 1996 aged 25 to 79 yr came from the source population with CRI aged 20 to 74 yr that was sampled in the Third National Health and Nutrition Examination Survey (midpoint 1991). GFR was estimated using the Modification of Diet in Renal Disease study equation. The prevalence of CRI (GFR 15 to 59 ml/min per 1.73 m(2)) was not different among black compared with white adults (2060 versus 2520 per 100,000; P = 0.14). For each 100 blacks with CRI in 1991, five new cases of ESRD developed in 1996, whereas only one case of ESRD developed per 100 whites with CRI (risk ratio, 4.8; 95% confidence interval, 2.9 to 8.4). The increased risk for blacks compared with whites was only modestly affected by adjustment for age, gender, and diabetes. Blacks with CRI had higher systolic (147 versus 136 mmHg; P = 0.001) and diastolic (82 versus 77 mmHg; P = 0.02) BP and greater albuminuria (422 versus 158 micro g urine albumin/mg urine creatinine; P = 0.01). The higher incidence of ESRD among blacks is not due to a greater prevalence of CRI among blacks. The key to understanding black-white differences in ESRD incidence lies in understanding the extreme differences in their progression from CRI to ESRD.
