DIABETES IN URBAN AFRICAN-AMERICANS .2. HIGH PREVALENCE OF MICROALBUMINURIA AND NEPHROPATHY IN AFRICAN-AMERICANS WITH DIABETES

OBJECTIVE-African-Americans with diabetes have an increased risk of en dstage renal disease, but underlying mechanisms are poorly understood. We undertook this study to evaluate prevalence and risk factors for r enal disease in an African-American population with diabetes. RESEARCH DESIGN AND METHODS-We measured urine albumin excretion in 578 consecu tive patients presenting for the first time to the Grady Memorial Hosp ital Diabetes Unit in Atlanta, GA. The unit serves an urban population that is predominantly African-American; 85% of patients have non-insu lin-dependent diabetes mellitus (NIDDM). Subjects provided 24-h and/or similar to 3-h urine collections for measurement of albumin and creat inine. RESULTS-Correlation of the albumin/creatinine ratio (mu g/mg) w ith the 24-h albumin excretion rate was 0.89 (P < 0.001, n = 123). Alt hough the median duration of diabetes was only 1 year, among all subje cts, the estimated prevalence of microalbuminuria (30-300 mg albumin/2 4 h) was 25% and that of nephropathy (>300 mg albumin/24 h) was 11%. A mong African-Americans with NIDDM (n = 466), the estimated prevalence of microalbuminuria was 24% and that of nephropathy was 12%; prevalenc e remained high (25 and 5%, respectively) among 219 patients with <1 y ear known duration of diabetes. Metabolic control was not associated w ith disease. However, among all subjects with NIDDM, the odds ratio fo r nephropathy among subjects with disease duration >5 years compared w ith those with disease duration <1 year was 4.65 (95% confidence inter val [CI] 2.24-9.79), and the odds ratio for nephropathy among subjects with hypertension compared with those without hypertension was 2.64 ( CI 1.42-4.93). Odds ratios were comparable among African-Americans wit h NIDDM. Trends were similar but less significant for subjects with mi croalbuminuria. CONCLUSIONS-Albuminuria can be identified reliably and conveniently by the albumin/creatinine ratio in brief urine collectio ns. In our patients, clinically significant albuminuria occurred in 36 % of persons at first presentation. Since increased risk was associate d with hypertension and control of hypertension can slow progression o f renal disease, screening for albuminuria and treatment of hypertensi on should be aggressive in urban populations of African-Americans with diabetes.