Objective: To compare prevalence rates of increased albumin excretion in the Epidemiology of Diabetes Complications Study (EDC) (in the U.S.) to similar rates in the EURODIAB study (in Europe) and determine if any differences relate to hypertension, glycemic control, or smoking status.
Research design and methods: The study population is made up of two epidemiological clinic-based IDDM populations with comparable ages (chi = 28 years, both studies), sex distribution (50% male, EURODIAB; 49% male, EDC), and duration characteristics. Comparison of two cross-sectional (prevalence) studies was made. Despite different laboratory assays, comparability was established for urinary albumin (r = 0.98) and GHb measures (r = 0.95). Hypertension was measured with an identical protocol. Renal status was determined by 24-h urine albumin excretion (< 20 micrograms/min normal, 20-200 micrograms/min microalbuminuria, > 200 micrograms/min macroalbuminuria) in EURODIAB. Identical cutoffs were used for EDC, though two of three samples (24-h, 4-h clinic, and/or overnight sample) had to be positive in one range. (Main findings are confirmed using only 24-h results from EDC.)
Results: The prevalence of macroalbuminuria was higher in EDC (27%) than in EURODIAB (12%). Rates of microalbuminuria were similar (22 vs. 25%, respectively). These patterns were seen at all durations and ages and in both sexes. Controlling for glycemic control, hypertension, or smoking did not account for the higher rate in EDC, nor did exclusion of subjects with raised serum creatinine.
Conclusions: Advanced renal disease is more prevalent in IDDM in EDC (Pittsburgh, PA) than in Europe. This is not explained by hypertension, glycemic control, or smoking.