EVOLUTION, RISK-FACTORS, AND PROGNOSTIC IMPLICATIONS OF ALBUMINURIA IN NIDDM

OBJECTIVE - To study the cumulative incidence of albuminuria and its d eterminants in NIDDM patients and nondiabetic subjects from the diagno sis and impact of albuminuria on cardiovascular mortality. RESEARCH DE SIGN AND METHODS - We performed a 10-year prospective observational st udy of 133 well-characterized middle-aged patients with newly diagnose d NIDDM and 144 control subjects. Both groups were examined at baselin e and after 5 and 10 years. Urinary albumin excretion was determined f rom timed 24-h (baseline and 5-year examinations) or overnight samples (10-year examination) Microalbuminuria was defined as urinary albumin excretion of 30-300 mg/24 h or 20-200 mu g/min, with the higher value s considered as macroalbuminuria. RESULTS - The cumulative incidence o f micro- and macroalbuminuria increased sharply after 5 years in NIDDM patients (baseline. 18.2 and 3.0%; 5 years: 18.9 and 1.8%: and 10 yea rs: 33.0 and 10.2%) but markedly less in control subjects (baseline: 1 .4 and 0%, P < 0.001 for diabetic patients vs, control subjects for an y albuminuria; 5 years: 6.0 and 0.8%, P < 0.01; 10 years: 11.9 and 0.8 %, P < 0.001). The most important determinant of the development of al buminuria was the metabolic control of diabetes in NIDDM patients duri ng the follow-up, whereas in nondiabetic subjects, the development of albuminuria was related to elevated blood pressure and lasting insulin levels. Baseline and 5-year albuminuria predicted subsequent cardiova scular mortality in diabetic patients, even when adjusted for multiple risk factors. The risk of cardiovascular death in NIDDM patients incr eased by simultaneous occurrence of hyperinsulinemia and albuminuria C ONCLUSIONS - The frequency of microalbuminuria in patients with NIDDM increases sharply with the duration of diabetes. Chronic hyperglycemia is the main risk factor for microalbuminuria in diabetic patients. Mi croalbuminuria accompanied by hyperinsulinemia is a powerful predictor of cardiovascular death in NIDDM patients.