Objective: To assess the degree of interindividual variation in the rate of progression of microalbuminuria and to identify determinants of progression of microalbuminuria in patients with NIDDM.
Research design and methods: In a prospective cohort study, 58 microalbuminuric NIDDM patients were followed for a period of at least 24 months. During this period, the level of microalbuminuria in these patients was assessed in triplicate 24-h urine samples on at least four separate visits. All patients had stable metabolic control and controlled blood pressure during follow-up. Microalbuminuria was defined as an albumin-to-creatinine ratio in 24-h urine of between 3 and 30 mg/mmol. The individual rates of progression of microalbuminuria were calculated from linear regression analysis. At baseline, the following data were collected for all patients: age, sex, ethnicity, time since diagnosis of NIDDM, smoking habits, drug use, blood pressure, BMI, HbA1c, serum creatinine, cholesterol, triglyceride, and HDL cholesterol concentrations.
Results: Microalbuminuria was found to progress linearly in time. Considerable differences in rates of progression of microalbuminuria were found, the absolute yearly change in albumin-to-creatinine ratio ranging from -5.2 to 12.9 mg/mmol. In bivariate analyses, serum triglyceride concentration, use of ACE inhibitors, mean arterial blood pressure, HDL cholesterol, and time since diagnosis of NIDDM correlated with progression of microalbuminuria (P < or = 0.05). In stepwise multiple regression analysis, a high triglyceride-to-HDL cholesterol ratio at baseline (P = 0.006) and the use of ACE inhibitors (P = 0.007) were identified as the only independent predictors of progression of microalbuminuria.
Conclusions: The rate of progression of microalbuminuria in NIDDM differs considerably between subjects. Diabetic dyslipidemia (high serum triglyceride and low HDL cholesterol) is a predictor of more rapid progression of microalbuminuria in patients with well-controlled blood pressure.