Clinical significance of microalbuminuria in Japanese subjects with non-insulin-dependent diabetes

In order to elucidate the clinical significance of microalbuminuria in non-insulin-dependent diabetes mellitus (NIDDM), 62 Japanese subjects with NIDDM and without proteinuria were followed for three years. After the three-year follow up, four (19%) of 21 microalbuminuric patients—albumin excretion rates (AER) greater than 15 μg/min—developed overt proteinuria, while none of the 42 normoalbuminuric patients did. Among these normoalbuminuric patients, eight patients (19.5%) developed microalbuminuria. The microalbuminuric patients who developed overt proteinuria had higher AER at the beginning of the study than the patients who stayed microalbuminuric. The patients who developed microalbuminuria showed a significantly higher systolic blood pressure in the final year than the patients who stayed normoalbuminuric. These results indicate that microalbuminuria precedes overt proteinuria in Japanese NIDDM, and progression of diabetic nephropathy is rapid and associated with a rise in blood pressure.