Relationship between urinary albumin excretion rate and renal histology in non-insulin-dependent diabetes mellitus: with reference to the clinical significance of microalbuminuria.

The present study demonstrates the relationship between urinary albumin excretion rate (AER) and renal structural changes in patients with non-insulin-dependent diabetes mellitus (NIDDM) without clinical proteinuria. Resting AER in 30 control subjects and 67 NIDDM patients were 10.4 +/- 4.8 (mean +/- SD) micrograms/min (range 4.3-21.1 micrograms/min) and 26.4 +/- 32.3 micrograms/min (range 0.4-155 micrograms/min), respectively. Persistent normoalbuminuria (less than 20 micrograms/min) and microalbuminuria (20-200 micrograms/min) were found in 43 (Group A) and 24 (Group B) diabetics. There were significant differences in age, diabetes duration, and frequency of retinopathy (background and proliferative) as well as that of proliferative retinopathy between Groups A and B, but not in the other clinical parameters such as body mass index, HbA1, Ccr, or systolic and diastolic blood pressure (SBP, DBP). When compared with 11 normoalbuminuric patients of similar age and equal diabetes duration to those in Group B, the sole difference in clinical parameters was the existence of proliferative retinopathy in Group B. Renal structural changes were investigated by light microscopy in 14 people in Group A and 13 people in Group B, and additionally in 5 NIDDM patients with both macroalbuminuria (greater than or equal to 200 micrograms/min) and normal or nearly normal renal function (Group C). The diffuse glomerular lesion (Gellman's classification) was grade I or II in A, II or III in B, and III in C.(ABSTRACT TRUNCATED AT 250 WORDS)