Sustained reduction of proteinuria in type 2 (non-insulin-dependent) diabetes following diet-induced reduction of hyperglycaemia.

To determine whether sustained control of hyperglycaemia in Type 2 (non-insulin-dependent) diabetic patients would diminish proteinuria, the effect of hypocaloric diet therapy (500 kcal/day) on proteinuria was assessed in obese, Type 2 diabetic patients (n = 24) and compared with results obtained for obese subjects with normal glucose tolerance (n = 7) and impaired glucose tolerance (n = 6). Diet therapy of similar mean duration resulted in similar percentage weight loss (mean percentage of original weight +/- SEM) in diabetic (13.6 +/- 1.6%), glucose intolerant (16.4 +/- 3.3%) and obese non-diabetic (11.0 +/- 1.0%) subjects. Following therapy, plasma glucose concentrations 2h after an oral glucose load declined in the diabetic (18.34 +/- 0.81 to 10.67 +/- 0.50 mmol/l, mean +/- SEM; p less than 0.001) and in the glucose intolerant subjects (10.2 +/- 0.3 to 7.3 +/- 0.4 mmol/l, p less than 0.01) while remaining unchanged in the obese non-diabetic subjects (7.09 +/- 0.23 to 6.77 +/- 0.32 mmol/l, NS). Concentrations of total protein of plasma origin and albumin in 24-h urine collections were quantified by a sensitive immunonephelometric assay using specific antisera. Initially, 24-h excretion of total protein and albumin were elevated in the diabetic [mg protein/24 h; (median +/- 95% confidence limits): 63 (42-138), p less than 0.05; albumin: 26 (14-56), p less than 0.05] and glucose intolerant subjects [protein: 52 (13-92), NS; albumin: 24 (3-61), NS] compared with the non-diabetic subjects [protein: 20 (5-38); albumin: 6.2 (3.5-9.5)].(ABSTRACT TRUNCATED AT 250 WORDS)