Proteinuria in newly diagnosed type II diabetic patients

Urinary excretion of albumin, IgG, and beta 2-microglobulin was examined in 132 (69 men, 63 women) newly diagnosed, middle-aged type II diabetic patients and in 144 (62 men, 82 women) nondiabetic control subjects. Both male (N = 57) and female (N = 29) diabetic patients with normal urinary sediment showed an increased excretion of albumin compared with the respective nondiabetic subjects, and male diabetic patients also had an increased IgG excretion. No consistent difference was found in urinary beta 2-microglobulin concentration between the diabetic and nondiabetic subjects. In all, 19.5% of the diabetic subjects with normal urinary sediment (12 men, 5 women) showed urinary albumin concentration exceeding the highest value (35 mg/24 h) found in nondiabetic subjects without renal disease. The urinary excretion of albumin in the diabetic subjects was not associated with the presence of hypertension or coronary heart disease or with the fasting blood glucose or serum insulin levels measured at diagnosis of diabetes. In male diabetic subjects with urinary albumin excretion greater than 35 mg/24 h, a reduced creatinine clearance was found, suggesting the presence of structural damage associated with diabetic nephropathy. The early increase of urinary albumin excretion in type II diabetic patients may be mostly functional in nature. However, some patients may have structural renal damage associated with diabetic nephropathy present at diagnosis.