GLOMERULAR AND TUBULAR PROTEINURIA IN TYPE-1 (INSULIN-DEPENDENT) DIABETIC-PATIENTS WITH AND WITHOUT RETINOPATHY

We compared the urinary excretion of albumin, transferrin, N-acetyl-beta-D-glucosaminidase and alpha-1-microglobulin in 78 Type 1 (insulin-dependent) diabetic patients: 39 with retinopathy and 39 without. The two groups were matched for age, sex and duration of diabetes. The patients with retinopathy had increased excretion (median and range) of albumin [1.7 (0.3-399.1) versus 1.0 (0.3-116.6) mg/mmol creatinine, P < 0.05], transferrin [114.2 (4.1-37126.2) versus 33.4 (1.0-4176.7) mu-g/mmol creatinine, P < 0.01] and N-acetyl-beta-D-glucosaminidase [23.8 (1.1-119.1) versus 15.0 (0.1-65.1) mu-mol/h/mmol creatinine, P < 0.05] but not alpha-1-microglobulin. Transferrin excretion correlated with albumin excretion. The prevalence of increased transferrin excretion (transferrinuria) was greater than that of microalbuminuria in patients both with and without retinopathy (P < 0.01 in both cases). Urinary transferrin seems likely to be predominantly of glomerular origin and merits prospective longitudinal evaluation as a potential index of the microangiopathic process.