Diabetic retinopathy related to degree of albuminuria and tubular (low molecular weight) proteinuria in insulin-dependent (type I) diabetes mellitus.

The urinary excretion of albumin (a marker of glomerular damage) and retinol binding protein (a low molecular weight protein marker of tubular dysfunction) was determined by sensitive immunochemical methods in 110 insulin-dependent (Type I) diabetic patients. We observed a statistically significant correlation between the urinary excretion levels of both proteins, in particular albumin, and the degree of retinopathy. The incidence of macroalbuminuria and tubular proteinuria was significantly higher in patients with manifest background retinopathy and proliferative retinopathy as compared to patients with no or slight retinopathy. The duration of diabetes was significantly correlated to the degree of retinopathy, but not to the urinary excretion of albumin and retinol binding protein.