Renal Outcome in Type 2 Diabetic Patients With or Without Coexisting Nondiabetic Nephropathies

Abstract

OBJECTIVE—To determine the risk factors for adverse renal outcome in type 2 diabetic patients who underwent renal biopsy and were followed-up longitudinally. RESEARCH DESIGN AND METHODS—We examined 68 consecutive patients with type 2 diabetes during the period of 1985–1999 who underwent renal biopsy for proteinuria ≥1 g/day, renal involvement (proteinuria or renal impairment) at the absence of retinopathy, renal involvement with duration of diabetes 120 μmol/l (P = 0.0005), presence of retinopathy (P < 0.00001) at the time of biopsy, and biopsy showing DGS (groups I and II) (P = 0.035). On multivariate analysis, retinopathy was the only independent variable correlated with end-stage renal failure. This study also showed that the association of hematuria or proteinuria with the absence of retinopathy constitutes the strongest indication for a nondiabetic lesion (positive predictive values of 94%). CONCLUSIONS—Patients with type 2 diabetes undergoing renal biopsy constitute a heterogeneous group by their clinical presentations and underlying pathology, but longitudinal studies on the renal outcome of these patients remain limited. Our study showed that renal biopsy is indicated in selective diabetic patients because of potentially treatable nephropathy and of a better prognosis than DGS.