CLINICAL AND HISTOLOGICAL CORRELATIONS OF DECLINE IN RENAL-FUNCTION IN DIABETIC-PATIENTS WITH PROTEINURIA

In 47 patients with diabetic nephropathy (29 type I, 18 type II) renal function and blood pressure (BP) (treated with or without an angioten sin-converting enzyme [ACE] inhibitor, enalapril [10 mg], in 38 hypert ensive patients) were followed over 4 years. A percutaneous renal biop sy was performed in all patients initially and repeated in a represent ative 19 patients with treated hypertension after 4 years. Mean glomer ular volume (MGV), interstitial fibrosis (IF), capillary volume, and s clerosed glomeruli (GS) were measured histomorphometrically. Mean fall in creatinine clearance (CCr) was 11.8% after 4 years with no differe nce between treatment groups or type of diabetes. BP both initially an d during treatment correlated with initial and final serum creatinine and CCr (P < 0.01). There were no histomorphometric differences betwee n type I and type II patients or hypertension treatment groups. Initia l IF correlated with initial and final serum creatinine and CCr (P < 0 .05) in all patients and type I patients alone, MGV correlated inverse ly with CCr in type I patients (P < 0.05). After 4 years, IF (24.8 vs. 30.0%, P < 0.01) and GS (26 vs. 37%, P < 0.05) increased significantl y, and increase in IF correlated with fall in CCr (P < 0.01). Proteinu ria and HbA(1) did not correlate with indexes of function or structure . In this longitudinal study of patients with diabetic nephropathy, th ere was a close relation between BP and renal function but no differen ce between treatment with enalapril and other hypertensive agents. The correlations between renal function and histology at entry and after 4 years suggest that IF is a co-determinant of renal function in diabe tic nephropathy.