A clinical-histological study of individuals with diabetes mellitus and proteinuria.

Coexistent renal pathology with diabetic glomerulosclerosis was found in 38 of 136 (28%) consecutive renal biopsies performed primarily for proteinuria in individuals with diabetes mellitus. The histological lesions found were glomerulonephritis (14), focal tubulointerstitial disease (23), and amyloidosis (1). Significant microscopic haematuria was present in 66% of all patients and did not help to distinguish non-diabetic disease. The severity of diffuse diabetic glomerular disease was independently associated with duration of diabetes, raised plasma creatinine, the presence of hypertension, clinical retinopathy and neuropathy, but not with type of diabetes, degree of proteinuria or glycosylated haemoglobin at the time of biopsy. Diffuse interstitial fibrosis was related to the severity of glomerular disease and, if severe, also with a significantly (p less than 0.01) higher plasma creatinine. Coexisting renal disease was found to be associated with a significantly higher plasma creatinine (p less than 0.01) independent of the severity of diabetic glomerulopathy. Coexistent pathology is a not uncommon finding in renal biopsies from diabetic patients with proteinuria. These lesions and their underlying causes may not only influence the renal function and natural history of renal disease in diabetic individuals, but may also determine the response of proteinuria to therapy.