Discordance between retinopathy and nephropathy in type 2 diabetes

The aim of this study was to investigate the relationship between the grade of retinopathy and the severity of glomerular lesions in patients with type 2 diabetes and to describe 5 patients without diabetic retinopathy for whom renal biopsy specimens demonstrated advanced diabetic nephropathy. A total of 221 patients with type 2 diabetes (139 males and 82 females) who consectively underwent renal biopsy between 1982 and 1996 were investigated. The severity of diffuse glomerular lesions was graded using the criteria of Gellman and coworkers, and diabetic retinopathy was classified as absent, nonproliferative, or proliferative. The incidence of advanced nephropathy without retinopathy for all 221 cases was 2.3%. Advanced nephropathy was present in 5 of the 122 (4.1%) patients without retinopathy. These 5 patients were all males and aged 50-70 (mean 61) years. Their clinical characteristics were not uniform, and no special clinical features distinguished the patients who were regarded as having possible advanced nephropathy without retinopathy. In our study, although concordance of retinopathy and nephropathy is relatively common, a little discordance was pronounced in Japanese type 2 diabetic patients. Our findings are consistent with the hypothesis that there are important differences in some aspects of the pathogenesis of retinopathy and nephropathy.