RELATIONSHIP BETWEEN RETINAL AND GLOMERULAR-LESIONS IN IDDM PATIENTS

Current knowledge regarding the concordance and discordance of the eye and kidney complications of diabetes is based on observations by opht halmoscopy of retinal structural changes, which may be present at earl y stages of the disorder, and renal functional changes, which only bec ome apparent at the later stages of the disease. For this reason we in vestigated the relationship between retinal structural lesions and qua ntitative measures of glomerular structure in patients with insulin-de pendent diabetes mellitus (IDDM). Renal biopsies were evaluated using morphometric techniques, and retinopathy classification was determined by retinal fundus photography in 86 patients with IDDM: age 30.4 +/- 7.3 years and duration of IDDM 18.9 +/- 6.3 years (mean +/- SD). Retin opathy score correlated with glomerular basement membrane width (r = 0 .39, P = 0.0002), mesangial volume fraction (VvMes/Glom) (r = 0.35, P = 0.0009), surface density of the peripheral capillary wall (SvPGBM/Gl om) (r = 0.34, P = 0.0013), and index of arteriolar hyalinosis (r = 0. 36, P = 0.0008). Abnormalities in VvMes/Glom and SvPGBM/Glom were more pronounced in patients with both retinopathy and hypertension. Four o f the 15 patients (27%) with either normal urinary albumin excretion ( UAE) or low-level microalbuminuria had advanced retinopathy but normal VvMes/Glom. In conclusion, the presence of advanced retinal disease w ith or without hypertension in patients with IDDM indicates a greater likelihood of advanced nephropathy as evidenced by increased VvMes/Glo m and decreased SvPGBM/Glom. However, marked discordance between retin opathy and nephropathy occurs, as illustrated by patients with normal UAE or low-level microalbuminuria, normal glomerular structural measur es, and advanced retinopathy.