Early changes in glomerular size selectivity in young adults with type 1 diabetes and retinopathy. Results from the Diabetes Incidence Study in Sweden

ObjectiveTo investigate the relationship between early-onset retinopathy and urinary markers of renal dysfunction.Research Design and MethodsThe Diabetes Incidence Study in Sweden (DISS) aims to register all new cases of diabetes in young adults (15–34 years). In 1987–1988, 806 patients were reported and later invited to participate in a follow-up study focusing on microvascular complications after ∼10 years of diabetes. In the present study, 149 patients with type 1 diabetes, completed eye examination, and urine sampling were included.ResultsThe patients with retinopathy (n=58, 39%) had higher HbA1c (P<.001) and urinary IgG2/creatinine (P<.05) and IgG2/IgG4 ratios (P<.05). Patients with maculopathy had the highest levels. No significant differences in urinary albumin/creatinine, glycosaminoglycans (GAGs)/creatinine, Tamm–Horsfall protein (THP)/creatinine, and IgG4/creatinine ratios were found. Women had higher urinary albumin/creatinine (P<.01) and urinary IgG2/creatinine ratios (P<.01) than men.ConclusionsYoung adults with type 1 diabetes and early-onset retinopathy had higher IgG2/creatinine and IgG2/IgG4 ratios than patients without retinopathy indicating that retinopathy is associated with a change in glomerular size selectivity. This was found in association with normal urinary albumin and THP excretion and may be suspected to reflect early general vascular changes.