Correlation of Serum Bilirubin Levels in Type 2 Diabetes Mellitus Patients with and without Diabetic Retinopathy

Abstract

BACKGROUND Diabetic retinopathy is becoming one of the common blinding disease in the world affecting people in both developing and developed countries.Basic mechanism thought to be of advanced glycation end products and othertoxic mediators causingtissue destruction and pathological process. Antioxidants have a major role in preventing this pathological process. Among various antioxidants some of the common blood products have thought to have a role. One among them is serum bilirubin. This study is done to know the correlation of diabetic retinopathy and serum bilirubin levels and thus know its importance in future in preventing progression of this blinding disease. METHODS A cross sectional study was done among OPD patients with type 2 diabetes for a period of one year. Inclusion criteria were diagnosed cases of type 2 diabetes for more than 1 year and age above 40 years. Exclusion criteria included all systemic diseases/drugs affecting liver function tests, confounding factors affecting serum bilirubin levels, extremely poor glycemic control and subjects in whom fundus was not visible due to media opacities excluding causes linked with diabetic retinopathy. After taking consent, detailed history and ophthalmic evaluation, venous blood was drawn and sent for serum bilirubin analysis. Diabetic retinopathy was classified according to ETDRS classification. Statistical study was done after compiling data. RESULTS Among the study subjects – 38.2% were diabetics. Common age group was 51 to 60 years with incidence of diabeties more in males 64.3%. Among diabetic retinopathy noted– mild NPDR was 31%, moderate NPDR was 35.7%, severe NPDR was 11.9%, very severe NPDR was 4.8% and PDR was 16.6 % respectively. The mean serum total bilirubin levels in non DR was 0.597 ± 0.17, mild NPDR was 0.4 ± 0. 15, moderate NPDR was 0.36 ±0.12, severe NPDR was 0.36±0.17, very severe NPDR was 0.35±0.07, low risk PDR was 0.3±0.10 and high risk PDR was 0.32±0.15 respectively. CONCLUSIONS This study concluded that severity of diabetic retinopathy was inversely proportional to the total, direct and indirect serum bilirubin levels. KEY WORDS Diabetic Retinopathy, Serum Bilirubin, Diabetes Mellitus, ETDRS