A cross-sectional study to determine the relationship between diabetic retinopathy and diabetic nephropathy in type 2 diabetes mellitus patients in South India

Abstract

This cross-sectional study aims to determine the risk factors and correlation between diabetic retinopathy (DR) and diabetic nephropathy (DN) in type 2 diabetes mellitus in South India. A hospital-based analytical cross-sectional study was conducted on 200 type 2 diabetes mellitus patients and were assessed for diabetic retinopathy and nephropathy. Patients were classified into two groups: no-diabetic nephropathy (Group A) and diabetic nephropathy (Group B) based on eGFR. Fundoscopy was performed in all patients to look for DR. Multivariate regression analysis was used to determine risk factors associated with diabetic nephropathy. This study was approved by the institutional review board, and written informed consent was obtained from all participants. Statistical Package for Social Sciences (SPSS) version 20.0 for Windows was used. Descriptive statistical methods were used to outline the basic characteristics, and a P value less than 0.05 was considered statistically significant. Differences between the groups were analyzed using independent-sample t-test for continuous variables and χ2 test for categorical variables. In this study, 52% patients with DN had retinopathy when compared to 23% patients in no-DN (P < 0.001). The distribution of different types of retinopathies was 44% NPDR, 28% PDR, and 32% CSME in patients with DN and 31% NPDR, 8% PDR, and 7% CSME in the no-DN group (P < 0.001). The age, hypertension, duration of diabetes, serum creatinine, urine protein levels, and diabetic retinopathy gradings were found to be more positively correlated with DN; no diabetic retinopathy and insulin treatment data showed negative correlation. Multivariate regression analysis confirmed age, creatinine, eGFR, DR, and CSME as risk factors for progression to DN (P < 0.05). The results of our study suggest that diabetic nephropathy has a positive correlation with diabetic retinopathy in type 2 diabetes mellitus patients. We found that PDR and CSME were associated with diabetic nephropathy, and PDR and CSME were risk factors for DN. Hence, renal parameters can be used as a reliable predictor for diabetic retinopathy in type 2 diabetes mellitus patients and also contribute to prevention of DR.