Diabetic retinopathy in noninsulin-dependent diabetes mellitus and its relation to serum insulin level

Abstract

Background: Insulin has been shown to directly influence retinal blood flow, vascular tone, and angiogenesis, all of which are active aspects of the pathogenesis of diabetic retinopathy (DR). Intensive administration of insulin can increase vascular endothelial growth factor, potentially leading to transient worsening of retinopathy. Aims: The aim of the study is to access the role of serum insulin levels in various stages of DR in type 2 diabetes mellitus (DM). Settings and Design: This was a tertiary care center-based, cross-sectional, case-control, observational study conducted from April 2014 to March 2015. Materials and Methods: A total of 79 patients were divided into groups - controls (No DM), No DR, nonproliferative DR (NPDR), and proliferative DR (PDR). Serum insulin level was compared with severity of DR. Statistical Analysis: Data were summarized and presented as mean ΁ standard error. The variables of the study groups were compared by analysis of variance. For pairwise comparison between the groups, Tukey′s test for multiple comparison was used. Results: No significant difference was found between insulin levels in No DM and No DR groups. On the other hand, the difference was statistically significant on comparison between No DM and NPDR (P < 0.001) and also between No DM and PDR (P < 0.05). However, no such difference in insulin level was observed on comparing NPDR and PDR groups. Conclusion: Serum insulin level has an association with the development of retinopathy patients of noninsulin-dependent DM. However, prospective interventional studies are required to establish such role of serum insulin in DR.