Correlation Between HbA1c Levels and Severity of Diabetic Retinopathy: A Cross-Sectional Evaluation

Abstract

Background: Diabetic retinopathy (DR) is a frequent microvascular complication of type 2 diabetes mellitus and the major cause of visual impairment. The most important factors affecting the development of DR are glycemic control and duration of diabetes. The purpose of this study was to determine the correlation between glycemic indices and the extent of DR in patients with type 2 diabetes mellitus.

Methods: This cross-sectional study (November 2022 to April 2023) included 150 patients with type 2 diabetes and was divided into three groups according to the severity of DR, which included No DR (n=60), Non-Proliferative DR (NPDR, n=58), and Proliferative DR (PDR, n=32). The ophthalmic examination was carried out in detail, and HbA1c and glucose levels were assessed with fasting blood samples. Demographic and clinical information were recorded. ANOVA, Pearson correlation, and multivariate logistic regression were used to analyze associations between glycemic indices, diabetes duration, and DR severity. 

Results: NPDR and PDR patients reported greater levels of HbA1c, longer duration of diabetes and elevated fasting glucose than patients with no DR. HbA1c had the most significant positive correlation with the severity of DR (r = 0.72, p < 0.001). Multivariate logistic regression found HbA1c (OR=1.92, 95% CI=1.48-2.51) and length of diabetes (OR=1.15, 95% CI=1.07-1.25) as independent predictors of DR.

Conclusion: DR severity is highly linked with poor long-term glycemic control and increased duration of diabetes. HbA1c monitoring and early ophthalmic examination is critical to prevent further development of the disease and minimize the risk of developing vision loss in patients.