Association of Serum Uric Acid Level with Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus

Abstract

Background: Diabetic retinopathy is a major microvascular complication of type 2 diabetes mellitus (T2DM), leading to vision impairment and blindness. Emerging evidence suggests that elevated serum uric acid levels may contribute to its development and progression.

Objectives: To assess serum uric acid levels in patients with T2DM, evaluate its association with diabetic retinopathy, and determine its relationship with the severity of diabetic retinopathy.

Methods: This was an observational, cross-sectional study conducted in the Department of General Medicine, among 140 T2DM between July 2023 – December 2024 a comprehensive clinical assessment, including vitals, systemic examination, anthropometry and laboratory tests (FBS, PPBS, HbA1c and serum uric acid) was conducted followed by an ophthalmological evaluation with fundus examination to assess diabetic retinopathy. Analysis was done using Stata v16.

Results: The study found a significant association between serum uric acid levels and diabetic retinopathy in T2DM patients. Serum uric acid levels were markedly higher in patients with DR (8.4 ± 1.3 mg/dL) compared to those without DR (5.4 ± 1.9 mg/dL) (P < 0.001), and levels increased progressively with disease severity. Patients with PDR had higher serum uric acid levels (9.2 ± 1.8 mg/dL) compared to those with NPDR (8.1 ± 0.9 mg/dL) (P < 0.001). Within NPDR, serum uric acid levels increased from mild (7.6 ± 0.7 mg/dL) to moderate (8.4 ± 0.7 mg/dL) to severe NPDR (10.4 ± 0.3 mg/dL) (P < 0.001). Serum uric acid levels also showed a significant positive correlation with glycaemic parameters, including fasting blood sugar (rp = 0.394, P < 0.001), postprandial blood sugar (rp = 0.419, P < 0.001), and glycated haemoglobin (rp = 0.411, P < 0.001). ROC analysis demonstrated that serum uric acid is a strong predictor of DR (AUC = 0.908), PDR (AUC = 0.702), and severe NPDR (AUC = 0.935), with high sensitivity and specificity.

Conclusion: This study found a significant association between elevated serum uric acid levels and the presence and severity of diabetic retinopathy in T2DM patients. Serum uric acid may serve as a potential biomarker for early identification and risk stratification of diabetic retinopathy.