Supplementary Material for: Non-High-Density Lipoprotein to High-Density Lipoprotein Cholesterol Ratio as a Predictive Biomarker for Diabetic Retinopathy Risk: A Population-Based Analysis of U.S. Adults

Background: Diabetic retinopathy (DR) is a severe complication of diabetes, and lipid imbalances play a key role in its progression. The non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) has been identified as a predictor of cardiovascular diseases, but its link to DR remains unclear. Objective: This study aims to assess the association between NHHR and DR risk in diabetic patients. Methods: Data from the 2005–2018 National Health and Nutrition Examination Survey (NHANES) were analyzed. Multivariate logistic regression models were used to evaluate the relationship between NHHR and DR. Non-linear associations were assessed using restricted cubic spline analysis. Results: Of the 4,935 participants, 1,193 had DR. Higher NHHR was strongly associated with increased DR risk. Each unit rise in NHHR increased the risk by 19% (OR = 1.19, 95% CI: 1.07–1.31, P < 0.05). In quartile analysis, participants in the highest NHHR quartile had nearly double the risk of DR compared to those in the lowest quartile (OR = 1.84, 95% CI: 1.62–2.06, P < 0.001). Subgroup analysis showed this association was consistent across different demographic groups, including age, gender, BMI, and smoking status. Conclusion: NHHR is significantly linked to DR risk in diabetic patients and may be a valuable biomarker for early detection and prevention strategies in clinical settings.