Association of serum lipid levels with retinal hard exudate area in African Americans with type 2 diabetes.

Purpose: Previous studies have yielded conflicting results regarding whether serum lipid levels are associated with retinal hard exudates in diabetic retinopathy. The majority of studies have assessed hard exudates only as a dichotomous trait (presence vs. absence) and included limited numbers of African Americans (AA). The purpose of this study was to determine if there are any associations between serum lipid levels and hard exudates in AA with type 2 diabetes (T2D).

Methods: 890 AA participants with T2D were enrolled from 5 sites. Macular fundus photographs were graded by masked ophthalmologist investigators. Hard exudate areas were measured using a semi-automated algorithm and ImageJ software. Multivariate regression models were used to determine the association between serum lipid levels and (1) presence of hard exudate and (2) area of hard exudate.

Results: Presence of hard exudates was associated with higher total cholesterol [(odds ratio (OR) = 1.08, 95 % confidence interval (CI) 1.03-1.13, P = 0.001)] and higher low-density lipoprotein (LDL) cholesterol (OR = 1.08, 95 % CI 1.03-1.14, P = 0.005) in models controlling for other risk factors. Hard exudate area was also associated with both higher total and LDL cholesterol levels (P = 0.04 and 0.01, respectively) in multivariate models controlling for other risk factors.

Conclusions: Higher total and LDL cholesterol were associated with the presence of hard exudates and a greater hard exudate area in AA with T2D. This information can be used to counsel diabetic patients regarding the importance of lipid control to decrease the risk of macular hard exudates.