A prospective study of serum lipids and risk of diabetic macular edema in type 1 diabetes.

We evaluated the relationships between serum lipid levels and clinically significant macular edema (CSME), hard exudates, and other diabetic retinopathy (DR) end points in a population with type 1 diabetes. We studied data from serum lipids that were measured annually among the 1,441 Diabetes Control and Complications Trial (DCCT) participants. We used proportional hazards regression models to examine the relationship of the cumulative average of lipid levels (total, LDL, and HDL cholesterol, total-to-HDL cholesterol ratio, and triglycerides) with development of CSME, hard exudate, DR progression, and development of proliferative DR (PDR). In models controlling for primary prevention versus secondary intervention subgroup, randomized treatment assignment, HbA(1c), and other risk factors, both total-to-HDL cholesterol ratio and LDL predicted development of CSME (rate ratio [RR] for extreme quintiles 3.84, P for trend = 0.03 for total-to-HDL cholesterol ratio, and RR 1.95, P for trend = 0.03 for LDL) and hard exudate (RR 2.44, P for trend = 0.0004 for total-to-HDL cholesterol ratio, and RR 2.77, P for trend = 0.002 for LDL). Relationships of lipids with progression of DR and development of PDR were weaker and not significant after adjustment for HbA(1c). Higher serum lipids are associated with increased risk of CSME and retinal hard exudate. Lipid-lowering treatment among type 1 diabetic subjects, recommended to prevent cardiovascular disease, may also decrease risk of CSME, an important cause of vision loss.