Fibrates and statins in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is one of the leading risk factors and causes of blindness worldwide. Tight glucose and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Photocoagulation is standard treatment for both DME and PDR. However, some patients suffer permanent visual loss despite therapy. Treatment with fibrates first showed reduction in hard exudates, an effect subsequently shown with statins in short term studies, in particular two randomized studies in patients with macular edema. In the FIELD study which pre-specified microvascular outcomes, fenofibrate reduced laser treatment for DME or PDR by 31%:164 (3.4%) patients on fenofibrate vs. 238 (4.9%) on placebo (p<0.001). In the ophthalmology sub-study of FIELD, the composite exploratory endpoint of 2-step progression of ETDRS retinopathy grade, macular edema or laser treatment was significantly reduced by 34%: 53 (11.1%) patients on fenofibrate vs. 75 (16.1%) on placebo (p=0.022). Conversely, there was no reduction in laser treatment or reduced progression of retinopathy in two large scale studies of statins where cardiovascular events were significantly reduced. Neither class of lipid-lowering drugs consistently improved visual acuity. In the ACCORD-EYE study, the combination of fenofibrate and simvastatin reduced by 40% the rate of progression of diabetic retinopathy compared with simvastatin alone. Other studies are needed to establish the place of lipid lowering drugs in the treatment of macular edema and the prevention of vision loss.