Effect of fenofibrate on the need for laser treatment for diabetic retinopathy (FIELD study): a randomised controlled trial

Abstract

Background: Laser treatment for diabetic retinopathy is often associated with visual fi eld reduction and other ocular side-eff ects. Our aim was to assess whether long-term lipid-lowering therapy with fenofi brate could reduce the progression of retinopathy and the need for laser treatment in patients with type 2 diabetes mellitus. Methods: The Fenofi brate Intervention and Event Lowering in Diabetes (FIELD) study was a multinational randomised trial of 9795 patients aged 50–75 years with type 2 diabetes mellitus. Eligible patients were randomly assigned to receive fenofi brate 200 mg/day (n=4895) or matching placebo (n=4900). At each clinic visit, information concerning laser treatment for diabetic retinopathy—a prespecifi ed tertiary endpoint of the main study—was gathered. Adjudication by ophthalmologists masked to treatment allocation defi ned instances of laser treatment for macular oedema, proliferative retinopathy, or other eye conditions. In a substudy of 1012 patients, standardised retinal photography was done and photographs graded with Early Treatment Diabetic Retinopathy Study (ETDRS) criteria to determine the cumulative incidence of diabetic retinopathy and its component lesions. Analyses were by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN64783481. Findings: Laser treatment was needed more frequently in participants with poorer glycaemic or blood pressure control than in those with good control of these factors, and in those with a greater burden of clinical microvascular disease, but the need for such treatment was not aff ected by plasma lipid concentrations. The requirement for fi rst laser treatment for all retinopathy was signifi cantly lower in the fenofi brate group than in the placebo group (164 [3·4%] patients on fenofi brate vs 238 [4·9%] on placebo; hazard ratio [HR] 0·69, 95% CI 0·56–0·84; p=0·0002; absolute risk reduction 1·5% [0·7–2·3]). In the ophthalmology substudy, the primary endpoint of 2-step progression of retinopathy grade did not diff er signifi cantly between the two groups overall (46 [9·6%] patients on fenofi brate vs 57 [12·3%] on placebo; p=0·19) or in the subset of patients without pre-existing retinopathy (43 [11·4%] vs 43 [11·7%]; p=0·87). By contrast, in patients with pre-existing retinopathy, signifi cantly fewer patients on fenofi brate had a 2-step progression than did those on placebo (three [3·1%] patients vs 14 [14·6%]; p=0·004). An exploratory composite endpoint of 2-step progression of retinopathy grade, macular oedema, or laser treatments was signifi cantly lower in the fenofi brate group than in the placebo group (HR 0·66, 95% CI 0·47–0·94; p=0·022). Interpretation: Treatment with fenofi brate in individuals with type 2 diabetes mellitus reduces the need for laser treatment for diabetic retinopathy, although the mechanism of this eff ect does not seem to be related to plasma concentrations of lipids.