The DIabetic Retinopathy Candesartan Trials (DIRECT) Programme, rationale and study design.

The DIabetic Retinopathy Candesartan Trials (DIRECT) Programme consists of three randomised, double-masked, parallel, placebo-controlled studies to determine the impact of treatment with candesartan on diabetic retinopathy. In Type 1 diabetes, 1,700 patients without retinopathy will be randomised into a primary prevention study, and 1,200 with non-proliferative retinopathy into a secondary prevention study. In Type 2 diabetes, 1,600 patients with non-proliferative retinopathy will be randomised.