Prevention and treatment of diabetic renal disease in type 2 diabetes: the BENEDICT study

Diabetic nephropathy (DN) is the leading cause of end-stage renal failure in Western countries and carries an increased risk for cardiovascular mortality. Studies have identified a number of factors that play a part in the development of DN. Among them, hypertension and proteinuria are the most important. In the early stages of DN, when albumin is present in the urine in very low quantities (microalbuminuria) and an increase is seen in BP, there is no loss of filtrate and patients respond well to prophylactic measures. Microalbuminuria is considered an early marker of DN. Prevention of the onset of microalbuminuria, therefore, could be considered as the primary means of preventing DN. The Bergamo Nephrologic Diabetes Complication Trial (BENEDICT) was a prospective, randomized, double-blind, parallel-group study that was organized in two phases. Phase A included 1204 patients and was aimed at assessing the efficacy of the angiotensin-converting enzyme (ACE) inhibitor trandolapril, the non-dihydropyridine calcium channel blocker verapamil, and the trandolapril plus verapamil combination as compared with placebo in prevention of microalbuminuria in hypertensive patients with type 2 diabetes and normal urinary albumin excretion rate. Phase B was aimed at assessing the efficacy of the combination as compared with trandolapril alone in prevention of macroalbuminuria in patients with microalbuminuria. The BENEDICT Phase A study showed that DN can be prevented by ACE inhibitor therapy. The beneficial effect of ACE inhibition is not enhanced by combined non-dihydropyridine calcium channel blocker therapy. The apparent advantage of ACE inhibitors over other agents includes a protective effect on the kidney against the development of microalbuminuria, which is a major risk factor for cardiovascular events and death in this population.