A Comparison Between Diuretics and Angiotensin-receptor Blocker Agents in Patients With Stage I Hypertension: PREVER-treatment Study

Cardiovascular disease (CVD) is already the leading cause of death in Brazil. The superiority of any particular agent among the groups of blood pressure-lowering drugs was investigated in various clinical trials. ALLHAT, the largest and better designed trial showed that chlorthalidone had similar efficacy to prevent fatal and non-fatal coronary events as an ACE inhibitor (lisinopril) and a calcium channel blocker agent (amlodipine). Chlorthalidone was superior to the other agents in the prevention of other cardiovascular outcomes, particularly heart failure. Amlodipine was superior to valsartan, an angiotensin-receptor blocker (ARB) agent, in the prevention of CHD and stroke. There is no head-to-head comparison between diuretics and ARB agents in the prevention of hard cardiovascular outcomes, and even the comparison of their blood pressure-lowering effects is scarcely described in the literature. Despite this, ARB agents are the leading brands in terms of profits in various countries in the world, including Brazil. This leadership is based on a strong commercial strategy, which includes the distortion of the evidences of clinical trials in favor of these drugs. The idea that they have blood pressure-independent effects is accepted by most, despite the evidences of better designed trials. The option by an ARB agent instead of a diuretic as the first line option in the public health system in Brazil would result in a large expenditure of resources, and there is a pressure to include them in the list of essential drugs provided by the government.

This is a nation-based trial, with 24 clinical centers distributed in 9 States. A Coordinating Committee is responsible for the elaboration of this proposal and for the main decisions of the trial. The organizational chart of the study will include an executive Committee, a safety committee, outcome committee, lab and EKG centers, and the research units.

Research questions

1. Is losartan more efficacious and safe than the association of chlorthalidone with amiloride as the first option to control blood pressure in patients with stage I hypertension?
2. Is losartan more efficacious than the association of chlorthalidone with amiloride as the first option to prevent the development of target-organ damage in patients with stage I hypertension?
3. Is losartan more efficacious than the association of chlorthalidone with amiloride as the first option to prevent the occurrence of major cardiovascular events in patients with stage I hypertension?

Methods