Effectiveness of low-dose diuretics for blood pressure reduction to optimal values in prehypertension: a randomized clinical trial.

BACKGROUND: To determine the effectiveness of low-dose diuretic therapy to achieve an optimal level of blood pressure (BP) in adults with prehypertension. METHODS: The PREVER-prevention trial was a randomized, parallel, double-blinded, placebo-controlled trial, with 18 months of follow-up, conducted at 21 academic medical centers in Brazil. Of 1772 individuals evaluated for eligibility, 730 volunteers with prehypertension who were aged 30-70 years, and who did not reach optimal blood pressure after 3 months of lifestyle intervention, were randomized to a fixed association of chlorthalidone 12.5 mg and amiloride 2.5 mg or placebo once a day. The main outcomes were the percentage of participants who achieved an optimal level of BP. RESULTS: A total of 372 participants were randomly allocated to diuretics and 358 to placebo. After 18 months of treatment, optimal BP was noted in 25.6% of the diuretic group and 19.3% in the placebo group (P < 0.05). The mean net reduction in SBP and DBP for the diuretic group compared with placebo was 2.8 mmHg (95% CI 1.1 to 4.5) and 1.1 mmHg (95% CI -0.09 to 2.4), respectively. Most participants in the active treatment group (74.5%) and in the placebo group (80.7%) continued to have BP in the prehypertension range or progressed to hypertension. CONCLUSION: Low-dose diuretic therapy increased the probability of individuals with prehypertension to achieve optimal BP but most of those treated continued to have a BP in the prehypertension range or progressed to having overt hypertension.