Background-—Prehypertension is associated with higher cardiovascular risk, target organ damage, and incidence of hypertension. The Prevention of Hypertension in Patients with PreHypertension (PREVER-Prevention) trial aimed to evaluate the efficacy and safety of a low-dose diuretic for the prevention of hypertension and end-organ damage. Methods and Results-—This randomized, parallel, double-blind, placebo-controlled trialwas conducted in 21 Brazilian academicmedical centers. Participants with prehypertensionwho were aged 30 to70 years andwho did not reach optimal blood pressure after 3 months of lifestyle intervention were randomized to a chlorthalidone/amiloride combination pill or placebo and were evaluated every 3 months during 18 months of treatment. The primary outcome was incidence of hypertension. Development or worsening of microalbuminuria, new-onset diabetes mellitus, and reduction of left ventricular mass were secondary outcomes. Participant characteristics were evenly distributed by trial arms The incidence of hypertension was significantly lower in 372 study participants allocated to diuretics compared with358 allocated to placebo (hazard ratio 0.56, 95%CI 0.38–0.82), resulting in a cumulative incidence of11.7% in the diuretic arm versus 19.5% in the placebo arm(P=0.004). Adverse events; levels of blood glucose, glycosylated hemoglobin, creatinine, and microalbuminuria; and incidence of diabetes mellitus were no different between the 2 arms. Left ventricular mass assessed through Sokolow-Lyon voltage and voltage-duration product decreased to a greater extent in participants allocated to diuretic therapy compared with placebo (P=0.02). Conclusions-—A combination of low-dose chlorthalidone and amiloride effectively reduces the risk of incident hypertension and beneficially affects left ventricular mass in patients with prehypertension
