Cardiovascular, mortality outcomes in hypertension similar between two thiazide diuretics

The use of chlorthalidone in the treatment of patients with hypertension does not appear to provide better protection against major cardiovascular outcome events or noncancer-related deaths when compared with hydrochlorothiazide, according to a study.

A total of 13,523 hypertensive patients (mean age 72 years) who had been receiving hydrochlorothiazide 25 or 50 mg daily were included in the study. They were randomized to continue treatment with hydrochlorothiazide or to switch to chlorthalidone at a daily dose of 12.5 or 25 mg.

The primary endpoint was a composite of nonfatal myocardial infarction, stroke, heart failure resulting in hospitalization, urgent coronary revascularization for unstable angina, and noncancer-related death. Safety was also evaluated.

At baseline, 12,781 patients (94.5 percent) had been taking hydrochlorothiazide at 25 mg per day. The mean baseline systolic blood pressure overall was 139 mm Hg. 

At a median follow-up of 2.4 years, the incidence of the composite primary endpoint events did not significantly differ between the chlorthalidone group and the hydrochlorothiazide group (10.4 percent vs 10.0 percent; hazard ratio, 1.04, 95 percent confidence interval, 0.94–1.16; p=0.45).

Likewise, the incidence of any components of the primary endpoint, when assessed individually, was similar in the two treatment groups.

In terms of safety, significantly more patients in the chlorthalidone group than in the hydrochlorothiazide group developed hypokalaemia (6.0 percent vs 4.4 percent; p<0.001).