Chlorthalidone versus hydrochlorothiazide in hypertension treatment: Do we have the evidence to decide?

摘要

Pharaiacologic treatment of hypertension, including the use of thiazide-type diuretics, has had a major impact on reducing the risk of stroke, heart failure, myocardial infarction, and death in the population. Although it generally is agreed that as a class, thiazide-type diuretics are effective in reducing blood pressure (BP) and preventing cardiovascular disease (CVD) in hypertensive persons, it is not clear whether all drugs in this class are equally safe and effective. This disagreement is reflected in recent hypertension guidelines, some of which specify a preference for certain agents within the class, for example, chlortha-lidone or indapamide,1 whereas others regard all agents in the class as generally equivalent.2 In the absence of evidence from randomized controlled trials that directly compare different diuretics in the treatment of hypertensive populations, various forms of indirect evidence have been used to inform clinical practice. Several studies, including small trials and one meta-analysis, have demonstrated pharmacoki-netic/pharmacodynamic profiles and novel mechanisms of action that favor chlorthalidone over hydrochlorothiazide in reducing BP in hypertensive persons.3"6 Similarly, observational cohort studies and network meta-analyses have provided assessments of the comparative effectiveness of chlorthalidone and hydrochlorothiazide in everyday practice, as well as indirect comparisons of the effects of chlorthalidone and other low-dose thiazide-type diuretics, including hydrochlorothiazide, on CVD outcomes.7"10 In this context, a large observational study recently reported head-to-head comparative data on the effects of newly prescribed chlorthalidone versus hydrochlorothiazide on CVD and safety outcomes in elderly patients.