The comparative effectiveness of hydrochlorothiazide and chlorthalidone in an observational cohort of veterans

Abstract

Indirect evidence suggests that chlorthalidone may be more effective than hydrochlorothiazide (HCTZ), but direct comparisons are lacking. Using national Veterans Administrative pharmacy data from 2003 to 2008, the authors performed a retrospective cohort study examining the effectiveness of chlorthalidone and HCTZ among new thiazide users. For 1 year following the thiazide start, rates of persistence of thiazide use, adequacy of response (defined as the absence of additional new antihypertensive medications following thiazide initiation), and an overall composite of treatment effectiveness incorporating both outcomes were examined. In this cohort of >125,000individuals, persistence of thiazide use was higher for HCTZ than chlorthalidone (72.0% vs 62.0%; P