Chlorthalidone vs Hydrochlorothiazide for Hypertension-CV Events: Did the Design Influence the Outcome?

The Diuretic Comparison Project (DCP)1 was a real world study planned to evaluate in a pragmatic manner whether Chlorthalidone (CTD), as compared with Hydrochlorothiazide (HCTZ), would reduce the risk of major nonfatal cardiovascular disease outcomes in elderly hypertensive participants (≥65 years) who were receiving HCTZ (25 or 50 mg) at baseline. This study being a real world study lacks the robustness of a randomized controlled trial. The principle limitation being unequal exposure of the two diuretics, prolonged unknown duration of exposure to HCTZ vs a short exposure to CTD (Median 2.4 years). In the high risk population with history of MI/Stroke, CTD conferred a lower risk of primary outcome as compared to low risk population where no significant difference in outcome was seen in both diuretics. Other factors included, lack of established dose equivalency of the two diuretics and absence of use of 12.5 mg HCTZ in older hypertensives. How to cite this article: Pareek A, Messerli FH, Ram CVS. Chlorthalidone vs Hydrochlorothiazide for Hypertension-CV Events: Did the Design Influence the Outcome? J Assoc Physicians India 2023;71(10):93-93.