Karen Margolis, MD, MPH
HealthPartners Institute, Minneapolis, MN
Stephen Fortmann, MD
Kaiser Permanente Center for Health Research, Portland, OR
Pilot Study for a Pragmatic Trial Comparing Chlorthalidone and Hydrochlorothiazide: Results and Lessons Learned
Comparative effectiveness; Hypertension; Thiazides; Pragmatic clinical trial; HCTZ; Chlorthalidone; Electronic health record
- The THIAZIDES pilot study was designed to evaluate feasibility of conducting a low-cost, pragmatic, multicenter trial that directly compares the effects of chlorthalidone (CTD) and hydrochlorothiazide (HCTZ) on cardiovascular events such as heart attack, stroke, heart failure, and mortality.
- The study used existing clinical and electronic health record (EHR) systems, with no study visits, to identify and recruit eligible study patients, distribute study medication, and collect operational, safety, and outcomes data.
Many study aspects worked well, including cluster randomization at the physician level, the willingness of physicians to take part in this kind of research, the high proportion of eligible patients receiving the intervention, and the completeness of EHR data and safety labs.
Challenges of this pilot study included difficulties with electronic discontinuation of medications, usability of real-time pharmacy data, issues with the chosen opt-out method, and higher out-of-pocket costs of the CTD medication.
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