Compared with hydrochlorothiazide (HCTZ), chlorthalidone did not reduce the incidence of major cardiovascular outcomes or non-cancer deaths in elderly veterans with hypertension, based on findings from the DCP trial presented Nov. 5 during AHA 2022 in Chicago. However, researchers did note some differences in subgroup analyses in patients treated with chlorthalidone.

The point-of-care clinical trial randomized more than 13,500 U.S. veterans to either HCTZ (25 or 50 mg/day) or chlorthalidone (12.5 or 25 mg/day). All participants were at least 65 years of age and the majority were men, white and non-Hispanic. A little more than half lived in urban areas. The average systolic blood pressure at the start of the study was 139 mm Hg.

After a median of about 2.5 years, results found heart disease and death rates for patients in the chlorthalidone group and the HCTZ group were nearly identical (9.4% and 9.3%, respectively). There were also no differences in secondary outcomes, including myocardial infarction (MI), stroke, heart failure and other cardiovascular outcomes, between the two groups.

According to researchers, however, further subgroup analysis did indicate some differences between the two groups. Among the roughly 10% of participants who had a prior stroke or MI, an average reduction of 27% in MI, stroke and heart failure deaths was observed. Yet patients without a prior stroke or MI had a roughly 12% increased risk of developing cardiovascular disease when taking chlorthalidone. Additionally, chlorthalidone was associated with an increase in hypokalemia.

"We were surprised by these results," said Areef Ishani, MD, who presented the results. "We expected chlorthalidone to be more effective overall, however, learning about these differences in patients who have a history of cardiovascular disease may affect patient care. It's best for people to talk with their health care clinicians about which of these medications is better for their individual needs."

Ishani and colleagues also added that more research is needed to further explore the results to determine how they may fit into treating the general population, including women.

Clinical Topics: Prevention, Statins, Hypertension

Keywords: AHA Annual Scientific Sessions, AHA22, Chlorthalidone, Hydrochlorothiazide, Hypertension, Cardiovascular Diseases, Antihypertensive Agents

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