HQ Team
December 24, 2022: A large, real-world clinical trial has found that two thiazide diuretics medicines prescribed for hypertension– chlorthalidone (CTD) and hydrochlorothiazide (HCTZ) are equally effective in preventing cardiovascular disease and non-cancer death.
Dr. Areef Ishani, principal investigator and director of the Minneapolis VA Health Care System’s Primary Care and Specialty Care Integrated Care Community, explains: “In 2020, Medicare reported that approximately 1.5 million people were prescribed CTD compared to 11.5 million prescribed HCTZ, despite guideline recommendations. This discrepancy between clinical guidelines and real-world usage is possibly related to the belief that CTD has a greater risk of adverse effects without clear evidence for differences in cardiovascular outcomes.”
Hypertension or high blood pressure affects nearly 1.13 billion people worldwide, according to the World health Organization, with around two-thirds of those in low- to middle-income countries.
Lifestyle changes can reduce hypertension in some cases. Doctors can prescribe various medications that lower blood pressure if lifestyle changes are ineffective. These include diuretics, beta-blockers, and ACE inhibitors.
This large-scale clinical trial was carried out in the Department of Veterans Affairs (VA) health system. It was a pragmatic trial — one that evaluates the effectiveness of interventions in real-life routine practice conditions — rather than a randomized control trial (RCT).
Pragmatic trials are carried out on patients under a particular treatment as part of their routine care. This real-world trial investigated whether CTD was more effective than HCTZ at preventing cardiovascular events in patients with hypertension.
A total of 13,523 people participated in the trial. All participants, of whom almost 97% were men, were aged 65 or above and were being treated with HCTZ.
Doctors, after consent, then randomly changed their medication to either HCTZ or CTD.
Following randomization, 6,767 participants remained on HCTZ, and 6,756 people changed to CTD. For those switching, their 25 mg dose of HCTZ was replaced with 12.5 mg CTD, and the 50mg HCTZ was replaced with 25 mg CTD.
The trial’s primary outcome was the first occurrence of a nonfatal cardiovascular disease event or non–cancer-related death. Participants were followed up until they withdrew from the trial, died, or until the end of the trial.
After a median follow-up of 2.4 years, 1,377 people experienced a primary outcome event. Of these, 702 were in the CTD group and 675 in the HCTZ group.
The two medications were equally effective at preventing cardiovascular disease or non-cancer death, which included heart attack, stroke, heart failure, or lack of blood flow requiring medical intervention.
