No difference in cardiac outcomes was found when the two diuretics were used to treat blood pressure
Highlighted research results:
In a study comparing the effectiveness of two high blood pressure medications (both diuretics) among older veterans, there was no difference in cardiovascular outcomes or non-cancer deaths.
There was also no difference in heart attack, stroke, heart failure or other cardiovascular outcomes.
In a small subgroup (10%) of people with a history of heart attack or stroke, there was a 27% reduction in death from heart attack, stroke and heart failure when treated with chlorthalidone. However, people with high blood pressure who did not suffer a heart attack or stroke had a 12% higher risk of developing cardiovascular disease when taking chlorthalidone. It’s unclear how to interpret this subgroup result in the context of the overall trial, which showed no difference between the two drugs, the researchers said.
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(NewMediaWire) – November 5, 2022 – CHICAGO Two common diuretics used to control blood pressure had no difference in cardiovascular outcomes, including death, according to the latest scientific research presented today at the American Heart Association’s 2022 Scientific Sessions Meeting held in person in Chicago and virtual, from November 5 to 7, 2022, is the premier global exchange of the latest scientific advances, research and evidence-based clinical practice updates in cardiovascular science.
Among more than 13,500 study participants, those treated with the blood pressure-lowering drug chlorthalidone appeared to have no difference in cardiovascular outcomes or non-cancer-related deaths compared with people treated with hydrochlorothiazide. However, among the small group who had a history of heart attack or stroke, those taking chlorthalidone reduced their risk of heart disease and death by an average of 27%.
The results are from a study investigating whether chlorthalidone was better than hydrochlorothiazide in preventing cardiovascular events among people with high blood pressure. According to Updated 2022 American Heart Association heart disease and stroke statistics, nearly half of American adults have high blood pressure, which is the leading cause of heart disease. Chlorthalidone and hydrochlorothiazide are diuretics that have been prescribed for more than 50 years and are considered the first line of treatment for high blood pressure. Based on earlier studies and other research suggesting that chlorthalidone better controlled blood pressure over 24 hours compared to hydrochlorothiazide, many experts believed that chlorthalidone would be more useful for reducing the risk of developing heart disease.
The researchers designed the Diuretic Comparison Project (DCP) as a point-of-care clinical trial that allowed participants and healthcare professionals to know which drugs were prescribed and to administer the drugs in a real-world setting. The care aspect offered several unique features to the trial, explained Areef Ishani, MD, the study’s corresponding author, director of the Integrated Care Community for Primary and Specialty Care in Minneapolis and director of the VA Midwest Health Care Network in Minneapolis.
“Patients can continue their normal care with their usual care team because we have integrated this trial into primary care clinics,” Ishani said. “We monitored the participants’ results using their electronic health record. This study was unobtrusive, cost-effective and inexpensive. In addition, we were able to recruit a large rural population, almost half of the participants, which is atypical for a study like ours where we usually have to rely to large academic medical centers.”
Researchers recruited more than 13,500 US veterans who were at least 65 years old and received care from 4,120 primary care professionals at 500 clinics. Participants were predominantly male (97%), white veterans (77%), non-Hispanic veterans (93%), and 55% lived in urban areas. At the start of the study, the average systolic blood pressure (the highest number in the blood pressure reading) was 139 mm Hg. Participants were randomized to one of two groups: 1) hydrochlorothiazide at a dose of 25 or 50 mg/day, or 2) an equivalent dose of 12.5 or 25 mg/day of chlorthalidone. The study looked at rates of heart attack, stroke, heart failure or death from liver cancer after a median of about 2.5 years.
The analysis of all research participants determined:
Heart disease and death rates for the chlorthalidone group (9.4%) and the hydrochlorothiazide group (9.3%) were almost identical;
There was also no difference in secondary outcomes (heart attack, stroke, heart failure or other cardiovascular outcomes) between participants taking the two different drugs.
However, differences were found in subgroup analysis:
Among participants who had a history of heart attack or stroke, those taking chlorthalidone reduced their risk of heart disease and death by an average of 27%;
Chlorthalidone tended to worsen these outcomes by an average of 12% in participants who did not have a history of heart attack or stroke.
“We were surprised by these results,” Ishani said. “We expected chlorthalidone to be more effective overall, however, knowing these differences in patients with a history of cardiovascular disease may impact patient care. It is best for people to talk to their clinicians about which of these drugs is better for their individual needs .
“More research is needed to investigate these results further because we don’t know how they might fit into treatment in the general population.”
The authors also note that there was a small statistical difference between participants who had low potassium levels, a risk factor for irregular heart rhythms, in the chlorthalidone group (6%) versus the hydrochlorothiazide group (4.4%). There was also a tendency for more people with low potassium to be hospitalized in the chlorthalidone group (1.5%) compared to the hydrochlorothiazide group (1.1%). More research is needed to determine whether these results are real differences or caused by the way participants were recruited. In addition, it is not clear how this applies to women or other populations.
Co-authors are Dr. med. William C. Cushman; Sarah M. Leatherman, Ph.D.; Robert A. Lew, Ph.D.; Patricia Woods, MSN, RN; Peter A. Glassman, MBBS, MA; Addison A. Taylor, MD; Cynthia Hau, MPH; Alison Klint, MS; Grant D. Huang, MPH, Ph.D., Mary T. Brophy, MD, MPH, Louis D. Fiore, MD, and Ryan E. Ferguson, Sc.D., MPH The authors’ findings are listed in the abstract.
The study was funded by the VA Cooperative Studies Program.
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