Long-term data showed negligible differences in mortality among hypertensive adults treated with thiazide-type diuretics, calcium channel blockers, or angiotensin-converting enzyme inhibitors in a review of nearly 33,000 individuals published in JAMA Network Open.
The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) study was designed to compare initial antihypertensive treatments with a calcium channel blocker (CCB; amlodipine), an angiotensin-converting enzyme (ACE) inhibitor (lisinopril) or an alpha-blocker (doxazosin), and a thiazide-type diuretic (chlorthalidone).
The composite primary outcome was fatal coronary heart disease (CHD) or nonfatal myocardial infarction (MI), but long-term data were lacking, wrote Jose-Miguel Yamal, PhD, of University of Texas Health Science Center at Houston, and colleagues. A previous study with 8-13 years of follow-up showed no significant differences in mortality between the treatment groups, the researchers noted.
In the current study, a prespecified secondary analysis of ALLHAT, the researchers added 11 more years of data for a total of 19-24 years of follow-up after randomization.
In the original ALLHAT, 32,804 adults aged 55 years and older with a diagnosis of hypertension and at least one additional coronary heart disease risk factor were followed for 4-8 years for all-cause mortality. A subgroup of 22,754 were followed for fatal or nonfatal cardiovascular disease (CVD) for a mean of 13.7 years, with a maximum of 23.9 years.
The study occurred from Feb. 23, 1994, to Dec. 31, 2017. The participants were randomized to receive a thiazide-type diuretic (15,002 patients), a CCB (8,898 patients), or an ACE inhibitor (8,904 patients).
The primary outcome was CVD mortality; secondary outcomes included all-cause mortality, combined fatal and nonfatal CVD (CVD morbidity), and both morbidity and mortality for coronary heart disease, stroke, heart failure, end-stage renal disease, and cancer.
At 23 years, CVD mortality rates per 100 persons were 23.7, 21.6, and 23.8 in the diuretic, CCB, and ACE inhibitor groups, respectively. The adjusted hazard ratios were 0.97 for CCB vs. diuretics and 1.06 for ACE inhibitors vs. diuretics.
Although the risk of stroke mortality and of combined fatal and nonfatal hospitalized stroke was higher in the ACE inhibitor group compared with the diuretic group (adjusted hazard ratios 1.19 and 1.11, respectively), this increase was no longer significant after adjustment for multiple comparisons. "In contrast to the in-trial and 8-year to 13-year analyses, we now observed that the lisinopril group had an increased risk of kidney disease mortality that emerged after approximately 13 years after randomization, but this effect was attenuated after adjustment for baseline variables," the researchers wrote in their discussion.
The findings were limited by several factors including the potential effect of unblinding if participants stopped the randomized drug, and by the lack of morbidity and mortality data on Canadian participants, Veterans Affairs participants, and those with no Medicare number, the researchers noted. Other limitations included the lack of data on posttrial medication use, blood pressure, and laboratory findings, they said.
However, the results over the follow-up period of up to 23 years supported those of the larger ALLHAT study, with similar outcomes among the drugs, and with 11 years of passive follow-up, "the results for lisinopril vs. chlorthalidone for stroke and stroke mortality are almost the same," they concluded.
Findings support current practice, but new drug data are needed
The current study was important to determine whether there was a significant difference in long-term morbidity and mortality between patients treated with thiazide diuretics, calcium channel blockers and ACE inhibitors, Noel Deep, MD, said in an interview.
"Previously reported data had indicated no significant differences between patients randomized to one of these three classes of antihypertensive medications during the trial period or at 8-13 years post-trial," said Dr. Deep, a general internist in private practice in Antigo, Wisc., who was not involved in the study. Dr. Deep is chief medical officer and a staff physician at Aspirus Langlade Hospital in Antigo.
"This study reinforces the previously noted benefits of the three classes of antihypertensive medications, as well as the higher rates of cardiovascular disease and stroke in the ACE inhibitor arm," he said.
In clinical practice, the results suggest that thiazide diuretics should be considered first-line agents for management of hypertension based on their noninferiority compared with ACE inhibitors and CCBs, and lower risk of stroke compared with ACE inhibitors, Dr. Deep said in an interview. "All three classes of antihypertensive medications are equally efficacious in blood pressure control and preventing all-cause mortality," he said.
More research is needed in the wake of the introduction of other classes of antihypertensives since the original ALLHAT trial, Dr. Deep said. "It would be beneficial to assess the relative benefit/risks of those medications compared to the thiazide diuretics, and I would also look at studies comparing beta blockers to the thiazide diuretics," he said. The question remains as to whether outcomes were affected by patients' use of other classes of antihypertensives after the trial period, he said.
The study was supported by the National Institute on Aging of the National Institutes of Health. The researchers had no financial conflicts to disclose. Dr. Deep had no financial conflicts to disclose and serves on the editorial advisory board of Internal Medicine News.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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