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.