Older patients put on beta-blockers after an acute myocardial infarction (MI) who remain free of recurrent ischemia for several years might well be able to stop taking the drugs safely, suggests an observational study.
Initiation of beta-blockers is supposed to be routine on discharge after an MI, but it's achieved inconsistently. In a new registry analysis, patients who remained without recurrent ischemia while still on beta-blockers 3 years after their MI seemed to gain no subsequent protection from the drugs.
Their risk of a composite endpoint of all-cause mortality or hospitalization for recurrent MI, ischemic stroke, or heart failure (HF) from years 3 to 8 was about the same whether they were off beta-blockers at 3 years, had taken them at less than half of full dose, or had maintained at least 50% of full dose.
The effect was observed even among patients who had HF or systolic dysfunction when they presented with their MI, in the analysis of about 6900 patients aged 65 or older discharged on beta-blockers in the CRUSADE registry.
The study was published online July 9 in Circulation: Cardiovascular Quality and Outcomes.
"The one take-home [message] is that if an older patient has survived to the 3-year post-MI anniversary, we should probably be thinking about whether or not we need to continue beta-blockers as part of the patient's pharmacotherapy long-term," lead author Jay S. Shavadia, MD, of Duke Clinical Research Institute, Durham, North Carolina, told theheart.org | Medscape Cardiology.
"In the majority of patients who are getting older, there are side effects of therapy, so if you're thinking of deprescribing, maybe beta-blockers should be one of the drugs you consider deprescribing early because there is no association with better long-term outcomes," he said.
To Beta or Not to Beta
Although it is an observational study from a "relatively ancient registry, it is nevertheless very provocative," Franz H. Messerli, MD, Icahn School of Medicine at Mount Sinai, New York City, and University of Bern, Switzerland, told theheart.org | Medscape Cardiology.
"It by and large confirms what we have been saying — and without exaggeration — in research that we published in the 1990s, that beta-blockers should not be used for hypertension in the elderly because there are no benefits,” said Messerli, who isn't connected with the CRUSADE analysis.
"The use of beta-blockers has been ingrained…They are supposedly cardioprotective post-MI, and — based on older guidelines — this meant that you needed to use a beta blocker for the rest of your life," he said.
"There is no longer any reason for that — maybe immediately after the MI, but not after the patient is hemodynamically stable. And putting a patient on a beta-blocker for the rest of his or her days condemns them to side effects that are really hard to bear."
Previous research supports the use of beta-blocker therapy for secondary prevention following MI, but the trials did not follow patients beyond 3 years, the authors note.
"How beta-blockers should be managed beyond 3 years post-MI, particularly in the elderly, is unknown," they write.
“What we've seen in contemporary MI care is a lot of other drug classes that are showing incremental benefit in cardiovascular outcomes in post-MI patients, so we weren't sure how much beta-blockers provide additional benefit," Shavadia said.
More Than Half Were Women
The group cross-linked data from the CRUSADE cohort to Centers for Medicare & Medicaid Services data to ascertain degree of beta-blocker treatment at the 3-year mark after their MI and to follow clinical outcomes over the next 5 years.
Of 6893 patients included in the analysis (mean age, 75 years; 53.7% women), 72.2% were still on a beta-blocker at 3 years. They were more likely to be in that group if they were female, had diabetes or a history of coronary bypass surgery, and had seen a cardiologist in the first 3 years after their MI.
The long-term rate of the cardiovascular composite endpoint was 52.4% for patients still on a beta-blocker compared with 55.4% for patients not taking a beta blocker at 3 years, P = .016.
However, after multivariable adjustment, the unadjusted association was no longer statistically significant, at a hazard ratio (HR) of 0.95 (95% confidence interval [CI], 0.88 - 1.03; P = .23). In adjusted analysis, were there no significant differences between those two groups in any component of the composite endpoint.
There were no significant interactions by specific beta-blocker used, among those that had been effective for HF in previous clinical trials, which included carvedilol, metoprolol, bisoprolol, and nebivolol.
Dosage also did not seem to affect the outcome. The long-term incidence of the composite endpoint was similar in patients who at 3 years were not on a beta-blocker (55.4%), on a beta blocker at less than 50% of the target dose (50.8%), or on one of the agents at 50% of the target dose or greater (54.2%).
Shavadia cautioned that the analysis was "observational, performed in a select group of patients, and did not look at causal associations." Further evidence from randomized trials is therefore necessary to define the role of beta-blocker therapy beyond 3 years after an MI, the study states.
The authors have disclosed no relevant financial relationships. Messerli discloses relationships with WebMD, the American College of Cardiology, The Lancet, Pfizer, Menarini, Sandoz, Boehringer Ingelheim, Medtronic, Novartis, and Dr. Reddy's Laboratories .
Circulation: Cardiovascular Quality and Outcomes. Published online July 9, 2019. Abstract
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Cite this: When Might Post-MI Beta-Blockers Be Safely Deprescribed? - Medscape - Jul 17, 2019.
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