Beta blockers have long been widely prescribed for patients with heart issues, but two recent studies question the benefit of the therapies in certain patients with strong heart function, one finding that long-term use of the drug did not lead to improved cardiovascular outcomes, the second one linking beta blockers to more risk of hospitalisation.
STAT reports that the first one, published in the journal Heart, looked at people who’d had a heart attack but didn’t develop heart failure or dysfunction in their heart’s pumping. Researchers found that long-term beta blocker use wasn’t associated with improved cardiovascular outcomes in this group.
The other study, published in JACC: Heart Failure, focused on people with heart failure who had mildly reduced and normal ejection fraction – a measure of a heart’s squeezing function. The authors found that beta blockers were linked to a greater risk of hospital admission in patients with higher squeezing power.
Beta blockers lead the heart to beat more slowly and are meant to lower stress on the heart.
Doctors have been prescribing the medications based on data from decades ago before recent advancements in cardiovascular care, and patients also often have comorbidities that lead doctors to prescribe beta blockers.
While the two studies are both observational, and the authors stressed the need for more research that follows patients over time, the findings still suggest that the longstanding practice of prescribing beta blockers merits reassessment.
Lakshmi Sridharan, an advanced heart failure and transplant cardiologist at Emory University who wasn’t involved in the studies, said the data are “all pointing to a similar direction that not all patients whom we used to historically, reflexively put on beta blockers, benefit from them”.
The study in Heart analysed health records from more than 43 000 adults in Sweden who experienced a heart attack but didn’t have heart failure or pumping dysfunction.
While there’s research supporting the use of beta blockers shortly after a heart attack in these types of patients, there’s little data looking at longer-term use, so the researchers focused on beta blocker usage one year after a heart attack.
Of the patients studied, most of them – 79% – were on beta blockers a year after a heart attack. After adjusting and weighting for factors such as demographics and comorbidities, the researchers found no difference in the risk of death and cardiovascular incidents between people who were and weren’t on beta blockers during a median follow up of 4.5 years.
Gorav Batra, the senior author and consultant cardiologist at Uppsala University in Sweden, said the care and treatment of patients with heart attacks has vastly improved over the past three decades.
That means patients experience less injury to their heart muscle from heart attacks, and so they may not need beta blockers long term to help them.
Sridharan noted that since the study was conducted in Sweden, its findings may not be generalisable to the US population.
Still, she said, it’s important to examine the use of beta blockers since heart attack care has advanced and since the drugs can come with side effects that affect patients’ quality of life, such as fatigue and depression. “That’s when the question of the risk-benefit ratio really comes into play for these patients,” she said.
The other study in JACC: Heart Failure looked at more than 400 000 people in the US over 65 who had heart failure with mildly reduced or normal squeezing function, described as an ejection fraction greater than 40%.
While studies have consistently shown the benefit of beta blockers in heart failure patients with significantly reduced squeezing power, measured as an ejection fraction less than 40%, there’s limited data on use of the drugs in people with stronger squeezing function.
Yet again here, most patients studied – 66% – were on beta blockers. After adjusting for factors like comorbidities and health history, and in a median follow-up of 38 months, the researchers found that as the ejection fraction number increased, the risk of hospitalisation for heart failure linked to beta blocker use also increased.
Among patients with a mildly reduced ejection fraction, beta blockers were associated with a lower risk of hospitalisation and death.
But among patients with greater squeezing function, particularly those with an ejection fraction over 60%, beta blockers were linked to higher hospitalisation rates.
The researchers also found that this trend held whether or not patients had hypertension, an irregular heartbeat, or coronary artery disease, which are three comorbidities that currently lead doctors to prescribe beta blockers.
The study suggests “you really have to pay attention to what the ejection fraction is” when treating heart failure patients, said Suzanne Arnold, the lead author and a professor of medicine at the University of Missouri-Kansas City.
Study 1 details
Association of beta-blockers beyond 1 year after myocardial infarction and cardiovascular outcomes
Divan Ishak, Suleman Aktaa, Lars Lindhagen, Joakim Alfredsson, Tatendashe Dondo, Claes Held, Tomas Jernberg, Troels Yndigegn, Chris Gale, Gorav Batra.
Published in Heart on 2 May 2023
Abstract
Objective
Beta-blockers (BB) are an established treatment following myocardial infarction (MI). However, there is uncertainty as to whether BB beyond the first year of MI have a role in patients without heart failure or left ventricular systolic dysfunction (LVSD).
Methods
A nationwide cohort study was conducted including 43 618 patients with MI between 2005 and 2016 in the Swedish register for coronary heart disease. Follow-up started 1 year after hospitalisation (index date). Patients with heart failure or LVSD up until the index date were excluded. Patients were allocated into two groups according to BB treatment. Primary outcome was a composite of all-cause mortality, MI, unscheduled revascularisation and hospitalisation for heart failure. Outcomes were analysed using Cox and Fine–Grey regression models after inverse propensity score weighting.
Results
Overall, 34 253 (78.5%) patients received BB and 9365 (21.5%) did not at the index date 1 year following MI. The median age was 64 years and 25.5% were female. In the intention-to-treat analysis, the unadjusted rate of primary outcome was lower among patients who received versus not received BB (3.8 vs 4.9 events/100 person-years) (HR 0.76; 95% CI 0.73 to 1.04). Following inverse propensity score weighting and multivariable adjustment, the risk of the primary outcome was not different according to BB treatment (HR 0.99; 95% CI 0.93 to 1.04). Similar findings were observed when censoring for BB discontinuation or treatment switch during follow-up.
Conclusion
Evidence from this nationwide cohort study suggests that BB treatment beyond 1 year of MI for patients without heart failure or LVSD was not associated with improved cardiovascular outcomes.
Study 2 details
Beta-Blocker Use and Heart Failure Outcomes in Mildly Reduced and Preserved Ejection Fraction
Suzanne Arnold, Daniel Silverman, Kensey Gosch, Michael Nassif, Margaret Infeld, Sheldon Litwin, Markus Meyer, and Timothy Fendler.
Published in JACC on 3 May 2023
Abstract
Background
Although studies consistently show that beta-blockers reduce morbidity and mortality in patients with reduced ejection fraction (EF), data are inconsistent in patients with heart failure with mildly reduced ejection fraction (HFmrEF) and suggest potential negative effects in heart failure with preserved ejection fraction (HFpEF).
Objectives
To examine the association of beta-blockers with heart failure (HF) hospitalisation and death in patients with HF and EF ≥40%
Methods
Beta-blocker use was assessed at first encounter in outpatients ≥65 years of age with HFmrEF and HFpEF in the U.S. PINNACLE Registry (2013-2017). The associations of beta-blockers with HF hospitalisation, death, and the composite of HF hospitalisation/death were assessed using propensity-score adjusted multivariable Cox regression models, including interactions of EF × beta-blocker use.
Results
Among 435,897 patients with HF and EF ≥40% (75,674 HFmrEF; 360,223 HFpEF), 289,377 (66.4%) were using a beta-blocker at first encounter; more commonly in patients with HFmrEF vs HFpEF (77.7% vs 64.0%; P < 0.001). There were significant interactions between EF × beta-blocker use for HF hospitalisation, death, and composite of HF hospitalisation/death (P < 0.001 for all), with higher risk with beta-blocker use as EF increased. Beta-blockers were associated with decreased risk of HF hospitalisation and death in patients with HFmrEF but a lack of survival benefit and a higher risk of HF hospitalisation in patients with HFpEF, particularly when EF was >60%.
Conclusions
In a large, real-world, propensity score-adjusted cohort of older outpatients with HF and EF ≥40%, beta-blocker use was associated with a higher risk of HF hospitalisation as EF increased, with potential benefit in patients with HFmrEF and potential risk in patients with higher EF (particularly >60%). Further studies are needed to understand the appropriateness of beta-blocker use in patients with HFpEF in the absence of compelling indications.
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