Half of all patients discharged from hospital after a heart attack are treated with beta-blockers unnecessarily. This is according to a new study published in the New England Journal of Medicine.

"I am convinced that this will influence future practice," says Tomas Jernberg, Professor at Karolinska Institutet and lead researcher of the study. "This study has already been mentioned in the European guidelines for cardiac care, so the results are in demand."

Today, when patients are discharged from hospitals after an acute heart attack, they are regularly treated with beta-blocker drugs such as metoprolol and bisoprolol.

Now new research shows that about half of them do not benefit from the treatment and should not receive it at all. These are the patients who have suffered a small heart attack and have retained heart function afterward.

The study began in September 2017 and patients were followed up until November 2023. More than 5,000 patients at 45 hospitals in Sweden, Estonia and New Zealand who suffered a small heart attack were randomized to either receive or not receive beta-blockers at discharge. By the end of the follow-up period, 7.9% of those receiving beta-blockers had the primary outcome of death or a new heart attack, compared to 8.3% of those not receiving beta-blockers. The project was led by researchers at Karolinska Institutet, Lund University and Uppsala University.

This difference is not statistically significant. Nor was there any difference between the groups in the secondary outcomes.

The result means that, unusually, the drug treatment becomes simpler and cheaper for all parties, says Jernberg.

"Typically, new research results in the addition of a medication to a patient's regimen. However, this study shows that patients will benefit from taking one fewer drug."

But he immediately warns patients not to stop their treatment on their own accord. The current study is only about the effect of starting treatment after a small heart attack, not after a larger one.

Nor does it show anything about the effects of stopping treatment. More importantly, stopping medication should always be done in consultation with the treating physician.

"This is for several reasons. There may be other causes, other diagnoses, behind the use of beta-blockers. Then there is the fact that if you are going to stop, you should stop beta-blockers gradually. If you do it too quickly, you can get some heart palpitations and other discomfort. So, it is very important that you talk to your doctor before stopping any heart medication," says Jernberg.