Heart-attack survivors are prescribed ACE inhibitors and statins to help prevent a second attack and death, and beta blockers are also used in certain cases. However, beta blockers offer no additional benefit for patients who take the other two medicines as prescribed, according to a new study. The international research group comprised researchers from the US, Finland and Australia.

Globally, there are differences in clinical guidelines relating to long-term use of beta blockers after a heart attack. For example, US guidelines still recommed prescribing beta blockers to nearly all heart attack survivors for long-term use. In Finnish and other European treatment guidelines, on the other hand, the use of beta blockers is restricted to patients with heart failure. However, the efficacy of beta blockers in today's patients is not fully understood, as the majority of clinical trials on beta blockers have been carried out before the use of ACE inhibitors and statins became common.

Published in the Journal of the American College of Cardiology, the study looked at more than 90,000 Medicare patients age 65 or older who had suffered a heart attack and were prescribed a beta blocker, an ACE inhibitor or an angiotensin receptor blocker, and statin as preventive therapies after they were discharged from the hospital. Researchers compared patients who adhered to taking all the three medicines and patients who only adhered to taking some of them.

“There was no increase in mortality in patients who did not take their beta blockers as prescribed when compared to patients who took all three medicines as prescribed,” says Docent Maarit Jaana Korhonen, the lead author of the study. At the time of the study, she was a Visiting Scholar at the University of North Carolina, and currently she works at the University of Turku.

Professor Juha Hartikainen from the University of Eastern Finland, a member of the research group, points out that patients should not stop taking their beta blockers or any other medicines prescribed to them without consulting a physician.

“We found an increased risk of mortality in patients who did not adhere to taking their ACE inhibitors or statins. Physicians and pharmacy professionals should emphasise the fact that it is vital for heart attack survivors to take their statins and ACE inhibitors as prescribed.”

Researchers followed how patients filled prescriptions during six months after tthe hospital discharge, and they also used register data to follow patient mortality up to 1.5 years later.

It is estimated that only approximately half of patients took all the three medicines as prescribed. Adherence to treatment was analysed on the basis of prescriptions filled at pharmacies. Patients were considered to adhere to their prescription drug regimen when they filled prescriptions to cover 80% of the monitoring period. “Our estimate of adherence is probably too optimistic, because we can’t know how much of the medicines patients eventually took,” the researchers say.

“For patients with multiple medical conditions and multiple medicines, the complexity of medication can pose a great challenge.”

The research group was led by Assistant Professor Gang Fang from the University of North Carolina. The group also involved researchers from the University of Iowa and Monash University.