A French study has provided evidence that extended use of beta-blockers does not provide any survival benefit for patients after acute myocardial infarction.
The findings validate what most Australian clinicians are already doing – discontinuing the drugs after about 12 months for MI patients without heart failure or LV dysfunction.
Associate Professor John Amerena, director of the Geelong Cardiology Research Unit, said a recent Australian poll had found about 80% of cardiologists agreed with the practice of ceasing beta-blockers at around 12 months.
“Beta-blockers have adverse metabolic effects and it is not the convention that we need extended therapy,” he said.
The French cohort study of 2,679 patients confirmed that early treatment with beta-blockers for patients admitted with MI was associated with a significant reduction in 30-day mortality (8.6 v 2.3%).
However the clinical utility of beta-blockers waned over time with beta-blocker use at discharge associated with a non-significant reduction in one-year mortality (7.8 v 3.4%). Beta-blocker use at one year was not associated with any survival benefit at five years (9.2 v 7.6%).
The study did however confirm the importance of long-term statin use with a 5-year mortality of 5.8% in treated patients compared to 16.9% in patients who had ceased statins.
Professor Amerena said the findings were welcome confirmatory evidence because all guidelines still recommended an extended period of beta-blocker use.
“The early evidence for those guidelines was based on clinical trials of beta-blockers before reperfusion therapy. It was beta-blockers versus nothing back then. We didn’t have stents, statins or bypass,” he said.
“So the evidence for beta-blockers is not particularly strong and may be downgraded even further in the future.”
He said similar cohort studies might emerge from other European countries with robust data sets such as Sweden, Denmark or Norway.
“If they can produce results that are concordant, that would certainly lend weight to the argument however this will be the level of data we can expect. Randomised controlled trials of continuing versus stopping beta-blockers at 12 months are unlikely.”