Ischaemic heart disease

Non-adherence to beta blockers doesn’t affect mortality

Yet another study has called into question the long held practice of prescribing beta blockers in combination with statins and ACE inhibitors or ARBs following MI.

Researchers from Monash University’s Centre for Medicine Use and Safety and the University of North Carolina analysed the pharmacy dispensing records of 90,000 US patients who had heart attacks to check their drug adherence and survival rates at 12 months.

Just six months after surviving a heart attack more than half of patients were non-adherent to medications prescribed to prevent a secondary event.

Survivors who did not take any of their medications as prescribed had a mortality rate of 14% compared to a mortality rate of 9.3% in patients who adhered to all three medicines.

The study also found that patients who stopped taking their beta blocker while continuing to take the other two medications had a 9.1% mortality rate at 12 months.

Speaking to the limbic, Dr Simon Bell from Monash University said the findings challenged the conventional wisdom of prescribing beta blockers to all patients post MI.

“In this particular study there were no additional survival benefits to taking beta blockers if patients continued to take their ACE inhibitor [or ARB] and the statin. Although, interestingly if you weren’t adherent to the ACE inhibitor or the stain in any combination then you also had higher risk of mortality.”

Earlier this year a large UK observational study reported findings suggesting beta blockers offered no mortality benefit in patients who had suffered an MI but without heart failure.

Dr Bell said the findings from both studies supported a growing trend away from routine of use beta blockers in all MI patients.

“The Australian guidelines changed last year and they suggest that the role of beta blockers is a little bit more limited than in the past so there probably is a trend away from long term management with beta blockers for all patients. These results would seem to suggest that that’s a legitimate move.”

However he was cautious about saying doctors should ditch the triple therapy regimen just yet.

“One of the key things we’re saying here is despite our findings people shouldn’t stop taking their beta blocker – these kinds of observational studies are important pieces of evidence but in themselves suggest the need for a randomised trial to see whether people really do just as well without the beta blocker.”

He expressed concern with patients’ high rate of non-adherence to drug therapy so soon after their MI.

“To me that highlights that doctors and pharmacists have an important role in encouraging people to adhere to their medications because people who are not adherent to all their medications or the ACE inhibitor or statin combination had poorer survival compared to those who were adherent.

The fact that there were roughly 50% of people who didn’t adhere to their medications at six months is really a reminder that we do need to be discussing adherence with our patients regularly and early.”

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