Beta blockers are not needed after a heart attack if the survivors are taking ACE inhibitors and statins. The study from the University of North Carolina at Chapel Hill finds is the first to challenge the current clinical guideline that heart-attack survivors should take all three drugs – beta blockers, ACE inhibitors and statins – for the rest of their lives.
Heart-attack survivors are usually prescribed all three drugs to help prevent a second attack and death. However, the beta blockers offer no additional benefit for patients who take the other two drugs as prescribed, according to the new study, which examined the trade-offs and consequences of using some of the medicines instead of others.
Researchers looked at more than 90,000 Medicare patients age 65 or older who had suffered a heart attack and were prescribed a beta blocker, ACE inhibitor or angiotensin receptor blocker and statin as preventive therapies after they were discharged from the hospital. Patients who only took the ACE inhibitor or an angiotensin receptor blocker and statin, as prescribed, were no more likely to die than those who took all three drugs.
The research team from UNC-Chapel Hill, Monash University, the University of Iowa and the University of Eastern Finland was led by Gang Fang, an assistant professor at the UNC Eshelman School of Pharmacy and senior author of the study.
Fang stressed that patients should not stop taking beta blockers or any other prescription medicine without first consulting their physician. “We are not saying that beta blockers have no value. It’s just that their benefits appear to have been eclipsed by the duo of ACE inhibitors and statins, which are relatively newer drugs,” Fang said.
Beta blockers were introduced more than 50 years ago and reduce blood pressure and heart rate. ACE inhibitors and angiotensin receptor blockers also reduce blood pressure and they have been around approximately 40 years. Statins reduce the amount of cholesterol and other fats in the bloodstream and have been in use for more than 30 years. For heart-attack patients, these drugs provide additional support to the heart.
For six months Fang’s team followed heart-attack survivors who filled prescriptions for all three drugs to study how well they adhered to their prescription drug regimen. Being adherent was defined as taking the medicines as prescribed at least 80% of the time. The team then followed the patients for up to 18 months to see how many died during that time. Six months after their heart attack about half the patients in the study had stopped taking at least one of their medications as prescribed, the researchers found.
For patients who took all three drugs as prescribed, the mortality rate at one year was 9.3%. For patients who adhered to ACE inhibitor or ARBs and statin prescriptions but not beta blockers, the mortality rate was 9.1%, a statistically insignificant difference. For patients not taking any of the medicines as prescribed, the mortality rate was 14.3%, a nearly 54% increase over adherent patients.
“The problem with this three-drug regimen is that it is difficult for people to take their medications as they are supposed to in the long term. This is especially true of older patients who are likely to already be taking many different drugs,” Fang said.
Fang also noted that patients in the study who had diabetes, dementia or both were more likely to die when taking beta blockers as prescribed. Further research is warranted, he said, and physicians should exercise more caution in prescribing beta blockers for elderly heart-attack survivors with diabetes or dementia.
Background: Angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARB), beta-blockers and statins are recommended after acute myocardial infarction (AMI). Patients may adhere to some, but not all, therapies.
Objectives: The authors investigated the effect of tradeoffs in adherence to ACE inhibitors/ARBs, beta-blockers, and statins on survival among older people after AMI.
Methods: The authors identified 90,869 Medicare beneficiaries ≥65 years of age who had prescriptions for ACE inhibitors/ARBs, beta-blockers, and statins, and survived ≥180 days after AMI hospitalization in 2008 to 2010. Adherence was measured by proportion of days covered (PDC) during 180 days following hospital discharge. Mortality follow-up extended up to 18 months after this period. The authors used Cox proportional hazards models to estimate hazard ratios of mortality for groups adherent to 2, 1, or none of the therapies versus group adherent to all 3 therapies.
Results: Only 49% of the patients adhered (PDC ≥80%) to all 3 therapies. Compared with being adherent to all 3 therapies, multivariable-adjusted hazard ratios (95% confidence intervals [CIs]) for mortality were 1.12 (95% CI: 1.04 to 1.21) for being adherent to ACE inhibitors/ARBs and beta-blockers only, 0.98 (95% CI: 0.91 to 1.07) for ACEI/ARBs and statins only, 1.17 (95% CI: 1.10 to 1.25) beta-blockers and statins only, 1.19 (95% CI: 1.07 to 1.32) for ACE inhibitors/ARBs only, 1.32 (95% CI: 1.21 to 1.44) for beta-blockers only, 1.26 (95% CI: 1.15 to 1.38) statins only, and 1.65 (95% CI: 1.54 to 1.76) for being nonadherent (PDC <80%) to all 3 therapies.
Conclusions: Patients adherent to ACE inhibitors/ARBs and statins only had similar mortality rates as those adherent to all 3 therapies, suggesting limited additional benefit for beta-blockers in patients who were adherent to statins and ACE inhibitors/ARBs. Nonadherence to ACE inhibitors/ARBs and/or statins was associated with higher mortality.
Maarit J Korhonen, Jennifer G Robinson, Izabela E Annis, Ryan P Hickson, J Simon Bell, Juha Hartikainen, Gang Fang