Who Needs Beta-Blockers? Analysis Raises Questions

Beta-blocker therapy has for decades been the standard of care for patients who have suffered a myocardial infarction (MI). Although there have been no randomized controlled trials of beta-blocker use in patients with stable coronary artery disease (CAD) or with risk factors for coronary disease, extrapolation of the data on post-MI beta-blocker treatment has led to the widespread use of these drugs in this population. A new analysis of data from a large international registry, however, finds that use of beta-blockers in patients with and without a history of CAD does not reduce cardiovascular events. The study entitled, Beta-blocker use and clinical outcomes in stable outpatients with and without coronary artery disease¹ was published online on October 2 in the Journal of the American Medical Association.

• What assumptions about beta-blocker therapy are addressed in the study?

• Why did beta-blockers not show any benefit in the populations studied?

• What criteria should be used now to determine whether or not a beta-blocker is indicated in different patient types? 

• How should primary care clinicians proceed with patients currently taking beta-blockers?

Discussing the study and providing answers to these and other questions are CardiologyNow host Dr Payal Kohli of the University of California San Francisco and her guest, the first author of the study, Dr Sripal Bangalore. Dr Bangalore is Assistant Professor of Medicine at New York University School of Medicine where he also is the Director of Research for the Cardiac Catheterization Laboratory and Director of the Cardiovascular Outcomes Program.  

Who Needs Beta-Blockers?

Take-Home Points
(1) The current practice of beta-blocker therapy in patients with risk factors for CAD or with established CAD without a previous acute coronary syndrome (ACS) is a result of extrapolation of data from original studies on the effect of these drugs in post-MI patients. When many of those studies were carried out, the potent medical therapies now routinely used and the practice of revascularization were not standard of care.

(2) This study reports that beta-blockers do not reduce the composite event rate of cardiovascular death/MI/stroke (at a mean follow-up time of 4.5 years) in patients with:
   a. Prior MI (several years after an ACS event)
   b. Known CAD/ischemia on stress testing
   c. Risk factors for CAD
The reason for this lack of efficacy is complex and may include improved use of background therapies, such as statins, aspirin, anti-platelet agents, and revascularization.

(3) Beta-blockers are still strongly indicated in patients with acute MI and patients with heart failure, and they should not be discontinued in these patients. In addition, alternative indications for beta-blocker therapy include migraine therapy, atrial fibrillation rate control, and stable angina. Although beta-blockers may provide symptom relief for these patients, they do not improve overall mortality in these groups.

(4) When determining whether or not to continue beta-blocker therapy for an individual patient, primary care physicians should consider the clinical trial evidence base, the indication for a beta-blocker, and the adverse-effect profile of these medications. It is reasonable to discontinue beta-blocker therapy in patients without another strong indication who fit into 1 of the 3 categories listed in (2), above.

Reference
1. Bangalore S, Steg G, Deedwania P, et al; for the REACH Registry Investigators. Beta-blocker use and clinical outcomes in stable outpatients with and without coronary artery disease. JAMA. 2012;308:1340-1349.

Additional Reading
Hunt SA, Abraham WT, Chin MH, et al. 2009 Focused update incorporated into the ACC/AHA 2005 Guidelines for the Diagnosis and Management of Heart Failure in Adults: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the International Society for Heart and Lung Transplantation. J Am Coll Cardiol. 2009;53:e1-e90.