How long should beta-blockers be used in CAD patients?

While beta-blocker use continues to be the standard of care for patients with coronary artery disease (CAD), especially for those patients who have had a myocardial infarction (MI), these drugs may not be effective long term, according to an online reportpublished Oct. 3 in JAMA.

Sripal Bangalore, MD, MHA, of New York University School of Medicine, and colleagues conducted a longitudinal, observational study to determine the long-term efficacy of beta-blockers to prevent cardiovascular events in stable patients with a prior history of MI, in those with CAD but no history of MI, and in those with only risk factors for CAD. Patients from the Reduction of Atherothrombosis for Continued Health (REACH) registry were divided into three cohorts to match the categories above and followed prospectively for 4 years. Outcomes assessed included cardiovascular outcomes, hospitalization, and vascular interventions.

Patients enrolled in the REACH registry were age 45 years and older, had established CAD, cerebrovascular disease, or peripheral arterial disease, or had at least three atherothrombotic risk factors. Patients were followed from August 2004 to April 2009. In the registry 14,043 patients (31%) had prior MI, 12,012 (27%) had documented CAD but without MI, and 18,653 (42%) had CAD risk factors only. Among these patients, 21,860 were included in the propensity score-matched analysis, so that the three cohorts were well balanced across comparator groups.

In the prior MI group, the events rates were not significantly different for patients using beta-blockers and those not using beta-blockers for the primary outcome (a composite of cardiovascular death, nonfatal MI, or nonfatal stroke) with a HR=0.90 (95% CI, 0.79-1.03; P=.14), the secondary outcome (hospitalization for atherothrombotic events or a revascularization procedure) with OR=0.91 (95% CI, 0.82-1.00), or any of the tertiary outcomes, including cardiovascular death, MI, and stroke.

In the CAD without MI group, the event rates were similar in those taking beta-blockers compared with those not taking beta-blockers for the primary outcome, for cardiovascular death, for stroke, and for MI. Those taking beta-blockers had higher rates for the secondary outcome and for hospitalization compared with patients not taking beta-blockers.

In the third cohort of patients with risk factors only, the event rates were higher in the patients on beta-blocker therapy compared to those not taking beta-blockers for the primary outcome, the secondary outcome, but not for MI and stroke.

"In this analysis…, beta-blocker use was not associated with a lower incidence of cardiovascular events among individuals with a prior history of MI, among individuals with CAD but no MI history, or among individuals with risk factors only for atherosclerotic disease," the authors commented. "Available evidence suggests that beta-blocker use is associated with benefit in patients with acute MI (without impending shock or heart block), and may be efficacious in the short-to-intermediate term duration for patients after MI and in those with chronic heart failure."