β-Blocker Use and Clinical Outcomes in Stable Outpatients With and Without Coronary Artery Disease
What is the association of β-blocker use with cardiovascular events in stable patients with a prior history of myocardial infarction (MI), in those with coronary artery disease (CAD) but no history of MI, and in those with only risk factors for CAD?
This was a longitudinal, observational study of patients in the Reduction of Atherothrombosis for Continued Health (REACH) registry who were divided into three cohorts: known prior MI (n = 14,043), known CAD without MI (n = 12,012), or those with CAD risk factors only (n = 18,653). Propensity score matching was used for the primary analyses. The primary outcome was a composite of cardiovascular death, nonfatal MI, or nonfatal stroke. The secondary outcome was the primary outcome plus hospitalization for atherothrombotic events or a revascularization procedure.
Among the 44,708 patients, 21,860 were included in the propensity score-matched analysis. With a median follow-up of 44 months (interquartile range, 35-45 months), event rates were not significantly different in patients with β-blocker use compared with those without β-blocker use for any of the outcomes tested, even in the prior MI cohort (489 [16.93%] vs. 532 [18.60%], respectively; hazard ratio [HR], 0.90; 95% confidence interval [CI], 0.79-1.03; p = 0.14). In the CAD without MI cohort, the associated event rates were not significantly different in those with β-blocker use for the primary outcome (391 [12.94%]) versus without β-blocker use (405 [13.55%]) (HR, 0.92; 95% CI, 0.79-1.08; p = 0.31), with higher rates for the secondary outcome (1,101 [30.59%] vs. 1,002 [27.84%]; odds ratio [OR], 1.14; 95% CI, 1.03-1.27; p = 0.01) and for the tertiary outcome of hospitalization (870 [24.17%] vs. 773 [21.48%]; OR, 1.17; 95% CI, 1.04-1.30; p = 0.01). In the cohort with CAD risk factors only, the event rates were higher for the primary outcome with β-blocker use (467 [14.22%]) versus without β-blocker use (403 [12.11%]) (HR, 1.18; 95% CI, 1.02-1.36; p = 0.02), for the secondary outcome (870 [22.01%] vs. 797 [20.17%]; OR, 1.12; 95% CI, 1.00-1.24; p = 0.04), but not for the tertiary outcomes of MI (89 [2.82%] vs. 68 [2.00%]; HR, 1.36; 95% CI, 0.97-1.90; p = 0.08) and stroke (210 [6.55%] vs. 168 [5.12%]; HR, 1.22; 95% CI, 0.99-1.52; p = 0.06). However, in those with recent MI (≤1 year), β-blocker use was associated with a lower incidence of the secondary outcome (OR, 0.77; 95% CI, 0.64-0.92).
The authors concluded that among patients with either CAD risk factors only, known prior MI, or known CAD without MI, the use of β-blockers was not associated with a lower risk of composite cardiovascular events.
This analysis of 44,708 patients reports that β-blockers was not associated with a lower risk of composite cardiovascular events among patients with either CAD risk factors only, known prior MI, or known CAD without MI. Current evidence does support the use of β-blockers in patients with acute MI and those with chronic heart failure, and we should continue to use β-blockers in these patients. Additional research is indicated to assess whether there are subgroups of stable CAD patients that may also benefit from β-blocker use.
Keywords: Odds Ratio, Coronary Artery Disease, Myocardial Infarction, Stroke, Propensity Score, Follow-Up Studies, Chronic Disease, Risk Factors, Registries, Outpatients, Heart Failure, Cardiovascular Diseases, Confidence Intervals
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