β-Blocker use following myocardial infarction: Low prevalence of evidence-based dosing

Background Quality improvement programs have shown increased use of beta-blockers post-myocardial infarction (MI), but there are no data on whether appropriate doses are administered. Methods In a prospective registry that enrolled consecutive patients with MI, we evaluated beta-blocker dosing at discharge after MI and 3 weeks later and assessed clinical predictors for treatment with very low doses. We studied 1,971 patients (70.8% male) with a mean age of 63.9 +/- 13.7 years, of whom 48.2% had an ST-elevation MI. Results beta-Blocker utilization rates following MI were 93.2% at discharge: 20.1% received < 25% of target dose, 36.5% received < 25% of target dose, 26.4% received 26% to 50% of target dose, and 17.0% received >50% of target dose. Between discharge and 3 weeks, 76.4% had no change in beta-blocker dose, with 11.9% and 11.6% having their dose reduced and increased, respectively. Absence of hypertension, acute percutaneous coronary intervention, older age, and no angiotensin-converting enzyme inhibitor therapy were consistent predictors of treatment with very low beta-blocker doses. Conclusions Underdosing of beta-blockers is highly prevalent among patients post-MI. This represents an important opportunity in quality improvement for the care of patients who have suffered an MI. (Am Heart J 2010; 160:435-442.e1.)