AHJ: Underdosing of beta-blockers post-MI is far too common

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Underdosing of beta-blockers is highly prevalent among patients post-MI, and represents an “important opportunity in quality improvement” for the care of patients who have suffered an MI, according to research published in the September issue of the American Heart Journal.

Quality improvement programs have shown increased use of beta-blockers post-MI, but there are no data on whether appropriate doses are administered, wrote Jeffrey J. Goldberger, MD, from Northwestern University, Feinberg School of Medicine in Chicago, along with the other PACE-MI investigators.

“Although guidelines and performance measures for the care of post-MI patients clearly indicate that virtually all such patients should be treated with beta-blocker therapy, the guidelines are silent on dosing,” the authors wrote.

In a prospective PACE-MI registry that enrolled consecutive patients with MI, the researchers evaluated beta-blocker dosing at discharge after MI and three weeks later and assessed clinical predictors for treatment with very low doses. They studied 1,971 patients (70.8 percent male) with a mean age of 63.9 years, of whom 48.2 percent had a STEMI.

Beta-blocker utilization rates following MI were 93.2 percent at discharge: 20.1 percent received 25 percent less than target dose; 36.5 percent received 25 percent of target dose; 26.4 percent received 26 to 50 percent of target dose; and 17 percent received 50 percent more than target dose, the authors wrote. Between discharge and three weeks, 76.4 percent had no change in beta-blocker dose, with 11.9 percent and 11.6 percent having their dose reduced and increased, respectively.

Goldberger and colleagues commented that the absence of hypertension, acute PCI, older age and no angiotensin-converting enzyme (ACE) inhibitor therapy was a consistent predictor of treatment with very low beta-blocker doses.

“Although clinical trials show that target doses can be achieved in substantial numbers of patients, the present data indicate that this does not happen in clinical practice. Although quality improvement initiatives have had enormous impact on the problem of beta-blocker underuse following MI, underdosing remains a significant problem,” the researchers wrote.

“It is therefore important to explore the clinical implications of underdosing, potential reasons for not achieving higher doses and further steps to address this issue,” concluded Goldberger and colleagues, adding that “innovative hospital discharge programs involving nurses and pharmacists” could impact outcomes.