October 7, 2015
Lower Beta-Blocker Doses Appear to Provide
Chicago—Less might be more when it comes to using beta-blockers in heart attack patients.
A new study, published recently in the Journal of the American College of Cardiology, found that patients taking a significantly lower dosage of beta-blockers survived as long, or even longer, than patients on higher doses tested in previous clinical trials.
Northwestern University researchers report that patients who received just one-fourth of the original clinical trial dose had up to a 20% to 25% decrease in mortality compared to the full dose group—the opposite of what was expected.
Beta-blockers, which block the effects of adrenaline on the heart, reduce arrhythmia, and help prevent heart failure, are prescribed to about 90% of patients who survive a heart attack, according to background information in the article.
Lead author Jeffrey Goldberger, MD, who launched the study when he discovered heart attack patients were being treated with much lower doses of beta-blockers than were used in clinical trials, said he was shocked by the results.
“I thought that was terrible quality of care,” said Goldberger, a professor of medicine in cardiology at Northwestern University Feinberg School of Medicine and a cardiologist at Northwestern Memorial Hospital. “We set out on a mission to show if you treat patients with the doses that were used in the clinical trials, they will do better. We expected to see patients treated with the lower doses to have worse survival. We were shocked to discover they survived just as well, and possibly even better.”
Goldberger said in a Northwestern press release that new research should be conducted to determine the most appropriate beta-blocker dose for individual patients to get the optimal benefit. He noted that earlier clinical trials did not assess the effects of different doses.
Lower doses are prescribed for a variety of reasons, he added, including possible side effects such as fatigue, sexual dysfunction, and depression. Furthermore, patients often are started on low doses in the hospital and then discharged before the dosage can be adjusted, Goldberger added.
For the study, researchers examined data in a multicenter registry on 6,682 patients who had suffered a heart attack. While all of the patients on beta-blockers survived longer than those who did not receive the drugs, the survival rate appeared to be affected by dosage. Unadjusted data showed that, of the patients who received the full dose, 14.7% died within 2 years, as did 12.9% of those receiving the half dose; 9.5% of those receiving the quarter dose; and 11.5% of those receiving the one-eighth dose.
“These data do not demonstrate increased survival in patients treated with beta-blocker doses approximating those used in previous randomized clinical trials compared with lower doses,” study authors point out. “These findings provide the rationale to re-engage in research to establish appropriate beta-blocker dosing after MI to derive optimal benefit from this therapy.”
“We now need to figure out how to dose it in individual patients,” Goldberger added. “That's something no one has considered in the decades that we have been using this medication. This huge gap in knowledge has been completely unexplored. Since this is medicine we use in every single heart attack patient, we ought to figure out how to use it properly.”
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