Post-MI beta blocker doses too low

December 15, 2010

New data show that while nearly all MI patients receive beta blockers, most patients receive suboptimal doses that are never increased.

Key Points

Care for patients with myocardial infarction (MI) may not be as good as quality measures suggest. New data show that while nearly all MI patients receive beta blockers, most patients receive suboptimal doses that are never increased.

"Beta blocker use is better than 93% at discharge," said Jeffrey Goldberger, MD, professor of medicine, Northwestern University Feinberg School of Medicine, Chicago. "We can attribute that to beta blockers post-MI becoming a quality measure. What we're not doing is ensuring that they are used at appropriate doses."

Pace-MI Trial

Registry data included beta blocker dose at discharge, Dr. Goldberger said. Physicians were queried 3 weeks after discharge for the current beta blocker dose. Researchers found that while 93.2% of patients were discharged on a beta blocker, only 17% of patients were receiving more than 50% of the recommended dose of metoprolol (Lopressor, Novartis), carvedilol (Coreg, GlaxoSmithKline), atenolol (Tenormin, AstraZeneca), propranolol (Inderal, Wyeth), or some other beta blocker.

The right dose

Beta blocker dosing is a sticky issue, said Joseph Saseen, PharmD, FCCP, BCPS, CLS, professor of Clinical Pharmacy, University of Colorado Denver School of Pharmacy. Much of the data on appropriate dosing comes from heart-failure patients. Many MI patients progress to heart failure, but not all do so. Up-titrating beta blocker doses may be less important in patients who do not progress to heart failure.

Older patients may also do well on lower doses of beta blockers. If the resting heart rate is about 60, Saseen noted, and does not spike dramatically during mild exercise such as walking, the patient is probably on an appropriate dose.

"This study is a good snapshot of beta blocker use post-MI, not the full picture," he said. "And there is good support for the notion that the beta blocker dose 3 weeks after discharge is a good indicator of dosage over the next year."

Short stays, less titration

Patients are traditionally started on a low dose of beta blocker and titrated up in the hospital, Dr. Goldberger said. But with shorter hospital stays, there is less time for managing dose titration. In many cases, it simply doesn't happen.

"Once you take a patient out of the post-MI setting, people tend to focus on absolutes like blood pressure and patient symptoms," he said. "They just don't think about beta blocker dosage. You don't need a physician to up the dose. You could just as easily use a pharmacist to follow up."

Quality systems

Tweaking existing quality systems can help, said Mary Andrawis, PharmD, MPH, director, clinical guidelines and quality improvement, American Society of Health-System Pharmacists. Most health systems evaluate beta blocker compliance with a simple yes/no question. Because dosing data are already captured, it should be possible to refine the quality measure to appropriate dose, not just any dose.

"Beta blockers will be one of the first and easiest of these measures to take," she said. "Refining and evolving our quality measures is something we could implement in lipid dosing, anticoagulation therapy, and other areas."

Pharmacy could also play a role in discharge counseling, Andrawis said. Including beta blocker dosing as part of the medication reconciliation process when patients move into the community is a reasonable extension of care.

"Part of the discharge process is ensuring that the patient is seen again for appropriate follow-up," she said. "Checking a beta blocker dose is exactly what a pharmacist should be looking for."