Acute MI may be undertreated in patients with mild cognitive impairment

Patients with mild cognitive impairment (MCI) who have an acute myocardial infarction (MI) may not receive all recommended treatments, according to a recent study.

Researchers compared receipt of treatments for acute MI in older patients with preexisting MCI and those without impaired cognition. The prospective study used data from Medicare, the American Hospital Association, and the Health and Retirement Study. MCI was measured by using the Modified Telephone Interview for Cognitive Status, with scores ranging from 0 to 27. Patients with a score of 7 to 11 were considered to have MCI, and those with a score of 12 to 27 were considered to have normal cognition. The main outcome measures were receipt of cardiac catheterization and coronary revascularization within 30 days and cardiac rehabilitation within one year of hospitalization for acute MI. The study results were published Aug. 13 by the Journal of General Internal Medicine.

The study included 609 patients ages 65 years and older who were hospitalized for acute MI between 2000 and 2011 and were followed through 2012. Of these, 492 (80.8%) had normal cognition (45.7% women; mean age, 77.1 years) and 117 (19.2%) had preexisting MCI (55.6% women; mean age, 82.3 years). After acute MI, patients with normal cognition, compared to those with preexisting MCI, had significantly higher rates of cardiac catheterization (77% vs. 50%; P<0.001), coronary revascularization (63% vs. 29%; P<0.001), and cardiac rehabilitation (22% vs. 9%; P=0.001). After adjustment for patient and hospital factors, the association of lower use with preexisting MCI persisted for cardiac catheterization (adjusted hazard ratio [HR], 0.65; P=0.007) and coronary revascularization (adjusted HR, 0.55; P=0.03) but was no longer seen for cardiac rehabilitation (adjusted HR, 1.01; P=0.98).

The researchers noted that misclassification of MCI was possible; that no information was available on severity of acute MI, delirium, or appropriateness of MI treatments; and that the effect size could have been exaggerated by unmeasured confounding or small sample size. However, they concluded that patients with preexisting MCI are less likely to receive cardiac catheterization and coronary revascularization, but not cardiac rehabilitation, after acute MI.

Going forward, more people are expected to be diagnosed with MCI due to mandated coverage of cognitive impairment assessment as part of the Medicare annual wellness benefit, the authors pointed out. “The care of [cardiovascular disease] in older patients with MCI is crucial for elders ≥85 because they comprise the fastest-growing segment of the U.S. population, they are most likely to have MCI, and their incidence of [acute] MI has increased,” they wrote. “The critical issue is that patients with MCI receive the care that they would want if properly informed.”

ACP Internist covered current evidence regarding MCI in its July/August 2019 issue.