Cognitive impairment ups risk of death in older AMI patients

Moderate-to-severe cognitive impairment is common among older patients hospitalized for acute myocardial infarction (AMI) and appears to increase the risk of midterm death in this population, a recent study has found.

“Routine cognitive screening may identify older AMI survivors at risk for poor outcomes who may benefit from closer oversight and support in the postdischarge period,” the researchers said.

A total of 3,041 patients with AMI (mean age 82±5 years, 56 percent male) recruited from 94 hospitals in the US were included in this study. The Telephone Interview for Cognitive Status was used to evaluate cognition: scores of <27 indicated mild impairment and <22 moderate-to-severe impairment.

The researchers determined the number of readmissions and death at 6 months postdischarge using participant report and medical record review. They also examined the associations between cognition and outcomes using multivariable adjusted logistic regression.

Mild and moderate-to-severe cognitive impairment was diagnosed in 11 percent and 6 percent of older hospitalized AMI patients, respectively. At 6 months, readmission occurred in 41 percent of participants, while 9 percent succumbed to death. [Am J Med 2021;134:910-917]

In adjusted analysis, both mild and moderate-to-severe cognitive impairment was found to heighten the risk of readmission (odds ratio [OR], 1.36, 95 percent confidence interval [CI], 1.08–1.72 and OR, 1.58, 95 percent CI, 1.18–2.12, respectively) and death (OR, 2.19, 95 percent CI, 1.54–3.11 and OR, 3.82, 95 percent CI, 2.63–5.56, respectively).

The association between moderate-to-severe cognitive impairment and death (OR, 1.69, 95 percent CI, 1.10–2.59) remained after adjusting for demographics, MI characteristics, comorbidity burden, functional status, and depression, but not for readmissions.

“While both mild and moderate-to-severe cognitive impairment were associated with substantially increased risk of death at 6 months postdischarge, the association persisted only among patients with moderate-to-severe impairment after adjustment for influential covariates,” the researchers said.

The explanation for this heightened mortality risk among AMI patients with moderate-to-severe cognitive impairment appeared to be multifactorial. First, moderate-to-severe cognitive impairment could hamper a patient’s ability to perform critical disease management tasks after discharge, such as medication management, symptom monitoring, and lifestyle changes.

Second, the death risk could partially be caused by lower rates of invasive cardiac treatments, as seen in earlier studies. Finally, cognitive impairment might be suggestive of a generalized frail state that is poorly equipped to handle stressors including AMI and hospitalization and predisposes one toward poor clinical outcomes. [J Gen Intern Med 2020;35:28-35; Ageing Res Rev 2013;12:840-851]

“[W]e believe [the third explanation] to be the most tenable rationale for the association between cognitive impairment and death after AMI,” the researchers said.

Furthermore, the finding that cognitive impairment of any severity did not correlate with readmission risk was consistent with other reports, but a 2019 study found significant associations. [J Am Geriatr Soc 2015;63:1880-1885; Heart 2019;105:1635-1641]

“It is important to note that cognitive impairment, both mild and moderate-to-severe, w[as] associated with increased risk of readmission in our unadjusted model,” the researchers said.

“However, we posit that adjustment for other important geriatric impairments, such as mobility impairment, a marker of frailty that has been shown to be an extremely potent predictor of outcomes among older AMI patients, may outweigh the risks posed by cognitive impairment for readmission,” they added. [JAMA Intern Med 2019;179:1669-1677; Circ Cardiovasc Qual Outcomes 2019;12e005320]