Long-Term Post-Discharge Risks in Older Survivors of Myocardial Infarction With and Without Out-of-Hospital Cardiac Arrest

BACKGROUND Out-of-hospital cardiac arrest (OHCA) associated with acute myocardial infarction (MI) confers high in-hospital mortality; however, among those patients who survive, little is known regarding their post-discharge mortality and health care use rates. OBJECTIVES The purpose of this study was to determine 1-year survival and readmission rates after hospital discharge of older MI survivors with and without OHCA. METHODS Using linked Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With the Guidelines and Medicare data, this study analyzed 54,860 patients with MI who were older than 65 years of age and who had been discharged alive from 545 U.S. hospitals between April 2011 and December 2012. Multivariable models examined the associations between MI-associated OHCA and 1-year post-discharge mortality or all-cause readmission rates. Patients discharged to hospice were excluded, given their known poor prognosis. RESULTS Following hospital discharge, compared with older MI survivors without OHCA (n = 54,219), those with OHCA (n = 641, 1.2%) were more likely to be younger, male, and smokers, but less likely to have diabetes, heart failure, or prior revascularization. OHCA patients presented more often with ST-segment elevation myocardial infarction (63.2% vs. 29.6%) and cardiogenic shock (29.0% vs. 2.2%); however, among in-hospital MI survivors, OHCA was not associated with 1-year post-discharge mortality (unadjusted 13.8% vs. 15.8%, p = 0.17, adjusted hazard ratio [HR]: 0.89; 95% confidence interval [CI]: 0.68 to 1.15). In contrast, MI survivors with OHCA actually had lower unadjusted and adjusted risk of the composite outcome of 1-year mortality or all-cause readmission than patients without OHCA (44.0% vs. 50.0%, p = 0.03, adjusted HR: 0.84; 95% CI: 0.72 to 0.97). CONCLUSIONS Among older patients with MI who survived to hospital discharge and were not discharged to hospice, those presenting with OHCA did not have higher 1-year mortality or health care use rates compared with those MI survivors without OHCA. These findings show that the early risk of adverse events in patients with OHCA does not persist after hospital discharge, and they support efforts to improve initial survival rates of older patients with MI and OHCA. (C) 2016 by the American College of Cardiology Foundation.