One-Year Survival Similar after MI With or Without Out-of-Hospital Cardiac Arrest

In one of the largest cohorts to date looking at long-term postdischarge outcomes of older patients with MI and concurrent, out-of-hospital cardiac arrest (OHCA), patients with OHCA surviving to hospital discharge had similar 1-year survival and lower health care utilization than patients with MI who did not have OHCA.

These data fill an important knowledge gap left by prior research on postdischarge outcomes among patients aged 65 or older with MI and concurrent OHCA, according to Christopher B. Fordyce, MD, MSc (Duke Clinical Research Institute, Durham, NC), and colleagues.

“This study shows that the early risk of adverse events in patients with OHCA is attenuated after hospital discharge and supports efforts to improve survival rates of older patients with MI and OHCA,” the researchers write online ahead of print in the May 3, 2016, issue of the Journal of the American College of Cardiology.

Similar Survival Rates

Fordyce and colleagues collected Medicare data on 54,860 patients with MI older than age 65 and linked these with the Acute Coronary Treatment and Intervention Outcomes Network (ACTION) Registry-Get With the Guidelines database. All patients had been discharged alive from 545 US hospitals between April 2011 and December 2012. Patients discharged to hospice were excluded.

After discharge, patients with OHCA were younger on average and more likely to be men and smokers compared with patients without OHCA. However, fewer of the patients with OHCA had diabetes, heart failure, or prior revascularization. A greater percentage of patients with OHCA presented to the hospital with STEMI (63.2% vs 29.6%) and cardiogenic shock (29.0% vs 2.2%).

Despite these differences, presence of OHCA had no significant effect on 1-year survival among discharged patients. In fact, patients with OHCA had significantly lower rates of the composite of mortality or readmission at 1 year compared with patients without OHCA.

Getting Patients to Discharge

Prior to this study, the feeling in the healthcare community was that patients with OHCA remained at high risk of mortality and hospital readmission, even after hospital discharge, and particularly in the older population, Fordyce told TCTMD in an e-mail.

“To our surprise, we found that patients with MI complicated by OHCA do very well compared to patients with MI alone,” Fordyce said. “This was true even after adjustment for several important potential confounders, including age, ejection fraction, and discharge interventions such as medication use, ICD implantation, and referral to cardiac rehabilitation.”

Fordyce called this find “fairly positive” and added that he supports continued efforts to improve survival of patients with OHCA in the prehospital and inpatient settings.

In an accompanying editorial, Rajat Deo, MD, MTR, and Andrew E. Epstein, MD (University of Pennsylvania, Philadelphia), discussed several of the reasons why these continued efforts are vital, including the fact that in this study 44.4% of patients with OHCA died in the hospital compared with only 5.9% of patients without OHCA.

“Although the authors demonstrate that older patients with MI and OHCA surviving to hospital discharge (not hospice) have comparable 1-year mortality and healthcare utilization rates than those without OHCA, OHCA with MI is neither inconsequential nor benign,” Deo and Epstein write. “Equally noteworthy and not included in the current analysis are the approximately one-half to a majority of patients with cardiac arrests attributable to MI who die out-of-hospital and never even make it to the emergency department or hospital, especially among elderly patients.”

Deo and Epstein also point out that the study results may be limited by the fact that patients in the study without OHCA were less likely to have one of several comorbidities including diabetes, PAD, chronic lung disease, or prior revascularization.

“It is very difficult to account for how comorbidities may have influenced outcomes, not only overall survival, but also survival to discharge home and not hospice,” they write.

Sources:

• Fordyce CB, Wang TY, Chen AY, et al. Long-term post-discharge risks in older survivors of myocardial infarction with and without out-of-hospital-cardiac arrest. J Am Coll Cardiol. 2016;67:1981-1990.
• Deo R, Epstein AE. Moving further upstream in the prevention of cardiac arrest and its complications. J Am Coll Cardiol. 2016;67:1991-1993.

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