Long-Term Post-Discharge Risks in Older Survivors of Myocardial Infarction With and Without Out-of-Hospital Cardiac Arrest
Key result
OHCA is not associated with increased 1-year mortality in older MI survivors discharged alive.
Why the study?
Little is known regarding post-discharge mortality and health care use rates among older MI survivors with out-of-hospital cardiac arrest (OHCA).
Does out-of-hospital cardiac arrest affect 1-year post-discharge mortality and readmission in older myocardial infarction survivors?
Key Points
- To evaluate one-year post-discharge survival and readmission rates among older survivors of myocardial infarction with and without out-of-hospital cardiac arrest.
- Analyzed linked registry and Medicare data for 54,860 patients older than 65 years discharged alive across 545 U.S. hospitals between April 2011 and December 2012, excluding hospice discharges.
- Used multivariable regression models to evaluate associations between out-of-hospital cardiac arrest and one-year post-discharge mortality and all-cause readmission.
- Survivors of out-of-hospital cardiac arrest presented more frequently with ST-segment elevation myocardial infarction (63.2% vs. 29.6%) and cardiogenic shock (29.0% vs. 2.2%) compared with non-cardiac arrest patients.
- Out-of-hospital cardiac arrest was not associated with increased 1-year mortality post-discharge (13.8% vs. 15.8%, p=0.17; adjusted HR: 0.89, 95% CI: 0.68 to 1.15).
Study Design
Type
Cohort (n=54,860)
Multicenter
Yes
Structured PICO
Does out-of-hospital cardiac arrest affect 1-year post-discharge mortality and readmission in older myocardial infarction survivors?
P
Population
54,860 older patients (age >65 years) who survived an acute myocardial infarction to hospital discharge, excluding those discharged to hospice, followed for 1 year.
E
Exposure
Out-of-hospital cardiac arrest (OHCA) associated with acute MI (exposure)
C
Comparator
Myocardial infarction without out-of-hospital cardiac arrest
O
Outcome
1-year post-discharge mortalityhard clinical
Main Result
Hazard Ratio: 0.89 (95% CI 0.68–1.15)
Absolute Event Rate: 13.8% vs 15.8%
p-value: p=0.17
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“To our surprise, we found that patients with MI complicated by OHCA do very well compared to patients with MI alone. 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.”
“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. 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.”
Implication
Among older MI patients who survive to hospital discharge, initial presentation with out-of-hospital cardiac arrest does not confer an increased risk of 1-year mortality or readmission compared to those without cardiac arrest.
Abstract
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.
Discussion
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Cite This Study
Fordyce et al. (2016) conducted a cohort in Myocardial Infarction survivors (n=54,860). Out-of-hospital cardiac arrest (OHCA) vs. MI survivors without OHCA was evaluated on 1-year post-discharge mortality (adjusted HR 0.89, 95% CI 0.68 to 1.15, p=0.17). Among older MI survivors discharged alive, out-of-hospital cardiac arrest was not associated with increased 1-year post-discharge mortality (adjusted HR 0.89; 95% CI 0.68-1.15; p=0.17).