Association of Inpatient vs. Outpatient Onset of ST-Elevation Myocardial Infarction With Treatment and Clinical Outcomes

Study Questions:

What are the incidence and variables associated with treatment and outcomes of patients with inpatient-onset ST-segment elevation myocardial infarction (STEMI)?

Methods:

This was a retrospective analysis of STEMIs occurring between 2008 and 2011 and identified in the California State Inpatient Database. STEMIs were classified as inpatient onset or outpatient onset. The authors determined associations among locations of onset of STEMI, resource utilization, and outcomes.

Results:

The analytic sample included 62,021 STEMIs identified at 303 hospitals. Of these, 4.9% occurred in patients hospitalized for non–acute coronary syndrome (ACS) indications. Nearly one half (49.6%) of inpatient-onset STEMIs occurred following a surgical procedure. In analyses adjusted for age, sex, comorbidities, and hospital characteristics, patients with inpatient-onset STEMI, compared to those with outpatient-onset STEMI, were less likely to undergo cardiac catheterization (33.8% vs. 77.8%; odds ratio [OR], 0.19; 95% confidence interval [CI], 0.16-0.21; p < 0.001) or percutaneous coronary intervention (21.6% vs. 65%; OR, 0.23; 95% CI, 0.21-0.26; p < 0.001). Compared to those with outpatient-onset STEMI, those with inpatient-onset STEMI had a more than 3 times higher adjusted mortality (OR, 3.05; 95% CI, 2.76-3.38; p < 0.001).

Conclusions:

Compared to patients with outpatient-onset STEMI, those with inpatient-onset STEMI have increased mortality, increased resource utilization, and lower odds of having cardiac catheterization or percutaneous coronary intervention.

Perspective:

This is an important multicenter study that characterizes outcomes of inpatient-onset STEMI, corroborating other observations in the literature of increased mortality in this cohort, compared to those with outpatient-onset STEMI. The authors demonstrated that patients with inpatient-onset STEMI were less likely to have cardiac catheterization or percutaneous coronary intervention; certainly, future studies should define patients with inpatient-onset STEMI who may benefit from an invasive approach. As the authors emphasize, their data imply that ‘systems designed to improve care of inpatient-onset STEMI have the potential for a significant beneficial effect on mortality.’

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, California, Cardiac Catheterization, Confidence Intervals, Percutaneous Coronary Intervention, AHA Annual Scientific Sessions


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