Comparison of Inhospital Mortality and Frequency of Coronary Angiography on Weekend Versus Weekday Admissions in Patients With Non–ST-Segment Elevation Acute Myocardial Infarction

Abstract

Patients with myocardial infarction admitted on weekends have been reported to less frequently undergo invasive angiography and experience poorer outcomes. We used the Nationwide Inpatient Sample database (2003 to 2011) to compare differences in all-cause inhospital mortality between patients admitted on a weekend versus weekday for an acute non-ST-segment elevation myocardial infarction (NSTEMI) and to determine if rates and timing of coronary revascularization contributed to this difference. A total of 3,625,271 NSTEMI admissions were identified, of which 909,103 (25.1%) were weekend and 2,716,168 (74.9%) were weekday admissions. Admission on a weekend versus weekday was independently associated with lower rates of coronary angiography (odds ratio [OR] 0.88; 95% confidence interval [CI] 0.89 to 0.90; p <0.001) or utilization of an early invasive strategy (EIS) (OR 0.480; 95% CI 0.47 to 0.48; p <0.001). Unadjusted inhospital mortality was significantly higher for the cohort of patients admitted on weekends (adjusted OR 1.02; 95% CI 1.01 to 1.04; p <0.001). However, this disparity was no longer significant after adjustment for differences in rates of utilization of EIS (OR 1.01; 95% CI 0.99 to 1.03; p= 0.11). In conclusion, this study demonstrates that among patients admitted with a diagnosis of an acute NSTEMI, admission on a weekend was associated with higher inhospital mortality compared with admission on a weekday and that lower rates of utilization of EIS contributed significantly to this disparity.