Inpatient- versus Outpatient-Onset Acute Coronary Syndrome: Comparison of Clinical Features and Outcomes

The clinical characteristics and outcomes among patients with inpatient-onset non-ST-segment-elevation acute coronary syndrome have not been fully investigated. Therefore, we conducted a retrospective single-center analysis of patients who were ≥18 years old and diagnosed with acute coronary syndrome at our hospital during 2014. We performed logistic regression analysis to evaluate outcomes and made adjustments for age, race, family history of premature coronary artery disease, and comorbidities. Our search through 31,274 hospital discharge records identified 683 cases of acute coronary syndrome: 32 were inpatient-onset and 651 were outpatient-onset. The inpatient-onset group was older (74.6 ± 9.6 vs 64 ± 12.8 yr; P <0.001), and patients were more likely to be black (28.1% vs 12.9%). Diagnoses at admission in the inpatient-onset group varied widely, including 4 cases of pneumonia and 3 of intestinal obstruction. The inpatient-onset group was less likely than the outpatient-onset group to undergo cardiac catheterization (34.4% vs 90.2%; adjusted odds ratio [AOR], 0.11; 95% CI, 0.05-0.28; P <0.001) or percutaneous coronary intervention (12.5% vs 61.6%; AOR, 0.16; 95% CI, 0.05-0.48; P=0.001), or to be discharged from the hospital (53.1% vs 88.9%; AOR, 0.26; 95% CI, 0.11-0.6; P=0.002). The inpatient-onset ACS group had longer hospital stays than did the outpatient-onset group (9.9 ± 8.9 vs 6.4 ± 5.2 d; P=0.03). We found that inpatient-onset acute coronary syndrome was associated with less interventional management, a longer hospital stay, and a lower likelihood of discharge to home.