Outcomes among patients with non-ST-elevation myocardial infarction on chronic anticoagulation: Insights from the National Inpatient Sample

Background: Chronic systemic anticoagulation use is prevalent for various thromboembolic conditions. Anticoagulation (usually through heparin products) is also recommended for the initial management of non-ST-elevation myocardial infarction (NSTEMI). Aims: To evaluate the in-hospital outcomes of patients with NSTEMI who have been on chronic anticoagulation. Methods: Using the National Inpatient Sample (NIS) years 2016–2020, NSTEMI patients and patients with chronic anticoagulation were identified using the appropriate International Classification of Diseases, 10th version (ICD-10) appropriate codes. The primary outcome was all-cause in-hospital mortality while the secondary outcomes included major bleeding, ischemic cerebrovascular accident (CVA), early percutaneous coronary intervention (PCI) (i.e., within 24 h of admission), coronary artery bypass graft (CABG) during hospitalization, length of stay (LOS), and total charges. Multivariate logistic or linear regression analyses were performed after adjusting for patient-level and hospital-level factors. Results: Among 2,251,914 adult patients with NSTEMI, 190,540 (8.5%) were on chronic anticoagulation. Chronic anticoagulation use was associated with a lower incidence of in-hospital mortality (adjusted odds ratio [aOR]: 0.69, 95% confidence interval [CI]: 0.65−0.73, p < 0.001). There was no significant difference in major bleeding (aOR: 0.95, 95% CI: 0.88−1.0, p = 0.15) or ischemic CVA (aOR: 0.23, 95% CI: 0.03−1.69, p = 0.15). Chronic anticoagulation use was associated with a lower incidence of early PCI (aOR: 0.78, 95% CI: 0.76−0.80, p < 0.001) and CABG (aOR: 0.43, 95% CI: 0.41−0.45, p < 0.001). Chronic anticoagulation was also associated with decreased LOS and total charges (adjusted mean difference [aMD]: −0.8 days, 95% CI: −0.86 to −0.75, p < 0.001) and (aMD: $−19,340, 95% CI: −20,692 to −17,988, p < 0.001). Conclusions: Among patients admitted with NSTEMI, chronic anticoagulation use was associated with lower in-hospital mortality, LOS, and total charges, with no difference in the incidence of major bleeding.