Abstract
BACKGROUND: Randomized trials show inconsistent estimates on risks of direct-acting oral anticoagulants (DOACs) versus warfarin in bleeding and mortality for atrial fibrillation (AF) patients. Trials are confounded by additional DOAC adherence support, while warfarin has a low time in therapeutic range. Few real-world studies compared emergency hospitalization risk between DOAC and warfarin users in AF. This study aimed to determine emergency hospitalization risk for AF patients on DOACs or warfarin in real-world settings. METHODS: A tapered-matched real-world cohort extracted data from 412 English general practices' primary care records linked with emergency department (ED) and hospitalization data from the ECLIPSE database. AF patients with new DOAC or warfarin prescriptions were included. The primary outcome was all-cause ED attendance; the secondary outcomes were ED re-attendance, nonelective hospitalization, and rehospitalization within 12 months. Weighted Cox regression estimated relative risk difference. RESULTS: 39 201 DOAC patients were matched with 13 145 warfarin patients. DOAC patients had a 25% higher likelihood of attending ED (odds ratio 1.25; 95% confidence interval [CI] 1.01-1.55). DOAC use also associated with higher ED re-attendance, nonelective hospitalization, and rehospitalization within 12 months: 1.41 (95% CI 1.00-1.98), 1.26 (1.00-1.57), and 1.54 (1.01-2.34), respectively, with p-values < .05. CONCLUSIONS: DOACs for AF thromboprophylaxis are associated with the increased risk of ED attendance, recurrent hospitalization, and numerical rise in ED re-attendance and first nonelective hospitalization compared to warfarin. However, these real-world data cannot establish if this difference results from medication adherence, lack of regular DOAC clinic monitoring, unmeasured confounders, or fundamental agent efficacy disparities.