Abstract WP160: Trends in Anticoagulants-Related Emergency Department Visits in the United States, 2016-2022

Introduction: The shift in anticoagulant use from warfarin to direct oral anticoagulants (DOACs) is well documented. Given DOACs’ more favorable safety profile, it is important to examine whether these changes in prescribing patterns have translated into differences in anticoagulant-related emergency department (ED) visits at the population level. Methods: We assessed national trends in anticoagulant-related ED visits using the Healthcare Cost and Utilization Project (HCUP) Nationwide Emergency Department Sample (NEDS) from 2016 to 2022. Anticoagulant-related visits were identified using ICD-10-CM codes and classified into two groups: adverse drug events (ADEs) or overdosing and underdosing. Sampling weights provided by NEDS were applied to generate representative incidence estimates. We also compared characteristics between ED visits related to ADEs/overdosing and those related to underdosing. Results: We identified 210,778 anticoagulant-related ED visits, representing an estimated 904,753 weighted visits nationally. Of these, 52.4% were male, the median age was 75 years, and 57.9% had atrial fibrillation. From 2016 to 2022, anticoagulant-related ED visits declined by 31.6%, from 157,244 to 107,531, driven primarily by a decrease in ADE- or overdose-related visits. In contrast, ED visits related to underdosing more than tripled, increasing from 6,497 in 2016 to 20,791 in 2022, and rising from 4.1% to 19.3% of all anticoagulant-related ED visits. When comparing ADE/overdose visits with underdose visits, ADE/overdose cases involved older patients (median age 76 vs 59 years), had a higher hospitalization rate (84.4% vs 73.1%) and were more likely to have atrial fibrillation (59.6% vs 42.5%). In contrast, underdose visits were more likely to involve Black patients (27.2% vs 11.4%), men (59.6% vs 51.6%), and those with Medicaid (25.0% vs 6.4%) or no insurance (9.7% vs 1.5%) compared with ADE/overdose visits. Conclusions: We observed a substantial decline in anticoagulant-related ED visits, particularly those attributed to ADEs or overdoses, likely reflecting the shift from warfarin to DOACs. In contrast, underdose-related visits more than tripled over the study period, raising concerns about potential off-label underdosing that could compromise treatment effectiveness. These findings underscore the need to further identify the drivers and clinical outcomes of underdosing and to ensure anticoagulants are used safely and in alignment with evidence-based guidelines.