Trends and predictors of leaving before medically advised in US emergency departments from 2016 to 2021

Background: Leaving before medically advised (BMA) is a significant issue in the US healthcare system, leading to adverse health outcomes and increased costs. Despite previous research, multi-year studies using up-to-date nationwide emergency department (ED) data, are limited. This study examines factors associated with leaving BMA from EDs and trends over time, before and during the COVID-19 pandemic. Methods: We conducted a pooled, cross-sectional study using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2016 to 2021. Multivariable logistic regression and interrupted time series (ITS) analyses were used to identify factors associated with leaving BMA and to examine trends over time, respectively. Results: Out of 721.0 million ED visits, 5.9 million (0.8 %) resulted in leaving BMA. Factors associated with higher odds of leaving BMA included public or no insurance coverage (Medicare: AOR = 1.74, 95 % CI = 1.12–2.70; Medicaid/CHIP/State-based: AOR = 1.86, 95 % CI = 1.40–2.45; Uninsured/Self-pay: AOR = 1.51, 95 % CI = 0.99–2.29), alcohol or substance use disorders (AOR = 2.19, 95 % CI = 1.77–2.70), arrival by ambulance (AOR = 1.68, 95 % CI = 1.31–2.15), and being male (AOR = 1.32, 95 % CI = 1.09–1.62). Conversely, hospital admissions (AOR = 0.11, 95 % CI = 0.05–0.21) and trauma or overdose related visits (AOR = 0.54, 95 % CI = 0.44–0.67) were associated with lower odds of leaving BMA. The COVID-19 pandemic significantly increased the odds of leaving BMA (AOR = 1.44, 95 % CI = 1.06–1.95), with an overall increase of 53.6 % in BMA-related ED visits observed post-March 2020 relatively to the previous years, particularly in the fourth quarters of 2020 and 2021 and second and third quarters of 2020. Conclusions: In this study, several demographics, socio-economic, and clinical characteristics were associated with higher incidences of leaving ED BMA. The COVID-19 pandemic also exacerbated BMA rates. These findings highlight the need for targeted interventions to improve patient-provider communication and ED triage efficiency, especially in resource-constrained facilities serving lower-income individuals.