Community care emergency room use and specialty care leakage from Veterans Health Administration hospitals.

Background: Care leakage from health systems can affect quality and cost of health care delivery. Identifying modifiable predictors of care leakage may help health systems avoid adverse consequences. Out-of-system emergency department (ED) use may be one modifiable cause of care leakage. Our objective was to investigate the relationship between out-of-system ED use and subsequent specialty care leakage.

Methods: We used the Veterans Health Administration's (VA) Corporate Data Warehouse data from January 2021 to July 2021. A total of 330,547 patients who had at least one ED visit (in-house or community care [CC]) in the index period (January 2021-March 2021) were included. Outcomes were the proportions of specialty care visits in the community within 30, 60, 90, and 120 days from the index ED visit. Instrumental-variables regressions, using VA ED physician capacity as an instrument for Veterans' CC ED use, were utilized to estimate the proportions of subsequent specialty care visits in the community. Estimates were adjusted for patient and facility characteristics.

Results: A CC ED visit was associated with increases in the proportions of specialty care visits in the community within 30, 60, 90, and 120 days from index visit. Within 30 days from index visit, CC ED patients were estimated to have a 45-percentage-point (pp; 95% confidence interval [CI], 43-47 pp) higher proportion of CC specialty care visits than patients with an in-house ED visit (p < 0.001). We observed similar, though slightly attenuated, results over long time periods since the index visit.

Conclusions: Veterans who have a CC ED visit have a greater proportion of subsequent specialty care visits in CC hospitals and clinics than Veterans with a VA ED visit. This relationship persists when we examine Veterans whose decision to go to a CC ED is influenced by VA ED physician capacity rather than general preferences for CC.