Importance The September 2018 public charge announcement led many undocumented immigrants to avoid public programs over immigration concerns. Whether this extended to Emergency Medicaid and increased self-pay emergency department (ED) visits is unclear. Objectives To assess whether the likelihood of self-pay ED visits (visits not covered by any third-party payer because patients lacked or declined insurance coverage) increased among likely undocumented patients vs US-born patients after the public charge announcement. Design, Settings, and Participants This retrospective cohort study analyzed ED encounters from major safety-net hospitals in Los Angeles County from May 1, 2017, to December 31, 2019. Adult patient encounters were classified as likely undocumented or US born; likely undocumented encounters were identified based on country of birth and lack of a valid Social Security Number and were further refined with insurance information data. Difference-in-differences and event study models estimated changes in self-pay ED visits after the September 22, 2018, public charge expansion announcement, comparing groups over time to capture differential changes. The study was conducted between September 2024 and August 2025. Main Outcomes and Measures The main outcome was the proportion of ED visits that were self-paid. Both difference-in-differences and event study approaches were used. Results A total of 375 258 ED patient encounters, including 200 852 (53.5%) US born (mean SD age, 41.0 16.2 years; 120 905 60.2% female) and 174 406 (46.5%) likely undocumented (mean SD age, 47.4 13.9 years; 92 802 53.2% female), were studied. After the announcement, self-pay status for ED visits increased by 2.10 (95% CI, 1.65-2.47) percentage points among undocumented patient encounters compared with US-born encounters, equivalent to approximately 1755 visits. Event study models found that the increase among likely undocumented patients persisted from November 2018 through August 2019, peaking at 17.8%. Conclusions and Relevance In this cohort study of ED encounters, likely undocumented patients had an increase of 2.10 (95% CI, 1.65-2.47) percentage points of self-pay for ED visits compared with US-born patients after the 2018 public charge announcement. This finding suggests how anti-immigrant policies can alter payment patterns, carrying implications for patient financial burden and safety-net hospital fiscal sustainability.
Haro-Ramos et al. (Thu,) studied this question.