Importance The 2016 presidential campaign was marked by intensified rhetoric around the deportation of undocumented immigrants. The association of such rhetoric with primary, emergency, and inpatient care among undocumented immigrants is unclear.

Objective To examine the association of increased anti-immigrant rhetoric during the 2016 presidential campaign with health care use among a group of Medicaid-ineligible patients largely composed of undocumented immigrants.

Design, Setting, and Participants Using a difference-in-differences (DID) approach, this cohort study analyzed health care use between January 1, 2014, and May 31, 2018, in a retrospective cohort of Medicaid and Medicaid-ineligible (>90% undocumented) adult and pediatric patients. The inflection point of interest was June 16, 2015, the date of Donald Trump’s announcement of candidacy, which represented a documented increase in anti-immigration rhetoric during the presidential campaign. Analyses were controlled for age, self-reported sex, and baseline comorbidities. Data analysis was conducted from August 28, 2018, to September 1, 2020.

Main Outcomes and Measures The DID of the number of completed primary care encounters before and after June 16, 2015, in Medicaid compared with Medicaid-ineligible patients. Secondary outcomes included the DID of emergency department (ED) visits and inpatient discharges over the same period.

Results There were 20 211 patients included in the analysis: 1501 (7.4%) in the sample of predominantly undocumented Medicaid-ineligible patients (861 [57.4%] female) and 18 710 (92.6%) in the Medicaid control group (10 443 [55.8%] female). The mean (SD) age as of 2018 in the Medicaid-ineligible group was 38.2 (15.4) years compared with 22.2 (16.5) years in the control group. There was a differential decrease in completed visits among Medicaid-ineligible children compared with Medicaid children (DID estimate, 0.8; 95% CI, 0.7-0.9) and Medicaid-ineligible adults (DID estimate, 0.8; 95% CI, 0.8-0.9). There was also a significant differential increase in ED visits among Medicaid-ineligible children (DID estimate, 2.3; 95% CI, 1.1-5.0). In addition, there was a differential decrease in inpatient discharges among Medicaid-ineligible adults (DID estimate, 0.5; 95% CI, 0.4-0.7), with no significant change in ED visits or ED admission rates in this group.

Conclusions and Relevance In this cohort study, there was a significant decrease in primary care use among undocumented patients during a period of increased anti-immigrant rhetoric associated with the 2016 presidential campaign, coincident with an increase in ED visits among children and a decrease in inpatient discharges among adults, with the latter possibly attributed to a decrease in elective admissions during this period.