Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Introduction: Congenital syphilis is rising in the United States, especially among infants born to women with limited prenatal care. Emergency departments (ED) offer opportunities for early detection, particularly among patients evaluated for urogenital sexually transmitted infection (STI) concerns. In October 2019, our health system implemented an ED STI order set that promoted HIV co-testing and included a preselected option for syphilis testing. In this study, we evaluated change in syphilis testing during the post-implementation period among ED encounters with both pregnancy and gonorrhea/chlamydia (GC/CT) testing.

Methods: We conducted a retrospective, quasi-experimental study across 20 EDs, using health record data from 2018 to 2023 for patients aged 15–44 years who received both pregnancy and GC/CT testing. We measured annual syphilis and HIV testing and positivity, stratified by pregnancy status. The primary study outcome was syphilis testing during the encounter; HIV testing and detection outcomes were secondary.

Results: Among 59,171 ED encounters with pregnancy and GC/CT testing, 5,178 (8.8%) involved pregnant patients, and 9,538 (16.1%) received syphilis testing. Syphilis testing among pregnant patients increased from .9% in 2018 to 46.1% in 2023 (+45.1 percentage points [95% CI, 40.4–49.6]). Testing among nonpregnant patients rose from 1.2% to 35.9% (+34.6 percentage points [95% CI, 33.3–35.9]). Overall, only 1,068 of 5,178 pregnant encounters received a syphilis test (20.6%). Among 1,068 syphilis-tested pregnant encounters, 15 (1.4%) were treponemal-positive and 9 (.8%; 843 per 100,000 tested) met the Centers for Disease Control and Prevention surveillance definition for active syphilis (approximately 1 per 119 tests). Using all pregnant encounters with GC/CT testing as the denominator, the encounter-based active syphilis rate was 173.8 per 100,000 (.17%). HIV testing increased similarly (pregnant: .4% in 2018 to 44.5% in 2023), while HIV positivity remained rare (2 pregnant; 13 overall).

Conclusion: Syphilis testing and case detection increased during the postimplementation period following introduction of a preselected STI order set in the electronic health record. Many encounters in the analytic cohort still did not include syphilis testing. These findings support the ED as an important setting for identifying syphilis in pregnancy while underscoring the need for further work to understand remaining testing gaps.