Demographic and clinical factors associated with Syphilis treatment initiation in a tribal health system: a retrospective cohort study

Background: American Indian/Alaska Native (AI/AN) individuals are disproportionately burdened by syphilis compared with other racial and ethnic groups. Early syphilis treatment is important to reduce transmission and prevent negative health outcomes. Understanding the characteristics of individuals who test positive and the factors associated with initiating treatment will support syphilis prevention and treatment efforts. Methods: Cherokee Nation conducted a retrospective cohort study of individuals who tested positive for syphilis between 2016 and 2023. Data were collected from electronic health records and analyzed descriptively using counts and percentages and inferentially using Chi-square tests and multivariable logistic regression. Results: Overall, 356 individuals tested positive for syphilis and 314 (88.2%) initiated treatment. Most individuals who tested positive were ≤ 34 years (60.7%), single (83.4%), diagnosed during the COVID-19 pandemic (75.8%), residing in a county with a Cherokee Nation clinic (84.3%), and had a non-emergency healthcare visit within one year (70.5%). Approximately half (52.0%) had documented substance use and 31.2% had an STI co-infection within one year. Individuals diagnosed outside of an emergency department or urgent care setting had higher odds of initiating treatment compared with those diagnosed in an emergency department or urgent care setting (aOR=2.01, 95% CI: 1.02–3.97). Individuals with an STI co-infection had higher odds of initiating treatment compared with those without an STI co-infection (aOR=2.96, 95% CI: 1.19–7.33). Conclusions: This study suggests that focusing public health and clinical syphilis treatment efforts on emergency department and urgent care providers and patients may increase syphilis treatment initiation.