The Tenacious Treponema: A Retrospective Examination of Syphilis Treatment Disparities in Washington, DC

Since 2000, there have been rising rates of syphilis infections nationally with higher incidence among minorities and persons living with human immunodeficiency virus (HIV) (PLWH). The purpose of this study was to determine syphilis treatment adequacy and factors associated with treatment delay.

This was a retrospective academic-public health collaboration with the District of Columbia Department of Public Health reviewing surveillance data of all primary, secondary, and early latent syphilis cases diagnosed between January 1, 2015, and December 31, 2019. Data were analyzed using multivariable logistic regression to identify factors associated with delayed treatment >14 days from diagnosis.

Among 1852 individuals diagnosed with early syphilis, 93% (1730/1852) were male; 48% (893/1852) were coinfected with HIV; 43% (n = 796/1852) were African American/Black, 27% (n = 492/1852) were White, and race/ethnicity was unknown for 17% (n = 318/1852) of cases. Among 679 PLWH for whom viral load (VL) was known, 41% (278/679) had a VL < 20 copies/mL, and 18% (123/679) had VL >10,000 copies/mL. Treatment adequacy overall was 96.5%. Median time to syphilis treatment was 6 days (interquartile range = 4-7). Factors associated with delay of treatment included refused/unknown race (adjusted odds ratio [aOR], 1.95; 95% confidence interval [CI], 1.00-3.79), and HIV VL > 10,000 copies/mL (aOR, 1.97; 95% CI, 1.08-3.58).

The factors we identified associated with delayed treatment may reflect systemic factors contributing to the increased rates of infection among key populations. This highlights the importance of targeted public health efforts with the goal of reducing transmission of both HIV and syphilis.