Background
To measure the incidence of syphilis diagnoses among people with HIV versus those without HIV in a national multiyear retrospective cohort.
Methods
Treponemal and nontreponemal tests, HIV status, and demographic data were identified among all individuals receiving Veterans Health Administration (VHA) care between January 1, 2009 and December 31, 2019. Syphilis testing rates and incident syphilis diagnoses as defined by a laboratory algorithm were stratified by HIV status.
Results
Syphilis was diagnosed in 1.2% (n=2,283) of 194,322 tested individuals in VHA care in 2019. Among individuals with HIV tested for syphilis, 6.1% met criteria for syphilis compared to 0.7% without HIV. Syphilis incidence in 2019 was 35/100,000, a 17% increase from 2009 (30/100,000). In 2019, syphilis incidence was 3,381 per 100,000 persons among individuals with HIV and 19 per 100,000 in those without HIV.
Conclusions
Using a laboratory-based diagnostic algorithm, a 178-fold difference in syphilis incidence was observed between individuals with and without HIV in 2019. United States syphilis incidence data that incorporates HIV status is needed. Interventions to monitor and prevent STIs should address the role of HIV status.