Differences in Syphilis Incidence Using a Laboratory Algorithm in People With and Without HIV in an 11-Year Nationwide Cohort Study

Abstract

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.

Good performance of syphilis rapid diagnostic test kits among young key populations in Thailand

“…Prevalence of syphilis infection among AYAs living with HIV in our study was higher than among AYAUH, similar to the United States, where the percentage of syphilis diagnosis in people living with HIV is 6.1% compared to 0.7% among people without HIV. 19 Because syphilis and HIV are two systemic STIs sharing common risk factors, the severe complications attributed to untreated syphilis can facilitate the transmission and acquisition of HIV infection. 4 At the CU Buddy Clinic, annual laboratory STI screenings were not included while the PrEP program was offered, which may have resulted in high prevalence of syphilis infection among AYAs living with HIV.…”

“…Exclusion criteria were previous diagnosis with syphilis infection. Due to known higher prevalence of syphilis among people living with HIV than other populations, 19 we enrolled 50 AYAs living with HIV and 150 AYAs unaffected by HIV (AYAUH).…”

Testing and Case Rates of Gonorrhea, Chlamydia, Syphilis, and HIV among People with Substance Use Disorders in the Veterans Health Administration

“…We considered nontreponemal test results positive if ( a ) the titer was at least 4 times greater than the most recent titer or ( b ) if the titer was ≥1:1 following a negative result or as the initial result in VHA records. For treponemal testing, patients were considered positive if they had a reactive treponemal test 365 days before or any time after the nontreponemal test 10 . To calculate percent positivity, the total number of treponemal and nontreponemal tests was determined for the denominator, where multiple tests drawn on the same date for an individual counted as a single test.…”

“…For treponemal testing, patients were considered positive if they had a reactive treponemal test 365 days before or any time after the nontreponemal test. 10 To calculate percent positivity, the total number of treponemal and nontreponemal tests was determined for the denominator, where multiple tests drawn on the same date for an individual counted as a single test. The total number of syphilis cases, according to the laboratory result algorithm described previously, was used as the numerator.…”