Burden of syphilis among people living with HIV: a large cross-sectional study from Türkiye

Syphilis and HIV are closely linked infections with shared transmission routes and risk factors. Despite effective screening and treatment options, the prevalence of syphilis remains high among people living with HIV (PLWH), especially in middle-income countries like Türkiye.

To investigate the seroprevalence of syphilis among PLWH using centralized laboratory data and to assess its distribution by age and sex.

A retrospective cross-sectional study was conducted by reviewing data derived from blood specimens submitted to our laboratory for routine CD4⁺ T cell enumeration, ultimately analyzing 2,768 PLWH between January 2022 and December 2024. Syphilis seropositivity was defined by concurrent positivity in both VDRL and TPHA tests. Demographic and clinical variables were analyzed using SPSS v.22.0.

Syphilis seropositivity was detected in 923 patients (33.3%). The prevalence was significantly higher among males (37.0%) compared to females (6.1%) (p < 0.001). The highest seroprevalence was observed in patients aged 31-40 years (37.4%). There was no significant difference in mean age between syphilis-positive and syphilis-negative groups (p > 0.05).

This study reveals a high burden of syphilis among PLWH in Türkiye, particularly in younger male populations. The findings underscore the necessity for routine syphilis screening, targeted prevention strategies, and integrated STI care within HIV programs.