Risk factors associated with prevalent and incident syphilis among an HIV-infected cohort in Northeast China.

BACKGROUND

Sexually transmitted infections (STIs) increase HIV infectivity through local inflammatory processes. Prevalent and incident STIs among people who live with HIV/AIDS (PLWHA) are indicators of high-risk sexual behaviors and imply potential spread of HIV. Little is known about the prevalence and incidence of concurrent syphilis and associated risk behaviors among PLWHA in China.

METHODS

A retrospective cohort study was conducted among PLWHA who attended the outpatient clinic of a designated AIDS treatment hospital in Shenyang, China, between March 2009 and May 2013. Physical examinations and syphilis serology were conducted at each visit. A questionnaire on demographic characteristics was also collected.

RESULTS

A total of 1010 PLWHA were enrolled, of whom 77.0% were men who have sex with men (MSM). The baseline syphilis prevalence among PLWHA was 19.8% (95% confidence interval [CI]:17.3-22.3%). During follow-up, 78.3% retained in the cohort, and contributed a median follow-up of 9.4 months (interquartile range: 5.9-18.7 months). Syphilis incidence among PLWHA was 18.7 (95% CI: 15.5-21.8) per 100 person years. Mulitvariate logistic analysis showed that receiving antiretroviral therapy (ART) (adjusted OR [aOR] = 0.48), older age (≥40 years vs. ≤24 years, aOR = 2.43), being MSM (aOR = 2.30) and having higher baseline HIV viral load (>100,000 copies/mL vs. ≤100,000 copies/mL, aOR = 1.56) were independent predictors for syphilis infection among PLWHA at enrollment (p < 0.05 for all). Mulivariate Cox regression found that receiving ART (adjusted hazard ratio [aHR] = 1.81), older age (≥40 years vs. ≤24 years, aHR: 5.17) and MSM status (aHR = 2.68) were independent risk factors for syphilis seroconversion (each p < 0.05).

CONCLUSIONS

Syphilis prevalence and incidence were high among PLWHA in Shenyang. A campaign focusing on detection and treatment of syphilis among PLWHA is urgently needed, especially one with a focus on MSM who are at a higher risk for syphilis.