Prevalence, incidence and risk factors of syphilis among men who have sex with men in China from 2013 to 2025: a systematic review and meta-analysis.

BACKGROUND

Syphilis has re-emerged in China in recent decades, particularly among men who have sex with men (MSM). We aimed to assess the prevalence, incidence, and associated factors of syphilis among MSM in China.

METHODS

We systematically searched major English (MEDLINE via PubMed, Web of Science, Embase, Scopus, Cochrane Library) and Chinese (CNKI, Wanfang, CBM, VIP, Airiti Library) databases for studies on syphilis prevalence or incidence among MSM in China published from January 1, 2013 to March 1, 2025. Study qualities were evaluated using the Hoy et al.'s risk-of-bias tool and the Newcastle-Ottawa Scale. Random-effects meta-analysis models were used to estimate pooled syphilis prevalence (%) and incidence (per 100 person-years, PYs) with 95% confidence intervals (CIs). Meta-regression analyses were performed to assess differences across subgroups.

RESULTS

A total of 441 studies (429 prevalence and 33 incidence) were included. The pooled syphilis prevalence among general MSM was 8.8% (95% CI: 8.3-9.4). Study location (R²=0.13) and study year (R²=0.11) each contributed significantly to the high heterogeneity observed (I² = 98.5%) among the general MSM prevalence studies. MSM with high-risk sexual behaviors or related risk factors exhibited higher prevalence. The pooled incidence among all MSM was 7.8 per 100 PYs (95% CI: 6.0-9.8), with similarly high heterogeneity (I² = 96.4%). Both syphilis prevalence and incidence declined over time.

CONCLUSION

Syphilis prevalence and incidence remain high among high-risk MSM subgroups in China. More rigorous studies and targeted interventions are needed to obtain more accurate estimates and to further reduce syphilis infection rates.