Risk factors of serofast state in patients undergoing syphilis: a meta-analysis of 17 cohort studies.

OBJECTIVE

The serofast state in syphilis refers to a persistent serological status where patients maintain stable specific antibody titers despite receiving standardized anti-syphilitic therapy, whose underlying mechanisms remain incompletely elucidated. This study aims to systematically identify risk factors associated with the occurrence of syphilitic serofast state through comprehensive clinical data analysis.

METHOD: We performed a systematic literature search in PubMed and Embase databases for studies published up to February 20, 2025. A random-effects model was employed for meta-analysis, with effect estimates expressed as relative risk (RR) presented with 95% confidence intervals (CIs). Methodological evaluations including sensitivity analyses and publication bias assessment were conducted to assess result robustness.

RESULTS

A total of 17 cohort studies involving 4,662 eligible participants were included in this meta-analysis. The pooled results demonstrated significant associations between serofast state and primary syphilis (RR = 0.65; 95% CI: 0.44-0.96), latent syphilis (RR = 2.14; 95% CI: 1.47-3.11), female gender (RR = 1.19; 95% CI: 1.01-1.41), HIV coinfection (RR = 1.40; 95% CI: 1.09-1.79), and lower rapid plasma reagin (RPR) titers (≤1:32) (RR = 1.47; 95% CI: 1.02-2.13). No statistically significant associations were observed for secondary syphilis (RR = 0.81; 95% CI: 0.59-1.12), age >40 years (RR = 1.41; 95% CI: 0.80-2.49), or benzathine penicillin treatment (RR = 0.99; 95% CI: 0.86-1.13). These findings were validated through leave-one-out sensitivity analysis.

CONCLUSION

Female gender, HIV coinfection, primary syphilis, latent syphilis, and low rapid plasma reagin (RPR) titers (≤1:32) emerged as significant risk factors for serofast state development, requiring particular attention during therapeutic management to optimize syphilis treatment outcomes.