Epidemiology of syphilis infection among drug users at methadone maintenance treatment clinics in China: systematic review and meta-analysis.

Illicit drug trade has re-emerged in China since 1979 and the number of drug addicts had increased. Syphilis is mainly spread through sexual contact and blood. The incidence of syphilis is high among drug users. Methadone maintenance treatment (MMT) clinics have been implemented in China since 2004. The aim of this study was to estimate the prevalence and risk factors of syphilis among drug users at MMT clinics in China between 2004 and 2013. Chinese and English databases (CBM, CNKI, Weipu, Pubmed) of literature were searched for studies reporting syphilis among drug users in MMT clinics from 2004 to 2013. The prevalence estimates and risk factors were summarized through a systematic review and meta-analysis of published literatures. In all, 29 eligible articles with a total of 8899 drug users, were selected in this review. The pooled prevalence of syphilis infection was 7.78% (95%CI: 5.83%-9.99%). The meta-analyses demonstrated significant differences in syphilis infection rates between men and women (OR = 0.34 [95%CI: 0.26-0.45]) but not between drug users and non-intravenous drug users (OR = 0.82 [95%CI: 0.51-1.32]). Enhanced detection of syphilis and health promotion is warranted in MMT clinics in China.