Syndemics of syphilis, HCV infection, and methamphetamine use along the east coast of China

Background: An upsurge in club drug use has been observed in recent years in some cities of China, especially methamphetamine, which is quickly replacing heroin to become the most widespread drug across the nation. This study investigated the type of drugs used, syphilis and hepatitis C virus (HCV) infection and the correlates for syphilis, HCV and unprotected commercial sex behavior among drug users in two cities along the east coast of China. Methods. A cross-sectional survey conducted in 2010 provided demographics, sexual and drug use behaviors, HIV knowledge and the utilization of intervention services among drug users. Blood samples were tested for HIV, syphilis, and HCV infection. Results: Of 805 eligible participants, 0.2% were infected with HIV, 3.7% with HCV, and 9.6% with syphilis. Of the participants, 96.6% were methamphetamine users, 11.9% reported ever having used ≥2 types of these drugs, and 11.4% reported ever injecting drugs. In the multivariable logistic regression analysis, participants infected with syphilis were more likely to be female (adjusted odds ratio (AOR)=2.8, 95% confidence interval (CI): 1.2-6.5), have ever had commercial sex in the past 12 months (AOR=2.0, 95% CI: 1.0-3.9), be infected with HCV (AOR=12.1, 95% CI: 4.1-20.3) and less likely to have ever had sex with regular partners in the past 12 months (AOR=0.2, 95% CI: 0.1-0.6). Participants infected with HCV were more likely to have ever injected drugs (AOR=2.7, 95% CI: 1.1-6.5) and be infected with syphilis (AOR=8.0, 95% CI: 3.5-18.0). Participants who had unprotected sex with commercial sex partners in the last sexual encounter were more likely to be female (AOR=2.9, 95% CI:1.7-4.9), have middle school or lower level education (AOR=3.4, 95% CI:2.0-5.5), never have received intervention in the last year (AOR=2.1, 95%CI:1.2-3.6) and be infected with syphilis (AOR=4.2, 95% CI:2.4-7.4). Conclusions: Methamphetamine is the predominant drug used among the drug users, the prevalence of syphilis and HCV infection are alarmingly high, and unprotected commercial sex was common among this group. The findings highlight the need for effective, multifaceted interventions addressing sexual and drug use-related risky behaviors among this group. Further research is needed to better understand the causal pathway of the syndemics.