HIV/AIDs Prospective Cohort Study Among Men Who Have Sex With Men In Beijing

Background: HIV/AIDS is now epidemic among MSM in China. Thelatest report revealed that29.4%of HIV infections can be attributed tomale-to-male sexual behaviors. In addition, the rapid spread of syphilis andother STDs is also worthy of consideration. Furthermore, a complicated sexualnetwork make MSM a significant bridging population in the spread of HIV,syphilis and other sexually transmitted diseases from high risk population togeneral population. Many cross-sectional studies and small sample prospectivecohort studies were conducted in recent years, there is no big sampleprospective cohort study to report the incidence and risk factors for HIV,syphilis and HSV-2seroconversion among MSM in China.A prospectivecohort study is needed to carry out in MSM, in order to take timely and adjustthe appropriate strategies and measures to control HIV, syphilis and HSV-2spread in this population.Objective:1To understand retention rate and factors associated with retention amongthe prospective cohort study of MSM in Beijing.2To explore the incidence and risk factors for HIV seroconversion amongMSM in Beijing.3To explore the incidence and risk factors for syphilis and herpes simplextype2virus(HSV-2) seroconversion among MSM in Beijing.Methods: This prospective cohort study was conducted baseline andfollow-up survey among MSM from August2009to April2011in Beijing.MSM were recruited through peer referring and internet advertising. Ineligibleparticipants were excluded from further study according to the inclusivecriteria and written informed consent and contact methods were obtained fromeach study participant, after that interviews were conducted to collect information at the beginning of follow-up survey, and then pre-test counseling,collecting blood samples, informing to participants the test results and HIVpost-test counseling in a week. Questionnaire-based interviews wereconducted to collect information on demographics (e.g., age, ethnicity,education), sexual behavior (e.g., self-identified sexual orientation, number ofmale sex partners in the past six months, frequency of condom using in thepast six months), frequency of illicit drug use in the six months and so on.Blood samples were collected and tested for HIV, syphilis and HSV-2infection at baseline and follow-up visits.Results:1809HIV-negative MSM were recruited in our study,769,692and574wereretained at the6-month,12-month and18-month follow-up visits, andretention rates were95.1%,85.5%and71.0%respectively. MultivariateLogistic analysis revealed that older than25years(OR=1.63，95%CI：1.19~2.24), lived in Beijing for2years or more(OR=1.58，95%CI：1.15~2.17),tested for HIV in the past one year(OR=1.61，95%CI：1.18~2.21), four or moremale partners in the past six months(OR=1.50，95%CI：1.02~2.21), and hadunprotected anal intercourse with male partners in the past sixmonths(OR=0.64，95%CI：0.47~0.88) were significantly associated with18-month retention.2The prevalence of HIV is6.3%(61/962) in the962MSM baselineconducted. Among809MSM tested negative for HIV antibody,65participants seroconverted for HIV infection during856.76PY follow-up, HIVincidence was7.59/100PY(95%CI：5.84~9.40). Multivariate Cox regressionanalysis revealed that younger than25years and25years old(HR=2.32，95%CI：1.39~3.87), recognized8friends or more who are MSM(HR=2.50，95%CI：1.49~4.20), monthly income less than2000yuan(HR=1.76，95%CI：1.06~2.95), four or more male partners in the past six months(HR=3.50，95%CI：2.11~5.81), had symptoms of STDs in the past one year(HR=1.91，95%CI：1.02~3.56), prepuce or phimosis in the physicalexamination(HR=2.47，95%CI：1.50~4.07), and syphilis infection(HR=2.62， 95%CI：1.53~4.49) were significantly associated with HIV seroconversion.3The prevalence of syphilis and HSV-2is17.7%(170/962) and5.3%(51/962) in the962MSM baseline conducted. Among632MSM test negativefor syphilis antibody at baseline,42MSM seroconverted for syphilis infectionduring714.16PY follow-up, syphilis incidence was5.88/100PY(95%CI：4.16~7.61). Among683MSM test negative for HSV-2antibody at baseline,87MSM seroconverted for HSV-2infection during788.39PY follow-up, HSV-2incidence was11.04/100PY(95%CI：8.85~13.22). Multivariate Coxregression analysis revealed that looking for partners from parks orbathhouses(HR=2.59，95%CI：1.39~4.84), had symptoms of STDs in the pastone year(HR=3.58，95%CI：1.82~7.04), symptoms of STDs in the physicalexamination(HR=3.35，95%CI：1.76~6.38), and HIV infection(HR=3.00，95%CI：1.28~7.02) were significantly associated with syphilis seroconversion.Multivariate Cox regression analysis revealed that older than25years（HR=2.11，95%CI：1.29~3.47), had commercial sex with male sex partnersin the past6months(HR=5.30，95%CI：1.88~14.99) and syphilisinfection(HR=2.15，95%CI：1.31~3.55) were significantly associated withHSV-2seroconversion.Conclusion:1The retention rates were95.1%,85.5%and71.0%respectively at the6-month,12-month and18-month follow-up visits. Older than25years,lived in Beijing for2years or more, tested for HIV in the past one year,four or more male partners in the past six months, and had unprotected analintercourse with male partners in the past six months were significantlyassociated with18-month retention in MSM in Beijing.2HIV incidence was7.59/100PY. Syphilis incidence was5.88/100PY.HSV-2incidence was11.04/100PY. The incidence of HIV, syphilis, andHSV-2is high among MSM in Beijing, effective prevention measuresshould be taken urgently to stop the epidemic.3It is significantly associated with HIV seroconversion in MSM thatyounger than25years old, recognized8friends or more who are MSM, monthly income less than2000yuan, four or more male partners in the pastsix months, symptoms of STDs in the past one year, prepuce or phimosis inthe physical examination, and syphilis infection.4It is significantly associated with syphilis seroconversion that looking forpartners from parks or bathhouses, had symptoms of STDs in the past oneyear, symptoms of STDs in the physical examination and HIV infection. Itis significantly associated with HSV-2seroconversion that older than25years, commercial sex with male sex partners in the past6months andsyphilis infection. It is existed synergistic relationship between HIVsyphilis and HSV-2in MSM, so the prevention and control of HIV andSTDS should be carried out simultaneously.