Abstract:Abstract: Objective To understand the effect of antiviral therapy on HIV transmission among serodiscordant partners. Methods In this retrospective cohort study, 797 cases of serodiscordant partners in Western Guangxi Baise City between 2005 and 2014 were selected for the study. The annual rate and baseline characteristics of HIV infection were analyzed in the HIV negative partners during follow-up, and stratified by treatment status of the partients. The HIV positive rate of the HIV negative partners was calculated in 100 person per year. COX proportional hazard model was used to estimate relative risks between the treatment and untreated groups. Kaplan-Meier analysis was used to calculate the probabilities of the HIV-negative partners remaining negative. Results In the 797 HIV-positive spouses with inconsistent serum results, there were 487 in the treated group and 310 patients in the untreated group, In the the treated group and the untreated group, the average age was (41.234 ± 12.326) years and (36.903 ± 12.267) years respectively, the mean baseline CD4+ count was (222.856 ± 145.112) cells/mm3 and (514.900 ± 233.792) cells/mm3 respectively, the median follow-up time was 29 months (IQR:15-46) and 31 months (IQR: 18-52) respectively. The two groups mainly included the male patients of 18-44 years with or without high-school education, being married, farmers or migrant workers, Zhuang nationality and heterosexual infection. During the follow-up period, a total of 33 HIV-negative spouses became HIV-positive, the positive rate was 1.414/100 person per year, among which 12 cases in the treatment group had seroconversion, the positive rate was 0.881/100 person per year and 21 cases in the untreated group had seroconversion, the positive rate was 2.159/100 person per year. There was an overall reduction of 68.2% in the risk of HIV transmission after antiretroviral treatment [adjusted HR = 0.318 (95% CI: 0.125, 0.807) ]. The treatment was significantly protective only in the second year of follow-up [adjusted HR = 0.157 (95% CI: 0.031, 0.786)], but not in the first year or in subsequent years. Conclusions In the real social environment, antiretroviral therapy has significant effect on prevention of HIV transmission among serodiscordant couples. However, the persistence of this protective effect in western Guangxi minority areas and even developing countries still need further observation and study, to better promote treatment-as-prevention of public health strategies.