HIV-1 Treatment-as-Prevention

The Chinese national observational cohort study suggests that the treatment-as-prevention (TasP) approach can be an effective public health HIV-1 prevention strategy. However, results from that study may have been biased because the follow-up time of index patients prior to their initiation of antiretroviral therapy (ART) was excluded. In this study, we correct for such bias by using an extended time-dependent Cox regression model to conduct a cohort study analysis of serodiscordant couples in Guangxi of China, inclusive of all followup time. During the follow-up of this observational cohort study of HIV-1 sero-discordant couples, the positive index partners may have never be treated with ART, or enter untreated but subsequently began treatment, or may have been treated immediately upon entry into the public health system. The treatment effectiveness of ART in HIV-1 acquisition among HIV-negative partners is assessed by the extended Cox regression model with treatment status as a time-varying covariate. A total of 6548 sero-discordant couples were included in the cohort study analysis. Among them, 348 negative partners sero-converted. HIV seroincidence was significantly higher among the nontreated (4.3 per 100 person-years, 3.7–4.9) compared with those receiving ART (1.8 per 100 person-years, 1.5–2.0). An overall 35% reduction in risk of HIV Heng Zhang, MD Hui Xing, MS, iming Shao, MD, PhD follow-up. Moreover, ART was found to be significantly inversely associated with multiple baseline characteristics of index partners. TasP may be feasible on a national or regional scale. In addition to other proven preventive strategies such as the use of condoms, ART adherence to maintain viral suppression would then be the key challenge for successful TasP implementation. (Medicine 94(24):e902) Abbreviations: AHR = adjusted hazard ratio, ART = antiretroviral therapy, CI = confidence interval, HIV = human immunodeficiency virus, HR = hazard ratio, TasP = treatment-as-prevention. INTRODUCTION A ntiretroviral therapy (ART) has significantly improved the prognosis of patients infected with human immunodeficiency virus type 1 (HIV-1) and decreased associated morbidity and mortality. ART also can reduce transmission of HIV-1 among HIV serodiscordant couples. The HIV Prevention Trials Network 052 (HPTN 052) study definitively showed the benefit of ART for the prevention of sexual transmission of HIV in serodiscordant heterosexual couples in 2011. Since the publication of this trial result, the World Health Organization (WHO) has recommended ART as a method for preventing HIV transmission among serodiscordant couples. Recently, a Chinese national observational cohort study showed risk reduction in HIV transmission among serodiscordant couples in a realworld setting, suggesting that the so-called treatment-as-prevention (TasP) approach is a possible and effective public health HIV prevention strategy. Unlike the HPTN 052 being a well-designed controlled randomized trial for a certain eligible population, key research challenges remain to assess the TasP effectiveness in real-world settings. In the aforementioned Chinese national observational cohort study, for example, TasP effectiveness was assessed by only comparing the follow-up time of index partners who never received any ART with the follow-up time of index partners after they had initiated ART; thus, the follow-up time of index patients from the baseline visit to their initiation of ART was not included for analysis. (‘‘Index partner’’ refers to individuals who were HIV-positive at baseline, but whose partner was HIVnegative). Such an assessment might result in a bias towards couples who are inherently less likely to transmit. To address this issue of possible bias in real-world settings, we use an extended time-dependent Cox regression model to conduct a cohort study analysis of serodiscordant couples in Guangxi of China. In this model, whether the index partner receives ART or ime-dependent covariate in the extended f this study is thus to more accurately ess on the transmission of HIV among www.md-journal.com | 1 serodiscordant couples in a real-world setting, such as Guangxi, China. The HIV epidemic among drug users was first detected in 1996 in Guangxi. By the end of 2004, Guangxi had accumulated the third highest number of HIV cases reported in China. HIV infection through drug injection accounted for 69% of reported HIV cases in 2003, but the proportion of HIV infections through sexual intercourse increased to 66% in 2009 in Guangxi. Since the Chinese National Comprehensive AIDS (acquired immune deficiency syndrome) Response Policy and ‘‘Four Frees and One Care’’ program were launched in 2003, the Chinese Center for Disease Control and Prevention (China CDC) has established national HIV databases. These cohort study databases can be used to study the effectiveness of ART on the transmission of HIV in serodiscordant couples. MATERIALS AND METHODS