Changes in condom use during a microbicide clinical trial in Pune, India

Researchers have raised concerns that microbicide use during clinical trials would displace condom use. We sought to understand whether condom use changed for participants in a microbicide clinical trial in Pune, India, to understand whether condom shifts were a legitimate concern. We hypothesize that women participating in a microbicide clinical trial in Pune, India, were more likely, on average, to report condom use at follow-up. We further hypothesize that men, whose female partners participated in a microbicide clinical trial were more likely, on average, to report condom use at follow-up. The outcome measure for reported condom use was a dichotomous variable to indicate whether or not the participant had used a male or female condom with a sexual partner since 2 months before enrollment or since the last survey, depending on the visit. Data are from semi-structured interviews at baseline, 2 months, 4 months, and 6 months with HPTN 059 clinical trial participants (100 women and 57 male partners). We used generalized estimating equations with a logit link function, exchangeable correlation, and a binomial family to model condom use. The odds of condom use for clinical trial women increased from baseline to 6 months by a factor of 3.7 (95% CI: 1.84-7.63) and the change in odds of condom use for clinical trial men from baseline to 6 months increased by a factor of 2.58 (95% CI: 1.37-4.85). We found concerns about microbicide use displacing condom use were not merited in this study population. The percent of participants reporting condom use declined from 4 to 6 months, suggesting that increases in condom use may only be during active study participation. Information about clinical trial factors that enabled these men and women to enact this important HIV prevention behavior is needed to develop interventions.