Use of a novel technology to track adherence to product use in a microbicide trial of short duration (MTN-007).

Adherence measurement in microbicide trials is challenging. To decrease recall and social desirability bias, we used an interactive voice response system (IVR) in a rectal microbicide trial. Forty-six participants were asked to report product use daily for 1 week. Participants received an incentive per call plus a bonus for calling every day. We examined adherence to calling the IVR and to gel use; we compared the latter to applicator counts. Adherence to calling the IVR daily was high (mean = 89.9 %, SD = 20.7 %). Adherence to gel use per IVR was very good (mean = 90.7 %, SD = 19.1 %), and consistent with applicator counts in 80.4 % of cases. Neither adherence to calling nor gel use were associated with temporal factors like day calls started, number of days since first call, or weekday vs. weekend. Daily reporting allowed identification of irregular product use. IVR appears useful for daily reporting in brief trials.