Recruitment and Retention Challenges in HIV Prevention Clinical Trials: Increasing Initial Retention by Utilizing a Mobile Assessment Unit for Conducting Research Activities in the Community

Background: Clinical trials testing HIV vaccines and other prevention interventions require the participation of individuals at high risk of infection. The evaluation of strategies that efficiently recruit, assess and enroll high risk individuals is important to the development of improved methods for the conduct of prevention trials. Methods: We compare strategies for the screening and enrollment of high risk women in two prevention trials. In both studies women were identified using community-based recruitment and pre-screening. All pre-screening activities for both studies were conducted on a mobile assessment unit (MAU), however, the studies differed with regard to the location of the subsequent screening visit. In one, the screening visit took place at a campus based clinical office while in the other screening occurred on the MAU. Results: In the office based study, 940 women were prescreened with 736 determined to be eligible to continue to a screening visit in the office. Of these, 254 (35%) presented for their screening visit. In the MAU based study, 472 women have been screened with 296 determined to be eligible and 207 (70%) returning for their initial screening visit. Potentially-eligible participants in the MAU based study were significantly more likely to return for screening (70% vs. 35%, p-value < 0.0001). Conclusions: Community-based research activities increase the likelihood of completion of initial screening visits. These data suggest that participants eligible for enrollment in HIV prevention research are more likely to return for subsequent screening visits if the location is the same in which prescreening visits occurred.