Background: Different mechanisms for delivery of rectal microbicides for HIV prevention are in development. We assessed acceptability of three distinct delivery mechanisms and identified preferences among mechanisms.
Methods: From 2009 to 2010 110 HIV-uninfected men and women who engage in receptive anal intercourse participated in a randomized crossover trial of rectal delivery products in Los Angeles. Eligible participants were assigned to a random sequence of three over-the-counter products (an enema, a lubricant filled applicator, and a suppository) distributed every two weeks over a six week period for use 3-5 times but not required during sex. Summary acceptability scores, from one to five, were created based on product evaluations obtained from computer-assisted self-interviews. Mixed linear models were fit to estimate preferences among products and to estimate age and gender effects.
Results: Seventy-eight percent of participants were male and the median age was 39.4 years old (IQR: 29.6, 49.3). Overall, the estimated mean acceptability scores were 3.5 (95% CI: 3.4, 3.6), 3.7 (95% CI: 3.6, 3.8), and 3.4 (95%: CI: 3.3, 3.5) for the enema, applicator, and suppository, respectively. Product preferences differed according to gender (interaction p=0.03) and age (interaction p=0.003). Males preferred the applicator to the suppository (difference: 0.2, p=0.01), but there was no preference between the applicator and the enema (difference: 0.1, p=0.21) or the enema and suppository (difference: 0.1, p=0.20). Females preferred the applicator to the enema (difference: 0.6, p=0.0003) and the suppository (difference: 0.5, p=0.003), but there was no preference between the enema and the suppository (difference: – 0.1, p=0.47). Product preferences among younger males were similar to those among women.
Conclusion: Overall, the applicator with lubricant was the most acceptable product; however, the magnitude of preference differed by gender and age. These findings should be considered in the development of rectal microbicides to enhance acceptability.
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