Patterns of Adherence to a Dapivirine Vaginal Ring for HIV-1 Prevention Among South African Women in a Phase III Randomized Controlled Trial.

Background: Persistent use of HIV prevention methods can be a challenge, particularly for some younger women. The long-acting, discreet, woman-centric dapivirine vaginal ring offers promise as a prevention method with less user burden, which could support continued use. We assessed dapivirine vaginal ring use to understand adherence patterns and identify characteristics influencing patterns.

Setting: Participants enrolled in South Africa in the MTN-020/ASPIRE randomized placebo-controlled trial.

Methods: We used group-based trajectory modeling to identify clusters of participants with similar longitudinal patterns of adherence in the last year of participation and potential predictors of group membership. Women with at least 1 year of follow-up were included (n = 626).

Results: Five adherence patterns were identified: (1) consistently high, 34%, (2) consistently moderate, 34%, (3) consistently low, 16%, (4) decreasing, 9%, and (5) increasing, 7%. Women younger than 22 years [adjusted odds ratio (AOR) 1.8, 95% confidence interval (CI): 1.0 to 3.0], using an intrauterine device (AOR 3.3, 95% CI: 1.4 to 7.8) or oral contraceptives (AOR 3.9, 95% CI: 1.7 to 8.9), experiencing menses (AOR 1.8, 95% CI: 1.1 to 3.0), and who reported inconsistent condom use (AOR 1.8, 95% CI: 1.0 to 3.3) were more likely to be classified as consistently low compared to consistently high (referent).

Conclusions: Most South African women successfully persisted with a moderate or high level of use. Encouraging ring replacement with completion of menses may help to decrease concerns about hygiene and improve persistence. Associations between contraception and persistent low adherence suggest efforts may be needed to ensure contraceptive method choice does not interfere with ring use.