Antiretroviral (ART) adherence can be challenging for postpartum women and may result in virologic failure (VF). We examined predictors of VF and viral re-suppression in postpartum women randomized to continue ART in PROMISE 1077HS.
Asymptomatic HIV+, non-breastfeeding women with pre-ART CD4 cell counts 400 cells/mm3 who started ART during pregnancy were randomized up to 42 days after delivery to continue or discontinue treatment. Women were enrolled from 12/2011-11/2014. The preferred regimen was LPV/RTV with TDF/FTC. Viral load and self-reported adherence were collected every 12 weeks. VF was defined as 2 consecutive viral loads >1,000 copies/mL after 24 weeks on ART. Viral re-suppression was defined as 2 consecutive viral loads 1,000 copies/mL after VF. For this analysis, self-reported adherence was dichotomized as missing versus not missing ART doses in the prior 4 weeks. Predictors of VF and re-suppression were examined using Cox proportional hazards univariable and multivariable regression, with adherence as a time-varying covariate. Other predictors were values at baseline.
Among the 802 women randomized to continue ART, median age at entry was 27 years (IQR 23-32) and median CD4 696 cells/mm3 (IQR 576-865). Participants were enrolled from South America/Caribbean (39%), Africa (28%), Asia (25%), and the United States (8%). Of 175 women with VF, 139 had resistance data available. Of these, 17/139 (12%) failed with resistance to their current regimen. There was an estimated 0.12 probability of VF by week 48, 0.20 by week 96, and 0.25 by week 144. In univariable regressions, self-report of any missed ART doses in the prior 4 weeks, younger age, region, and shorter duration of pre-entry ART were predictive of VF. In the final multivariable model for VF, significant predictors included missed ART doses within the prior 4 weeks, younger age, shorter duration of pre-entry ART, and region (South America/Caribbean) (Table). Among the 175 (22%) women with VF, the probability of re-suppression was 0.37 by 48 weeks, 0.48 by 96 weeks, and 0.57 by 144 weeks. There were no statistically significant predictors of re-suppression.
A simple 4-week ART recall question predicted first VF among women in PROMISE 1077HS. Postpartum women who have VF are high risk for continued viremia, and further research should explore strategies that can successfully support ART adherence for this vulnerable population.