25493600

PMC4397579

2-D43 TW01039-06/TW/FIC NIH HHS/United States
5T32AI070114/AI/NIAID NIH HHS/United States
P30 AI050410/AI/NIAID NIH HHS/United States
P30-AI50410/AI/NIAID NIH HHS/United States
R24 TW007988/TW/FIC NIH HHS/United States
U48-CCU409660-09/PHS HHS/United States
U48-DP000059-01/DP/NCCDPHP CDC HHS/United States
U48-DP001944-01/DP/NCCDPHP CDC HHS/United States

CDC Public Access

Objective

Estimate association between postpartum antiretroviral adherence and breastmilk HIV-1 transmission

Design

Prospective cohort study

Methods

Mother-infant pairs were randomized after delivery to immediately begin receiving 28 weeks of either triple maternal antiretrovirals (zidovudine, lamivudine, and either nevirapine, nelfinavir, or lopinavir-ritonavir) or daily infant nevirapine as part of the Breastfeeding, Antiretrovirals, and Nutrition study. Associations between postpartum antiretroviral adherence and rate of breastmilk HIV-1 transmission were estimated using Cox models. We measured adherence over four postpartum time intervals using pill count, suspension bottle weight, and maternal self-report. Adherence was categorized and lagged by one interval. Missing adherence measures were multiply imputed. Infant HIV-1 infection was determined by DNA PCR every 2-6 weeks. The primary endpoint was infant HIV-1 infection by 38 weeks of age among infants alive and uninfected at 5 weeks.

Results

Analyses included 1479 mother-infant pairs and 45 transmission events. Using pill count and bottle weight information, 22-40% of mother-infant pairs at any given interval were <90% adherent. Having ≥90% adherence was associated with a 52% (95% CI 3-76%) relative reduction in the rate of breastmilk HIV-1 transmission, compared with having <90% adherence when controlling for study arm, breastfeeding status, and maternal characteristics. Complete case analysis rendered similar results (n=501; relative reduction 59%, 95% CI 6-82%).

Conclusion

Non-adherence to extended postpartum ART regimens in ‘real world’ settings is likely to be higher than that seen in BAN. Identifying mothers with difficulty adhering to antiretrovirals, and developing effective adherence interventions, will help maximize benefits of ARV provision throughout breastfeeding.