Adherence to Antiretroviral Therapy During and After Pregnancy: Cohort Study on Women Receiving Care in Malawi's Option B+ Program

Abstract

Background: Adherence to antiretroviral therapy (ART) is crucial to preventing mother-to-child transmission of human immunodeficiency virus (HIV) and ensuring the long-term effectiveness of ART, yet data are sparse from African routine care programs on maternal adherence to triple ART.

Methods: We analyzed data from women who started ART at 13 large health facilities in Malawi between September 2011 and October 2013. We defined adherence as the percentage of days "covered" by pharmacy claims. Adherence of ≥90% was deemed adequate. We calculated inverse probability of censoring weights to adjust adherence estimates for informative censoring. We used descriptive statistics, survival analysis, and pooled logistic regression to compare adherence between pregnant and breastfeeding women eligible for ART under Option B+, and nonpregnant and nonbreastfeeding women who started ART with low CD4 cell counts or World Health Organization clinical stage 3/4 disease.

Results: Adherence was adequate for 73% of the women during pregnancy, for 66% in the first 3 months post partum, and for about 75% during months 4-21 post partum. About 70% of women who started ART during pregnancy and breastfeeding adhered adequately during the first 2 years of ART, but only about 30% of them had maintained adequate adherence at every visit. Risk factors for inadequate adherence included starting ART with an Option B+ indication, at a younger age, or at a district hospital or health center.

Conclusions: One-third of women retained in the Option B+ program adhered inadequately during pregnancy and breastfeeding, especially soon after delivery. Effective interventions to improve adherence among women in this program should be implemented.

Keywords: HIV; Option B+; adherence; antiretroviral therapy; mother-to-child-transmission.

Figure 1.

Flow of eligibility of study participants. Abbreviation: ART, antiretroviral therapy.

Figure 2.

Probability of maintaining adequate adherence (≥90%) at every clinic visit (lines) and 95% confidence intervals (shaded areas) compared according to pregnancy and breastfeeding status at the start of antiretroviral therapy (ART).

Figure 3.

Adherence during 3-month intervals after antiretroviral therapy (ART) initiation. Adherence is compared according to pregnancy and breastfeeding status at start of ART: pregnant (A, C) or breastfeeding (B, D). Observed and inverse probability of censoring weighted (IPCW) estimates are shown for adherence levels during 3-month intervals after ART initiation. Data represent percentages (with 95% confidence intervals) of women with adherence of <90% or ≥90%. Observed data include women retained in care by the end of the interval. IPCW-adjusted data represent a pseudopopulation that would have been observed without censoring.

Figure 4.

Adherence before and after delivery. Observed (A) and inverse probability of censoring weighted (IPCW) (B) estimates are shown; data represent percentages (95% confidence intervals) of women with adherence of <90% or ≥90% during pregnancy and in 3-month intervals after delivery. IPCW-adjusted estimates are adjusted for censoring, representing a pseudopopulation that would have been observed without censoring. Data are from 765 women who started antiretroviral therapy (ART) during pregnancy and could be linked to infant records (see Figure 1).