Predictors of Viremia in Postpartum Women on Antiretroviral Therapy

Risa M. Hoffman, MD, MPH; Meredith G. Warshaw, MSS, MA; K. Rivet Amico, PhD; Jose Pilotto, MD, PhD; Gaerolwe Masheto, MD; Jullapong Achalapong, MD; Elizabeth Machado, MD, PhD; Kulkanya Chokephaibulkit, MD; Geraldo Duarte, MD; Esau João, MD, PhD; Kathleen K. Graham, PharmD; Katherine M. Knapp, MD; Alice M. Stek, MD; Gwendolyn B. Scott, MD; Anne Coletti, MS; Amy J. Loftis, BS; Nahida Chakhtoura, MD; Judith S. Currier, MD

Disclosures

J Acquir Immune Defic Syndr. 2020;83(1):72-80. 

In This Article

Abstract and Introduction

Abstract

Background: HIV-infected, postpartum women on antiretroviral therapy (ART) have high rates of viremia. We examined predictors of postpartum viremia in the PROMISE study.

Methods: Women with pre-ART CD4+ T-cell counts ≥400 cells/mm3 who started ART during pregnancy were randomized postpartum to continue ART (CTART) or discontinue ART (DCART). Viral load and self-reported adherence were collected every 12 weeks, up to 144 weeks. Women in DCART reinitiated therapy when clinically indicated. Viremia was defined as 2 consecutive viral loads >1000 copies/mL after 24 weeks on ART. Adherence was dichotomized as missing versus not missing ART doses in the past 4 weeks. Predictors of viremia were examined using Cox proportional hazards regression with adherence as a time-varying covariate.

Results: Among 802 women in the CTART arm, median age at entry was 27 years and median CD4+ T-cell count 696 cells/mm3. Of 175 women in CTART with viremia (22%), 141 had resistance data, and 12% had resistance to their current regimen. There was an estimated 0.12 probability of viremia by week 48 and 0.25 by week 144. Predictors of viremia included missed ART doses within the past 4 weeks, younger age, shorter duration of pre-entry ART, and being from the South American/Caribbean region. Of 137 women in DCART who reinitiated therapy, probability of viremia was similar to CTART (0.24 by week 96; 0.27 by week 144).

Conclusions: Rates of postpartum viremia are high and viremia is more likely in younger postpartum women who start ART later in pregnancy. Interventions should target these higher-risk women.

Introduction

More than 1 1/2 million HIV-infected women become pregnant and deliver annually, and most of these women receive antiretroviral therapy (ART) antepartum and are expected to continue lifelong ART after delivery.[1] Previous studies have shown high rates of nonadherence and loss of virologic control among postpartum HIV-infected women.[2,3] A systematic review and meta-analysis of over 20,000 postpartum women from 51 studies ranging from the US to Africa found that only 53% [95% confidence interval (CI): 32.8% to 79.7%] of postpartum women had optimal adherence.[2] Predictors of poor adherence and viremia have included younger age,[3,4] nondisclosure/stigma,[5] recent HIV diagnosis,[4] substance use,[6] and a low level of health literacy about HIV and ART.[5]

The clinical benefits of postpartum ART were reported from the "HAART (highly active antiretroviral therapy) Standard (HS)" component of the Promoting Maternal and Infant Safety Everywhere (PROMISE HS) study, a trial of women with pre-ART CD4+ T-cell counts of ≥400 cells/mm3 randomized to continue or discontinue three-drug ART after delivery, conducted in settings where women did not breastfeed after delivery.[7] The study was initiated before the results of the Strategic Timing of AntiRetrovial Treatment (START) study, which showed the clinical benefits of immediate treatment of HIV regardless of clinical stage and CD4+ T-cell count.[8] Despite improved clinical outcomes with continued ART, PROMISE 1077HS revealed high rates of viremia (23%) alongside low rates of resistance-associated mutations, suggesting nonadherence.[7] The PROMISE 1077HS study design provides a unique opportunity to explore predictors of postpartum viremia in women on ART, and to compare differences among women who remained on ART postpartum to those who stopped and reinitiated later for clinical indications. We hypothesized that women who continued ART postpartum would have higher rates of viremia because of high self-rated health compared with women who discontinued ART postpartum and started later for clinical indications. We also explore rates of viral resuppression following loss of virologic control among women randomized to continue ART postpartum.

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