ART history prior to conception: trends and association with postpartum disengagement from HIV care in Khayelitsha, South Africa (2013–2019): a retrospective cohort study

INTRODUCTION: In recent years, the expansion of HIV treatment eligibility has resulted in an increase in people with antiretroviral therapy (ART) experience prior to pregnancy but little is known about postpartum engagement in care in this population. We examined differences in disengagement from HIV care after delivery by maternal ART history before conception. METHODS: We analysed data from people living with HIV (aged 15-49) in Khayelitsha, South Africa, with ≥1 live birth between April 2013 and March 2019. We described trends over time in ART history prior to estimated conception, classifying ART history groups as: (A) on ART with no disengagement (>270 days with no evidence of HIV care); (B) returned before pregnancy following disengagement; (C) restarted ART in pregnancy after disengagement; and (D) ART new start in pregnancy. We used Kaplan-Meier curves and proportional-hazards models (adjusted for maternal age, number of pregnancy records and year of delivery) to examine the time to disengagement from delivery to 2 years postpartum. RESULTS: Among 7309 pregnancies (in 6680 individuals), the proportion on ART (A) increased from 19% in 2013 to 41% in 2019. The proportions of those who returned (B) and restarted (C) increased from 2% to 13% and from 2% to 10%, respectively. There was a corresponding decline in the proportion of new starts (D) from 77% in 2013 to 36% in 2019. In the first recorded pregnancy per person in the study period, 26% (95% CI 25-27%) had disengaged from care by 1 year and 34% (95% CI 33-36%) by 2 years postpartum. Individuals who returned (B: aHR 2.10, 95% CI 1.70-2.60), restarted (C: aHR 3.32, 95% CI 2.70-4.09) and newly started ART (D: aHR 2.41, 95% CI 2.12-2.74) had increased hazards of postpartum disengagement compared to those on ART (A). CONCLUSIONS: There is a growing population of people with ART experience prior to conception and postpartum disengagement varies substantially by ART history. Antenatal care presents an important opportunity to understand prior ART experiences and an entry into interventions for strengthened engagement in HIV care.