Outcomes after loss to follow-up for pregnant and postpartum women living with HIV and their children in Kenya: A prospective cohort study

Abstract

Background: Many prevention of vertical transmission (PVT) studies assess outcomes within 12 months postpartum and exclude those lost to follow-up (LTFU), potentially biasing outcomes toward those retained in care. Setting: Five public facilities in western Kenya. Methods: We recruited women living with HIV (WLH) ≥18 years enrolled in antenatal clinic (ANC). WLH retained in care (RW) were recruited during pregnancy and followed with their children through 6 months postpartum; WLH LTFU (LW, last visit >90 days) after ANC enrollment and ≤6 months postpartum were recruited through community tracing. Re-contact at 3 years was attempted for all participants. Primary outcomes were retention and child HIV-free survival. Generalized linear regression was used to estimated risk ratios (RR) for associations with becoming LTFU by 6 months postpartum, adjusting for age, education, facility, travel time to facility, gravidity, income, and new vs. known HIV positive at ANC enrollment. Results: 333 WLH (222 RW, 111 LW) were recruited from 2018-2019. More LW versus RW were newly diagnosed with HIV at ANC enrollment (49.6% vs. 23.9%) and not virally suppressed at study enrollment (40.9% vs. 7.7%). 6-month HIV-free survival was lower for children of LW (87.9%) versus RW (98.7%). At 3 years, 230 WLH were retained in care (including 51 previously LTFU before 6 months), 30 transferred, 70 LTFU, and 3 deceased. 3-year child HIV-free survival was 81.9% (92.0% for children of RW, 58.6% for LW), 3.7% were living with HIV, 3.7% deceased, and 10.8% had unknown HIV/vital status. Being newly diagnosed with HIV at ANC enrollment was the only factor associated with becoming LTFU (aRR 1.21, 95% CI 1.11-1.31). Conclusion Outcomes among those LTFU were worse than those retained in care, underscoring the importance of retention in PVT services. Some, but not all, LW re-engaged in care by 3 years, suggesting that PVT services must better address the barriers and transitions women experience during pregnancy and postpartum.