Receipt of infant HIV DNA PCR test results is associated with a reduction in retention of HIV-exposed infants in integrated HIV care and healthcare services: a quantitative sub-study nested within a cluster randomised trial in rural Malawi

BACKGROUND: Retention of HIV-infected mothers in integrated HIV and healthcare facilities is effective at reducing mother-to-child-transmission (MTCT) of HIV. In the context of Option B+, we examined maternal and HIV-exposed infant retention across three study arms to 18 months postpartum: mother-and-infant clinics (MIP), MIP with short-messaging service (MIP + SMS) and standard of care (SOC). In particular, we focused on the impact of mothers receiving an infant's HIV PCR test result on maternal and infant study retention. METHODS: A quantitative sub-study nested within a cluster randomised trial undertaken between May 2013 and August 2016 across 30 healthcare facilities in rural Malawi enrolling HIV-infected pregnant mothers and HIV-exposed infants on delivery, was performed. Survival probabilities of maternal and HIV-exposed infant study retention was estimated using Kaplan-Meier curves. Associations between mother's receiving an infant's HIV test result and in particular, an infant's HIV-positive result on maternal and infant study retention were modelled using time-varying multivariate Cox regression. RESULTS: Four hundred sixty-one, 493, and 396 HIV-infected women and 386, 399, and 300 HIV-exposed infants were enrolled across study arms; MIP, MIP + SMS and SOC, respectively. A total of 47.5% of mothers received their infant's HIV test results < 5 months postpartum. Receiving an infant's HIV result by mothers was associated with a 70% increase in infant non-retention in the study compared with not receiving an infant's result (HR = 1.70; P-value< 0.001). Receiving a HIV-positive result was associated with 3.12 times reduced infant retention compared with a HIV-negative result (P-value< 0.001). Of the infants with a HIV-negative test result, 87% were breastfed at their final study follow-up. CONCLUSIONS: Receiving an infant's HIV test result was a driving factor for reduced infant study retention, especially an infant's HIV-positive test result. As most HIV-negative infants were still breastfed at their last follow-up, this indicates a large proportion of HIV-exposed infants were potentially at future risk of MTCT of HIV via breastfeeding but were unlikely to undergo follow-up HIV testing after breastfeeding cessation. Future studies to identify and address underlying factors associated with infant HIV testing and reduced infant retention could potentially improve infant retention in HIV/healthcare facilities. TRIAL REGISTRATION: Pan African Clinical Trial Registry: PACTR201312000678196