Impact of the Umoyo mother-infant pair model on HIV-positive mothers' social support, perceived stigma and 12-month retention of their HIV-exposed infants in PMTCT care: evidence from a cluster randomized controlled trial in Zambia.

BACKGROUND: Public health systems in resource-constrained settings have a critical role to play in the elimination of HIV transmission but are often financially constrained. This study is an evaluation of a mother-infant-pair model called "Umoyo," which was designed to be low cost and scalable in a public health system. Facilities with the Umoyo model dedicate a clinic day to provide services to only HIV-exposed infants (HEIs) and their mothers. Such models are in operation with reported success in Zambia but have not been rigorously tested. This work establishes whether the Umoyo model would improve 12-month retention of HEIs. METHODS: A cluster randomized trial including 28 facilities was conducted across two provinces of Zambia to investigate the impact on 12-month retention of HEIs in care. These facilities were offering Prevention of Mother-to-Child-Transmission (PMTCT) services and supported by the same implementing partner. Randomization was achieved by use of the covariate-constrained optimization technique. Secondary outcomes included the impact of Umoyo clinics on social support and perceived HIV stigma among mothers. For each of the outcomes, a difference-in-difference analysis was conducted at the facility level using the unweighted t test. RESULTS: From 13 control (12-month retention at endline: 45%) and 11 intervention facilities (12-month retention at endline: 33%), it was found that Umoyo clinics had no impact on 12-month retention of HEIs in the t test (- 11%; 99% CI - 40.1%, 17.2%). Regarding social support and stigma, the un-weighted t test showed no impact though sensitivity tests showed that Umoyo had an impact on increasing social support (0.31; 99% CI 0.08, 0.54) and reducing perceived stigma from health care workers (- 0.27; 99% CI - 0.46, - 0.08). CONCLUSION: The Umoyo approach of having a dedicated clinic day for HEIs and their mothers did not improve retention of HEIs though there are indications that it can increase social support among mothers and reduce stigma. Without further support to the underlying health system, based on the evidence generated through this evaluation, the Umoyo clinic day approach on its own is not considered an effective intervention to increase retention of HIV-exposed infants. TRIAL REGISTRATION: Pan African Clinical Trial Registry, ID: PACTR201702001970148 . Prospectively registered on 13 January 2017.