Process, impact and economic evaluation of differentiated service delivery models for HIV treatment in Mozambique

Abstract

HIV treatment has been available in Mozambique since 2004. However, coverage and retention on antiretroviral therapy (ART) remains suboptimal. In November 2018, the Ministry of Health launched guidelines to implement eight Differentiated Service Delivery Models (DSDMs) for HIV treatment that aimed to increase health system efficiency and ultimately reduce HIV associated mortality. We conducted a process, impact and economic evaluation of the implementation of these models. For the process evaluation, we applied the Consolidated Framework for Implementation Research (CFIR) to identify determinants of successful implementation of DSDMs through in-depth interviews of managers and providers. For the impact evaluation, an uncontrolled interrupted time series analysis compared 12-month retention after ART initiation in the pre- and post-implementation of DSDMs periods, and explored the effect of COVID-19 on ART retention. The economic evaluation consisted of a cost-effectiveness analysis of three years of DSDMs implementation (2019-2021), and a budget impact analysis for 2022-2024 period. The CFIR constructs of Relative Advantage, Complexity, and Patient Needs and Resources, were identified as facilitators of implementation, whereas Available Resources and Access to Knowledge and Information were identified as substantial barriers. COVID-19 (an inductive theme) improved uptake of individual DSDMs that reduced patient visits, but interrupted implementation of group-based models. Our impact evaluation included 613 facilities and 1,094,430 clients who started ART during the study period, of whom 65% were women and 7%, 20% and 73% were children, adolescents and young adults, and adults, respectively. The overall impact was an increase in 24.5 (95% CI, 21.1 to 28.0) percentage points in 12-month retention. The smallest impact was observed in children (6.1% (95% CI, 1.3% to 10.9%)) and the largest was observed in males (29.7% (95% CI, 25.6% to 33.7%). COVID-19 had a negative effect on 12-month retention (-10·0% (95% CI, -18·2% to -1·8)). In the economic evaluation, the DSDMs dominated the conventional model of treatment by being less expensive and more effective in retaining clients 12-months after ART initiation. The mean increase in ART retention and decrease in costs were 14.9% and US$ 6,070,391 per year, respectively, and their implementation was estimated to save approximately US$14 million to the health system from 2022 to 2024. This dissertation contributes to implementation science literature by comprehensively evaluating the nationawide implementation of eight DSDMs and informing on their health and economic impact, as well as on the determinants of their successful implementation.