Assessing the implementation of a multi-component hypertension program in a Guatemalan under-resourced dynamic context: An application of the RE-AIM/PRISM extension for sustainability and health equity.

Background: The COVID-19 pandemic necessitated rapid changes in the delivery of care across public primary care settings in rural Guatemala in 2020. In response, a hypertension program implemented within the public primary care system required multiple adaptations, providing an illustrative example of dynamic implementation amidst changing context in an under-resourced setting. This study describes the evolvability of an evidence-based intervention (EBI; protocol-based hypertension treatment) and one of its main implementation strategies (team-based collaborative care) during the COVID-19 pandemic and discusses implications for health equity and sustainability. Methods: This convergent mixed methods analysis assessed implementation across five Ministry of Health districts during the initial phase of the pandemic. Qualitative and quantitative data were collected, analyzed, and integrated, informed by the RE-AIM (Reach, Effectiveness, Adoption, Implementation Maintenance) Framework's extension for sustainability, and its contextual enhancement, PRISM (Pragmatic, Robust, Implementation and Sustainability Model). For RE-AIM, we focused on the "Implementation" domain, operationalizing it qualitatively as continued delivery and adaptations to the EBI and implementation strategy, and quantitatively as the extent of delivery over time. We conducted 18 in-depth interviews with health providers / administrators (n=8) and study staff (n=10) and performed a matrix-based thematic-analysis. Qualitative results informed the selection of quantitative implementation summarized as behavior over time graphs. Quantitative implementation data and illustrative quotes are presented as joint displays. Results: In relation to implementation, several organic adaptations hindered delivery, threatened sustainability, and may have exacerbated health inequities. Planned adaptations enhanced program delivery and may have supported improved equity and sustainability. Salient PRISM factors that influenced implementation included "Organizational perspective of the EBI", "Fit" and "Implementation and sustainability infrastructure". Facilitators to continued delivery included the perception that the EBI is beneficial, program champions, and healthcare team organization. Barriers included the perception that the EBI is complicated, competition with other primary care activities, and temporary suspension of services due to COVID-19. Conclusions: Multi-level contextual changes led to numerous adaptations of the EBI and implementation strategy. Systems thinking approaches may shed light on how a program's sustainability and its equitable delivery are influenced by adaptations over time in response to dynamic, multi-level contextual factors. Trial registration: NCT03504124.