Process Evaluation of a Metformin RCT for People Living with HIV with Pre-Diabetes in Tanzania (META Trial): a study protocol

<ns3:p> Background Diabetes is a common comorbidity among people living with HIV. As the prevalence of diabetes rises across sub-Saharan Africa (SSA), there is an urgent need for effective interventions to address diabetes and pre-diabetic conditions in HIV patients. The META (Metformin Treatment in Africa) trial aims to assess the effectiveness of metformin in preventing diabetes among people living with HIV (PLHIV) on antiretroviral therapy (ART) who have pre-diabetes. This paper presents the process evaluation, which explores the feasibility, acceptability, and perceived effectiveness of the META trial and its intervention in real-world clinical settings in Dar es Salaam, Tanzania. Methods A mixed methods approach will be employed using a pragmatic realist theoretical framework. Qualitative data will be gathered through in-depth semi-structured interviews using stratified purposive sampling of trial participants (n=20), policymakers (n=10) and focus group discussions with associated health care providers and clinicians working in HIV and non-communicable disease care (n=20). Short cross-sectional surveys will be administered prior to interviews. Data collection will take place across five health facilities in Dar es Salaam, Tanzania. Qualitative data analysis will be complemented by Braun and Clarke’s ‘Reflexive Thematic Analysis’ technique, and survey data will be analysed using SPSS. Discussion The study’s pragmatic realist framework is expected to produce findings with greater depth, scope, and practical relevance. The study findings will contribute to existing knowledge regarding the experiential components of trials involving persons on ART and/or with pre-diabetes, as well as metformin-based interventions. Findings will support interpretation of trial outcomes, highlight facilitators and barriers to implementation, and provide evidence to guide future policy, scale-up, and integration of diabetes prevention strategies into HIV care in SSA. <ns3:bold>Process evaluation registration:</ns3:bold> Clinicaltrials.gov, NCT06743698 <ns3:bold>Trial registration:</ns3:bold> ISRCTN77382043 </ns3:p>