Abstract Background Few economic evaluations distinguish between the cost and impact of evidence-based interventions and the strategies used to improve their implementation. This distinction is essential for understanding whether a strategy is cost-effective, why it works, and the resources required to replicate its success. The Systems Analysis and Improvement Approach Hypertension (SAIA-HTN) trial evaluated an implementation strategy (“SAIA”) designed to improve hypertension care among people living with HIV (PLHIV) in Mozambique. We developed a mathematical model to estimate the cost-effectiveness of both the evidence-based intervention (including hypertension screening, pharmacological treatment and follow up, and lifestyle modifications such as diet and exercise) and the SAIA implementation strategy. Methods We constructed a decision-analytic, state-transition model that simulated cardiovascular risk, outcomes, and associated costs for PLHIV receiving hypertension care in Mozambique using a health systems perspective. Model inputs came from published epidemiological studies and primary data from the SAIA-HTN trial on intervention and implementation strategy effectiveness and costs. We estimated the incremental cost-effectiveness (willingness to pay 647/DALY averted, GDP per capita in Mozambique) of rolling out both components, compared to a “status quo” scenario where screening and treatment of hypertension remained at their current (very low) levels. Costs were reported in 2023 US dollars, and costs and outcomes were discounted at 3% over a ten-year time horizon. Results Scaling up screening and pharmacological treatment of hypertension in Mozambique would have an incremental cost-effectiveness ratio (ICER) of around 212 per disability-adjusted life year (DALY) averted and cost an additional 4. 61 per person per year. Incremental to the intervention, the SAIA implementation strategy would have an ICER of 44 per DALY averted and cost an additional 0. 79 per person per year. The average reduction in ten-year cardiovascular risk would be 29. 3% for the intervention and 40. 3% if the SAIA implementation strategy were co-introduced. Conclusions Our model is a tool for implementation scientists, policymakers, and researchers aiming to assess cardiovascular interventions and associated implementation strategies among PLHIV. Its application to SAIA-HTN suggests that this is a cost-effective strategy for improving hypertension care, but only in the presence of adequate blood pressure equipment, training, and medications. Our study shows how implementation strategies require a minimum threshold of health system readiness to generate meaningful health impact. Trial registration ClinicalTrials. gov (NCT04088656).
Malhotra et al. (Wed,) studied this question.