Economic evaluation protocol of two randomized trials of a mHealth Intervention for noncommunicable diseases patients with depressive symptoms in São Paulo, Brazil, and Lima, Peru (Preprint)

BACKGROUND Mobile health (mHealth) interventions provide significant strategies for improving access to health services [1], offering one potential solution to reduce the mental health treatment gap. Economic evaluation can contribute with evidence to the local policy of and program development in mental health. OBJECTIVE This paper presents the protocol for an economic evaluation conducted alongside two randomized controlled trials (RCTs) to evaluate the effectiveness of a psychological intervention delivered through a technological platform (CONEMO) to treat depressive symptoms in people with diabetes and/or hypertension. METHODS The economic evaluation uses a within-trial analysis to evaluate the incremental costs and health outcomes of CONEMO compared to usual enhanced care from society and public health system perspectives. We recruited participants from the public health systems in Sao Paulo, Brazil (n=880), and Lima, Peru (n=432), and randomized to intervention or enhanced usual care groups RCTs. We will conduct cost-effectiveness and cost-utility analyses, providing estimates of the cost to decrease depressive symptoms by 50% or more. The cost per quality-adjusted life-year (QALY) gained. For effectiveness, our primary outcome is the proportion of participants with a 50% reduction in the Patient Health Questionnaire (PHQ- 9) score at 3-month - calculated through logistic regression. For utility, our primary outcome is the QALYs gained, measured by the EQ-5D-3L. We assessed each dimension at months 3 and 6. Costs will include both direct and indirect costs. The method of measurement will be mixed methods, with a combination of the Top-down and Bottom-up approaches. We will collect unit costs from the RCTs and national administrative databases. We will also calculate incremental cost-effectiveness ratios (ICERs) and display 95% confidence intervals (CI) from non-parametric bootstrapping (1000 replicates). We will calculate the incremental cost-effectiveness rate, as well as a deterministic and probabilistic sensitivity analysis. Finally, we will draw a Cost-Effectiveness Acceptability Curve (CEAC) to compare a range of possible cost-effectiveness limits. RESULTS The economic evaluation project had its project charter in June 2018 and is expected to be completed in September 2021. The final results will be available in the second half of 2021. CONCLUSIONS We expect to assess if CONEMO plus enhanced usual care is a cost-effective strategy to improve depressive symptoms in this population compared to usual enhanced care. This study will assist health managers in allocating additional resources for mental health initiatives and will inform policymakers. It also provides a basis for further research on how this emerging technology and enhanced usual care can improve mental health and well-being in low-income settings. CLINICALTRIAL ClinicalTrials.gov - Brazil NCT02846662 and Peru NCT03026426