Protocol for the Economic Evaluation of Group Interpersonal Therapy for Postnatal Depression Compared with High-Quality Standard Care in Kenya and Lebanon (SUMMIT Trial)

Introduction One in six women experience postnatal depression globally. Treatment is often unavailable, which increasing risks of long-term depression among mothers and poorer developmental outcomes for their children. This protocol outlines the first within-trial economic evaluation to inform policymakers about the value for money of culturally adapted group interpersonal therapy (group-IPT) to improve child cognitive development and postnatal depression outcomes. Methods We will conduct a full economic evaluation of group-IPT within the Supporting Mothers’ Mental Health with Interpersonal Therapy (SUMMIT) trial. SUMMIT is an individually randomised, controlled superiority trial in Kenya and Lebanon. The economic evaluation will adopt a societal perspective, comprising provider and patient perspectives. This will be based on an intention-to-treat analysis, over a 52-week time horizon in line with trial follow-up. The cost and cost-effectiveness of group-IPT will be compared with high-quality standard care in the control arm. Costs and outcomes will be analysed to estimate an incremental cost-effectiveness ratio (ICER) based on child cognitive development, the primary trial outcome. We will also estimate ICERs for statistically significant secondary trial outcomes, which include maternal depression and quality of life. Two-way sensitivity analyses will vary cost drivers and outcomes within confidence bounds to investigate uncertainty. To inform policymakers on affordability, we will estimate the cost of group-IPT at scale relative to available public resources. We will also investigate how group-IPT outcomes are distributed across socioeconomic groups and whether participating mothers experience financial hardship due to care-seeking. Ethics and dissemination The SUMMIT trial and economic evaluation received ethical approval from University College London’s Research Ethics Committee in the United Kingdom (23699/001), Saint Joseph University Secretariat of the University Ethics Centre in Lebanon (CEHDF 1854) and Kenyatta National Hospital and the University of Nairobi in Kenya (KNH/ERC/Mod&SAE/425). Economic evaluation results will be disseminated to various local and international stakeholders via peer-reviewed journal publications, policy briefs, conferences and workshops. Trial registration number The ISRCTN Registry: ISRCTN15154316. Registered on 27 September 2023: https://doi.org/10.1186/ISRCTN15154316