Study Protocol for a Delphi Process to Develop a Climate Impact Extension to the Consolidated Health Economic Evaluation Reporting Standard (CHEERS) 2022-the CHEERS ClimatE Checklist.

introductionThe healthcare sector has significant environmental impacts, particularly through greenhouse gas emissions. Reducing its climate footprint is therefore essential for achieving political goals such as net-zero and climate-friendly healthcare. While health economic evaluation (HEE) methods compare the costs and consequences of two or more interventions, these analyses rarely consider climate impacts. Some studies have begun to determine climate impacts parallel to or integrated into HEEs. Life cycle assessment (LCA) could be used to integrate climate impacts by considering these results as effects or monetised climate footprints. However, a reporting standard is needed for using these climate-extended economic evaluations in evidence-based decision-making. This protocol describes using an online Delphi process to incorporate climate impacts into the Consolidated Health Economic Evaluation Reporting Standard (CHEERS), called CHEERS Climate Extension (CHEERS ClimatE). METHODS AND ANALYSIS: The development of CHEERS ClimatE will proceed through five key stages. First, the preliminary steering group develops in consultation with an advisory board a proposal for the CHEERS ClimatE reporting standard based on a transparency checklist that combines three standards for carbon footprint calculations into the CHEERS framework. The mapping was complemented by reviewing studies that incorporate climate impacts in HEE. Second, for the Delphi process, international experts in HEE and LCA with at least one year of academic experience will be invited to participate in an online pre-survey. We aim to recruit at least 40 participants. Expecting various drop-outs, we aim to reach a consensus with at least 20 participants per Delphi round. Third, an expected three-round Delphi process will be conducted to validate and refine the proposed elements. Participants will rate each item using a 9-point Likert scale and will have the opportunity to comment on each item and propose new items. Consensus is defined with the target of a 70% agreement. Unless consensus is reached, a moderated video conference may be held as a fourth round. Fourth, following other CHEERS extensions, the consented checklist will be piloted using thematically relevant case studies. While substantial changes are not anticipated, minor revisions to individual items may be considered and ratified by the steering group and advisory board. The fifth stage is the publication of the final checklist. ETHICS AND DISSEMINATION: This study has been approved by the ethics committee of the University of Bremen (2024-25). The findings of the Delphi study will be published in a peer-reviewed journal and presented at conferences.