Early assessment and intervention by a dedicated health and social care professional team in the emergency department in older adults compared to treatment-as-usual: Health Economic Analysis Plan for within-trial cost effectiveness analysis Corcoran, Cian Ruiz-Adame Reina, Manuel Trépel, Dominic Health Economics Protocol Paper Health Economic Analysis Plan Protocol Paper Background: Older adults (aged over 65 years) experience high rates of adverse outcomes after presenting to emergency departments (EDs). The OPTI-MEND trial aimed to examine what impact intervention and early assessment by a dedicated health and social care professional (HSCP) team can have on quality of care for older adults in EDs. This paper presents the finalized Health Economic Analysis Plan (HEAP) specifying how the within-trial cost effectiveness analysis (CEA) will be conducted. Methods: This HEAP was developed retrospectively in collaboration with the OPTI-MEND team and the trial health economist to provide a plan to conduct the CEA. The HEAP aimed to fulfil international recommendations from a consensus of the required items for inclusion in HEAPs. In line with best practice guidelines, and to ensure full visibility in the scientific process, this paper makes the HEAP available in the public domain. Results: This HEAP illustrates the plan we followed when conducting our CEA. As this paper is a protocol it has no concrete results. A detailed list of all items in the HEAP are provided as Extended data on Open Science Framework at https://doi.org/10.17605/OSF.IO/YVG2P. Conclusions: Cost effectiveness analysis is an opportunity to extend beyond the primary clinical analysis of a trial. Congruent to a trial’s statistical analysis plan (SAP), a HEAP outlines the plan for estimating cost effectiveness and avoiding potentially spurious post-hoc analysis and questionable policy recommendations. 2025-01-29T08:02:14Z 2025-01-29T08:02:14Z 2023 journal article Corcoran, C., Ruiz-Adame, M., & Trépel, D. (2023). Early assessment and intervention by a dedicated health and social care professional team in the emergency department in older adults compared to treatment-as-usual: Health Economic Analysis Plan for within-trial cost effectiveness analysis. HRB Open Research, 6, 22. https://doi.org/10.12688/hrbopenres.13693.1 https://hdl.handle.net/10481/100869 10.12688/hrbopenres.13693.1 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional HRB Open Research