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

Introduction

Older adults disproportionately experience adverse outcomes following presentation within Emergency Departments (EDs) (Cassarino et al., 2021). The OPTI-MEND trial introduced a dedicated team of health and social care professionals in the emergency department to focus on timely assessment and intervention among people aged 65 years and over and, compared to usual care, examined how the teams changed length of stay and emergency readmissions (Cassarino et al., 2021). The trial was conducted between December 2018 and May 2019 at University Hospital Limerick in Limerick, Ireland. The primary clinical analysis showed that “early assessment and intervention by a dedicated ED-based HSCP team reduced ED length of stay and the risk of hospital admissions among older adults, as well as improving patient satisfaction” (Cassarino et al., 2021).

By extension of this primary clinical analysis, OPTI-MEND plans to conduct a within-trial cost effectiveness analysis. To estimate the joint distribution of costs and effects, the economic component examines how early assessment and intervention by a dedicated HSCP team might change health-related quality of life (as the effect on health outcomes) and, following intervention, the changes in resource use (to estimate salient costs). The aim of this economic evaluation is to report the incremental cost effectiveness ratio (ICER) of this new service (HSCP teams) compared to treatment as usual. Furthermore, as cost effectiveness analyses aim to inform healthcare decision makers on the evidence supporting implementing a policy of HSCP services, analysis of uncertainty will report the probability of whether intervention represents value for money to the Irish Health Service Executive (HIQA, 2020).

Part of the aim of making available this HEAP is to illustrate how the CEA will be carried out. This is part of the Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS, 2022) Statement: Updated Reporting Guidance for Health Economic Evaluations (CHEERS) checklist (item 4) (Husereau et al., 2022) which requests that a CEA “indicates whether a health economic analysis plan was developed and where available” (Husereau et al., 2022).

Methods

This HEAP was developed retrospectively in collaboration with the OPTIMEND trial team and according to the consensus items laid out by Thorn et al. (2021) in their Delphi consensus survey of experts. Information was taken from the original paper by Cassarino et al. (2021), from the CEA working paper, and from the co-authors of the CEA paper.

In line with the data collection for the clinical effectiveness study, data for the economic evaluation was collected at baseline (immediately post index visit) and at two subsequent follow-up timepoints: 30-days post visit and 6-months post visit. All analyses will be carried out after the completion of the trial, using STATA 17 (software).

Health state utilities will be estimated based on responses to the EQ-5D-5L questionnaire and the Irish value set (Hobbins et al., 2018b). The area under the curve approach will then be used to estimate quality adjusted life years (QALYs) across the three timepoints described above.

Data on individual participant resource usage post ED discharge was collected and will be multiplied by its Irish Unit Cost (Smith et al., 2021). This information will be used to inform the total cost calculations for each individual participant according to the formula below, specifying data to estimate cost at each timepoint (T):

A CEA will then be carried out to calculate the incremental cost effectiveness ratio (ICER) of the intervention according to the formula:

Treatment vs control group cost and QALY differences will be estimated according to Zellner’s (1962) SURE method. We will then carry out (10,000 replications) non-parametric bootstrapping on random samples of our data. We will demonstrate the joint distribution of costs and outcomes using confidence ellipses around the ICER at the 50%, 75%, and 95% levels.

Where there is participant-attrition, participants who were still living at the end of the trial will be removed from the final analysis. Participants who passed away during the trial will be included in the final analysis, their health utility and health care use will be 0 from the date of their death onwards. Our regression will be carried out on the participants for whom data is available across all three time points.

Results

A full description of the agreed Health Economic Analysis Plan (HEAP) can be found as Extended data on Open Science Framework (Corcoran, 2023).

Discussion

Cost effectiveness analysis examines whether adding HSCP teams within ED care for older adults represents value for money to the Irish Health Service. Importantly, this form of analysis both considers if it improves health outcomes - expressed as Quality-Adjusted life Years (QALYs) - and patterns of resource use (to estimate total costs to the system) and whether the incremental cost of providing HSCP teams adds sufficient value to be recommended as a future part of usual care.

The requirement of providing a HEAP is important to ensure that such a policy experiment conforms to a specified statistical plan and averts the temptation for post hoc analysis which may lead to spurious policy recommendations.

Dissemination

This paper will be disseminated along with the Cost-Effectiveness Analysis that this HEAP corresponds to.

Study status

This paper is a protocol (Health Economic Analysis Plan) for a Cost-Effectiveness Analysis that is currently in the process of being published. The original study that both the Cost-Effectiveness Analysis and this paper are related to was published in 2021 (Cassarino et al.).