Key patient characteristics for the acknowledgement of patient heterogeneity in economic evaluations in severe mental illness: A Delphi consensus exercise

<b>Background </b><br/>Patient heterogeneity is defined as variation across people, explainable by their characteristics. Heterogeneity in the population with severe mental illness (SMI) is highly relevant. Economic evaluations commonly use population averages, which do not account for patient heterogeneity. <br/><br/><b>Aims</b><br/>To identify patient characteristics that should be considered for inclusion in economic evaluations in SMI. <br/><br/><b>Methods </b><br/>SMI researchers working in the UK were recruited via email. Recruitment took a purposive and snowball sampling approach. The first and second surveys were completed individually online with a consensus threshold set at ≥75%. The final stage to finalise consensus comprised a ranking task and an online meeting to prioritise the list of patient characteristics. <br/><br/><b>Results</b><br/>The consensus exercise identified 28 characteristics to account for patient heterogeneity. A prioritised list of ten key characteristics was also produced and included age, socioeconomic status, ethnicity, symptom types and severity, diagnosis, gender identity and/or sex registered at birth, baseline health and/or quality of life, adverse childhood experiences, support network and comorbidities.<br/><br/><b>Conclusions </b><br/>This list helps researchers identify, a priori, key patient characteristics. Studies are needed to validate the findings of the consensus exercise with data collection and analysis. We acknowledge that feasibility constraints may affect research. <br/><br/>