Content comparison of utility and effectiveness instruments to the Prosthetic Interventions Core Outcome Set: a step to inform the benefits measured in lower-limb prosthetic health economic evaluations

Health Economic Evaluations (HEEs) calculate a cost-benefit ratio using utility and effectiveness instruments. It is unknown whether existing instruments measure the items of the Prosthetic Interventions Core Outcome Set (PI-COS) that represent the benefits most important to lower-limb prosthesis users and funders. Comparing the content of existing instruments against the PI-COS will support instrument selection for future prosthetic HEEs. Utility and effectiveness instruments used to evaluate prosthetic interventions were identified and their International Classification of Functioning, Disability and Health framework (ICF) linking results were extracted. Content of each instrument was compared to the PI-COS through three metrics: content density, content diversity and bandwidth. Of the 130 utility and effectiveness instruments, 24 had previously been linked to the ICF. The instrument with the greatest bandwidth (i.e., broadest content coverage of the PI-COS) was the SF-36 given it linked to 6 of the 14 items of the PI-COS. Combining PROMIS subscales and short-forms allow measurement of a greater range of the PI-COS items. There is no perfect fit instrument providing coverage of the PI-COS using the metrics of content density, content diversity and bandwidth. The PROMIS instrument may provide increase coverage of the PI-COS in future HEEs. Existing utility and effectiveness instruments provide varying levels of coverage of the Prosthetic Interventions Core Outcome Set (PI-COS), which describes the outcomes most important to prosthetic users and funders.Rehabilitation professionals can use the content mapping in this study to guide the selection of an instrument that best measures the benefits of a lower-limb prosthetic intervention given the purpose of study.Future health economic evaluations of lower-limb prosthetic interventions should use utility and effectiveness instruments that provide the greatest coverage of the PI-COS and as such, we recommend the 42 questions of the combined PROMIS-29 + 2 and the PROMIS Physical Function with Mobility Aid short-form. Existing utility and effectiveness instruments provide varying levels of coverage of the Prosthetic Interventions Core Outcome Set (PI-COS), which describes the outcomes most important to prosthetic users and funders. Rehabilitation professionals can use the content mapping in this study to guide the selection of an instrument that best measures the benefits of a lower-limb prosthetic intervention given the purpose of study. Future health economic evaluations of lower-limb prosthetic interventions should use utility and effectiveness instruments that provide the greatest coverage of the PI-COS and as such, we recommend the 42 questions of the combined PROMIS-29 + 2 and the PROMIS Physical Function with Mobility Aid short-form.