Quality of instruments to assess the process of shared decision-making: a comprehensive systematic review and COSMIN quality appraisal

Objective Shared decision-making (SDM) is a key component of patient-centred care and major driver of healthcare policy, clinical practice and research globally. Widespread implementation of SDM is hindered by uncertainty about how to best measure decision-making processes. A seminal methodological review of SDM instruments published in 2018 identified widespread deficiencies in instrument quality and provided recommendations for improvement. This systematic review and COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) quality appraisal aims to provide an update SDM instrument inventory, re-evaluated progress in the field and provided future direction for researchers, funders and policymakers. This systematic review and COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) quality appraisal aims to provide an update SDM instrument inventory, re-evaluated progress in the field and provided future direction for researchers, funders and policymakers.

Design A systematic search of six databases (September 2017–December 2024) identified studies of instruments measuring the process of SDM. Instrument appraisal followed COSMIN guidelines in a three-step process: appraisal of the methodological quality of instruments and of the quality of the measurement properties of newly identified measures (steps i, ii). This informed the comprehensive best-evidence synthesis which included the data from the original review (step iii).

Results A total of 127 studies were included describing the development and/or evaluation of 105 unique instruments to measure the process of SDM. Some 61 new instruments were identified since the last review, of which 35 (57%) were translations/revisions to existing ones. The best-evidence synthesis revealed positive results for internal consistency (72%), structural validity (75%) and intrarater reliability (50%), but also negative or unknown results for test–retest reliability (58%), content validity (54%) and intrarater reliability (50%), where evaluated. No single instrument consistently showed positive evidence across all relevant measurement properties. Evidence gaps for many properties remain.

Conclusion This updated inventory guides researchers, clinicians and policymakers to the most appropriate instrument for an intended context/population. There was a proliferation of new, primarily patient-reported measurement instruments, but no single instrument had sufficient evidence of measurement quality. Methods were aligned with the original review and applied the 2011 COSMIN checklist which was updated in 2024, although using a previous checklist version is unlikely to affect overall conclusions. We recommend an international consensus with key interest holders on preferred instrument(s) for further validation and future core measurement set for efficient evidence synthesis.