Disease-nonspecific Activity Outcome Measures for Adult Rehabilitation Populations: A COSMIN-based Systematic Review of Psychometric Properties.

OBJECTIVES: This study identified and characterized disease-nonspecific, clinician-administered, or performance-based activity outcome measures used in adult rehabilitation and evaluated their measurement properties using the COSMIN framework. METHODS: We systematically searched MEDLINE, CINAHL, PsycINFO, Web of Science, the Cochrane Library, and Ichushi-Web. We included peer-reviewed original studies in adult rehabilitation samples that evaluated at least one measurement property of disease-nonspecific, clinician-administered, or performance-based activity measures, in which at least 50% of items assessed basic movements, mobility, or self-care. We excluded patient-reported or disease-specific instruments and pediatric samples. Two reviewers independently screened records, extracted instrument characteristics and measurement properties, and assessed methodological quality using the COSMIN Risk of Bias checklist. The certainty of evidence for each measurement property was graded using the COSMIN-modified GRADE approach. RESULTS: We included 83 studies reporting on 20 measures. The Barthel Index (BI), Modified Barthel Index (MBI), Functional Independence Measure (FIM), and de Morton Mobility Index (DEMMI) accounted for most psychometric evaluations. Internal consistency and inter-rater or test-retest reliability were generally acceptable, whereas evidence for structural validity, construct validity, responsiveness, and measurement error was limited and heterogeneous. Content mapping indicated substantial variation in coverage of basic movements, mobility, and self-care, with only a subset of instruments demonstrating relatively broad activity coverage. CONCLUSIONS: Only a limited set of generic activity measures has, at best, moderate-certainty evidence for internal consistency and reliability in adult rehabilitation. These findings provide a practical basis for selecting measures by care phase and highlight priority targets for future disease-nonspecific activity measures.