Criteria for validating comprehensive ICF Core Sets and developing brief ICF Core Set versions.

Objective: To describe the empirical processes used to (i) validate the comprehensive International Classification of Functioning, Disability and Health (ICF) Core Sets, and (ii) develop brief ICF Core Sets from the ICF Categories of these more comprehensive ICF Core Sets.
Design: Prospective multi-centre cohort study.
Patients: PATIENTS receiving rehabilitation interventions for musculoskeletal, neurological or cardiopulmonary injury or disease in acute hospitals or early post-acute rehabilitation facilities.
Methods: Functioning was coded using the ICF. For validation, absolute and relative frequencies (prevalences) of impairment, limitation or restriction were reported at admission and end-point (discharge or 6 weeks after admission). Aspects not covered were extracted and translated into the best corresponding ICF category. The criterion for selecting candidate categories for the brief ICF Core Sets was based on their ability to discriminate between patients with high or low functioning status. Discrimination was assessed using multivariable regression models, the independent variables being all of the ICF categories of the respective comprehensive ICF Core Set. Analogue ratings of overall functioning as reported by patients and health professionals were used as dependent variables.
Conclusion: We present an algorithm to identify candidate categories for brief ICF Core Sets extracted from the comprehensive acute and post-acute ICF Core Sets.