Systemwide clinical assessment of functioning based on the International Classification of Functioning, Disability and Health (ICF) in China: Interrater reliability, convergent, known group, and predictive validity of the ICF Generic-6.

OBJECTIVE: To validate the ICF Generic-6 in daily routine clinical practice in Mainland China. Specific objectives were to a) analyse the interrater reliability, b) convergent validity, c) known group validity and d) predictive validity of the ICF Generic-6.

DESIGN: Multi-centre prospective cohort study.

SETTING: 50 hospitals from 20 provinces of Mainland China.

PARTICIPANTS: 4510 patients from departments of Rehabilitation, Orthopaedics, Neurology, Cardiology, Pneumology, and Cerebral Surgery of the participating hospitals with different health condition were included in this study.

INTERVENTION: Not applicable.

MAIN OUTCOME MEASURE: The assessment was undertaken by nurses with ICF Generic-6 in combination with a numeric rating scale. Interrater reliability was evaluated with intraclass correlation coefficients (ICC). Convergent validity was evaluated with Spearman correlation coefficients between ICF Generic-6 and SF-12 items. Known group-validity was examined by comparing discharge scores between different discharge destinations. Predictive validity was determined by employing ICF Generic-6 baseline scores for estimating length of hospital stay with a loglogistic survival model with gamma shared frailty and cost of in-hospital treatment with a mixed effects generalized linear regression model of the gamma family.

PRINCIPLE FINDING: The interrater reliability of items and score of ICF Generic-6 was good with ICCs ranging from 0.67 to 0.87. ICF Generic-6 items were further correlated with respective SF-12 items. Discharge scores of patients differed significantly by discharge destination. The ICF Generic-6 admission score was a significant predictor of length of stay and treatment cost.

CONCLUSIONS: The ICF Generic-6 administered in combination with a 0 to 10 numeric rating scale is a reliable and valid tool for the collection of minimal information on functioning across various clinical settings.