The Reliability and Validity of the Brief ICF Core Set in Patients with Chronic Obstructive Pulmonary Disease

To analyze the reliability and validity of the Brief international classification of functioning, disability and health (ICF) core set for chronic obstructive pulmonary disease (COPD).

A cross-sectional study was conducted in four tertiary hospitals in Tianjin, China. A total of 100 patients with COPD were selected to evaluate functioning and disability involving body functions, body structures, activities and participation as well as environmental factors of the Brief ICF core set for COPD. Internal consistency was calculated by Cronbach's α. Content validity was examined using the content validity index (CVI), scale-level CVI/universal agreement, and scale-level CVI/average agreement (S-CVI/Ave). In addition, construct validity and convergent validity were also examined.

The Brief ICF core set for COPD had a high internal consistency, 0.873 for the total scale, with values of 0.750, 0.640, and 0.843 for body functions, body structures, and activity and participation, respectively. The content validity was calculated by the CVI, scale-level CVI/universal agreement, and S-CVI/Ave at values of 0.80-1, 0.929, and 0.986, respectively. Meanwhile, the ICF core set for COPD had good convergent validity, correlating with the mMRC dyspnea score (r=0.690, P<0.01), and there were significant correlations between the ICF core set for COPD and COPD clinical severity grade (r=0.363, P<0.01). A four-factor model of functions and disability in the Brief ICF core set for COPD had the best fit according to confirmatory factor analysis (CFA).

The Brief ICF core set for COPD is a reliable and valid convenient instrument for assessing comprehensive problems in the functioning of patients with COPD, which can be used to design and to evaluate rehabilitation strategies.