COPD-Disability-Index (CDI) – ein neues Verfahren zur Erfassung der COPD-bedingten Beeinträchtigung

Abstract

The aim of the present study was to evaluate anew scale for assessing COPD-related disability. The scale is an adaptation of the pain disability index (PDI), which is a standard instrument in diagnosing disability in chronic pain patients. An 11-point rating scale is used to assess disability in seven different areas of life. The present study comprised a sample of 143 COPD patients (GOLD II-IV) and 105 spouses. A principal axes factor analysis revealed a one-factor solution explaining 63.4% of the variance. In the present sample, the scale showed good internal consistency (patients' self-report: Cronbach's alpha=0.92, spouses' report: Cronbach's alpha=0.91). The scale further demonstrated high correlations with questionnaires assessing related constructs [St. George's Respiratory Questionnaire (SGRQ): Pearson's correlation coefficients r=0.59 to 0.83, p<or=0.01; European Quality of Life Questionnaire (EuroQol): r=-0.59, p<or=0.01] and functional parameters (Shuttle-Walk-Distance: r=-0.47, p<or=0.01; FEV(1)% pred: r=-0.26, p<or=0.01), as well as low correlations with questionnaires assessing distant constructs [social support (F-SozU): r=-0.09, social strain (F-SozU): r=0.17, p<or=0.05, satisfaction with relationship: r=-0.10], suggesting good discriminant and convergent validity. The COPD disability index is a short, user-friendly, reliable and valid measure to assess COPD-related disability.