Combining both generic and disease-specific properties: development of the McGill COPD quality of life questionnaire

Presently, a generic and a disease-specific questionnaire are often co-administered to capture the different domains of quality of life in chronic obstructive pulmonary disease (COPD) subjects. A health-related-quality of life (HRQL) questionnaire in COPD combining both generic and disease-specific properties is needed.

To develop a new, hybrid-HRQL questionnaire, the McGill-COPD-questionnaire, with qualities of both generic and disease-specific instruments. Using pre-defined criteria, we selected items from the SF-36 to complement the items from a COPD-specific-module to create the new hybrid-HRQL-questionnaire. Domains were identified via confirmatory factor analysis. The McGill COPD questionnaire is available in English and French; it assesses three domains: symptoms, physical-function and feelings, has 29 items: 17 from the COPD-specific-module and 12 from the SF-36. The symptom sub-scale has 6 items, all from the COPD-specific-module; the feelings sub-scale has 10 items, 5 each from COPD-specific-module and SF-36 and the physical-function sub-scale has 13 items, 6 from COPD-specific-module and 7 from SF-36. The McGill COPD questionnaire was developed using a novel method of combining items from the SF-36 and a COPD-specific-module. Thus, this new questionnaire has items from a generic-questionnaire and a disease-specific-module and, hence, is promising to be a stand alone quality-of-life questionnaire for COPD subjects.