Development, validity and responsiveness of the Clinical COPD Questionnaire

Thys van der Molen¹^,5 , Brigitte WM Willemse² , Siebrig Schokker¹ , Nick HT ten Hacken³ , Dirkje S Postma³ and Elizabeth F Juniper⁴

¹Department of General Practice, University of Groningen, Groningen, The Netherlands

²Department of Pathology, University Hospital Groningen, Groningen, The Netherlands

³Department of Pulmonary Diseases, University Hospital Groningen, Groningen, The Netherlands

⁴Department of Clinical Epidemiology and Biostatisitics, Mc Master University of Health Sciences, Hamilton, Ontario, Canada

⁵Department of General Practice and Primary Care, University of Aberdeen, Scotland, United Kingdom

author email corresponding author email

Health and Quality of Life Outcomes 2003, 1:13doi:10.1186/1477-7525-1-13


Published:	28 April 2003

Abstract

Background

The new Global Obstructive Lung Disease (GOLD) guidelines advice to focus treatment in Chronic Obstructive Pulmonary Disease (COPD) on improvement of functional state, prevention of disease progression and minimization of symptoms. So far no validated questionnaires are available to measure symptom and functional state in daily clinical practice. The aim of this study was to develop and validate the Clinical COPD Questionnaire (CCQ).

Methods

Qualitative research with patients and clinicians was performed to generate possible items to evaluate clinical COPD control. Thereafter, an item reduction questionnaire was sent to 77 international experts. Sixty-seven experts responded and the 10 most important items, divided into 3 domains (symptoms, functional and mental state) were included in the CCQ (scale: 0 = best, 6 = worst).

Results

Cross-sectional data were collected from 119 subjects (57 COPD, GOLD stage I-III; 18 GOLD stage 0 and 44 (ex)smokers). Cronbach's α was high (0.91). The CCQ scores in patients (GOLD 0-III) were significantly higher than in healthy (ex)smokers. Furthermore, significant correlations were found between the CCQ total score and domains of the SF-36 (ρ = 0.48 to ρ = 0.69) and the SGRQ (ρ = 0.67 to ρ = 0.72). In patients with COPD, the correlation between the CCQ and FEV₁%pred was ρ =-0.49. Test-retest reliability was determined in 20 subjects in a 2-week interval (Intra Class Coefficient = 0.94). Thirty-six smokers with and without COPD showed significant improvement in the CCQ after 2 months smoking cessation, indicating the responsiveness of the CCQ.

Conclusion

The CCQ is a self-administered questionnaire specially developed to measure clinical control in patients with COPD. Data support the validity, reliability and responsiveness of this short and easy to administer questionnaire.