Elsevier

Respiratory Medicine

Volume 104, Issue 11, November 2010, Pages 1675-1682
Respiratory Medicine

Reliability and validity of the clinical COPD questionniare and chronic respiratory questionnaire

https://doi.org/10.1016/j.rmed.2010.04.023Get rights and content
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Summary

Background

Questionnaires are often used in assessing health-related quality of life in patients with chronic obstructive pulmonary disease (COPD). It is important that these questionnaires have good reliability, validity, and responsiveness. The aim of this study was to investigate and compare these properties in the disease specific Clinical COPD Questionnaire (CCQ) and the Chronic Respiratory Questionnaire self-reported (CRQ-SR).

Methods

Two hundred ninety six participants with spirometry confirmed mild to moderate COPD were included in a smoking cessation trial. It was assumed that health-related quality of life would improve in participants who stopped smoking. The questionnaires were administered at baseline and at weeks 5, 26, and 52 after the target quit date.

Results

At baseline, 292 (97%) participants returned the CCQ and 296 (100%) the CRQ-SR questionnaire. For both instruments, the internal consistency was good (Cronbach’s alpha >70%) as was the convergent validity with each other but not with spirometry. The CCQ was responsive to improvements in respiratory symptoms at both week 26 (−1.02, SD = 0.81) and 52 (−1.04, SD = 0.91) and in the total score at week 26 (−0.54, SD = 0.50) and 52 (−0.43, SD = 0.44). The mastery domain and the total score of the CRQ-SR were responsive at week 26 (1.14, SD = 0.82; 0.67, SD = 0.97 respectively) but not at week 52 (0.04, SD = 0.93; 0.38, SD = 0.57 respectively).

Conclusion

Both the CCQ and CRQ-SR are equally reliable and valid. The long-term responsiveness of the CCQ is better. Both questionnaires can be used in future studies involving patients with mild to moderate COPD. However, when the follow-up exceeds 26 weeks, the CCQ is the recommended alternative.

Netherlands Trial Register: ISRCTN 64481813.

Keywords

Chronic obstructive pulmonary disease
Health-related quality of life
Questionnaire
Reliability
Validity
Responsiveness

Abbreviations

COPD
chronic obstructive pulmonary disease
HRQoL
health-related quality of life
CCQ
clinical COPD questionnaire
CRQ
chronic respiratory questionnaire
CRQ-SR
CRQ self reported
CRQ-IL
CRQ interviewer led
GOLD
global initiative for chronic obstructive lung disease
Post-bd.
post bronchodilator
FEV1
forced expiratory volume in 1 s
FVC
forced vital capacity
MCID
minimal clinically important difference

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