Background: French versions of the Chronic Respiratory Questionnaire (CRQ) and the St George's Respiratory Questionnaire (SGRQ) have largely been used in Canada, although the process by which they were translated remains unknown and the psychometric properties of these translated versions have not been assessed in a properly designed study.
Objective: To translate and evaluate the psychometric properties of the French-Canadian versions of the CRQ and the SGRQ.
Methods: The questionnaires were translated according to standardized guidelines for cross-cultural adaptation. Measurements were made at baseline and again after two weeks in 27 chronic obstructive pulmonary disease (COPD) patients known to have stable disease. Measurements were also taken pre- and post-treatment in patients with acute exacerbation of COPD (33 patients) or in pulmonary rehabilitation (32 patients).
Results: The CRQ showed high test-retest reliability (the majority above 0.70), although it was slightly lower for the dyspnea dimension (0.58 to 0.65). The SGRQ also showed high test-retest reliability (above 0.80), although it was lower for the symptoms dimension (0.54 to 0.58). The internal consistency reliability coefficients ranged from 0.73 to 0.90 for the CRQ and above 0.80 for the SGRQ, except for the symptoms dimension. The Pearson's correlation coefficients were low (less than 0.30) between most of the translated questionnaire dimension scores and forced expiratory volume in 1 s, 6 min walking test and dyspnea measures. The correlation was generally high (greater than 0.50) between the two questionnaires and the 36-item short form health survey, and for those domains that measured the same construct. The changes in the total and subscale scores of the CRQ and the SGRQ (except for the symptoms domain) were all largely above the variability of the score in the stable disease group.
Conclusion: The present study confirms that the French-Canadian translated versions of the CRQ and the SGRQ perform well with respect to their psychometric properties. They are both suitable for their intended purpose, ie, to detect change in health status in patients with COPD when assessing if a treatment is beneficial. However, the symptoms domain of the SGRQ cannot be used to assess acute change with respect to a given therapy.