Quality of life in patients with chronic respiratory disease: the Spanish version of the Chronic Respiratory Questionnaire (CRQ)

The aim of this study was to translate the Chronic Respiratory Questionnaire (CRQ) into Spanish and to test its measurement properties. The study was performed in 60 patients with chronic obstructive pulmonary disease (forced expiratory volume in one second (FEV1) mean+/-SD 35+/-14% of reference value). A rigorous process of forward and back translation and review produced an easily comprehensible questionnaire, which was administered together with measures of pulmonary function and exercise capacity. The patients were randomly allocated to one of two groups: 30 received respiratory rehabilitation and the other 30 received standard community care only. Weak to moderate statistically significant correlations (0.2-0.38) were found between the domains of the CRQ and pulmonary function and exercise measures. For the three CRQ domains that measure differences between patients at a point in time, Crohnbach's alpha and intraclass correlation coefficients were: fatigue 0.80 and 0.80; emotional function 0.86 and 0.68; and mastery domains 0.84 and 0.67, respectively. Scores remained stable in patients who were deemed clinically stable, and showed large statistically significant improvement (p<0.0001) in patients in the rehabilitation programme. Only low correlations were found between the changes in CRQ and the changes in pulmonary function and exercise capacity. The index of responsiveness was 0.92 for fatigue, and 0.91 for dyspnoea, emotional function and mastery. In conclusion, the Spanish translation of the Chronic Respiratory Questionnaire is likely to be useful for measuring differences between patients, and particularly for measuring the effects of intervention on quality of life in chronic respiratory disease.