[The validity and sensitivity to change of the Spanish self-administered version of the chronic respiratory questionnaire (CRQ-SAS)].
INTRODUCTION
The interviewer-administered chronic respiratory questionnaire (CRQ-IA) is widely used and has demonstrated excellent properties for measuring health-related quality of life (HRQL) in patients with chronic obstructive pulmonary disease (COPD). However, the self-administered version (CRQ-SAS) in Spanish has not been validated. The aim of this trial was to evaluate the validity and the sensitivity of the Spanish version of the CRQ-SAS in patients with COPD.


MATERIAL AND METHODS
We randomized 40 patients with COPD (33 treated with pulmonary rehabilitation and 7 with liquid oxygen therapy) to one of the two methods of administration of CRQ (SAS vs. IA) both before and 8 weeks after the treatment. In addition, patients completed the SF-36 questionnaire, pulmonary function tests, and six-minute walk test.


RESULTS
The CRQ-SAS demonstrated good longitudinal construct validity on all domains with a range of correlations, for the change scores, between 0.46 (P=.05) and 0.71 (P=.01). Regarding sensitivity to change, we observed a minimal clinically significant change in most domains (fatigue 0.71 [P=.02], emotional factor 0.62 [P=.04], control of the disease 0.83 [P=.06]).


CONCLUSIONS
The Spanish version of CRQ-SAS is valid for evaluating HRQL in COPD patients. The correlations of the CRQ-SAS with other tools provide construct validity and show good sensitivity to change.