Development of a self-reported Chronic Respiratory Questionnaire (CRQ-SR)

BACKGROUND: The Chronic Respiratory Questionnaire (CRQ) is an established measure of health status for chronic obstructive pulmonary disease (COPD). It has been found to be reproducible and sensitive to change, but as an interviewer led questionnaire is very time consuming to administer. A study was undertaken to develop a self-reported version of the CRQ (CRQ-SR) and to compare the results of this questionnaire with the conventional interviewer led CRQ (CRQ-IL). METHODS: Fifty two patients with moderate to severe COPD participated in the study. Subjects completed the CRQ-SR 1 week after completing the CRQ-IL, and a further CRQ-SR was administered 1 week later. For patients in group A (n=27) the dyspnoea provoking activities that they had previously selected were transcribed onto the second CRQ-SR, while patients in group B (n=25) were not informed of their previous dyspnoea provoking activities when they completed the second CRQ-SR. To assess the short term reproducibility and reliability of the CRQ-SR it was then administered twice at an interval of 7-10 days to a further group of 21 patients. The CRQ-IL was not administered. Longer term reproducibility was examined in 39 stable patients who completed the CRQ-SR at initial assessment and then again 7 weeks later. RESULTS: Mean scores per dimension, mean differences, and limits of agreement are given for each dimension in the comparison of the two questionnaires. There were no statistically significant differences between the CRQ-IL and CRQ-SR in the mastery and fatigue dimensions (p>0.05). A statistically significant difference between the two scores was found in the dyspnoea dimension (p=0.006) and the emotional function dimension (p=0.04), but these differences were well within the minimum clinically important threshold. No statistically significant difference in the mean dyspnoea score was seen between groups A and B. The CRQ-SR was found to be reproducible both in the short term and after the longer period of 7 weeks, with no statistically or clinically significant differences in any dimension. Test-retest reliability was found to be high in each dimension, both in the short and longer term. CONCLUSIONS: The CRQ-SR is a reproducible, reliable, and stable measure of health status. It compares well with the CRQ-IL but cannot be used interchangeably. The main advantage of the CRQ-SR over the CRQ-IL is that is quick to administer, reducing assessment time and hence cost.