The adaptations of a quality of life questionnaire for routine use in clinical practice: the Chronic Respiratory Disease Questionnaire in cystic fibrosis.

The assessment of quality of life (QoL) is necessary to monitor the course of disease and to assess the effect of new and existing interventions in clinical practice. This will only be achieved if QoL can be measured accurately and routinely. The aim of this study was to demonstrate the methodology involved in the adaptation and shortening of the Chronic Respiratory Disease Questionnaire (CRDQ) in a population of adults with cystic fibrosis (CF). A single interviewer administered the CRDQ to a sample of 45 adult patients (32 males) with CF prior to assessment of spirometric measures of lung function. Those patients whose lung function was stable at the time of study and who could attend for a retest within 14 days were asked to complete the questionnaire at a subsequent visit (n = 10). The mean interval between visits was 7 days (range 5-14 days). Correlations between spirometry and CRDQ dimensions ranged from -0.003 to 0.426. The fatigue, emotion and mastery dimensions showed high internal consistency and adequate construct validity. In the small number of patients suitable for retest, the results indicated that the dimensions exhibited adequate test-retest reliability. In contrast, low internal consistency was demonstrated for the dyspnoea dimension. The fatigue, emotion and mastery dimensions could be reduced, in terms of their number of items, without a substantial loss in explanatory power. This study suggests that QoL measurement can be made convenient and, thus, more easily accessible for routine clinical assessment.