Responsiveness, longitudinal- and cross-sectional construct validity of the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) in Dutch children with asthma

Abstract

Health-related quality of life is an important measure in evaluations of the management of childhood asthma. In this study, we assessed psychometric properties, responsiveness, and longitudinal and cross-sectional construct validity of the Dutch version of the 23-item Pediatric Asthma Quality of Life Questionnaire (PAQLQ). The study group consisted of 238 6-18-year olds with asthma, with complete respiratory symptom diaries in the course of one winter season; each child had one (or more) PAQLQ measurement(s) concerning one (or more) week(s) with relatively many symptoms (n = 238). Each child also had one PAQLQ measurement concerning another week with relatively few symptoms (n = 238). The PAQLQ scores of the 238 children for a week with few symptoms (the symptom diary scores remained below a predefined level everyday) were compared with their PAQLQ scores for another week with many symptoms (on day 1 of that week, symptom diary scores had been above the predefined level). Additionally, in a subgroup of the study group that had experienced two or more 'weeks with many symptoms' (n = 101), we compared the PAQLQ-scores for two different weeks with many symptoms of these children. Only the domain Emotions showed a ceiling effect (>25% had the maximum score). All Cronbach's alpha's of the PAQLQ total score and domains were >0.70, except for Activities (alpha = 0.54). Mean PAQLQ-scores were significantly different (p < 0.01; n = 238) between one week with few symptoms and another week with many symptoms. Contrary, in the subgroup of children with PAQLQ-measurements regarding more than one week with many symptoms (n = 101), mean PAQLQ-scores did not differ significantly (p > or = 0.05) between 1 week with many symptoms and another week with many symptoms. These results indicate responsiveness. (Changes in) lower respiratory tract symptoms, indicative of asthma severity, correlated better with (changes in) PAQLQ scores than (changes in) upper respiratory tract symptoms, which supports the longitudinal and cross-sectional construct validity. The assessed properties of the PAQLQ linguistic validation into Dutch were similar to those originally established for the PAQLQ in Canada. This study showed that the Dutch PAQLQ has adequate psychometric properties, excellent responsiveness, and that the longitudinal and cross-sectional construct validity is supported.