Psychometric properties of the TACQOL-asthma, a disease-specific measure of health related quality-of-life for children with asthma and their parents

The disease-specific-TACQOL-asthma questionnaire measures health-status and appraisal of health status. The TACQOL-asthma evaluates the personal feelings about problems in the domains, ‘complaints, situations, emotions, treatment and medication’. The TACQOL-asthma can be used alone or in combination with the generic TACQOL. Our objective was to study the psychometric properties of the TACQOL-asthma-questionnaire. Responses of 298 parents and children with asthma (age eight to 16 years) in four paediatric practices in the northern part of the Netherlands were studied. The factor-analysis and item-domain correlation analysis show a moderate to strong correlation between the different items and their hypothesised domains. For all items, the correlation of the separate item with the hypothesized domain is stronger than with any other domain. The internal consistency (Cronbach's alpha) of the domains is moderate to good. Concurrent correlation with the Paediatric-Asthma-Quality-of-Life-Questionnaire-(PAQLQ) was significant. Effect sizes of differences between asthma-severity classes in TACQOL-asthma and PAQLQ-scores were similar and of clinical importance. This study validates the TACQOL-asthma as a new disease-specific questionnaire. The TACQOL-asthma ensures a measurement of health status as well as appraisal ofhealth problems. The TACQOL-asthma has good reliability and validity properties to serve as an evaluative and discriminate disease-specifichealth-related-quality-of-life questionnaire.