Development and validation of a disease-specific quality-of-life measure for children with achalasia.

Background: Achalasia is an uncommon oesophageal motility disorder occasionally affecting children. Children with achalasia can experience significant morbidity, and quality-of- life (QoL) has never been studied in this population.
Aim: The aim was to develop a disease-specific quality-of-life (DS-QoL) measure for children with achalasia.
Methods: Item response theory methods were used to develop the DS-QoL measure. The construct validity of this measure was assessed by comparing items and domains with the generic PedsQL questionnaire. Reliability was assessed using Cronbach's alpha coefficient for internal consistency.
Results: 17 children completed the final DS-QoL measure, which consisted of 20 items in three domains. The completion rate for items was 99%. "Floor and ceiling effects" ranged from 0-19%. Construct validity was good with significant correlation between 2 domains and 2 items on the PedsQL. Reliability was excellent, with Cronbach's alpha coefficient ranging from 0.78-0.93.
Conclusions: This DS-QoL measure is appropriate for use in children with achalasia and has shown good results in this validation study. Further work in higher numbers is necessary to determine discriminant validity and test-retest reliability.