Development and validation of a health-related quality of life questionnaire for pediatric patients with interstitial lung disease.

Purpose: Children's interstitial lung disease (chILD) is often associated with multiple burdens and chronic impairment of health-related quality of life. Patient reported outcomes describe the patients' perspective on medical conditions and their treatments. We aimed to develop and evaluate the psychometric properties of a chILD-specific PRO (chILD-QoL) as an instrument for monitoring the patients' health status.

Methods: Items were generated through focus groups with parents, patients, and interviews with pediatric pulmonologists. After a pretest of the German pilot version, the questionnaire was refined and translated into four European languages. Psychometric properties of the questionnaire were analyzed within a multi-center collaborative throughout Europe involving 180 parents of children with an interstitial lung disease and 65 pediatric patients.

Results: The final instrument is available in different developmentally adapted versions from infancy to adolescence, comprising between 5 and 11 items. The scales showed high internal consistency (Cronbachs'α between 0.85 and 0.94). Convergent validity was indicated by moderate to high correlations (r = 0.43-0.91) with the Pediatric Quality of Life Questionnaire (PedsQL™ 4.0 Core module). Lower scores were significantly associated with dyspnoea (t  = 3.18, P = 0.002), tachypnoea (t  = 2.95, P = 0.002), and with worse clinical course of lung disease (t  = 3.96, P < 0.05) as reported by the physicians.

Conclusions: The results indicate the reliability and validity of the chILD-QoL for pediatric patients with interstitial lung diseases. It can be used for screening and monitoring subjective health status as perceived by the patients and/or their caregivers, as well as for evaluation of health-related quality of life in clinical trials and intervention research.