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

Abstract

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. 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. 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 (tproxy = 3.18, P = 0.002), tachypnoea (tproxy = 2.95, P = 0.002), and with worse clinical course of lung disease (tself = 3.96, P < 0.05) as reported by the physicians. 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.