title: Development and Psychometric Evaluation of the MetabQoL 1.0: A Quality of Life Questionnaire for Paediatric Patients with Intoxication-Type Inborn Errors of Metabolism.
abstract: BACKGROUND
  This study is part of the "European network and registry for intoxication type metabolic diseases" (E-IMD) project. Intoxication-type inborn errors of metabolism (IT-IEM) such as urea cycle disorders (UCD) and organic acidurias (OA) have a major impact on patients' lives. Patients have to adhere to strict diet and medication and may suffer from metabolic crises and neurocognitive impairment. Disease-specific health-related quality of life (HrQoL) assessment questionnaires are the method of choice to estimate the subjective burden of a disease. To date, no such instrument is available for IT-IEM.
  
  
  METHODS
  Disease-specific patient- and parent-reported HrQoL questions were constructed in German based on focus group interviews with patients and parents. Questionnaires for patients from 8 to 18 years were piloted with 14 participants (n = 9 children and adolescents, n = 5 parents) by cognitive debriefing and tested psychometrically with 80 participants (n = 38 patients, n = 42 parents) for item characteristics, validity, and reliability to construct the first version of a disease-specific HrQoL questionnaire.
  
  
  RESULTS
  Twenty-eight questions were selected based on item descriptives. Scales of self- and proxy questionnaires demonstrated acceptable to excellent reliability in terms of internal consistency (Cronbach's α = 0.70-0.93). Scales and total scores correlated with those of generic HrQoL questionnaires, showing convergent validity.
  
  
  CONCLUSIONS
  The MetabQoL 1.0 questionnaire exhibits sound psychometric properties and is a promising step towards assessing patient-reported outcomes in research and clinical practice. It provides a solid basis for translation into other languages and further elaboration and psychometric exploration in larger populations.
authors.affiliation: Division of Metabolism, Children's Research Center, University Children's Hospital, Zurich, Switzerland.|Department of Psychosomatics and Psychiatry, Children's Research Center, University Children's Hospital, Zurich, Switzerland.|radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland.|Division of Child and Adolescent Health Psychology, Department of Psychology, University of Zurich, Zurich, Switzerland.
authors.forename: Nina A
authors.initials: NA
authors.lastname: Zeltner
authors.affiliation: Division of Metabolism, Children's Research Center, University Children's Hospital, Zurich, Switzerland.|radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland.|Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Baumgartner
authors.affiliation: Center for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Aljona
authors.initials: A
authors.lastname: Bondarenko
authors.affiliation: Division of Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Ensenauer
authors.affiliation: Clinic for Pediatrics, Inherited Metabolic Disorders, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Daniela
authors.initials: D
authors.lastname: Karall
authors.affiliation: Center for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kölker
authors.affiliation: University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Chris
authors.initials: C
authors.lastname: Mühlhausen
authors.affiliation: Clinic for Pediatrics, Inherited Metabolic Disorders, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Scholl-Bürgi
authors.affiliation: Division of Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Thimm
authors.affiliation: Department of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Quitmann
authors.affiliation: Center for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Burgard
authors.affiliation: Department of Psychosomatics and Psychiatry, Children's Research Center, University Children's Hospital, Zurich, Switzerland.|Division of Child and Adolescent Health Psychology, Department of Psychology, University of Zurich, Zurich, Switzerland.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Landolt
authors.affiliation: Division of Metabolism, Children's Research Center, University Children's Hospital, Zurich, Switzerland. martina.huemer@kispi.uzh.ch.|radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland. martina.huemer@kispi.uzh.ch.|Department of Paediatrics, LKH Bregenz, Bregenz, Austria. martina.huemer@kispi.uzh.ch.
authors.forename: Martina
authors.initials: M
authors.lastname: Huemer
keywords: Inborn errors of metabolism; Organic acidurias; Quality of life; Questionnaire; Urea cycle disorders