title: Quality of life, psychological adjustment, and adaptive functioning of patients with intoxication-type inborn errors of metabolism - a systematic review.
abstract: BACKGROUND
  In recent decades, considerable progress in diagnosis and treatment of patients with intoxication-type inborn errors of metabolism (IT-IEM) such as urea cycle disorders (UCD), organic acidurias (OA), maple syrup urine disease (MSUD), or tyrosinemia type 1 (TYR 1) has resulted in a growing group of long-term survivors. However, IT-IEM still require intense patient and caregiver effort in terms of strict dietetic and pharmacological treatment, and the threat of metabolic crises is always present. Furthermore, crises can affect the central nervous system (CNS), leading to cognitive, behavioural and psychiatric sequelae. Consequently, the well-being of the patients warrants consideration from both a medical and a psychosocial viewpoint by assessing health-related quality of life (HrQoL), psychological adjustment, and adaptive functioning. To date, an overview of findings on these topics for IT-IEM is lacking. We therefore aimed to systematically review the research on HrQoL, psychological adjustment, and adaptive functioning in patients with IT-IEM.
  
  
  METHODS
  Relevant databases were searched with predefined keywords. Study selection was conducted in two steps based on predefined criteria. Two independent reviewers completed the selection and data extraction.
  
  
  RESULTS
  Eleven articles met the inclusion criteria. Studies were of varying methodological quality and used different assessment measures. Findings on HrQoL were inconsistent, with some showing lower and others showing higher or equal HrQoL for IT-IEM patients compared to norms. Findings on psychological adjustment and adaptive functioning were more consistent, showing mostly either no difference or worse adjustment of IT-IEM patients compared to norms. Single medical risk factors for HrQoL, psychological adjustment, or adaptive functioning have been addressed, while psychosocial risk factors have not been addressed.
  
  
  CONCLUSIONS
  Data on HrQoL, psychological adjustment, and adaptive functioning for IT-IEM are sparse. Studies are inconsistent in their methodological approaches, assessment instruments and norm populations. A disease-specific standard assessment procedure for HrQoL is not available. Psychosocial risk factors for HrQoL, psychological adjustment, or adaptive functioning have not been investigated. Considering psychosocial variables and their corresponding risk factors for IT-IEM would allow evaluation of outcomes and treatments as well as the planning of effective social and psychological interventions to enhance the patients' HrQoL.
authors.affiliation: Division of Metabolism, Children's Research Center and University Children's Hospital Zurich, Zurich, Switzerland. nina.zeltner@kispi.uzh.ch.|Department of Psychosomatics and Psychiatry, Children's Research Center and University Children's Hospital Zurich, Zurich, Switzerland. nina.zeltner@kispi.uzh.ch.|Radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland. nina.zeltner@kispi.uzh.ch.|Department of Child and Adolescent Health Psychology, Institute of Psychology, University of Zurich, Zurich, Switzerland. nina.zeltner@kispi.uzh.ch.
authors.forename: Nina A
authors.initials: NA
authors.lastname: Zeltner
authors.affiliation: Division of Metabolism, Children's Research Center and University Children's Hospital Zurich, 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.
authors.forename: Martina
authors.initials: M
authors.lastname: Huemer
authors.affiliation: Division of Metabolism, Children's Research Center and University Children's Hospital Zurich, Zurich, Switzerland. matthias.baumgartner@kispi.uzh.ch.|Radiz - Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland. matthias.baumgartner@kispi.uzh.ch.|Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland. matthias.baumgartner@kispi.uzh.ch.
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Baumgartner
authors.affiliation: Department of Psychosomatics and Psychiatry, Children's Research Center and University Children's Hospital Zurich, Zurich, Switzerland. markus.landolt@kispi.uzh.ch.|Department of Child and Adolescent Health Psychology, Institute of Psychology, University of Zurich, Zurich, Switzerland. markus.landolt@kispi.uzh.ch.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Landolt
mesh_terms: D000223:Adaptation, Psychological; D006801:Humans; D008661:Metabolism, Inborn Errors / Q000150:complications / Q000523:psychology*; D011788:Quality of Life / Q000523:psychology*; D012307:Risk Factors