title: Development of the Liverpool Adverse Drug Reaction Avoidability Assessment Tool.
abstract: OBJECTIVE
  To develop and test a new tool to assess the avoidability of adverse drug reactions that is suitable for use in paediatrics but which is also applicable to a variety of other settings.
  
  
  METHODS
  The study involved multiple phases. Preliminary work involved using the Hallas scale and a modification of the existing Hallas scale, to assess two different sets of adverse drug reaction (ADR) case reports. Phase 1 defined, modified and refined a new tool using multidisciplinary teams. Phase 2 involved the assessment of 50 ADR case reports from a prospective study of paediatric inpatients by individual assessors. Phase 3 compared assessments with the new tool for individuals and groups in comparison to the 'gold standard' (the avoidability outcome set by a panel of senior investigators: an experienced clinical pharmacologist, paediatrician and pharmacist).
  
  
  METHODS
  Inter-rater reliability (IRR), measure of disagreement and utilization of avoidability categories.
  
  
  RESULTS
  Preliminary work-Pilot phase: results for the original Hallas cases were fair and pairwise kappa scores ranged from 0.21 to 0.36. Results for the modified Hallas cases were poor, pairwise kappa scores ranged from 0.06 to 0.16. Phase 1: on initial use of the new tool, agreement between the two multidisciplinary groups was found on 13/20 cases with a kappa score of 0.29 (95% CI -0.04 to 0.62). Phase 2: the assessment of 50 ADR case reports by six individual reviewers yielded pairwise kappa scores ranging from poor to good 0.12 to 0.75 and percentage exact agreement (%EA) ranged from 52-90%. Phase 3: Percentage exact agreement ranged from 35-70%. Overall, individuals had better agreement with the 'gold standard'.
  
  
  CONCLUSIONS
  Avoidability assessment is feasible but needs careful attention to methods. The Liverpool ADR avoidability assessment tool showed mixed IRR. We have developed and validated a method for assessing the avoidability of ADRs that is transparent, more objective than previous methods and that can be used by individuals or groups.
authors.affiliation: Paediatric Medicines Research Unit, Institute in the Park, Alder Hey Children's NHS Foundation Trust, Liverpool, United Kingdom.
authors.forename: Louise E
authors.initials: LE
authors.lastname: Bracken
authors.affiliation: Department of Women's & Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Nunn
authors.affiliation: Department of Biostatistics, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Jamie J
authors.initials: JJ
authors.lastname: Kirkham
authors.affiliation: Paediatric Medicines Research Unit, Institute in the Park, Alder Hey Children's NHS Foundation Trust, Liverpool, United Kingdom.|School of Health, University of Central Lancashire, Preston, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Peak
authors.affiliation: Paediatric Medicines Research Unit, Institute in the Park, Alder Hey Children's NHS Foundation Trust, Liverpool, United Kingdom.|School of Health, University of Central Lancashire, Preston, Lancashire, United Kingdom.
authors.forename: Janine
authors.initials: J
authors.lastname: Arnott
authors.affiliation: Institute of Child Health, University College London, London, United Kingdom.
authors.forename: Rosalind L
authors.initials: RL
authors.lastname: Smyth
authors.affiliation: Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Munir
authors.initials: M
authors.lastname: Pirmohamed
authors.affiliation: Paediatric Medicines Research Unit, Institute in the Park, Alder Hey Children's NHS Foundation Trust, Liverpool, United Kingdom.|Department of Women's & Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.|Liverpool Women's NHS Foundation Trust, Liverpool, United Kingdom.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Turner
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D000465:Algorithms; D015984:Causality; D002648:Child; D003625:Data Collection; D003657:Decision Making; D064420:Drug-Related Side Effects and Adverse Reactions / Q000517:prevention & control*; D006801:Humans; D015588:Observer Variation; D010372:Pediatrics; D010600:Pharmacology; D010865:Pilot Projects; D011446:Prospective Studies; D015203:Reproducibility of Results; D012984:Software; D006113:United Kingdom