title: Using an epidemiological model to investigate unwarranted variation: the case of ventilation tubes for otitis media with effusion in England.
abstract: OBJECTIVE
  To investigate unwarranted variation in ventilation tube insertions for otitis media with effusion in children in England. This procedure is known to be 'overused' from clinical audits, as only one in three ventilation tube insertions conforms to the appropriateness criteria of the National Institute for Health and Care Excellence (NICE); but audits cannot identify the scale of 'underuse' - i.e. patients who would benefit but are not treated.
  
  
  METHODS
  To explore both 'underuse' and 'overuse' of ventilation tubes for otitis media with effusion, we developed an epidemiological model based on: definitions of children with otitis media with effusion expected to benefit from ventilation tubes according to NICE guidance; epidemiological and clinical information from a systematic review; and expert judgement. A range of estimates was derived using Monte Carlo simulation and compared with the number of ventilation tubes provided in the English National Health Service in 2010.
  
  
  RESULTS
  About 32,200 children in England would be expected to benefit from ventilation tubes for otitis media with effusion per year (between 20,411 and 45,231 with 90% certainty). The observed number of ventilation tubes for otitis media with effusion-associated diagnoses was 16,824.
  
  
  CONCLUSIONS
  The expected population capacity to benefit from ventilation tubes for otitis media with effusion based on NICE guidance appeared to exceed, by far, the number of ventilation tubes provided in the English National Health Service. So, while there is known 'overuse', there also may be substantial 'underuse' of ventilation tubes for otitis media with effusion if NICE criteria were applied. Future investigations of unwarranted variation should, therefore, not only focus on the patients who are treated but also consider the potential for benefit at the population level.
authors: Doctoral Student, Department of Management, London School of Economics and Political Science, England, UK L.K.Schang@lse.ac.uk.
authors: Laura
authors: L
authors: Schang
authors: Research Assistant, Department of Management, London School of Economics and Political Science, England, UK.
authors: Chiara
authors: C
authors: De Poli
authors: Fellow, Department of Management, London School of Economics and Political Science, England, UK.
authors: Mara
authors: M
authors: Airoldi
authors: Professor of Management Science, Department of Management Science, Strathclyde Business School, University of Strathclyde, Scotland, UK.
authors: Alec
authors: A
authors: Morton
authors: Clinical Academic Lecturer, Ear Institute, University College London, England, UK.
authors: Natalie
authors: N
authors: Bohm
authors: Professor of Integrated Community Child Health, General and Adolescent Paediatrics Unit, UCL Institute of Child Health, England, UK.
authors: Monica
authors: M
authors: Lakhanpaul
authors: NIHR Research Professor and Professor of Paediatric Otorhinolaryngology, Ear Institute, University College London, England, UK.
authors: Anne
authors: A
authors: Schilder
authors: Professor of Policy Analysis, Department of Management, London School of Economics and Political Science, England, UK.
authors: Gwyn
authors: G
authors: Bevan
mesh_terms: D002648:Child; D002675:Child, Preschool; D004739:England; D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008876:Middle Ear Ventilation / Q000706:statistics & numerical data*; D015233:Models, Statistical; D009010:Monte Carlo Method; D010034:Otitis Media with Effusion / Q000601:surgery*; D013222:State Medicine / Q000706:statistics & numerical data; D006113:United Kingdom
keywords: epidemiological models; otitis media with effusion; unwarranted variations