title: Understanding administrative coding of emergency department visits for unspecified acute allergic reactions.
abstract: OBJECTIVE
  Emergency department (ED) visits for food-related acute allergic reactions enable estimation of temporal trends in food allergy prevalence. To use this approach in New Zealand requires an understanding of the proportion of ED visits coded as 'anaphylaxis, unspecified' or 'allergy, unspecified' that are food-related allergic reactions.
  
  
  METHODS
  We reviewed all ED presentations of children, coded as 'anaphylaxis, unspecified' or 'allergy, unspecified', from 1988-2011 to the Auckland City Hospital ED. Charts were reviewed independently by two investigators to determine agreement on categorisation of presentations as being food-related acute allergic reactions. We compared ED presentation rates in different time intervals using rate ratios (RR) and 95% confidence intervals (CI).
  
  
  RESULTS
  Sixty-five (29%) of the 221 ED presentations given a discharge code of 'anaphylaxis, unspecified' or 'allergy, unspecified', were a food-related allergic reaction. Inter-observer agreement was very good (kappa >0.80). The ED presentation rate with food-related allergic reactions in 2004-2011 was 98% higher than in 1988-1995 (RR=1.98, 95%CI 1.10-3.72). By contrast, ED presentation rates for non-food-related allergic reactions did not change over these years.
  
  
  CONCLUSIONS
  ED presentations for food-related allergic reactions are identifiable from within ED presentations coded as 'anaphylaxis, unspecified' or 'allergy, unspecified'. ED presentations for food-related allergic reactions have increased over time in Auckland.
authors.forename: Colleen
authors.initials: C
authors.lastname: McMilin
authors.forename: Carlos
authors.initials: C
authors.lastname: Camargo
authors.forename: Susan
authors.initials: S
authors.lastname: Morton
authors.affiliation: paediatrics: Child & Youth Health, University of Auckland. cc.grant@auckland.ac.nz.
authors.forename: Cameron
authors.initials: C
authors.lastname: Grant
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000707:Anaphylaxis / Q000145:classification* / Q000175:diagnosis / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D059019:Clinical Coding; D004636:Emergency Service, Hospital; D005260:Female; D005512:Food Hypersensitivity / Q000145:classification* / Q000175:diagnosis / Q000453:epidemiology; D006779:Hospitals, Public; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D038801:International Classification of Diseases; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence