title: Population-based drug-related anaphylaxis in children and adolescents captured by South Carolina Emergency Room Hospital Discharge Database (SCERHDD) (2000-2002).
abstract: OBJECTIVE
  Anaphylaxis is a life-threatening condition; drug-related anaphylaxis represents approximately 10% of all cases. We assessed the utility of a statewide emergency department (ED) database for identifying drug-related anaphylaxis in children by developing and validating an algorithm composed of ICD-9-CM codes.
  
  
  METHODS
  There were 1 314,760 visits to South Carolina (SC) emergency departments (EDs) for patients <19 years in 2000-2002. We used ICD-9-CM disease or external cause of injury codes (E-codes) that suggested drug-related anaphylaxis or a severe drug-related allergic reaction. We found 50 cases classifiable as probable or possible drug-related anaphylaxis and 13 as drug-related allergic reactions. We used clinical evaluation by two pediatricians as the 'alloyed gold standard'1 for estimating sensitivity, specificity, and positive predictive value (PPV) of our algorithm.
  
  
  RESULTS
  ED-treated drug-related anaphylaxis in the SC pediatric population was 1.56/100,000 person-years based on the algorithm and 0.50/100,000 person-years based on clinical evaluation. Assuming the disease codes we used identified all potential anaphylaxis cases in the database, the sensitivity was 1.00 (95%CI: 0.79, 1.00), specificity was 0.28 (95%CI: 0.16, 0.43), and the PPV was 0.32 (0.20, 0.47) for the algorithm. Sensitivity analyses improved the measurement properties of the algorithm.
  
  
  CONCLUSIONS
  E-codes were invaluable for developing an anaphylaxis algorithm although the frequently used code of E947.9 was often incorrectly applied. We believe that our algorithm may have over-ascertained drug-related anaphylaxis patients seen in an ED, but the clinical evaluation may have under-represented this diagnosis due to limited information on the offending agent in the abstracted ED records. Post-marketing drug surveillance using ED records may be viable if clinicians were to document drug-related anaphylaxis in the charts so that billing codes could be assigned properly.
authors.affiliation: Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7521, USA. sue_west@unc.edu
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: West
authors.forename: Aimee A
authors.initials: AA
authors.lastname: D'Aloisio
authors.forename: Tamar
authors.initials: T
authors.lastname: Ringel-Kulka
authors.forename: Anna E
authors.initials: AE
authors.lastname: Waller
authors.forename: W
authors.initials: W
authors.lastname: Clayton Bordley
mesh_terms: D000293:Adolescent; D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data*; D000465:Algorithms; D000707:Anaphylaxis / Q000139:chemically induced / Q000453:epidemiology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D008499:Medical Records / Q000706:statistics & numerical data; D010351:Patient Discharge / Q000706:statistics & numerical data*; D010865:Pilot Projects; D011358:Product Surveillance, Postmarketing / Q000379:methods / Q000706:statistics & numerical data; D013022:South Carolina / Q000453:epidemiology