title: A systematic review of validated methods to capture several rare conditions using administrative or claims data.
abstract: OBJECTIVE
  To identify and assess billing, procedural, or diagnosis code, or pharmacy claim-based algorithms used to identify the following health outcomes in administrative and claims databases: acute disseminated encephalomyelitis (ADEM), optic neuritis, tics, and Henoch Schönlein purpura (HSP).
  
  
  METHODS
  We searched the MEDLINE database from 1991 to September 2012 using controlled vocabulary and key terms related to the conditions. We also searched the reference lists of included studies. Two investigators independently assessed the full text of studies against pre-determined inclusion criteria and extracted case validation data from those studies meeting inclusion criteria.
  
  
  RESULTS
  Two eligible studies addressed ADEM, two addressed optic neuritis, and four studies addressed tics. Only one study addressed HSP. Among these, one study of ADEM reported a positive predictive value of 66%, however the identification algorithm contained a combination of International Classification of Diseases (ICD) codes and other identification methods and the performance of the ICD-9 codes alone was not reported. No other studies reported validation data.
  
  
  CONCLUSIONS
  The lack of data on the validity of algorithms to identify these conditions may hamper our ability to determine incidence patterns with respect to infection and vaccination exposures. Further epidemiologic research to define validated methods of identifying cases could improve surveillance using large linked healthcare databases.
authors: Department of Neurology, Vanderbilt University Medical Center, 1161 21st Ave S, MCN A0118, Nashville, TN 37232, USA. Electronic address: christopher.lee@vanderbilt.edu.
authors: Christopher D
authors: CD
authors: Lee
authors: Vanderbilt Vaccine Research Program, Vanderbilt University Medical Center, 1161 21st Avenue, CCC 5326 Medical Center North, Nashville, TN 37232, USA. Electronic address: elizabeth.williams@vanderbilt.edu.
authors: S Elizabeth
authors: SE
authors: Williams
authors: Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, Vanderbilt University Medical Center, Suite 600, 2525 West End Avenue, Nashville, TN 37203-1738, USA. Electronic address: nila.sathe@vanderbilt.edu.
authors: Nila A
authors: NA
authors: Sathe
authors: Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Suite 600, 2525 West End Avenue, Nashville, TN 37203-1738, USA. Electronic address: melissa.mcpheeters@vanderbilt.edu.
authors: Melissa L
authors: ML
authors: McPheeters
mesh_terms: D000465:Algorithms; D016208:Databases, Factual / Q000706:statistics & numerical data*; D004673:Encephalomyelitis, Acute Disseminated / Q000453:epidemiology*; D004812:Epidemiologic Methods; D006801:Humans; D011695:IgA Vasculitis / Q000453:epidemiology*; D015994:Incidence; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D038801:International Classification of Diseases / Q000706:statistics & numerical data; D009902:Optic Neuritis / Q000453:epidemiology*; D020323:Tics / Q000453:epidemiology*
keywords: ACE; ADEM; Acute disseminated encephalomyelitis; Administrative data; FDA; HMO; HSP; Henoch Schönlein purpura; ICD; International Classification of Diseases; MS; ON; Optic neuritis; TCV; Tics; US Food and Drug Administration; acute disseminated encephalomyelitis; angiotensin converting enzyme; health maintenance organization; multiple sclerosis; optic neuritis; thimerosal containing vaccines