title: How accurate is ICD coding for epilepsy?
abstract: OBJECTIVE
  Assess the validity of ICD-9-CM and ICD-10 epilepsy coding from an emergency visit (ER) and a hospital discharge abstract database (DAD).
  
  
  METHODS
  Two separate sources of patient records were reviewed and validated. (1) Charts of patients admitted to our seizure monitoring unit over 2 years (n = 127, ICD-10 coded records) were reviewed. Sensitivity (Sn), specificity (Sp), and positive and negative predictive values (PPV and NPV) were calculated. (2) Random sample of charts for patients seen in the ER or admitted to hospital under any services, and whose charts were coded with epilepsy or an epilepsy-like condition, were reviewed. Two time-periods were selected to allow validation of both ICD-9-CM (n = 486) and ICD-10 coded (n = 454) records. Only PPV and NPV were calculated for these records. All charts were reviewed by two physicians to confirm the presence/absence of epilepsy and compare to administrative coding.
  
  
  RESULTS
  Sample 1: Sn, Sp, PPV, and NPV of ICD-10 epilepsy coding from the seizure monitoring unit (SMU) chart review were 99%, 70%, 85%, and 97% respectively. Sample 2: The PPV and NPV for ICD-9-CM coding from the ER database were, respectively, 99% and 97% and from the DAD were 98% and 99%. The PPV and NPV for ICD-10 coding from the ER database were, respectively, 100% and 90% and from the DAD were 98% and 99%. The epilepsy subtypes grand mal status and partial epilepsy with complex partial seizures both had PPVs >75% (ICD-9-CM and ICD-10 data).
  
  
  CONCLUSIONS
  Administrative emergency and hospital discharge data have high epilepsy coding validity overall in our health region.
authors.affiliation: Division of Neurology, Department of Clinical Neurosciences, University of Calgary, Alberta, Canada. njette@ucalgary.ca
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jetté
authors.forename: Aylin Y
authors.initials: AY
authors.lastname: Reid
authors.forename: Hude
authors.initials: H
authors.lastname: Quan
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
authors.forename: Samuel
authors.initials: S
authors.lastname: Wiebe
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D002648:Child; D039702:Current Procedural Terminology; D016208:Databases, Factual / Q000706:statistics & numerical data; D004636:Emergency Service, Hospital / Q000592:standards / Q000706:statistics & numerical data; D004827:Epilepsy / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005568:Forms and Records Control / Q000592:standards* / Q000706:statistics & numerical data; D006801:Humans; D007344:Insurance Claim Reporting; D038801:International Classification of Diseases / Q000706:statistics & numerical data*; D008297:Male; D008485:Medical Audit / Q000379:methods; D008499:Medical Records / Q000592:standards* / Q000706:statistics & numerical data; D008500:Medical Records Department, Hospital / Q000592:standards / Q000706:statistics & numerical data; D010351:Patient Discharge / Q000592:standards / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018571:Sentinel Surveillance