title: Validation of the National Health Insurance Research Database with ischemic stroke cases in Taiwan.
abstract: OBJECTIVE
  The National Health Insurance Research Database (NHIRD) is commonly used for pharmacoepidemiological research in Taiwan. This study evaluated the validity of the database for patients with a principal diagnosis of ischemic stroke.
  
  
  METHODS
  This cross-sectional study compares records in the NHIRD with those in one medical center. Patients hospitalized for ischemic stroke in 1999 were identified from both databases. The discharge notes, laboratory data, and medication orders during admission and the first discharge visit were reviewed to validate ischemic stroke diagnoses and aspirin prescribing in the NHIRD. Agreement between the two databases in comorbidities of ischemic stroke diagnosis was evaluated using ICD-9 codes.
  
  
  RESULTS
  Three hundred and seventy two cases were identified from the NHIRD; among them, 364 cases (97.85%) were confirmed as ischemic stroke by radiology examination and clinical presentation. Among these confirmed cases, 344 (94.51%) were assigned 'ischemic stroke' as the principal diagnosis in the NHIRD. The overall agreement of comorbid diagnoses between the databases was 48.39%. The PPV for selected conditions also varied widely, from 0.50 for fracture to 1.00 for colon cancer. The accuracy of recorded aspirin prescriptions was higher in first post-discharge visits (PPV = 0.94) than during hospitalization (PPV = 0.88).
  
  
  CONCLUSIONS
  The accuracy of the NHIRD in recording ischemic stroke diagnoses and aspirin prescriptions was high, and the NHIRD appears to be a valid resource for population research in ischemic stroke.
authors.affiliation: Institute of Biopharmaceutical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Ching-Lan
authors.initials: CL
authors.lastname: Cheng
authors.forename: Yea-Huei Yang
authors.initials: YH
authors.lastname: Kao
authors.forename: Swu-Jane
authors.initials: SJ
authors.lastname: Lin
authors.forename: Cheng-Han
authors.initials: CH
authors.lastname: Lee
authors.forename: Ming Liang
authors.initials: ML
authors.lastname: Lai
mesh_terms: D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use; D002545:Brain Ischemia / Q000150:complications*; D003430:Cross-Sectional Studies; D016208:Databases, Factual / Q000592:standards*; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D006801:Humans; D007345:Insurance Claim Review / Q000706:statistics & numerical data*; D009313:National Health Programs / Q000592:standards*; D017891:Pharmacoepidemiology / Q000379:methods; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D020521:Stroke / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology; D013624:Taiwan
chemical_list: D001241:Aspirin