Lack of accuracy of the international classification of disease, ninth (ICD-9) codes in identifying patients with encephalitis

  • Mohammed SamannodiEmail author
  • Michael Hansen
  • Rodrigo Hasbun
Letter to the Editors

Dear Sirs,

The International Classification of Disease (ICD) codes are used worldwide and are usually collected and comprised in administrative databases. These data are a valuable source of information for both inpatient and outpatient healthcare encounters. ICD-9 codes have been widely used in studies utilizing large national databases that evaluate the clinical epidemiology of encephalitis in the United States [1]. Many studies have showed that ICD-9 codes have different accuracy in other diseases [2, 3, 4]. To our knowledge, this is the first study in the United States to evaluate the diagnostic accuracy of ICD-9 codes in encephalitis.

We conducted a retrospective study of all adults with an ICD-9 discharge diagnosis of encephalitis. The study was collected from 17 hospitals from the Memorial Hermann Health (MHH) System and Harris Health System (HHS) in the Greater Houston area between March of 2010 and July of 2015. Medical records were reviewed independently by two physicians and...


Compliance with ethical standards

Conflicts of interest

All authors have no conflicts of interest.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Division of Infectious Disease, Department of MedicineMcGovern Medical School at University of Texas Health Sciences CenterHoustonUSA
  2. 2.Department of Family MedicineBaylor College of MedicineHoustonUSA

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