title: Accuracy of ICD-9-CM codes in identifying infections of pneumonia and herpes simplex virus in administrative data.
abstract: OBJECTIVE
  Clinical epidemiology studies increasingly rely on electronic medical records data. The validity of International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes is crucial as they are often used to identify conditions of interest. We evaluated the use of archived ICD-9-CM codes to identify two representative infection-related conditions, pneumonia and herpes simplex virus (HSV), in a defined health system.
  
  
  METHODS
  Records were obtained for a sample of 175 and 179 patients with ICD-9-CM codes for pneumonia and HSV, respectively. An adjudicated case status was assigned for each subject.
  
  
  RESULTS
  The presence of a single ICD-9-CM code had a positive predictive value of 88% for pneumonia and 86% for HSV. False positives (noncases) accounted for less than 10% of records evaluated for each condition.
  
  
  CONCLUSIONS
  Our study demonstrates that ICD-9-CM codes for pneumonia and HSV were valid markers of a true history of these conditions, suggesting that ICD-9-CM codes can be used to successfully identify infection-related conditions in epidemiologic studies. However, validation studies for individual conditions may help identify condition-specific strategies to improve the performance of diagnostic codes.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20852-7234, USA. jennifer.drahos@nih.gov
authors.forename: Jennifer
authors.initials: J
authors.lastname: Drahos
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Vanwormer
authors.forename: Robert T
authors.initials: RT
authors.lastname: Greenlee
authors.forename: Ola
authors.initials: O
authors.lastname: Landgren
authors.forename: Jill
authors.initials: J
authors.lastname: Koshiol
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D059019:Clinical Coding / Q000592:standards*; D016208:Databases, Factual; D057286:Electronic Health Records; D005260:Female; D006561:Herpes Simplex / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000145:classification* / Q000175:diagnosis; D012680:Sensitivity and Specificity; D018139:Simplexvirus / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D055815:Young Adult