Epidemiology and Infection

Original Papers

ICD-10 codes are a valid tool for identification of pneumonia in hospitalized patients aged xs2A7E65 years

S. A. SKULLa1a2 c1, R. M. ANDREWSa2, G. B. BYRNESa3, D. A. CAMPBELLa3a4, T. M. NOLANa3, G. V. BROWNa5 and H. A. KELLYa3a6

a1 Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia

a2 Menzies School of Health Research, Darwin, Northern Territory, Australia

a3 School of Population Health, University of Melbourne, Victoria, Australia

a4 Monash Institute of Health Services Research, Monash Medical Centre, Clayton, Victoria, Australia

a5 Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Victoria, Australia

a6 Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia


This study examines the validity of using ICD-10 codes to identify hospitalized pneumonia cases. Using a case-cohort design, subjects were randomly selected from monthly cohorts of patients aged xs2A7E65 years discharged from April 2000 to March 2002 from two large tertiary Australian hospitals. Cases had ICD-10-AM codes J10–J18 (pneumonia); the cohort sample was randomly selected from all discharges, frequency matched to cases by month. Codes were validated against three comparators: medical record notation of pneumonia, chest radiograph (CXR) report and both. Notation of pneumonia was determined for 5098/5101 eligible patients, and CXR reports reviewed for 3349/3464 (97%) patients with a CXR. Coding performed best against notation of pneumonia: kappa 0·95, sensitivity 97·8% (95% CI 97·1–98·3), specificity 96·9% (95% CI 96·2–97·5), positive predictive value (PPV) 96·2% (95% CI 95·4–97·0) and negative predictive value (NPV) 98·2% (95% CI 97·6–98·6). When medical record notation of pneumonia is used as the standard, ICD-10 codes are a valid method for retrospective ascertainment of hospitalized pneumonia cases and appear superior to use of complexes of symptoms and signs, or radiology reports.

(Accepted March 28 2007)

(Online publication April 20 2007)


c1 Author for correspondence: Dr S. A. Skull, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Rd, Parkville, Victoria, Australia 3052. (Email: saskull@unimelb.edu.au)