How Accurate Are International Classification of Diseases-10 Diagnosis Codes in Detecting Influenza and Pertussis Hospitalizations in Children?

Influenza and pertussis are major causes of pediatric morbidity. We measured the accuracy of their International Classification of Diseases (ICD-10-AM) diagnosis codes using linked population-based laboratory and hospital data in 245,249 children. Influenza diagnosis codes had high specificity (98.6%) and modest positive predictive value (PPV; 84.1%) and sensitivity (86.1%, 95% CI: 83.4%-88.6%) for a laboratory-confirmed episode. For pertussis diagnosis codes, PPV (86.8%) and specificity (98.9%) were high, but sensitivity was poor (27.8%, 95% CI: 23.5%-32.4%). Measures varied according to age, remoteness, Aboriginality, severity, and detection method. Both laboratory and hospitalization data are needed to accurately determine the burden of pediatric influenza and pertussis.