Epidemiology and Infection

Original Papers

Other Respiratory infections

Pneumonia in US hospitalized patients with influenza-like illness: BioSense, 2007–2010

S. R. BENOITa1 c1, H. BURKOMa2, A. F. McINTYREa3, K. KNISSa3, L. BRAMMERa3, L. FINELLIa3 and S. JAINa3

a1 Division of Notifiable Diseases and Healthcare Information (proposed), Office of Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA

a2 National Security Technology Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA

a3 Influenza Division, National Center for Immunization and Respiratory Diseases, CDC, Atlanta, GA, USA


We used data from BioSense, a national electronic surveillance system, to describe pneumonia in hospitalized patients with influenza-like illness (ILI). Ninety-five hospitals from 20 states reported ICD-9-CM-coded inpatient final diagnosis data during the study period of September 2007 to February 2010. We compared the characteristics of persons with and without pneumonia among those with ILI-related hospitalizations. BioSense captured 26 987 ILI-related inpatient hospitalizations; 8979 (33%) had a diagnosis of pneumonia. Analysis of trends showed highest counts of pneumonia during the 2007–2008 season and the second 2009 pandemic wave. Pneumonia was more common with increasing age. Microbiology and pharmacy data were available for a subset of patients; 107 (5%) with pneumonia had a bloodstream infection and 17% of patients were prescribed antiviral treatment. Our findings demonstrate the potential utility of electronic healthcare data to track trends in ILI and pneumonia, identify risk factors for disease, identify bacteraemia in patients with pneumonia, and monitor antiviral use.

(Received November 18 2011)

(Revised May 25 2012)

(Accepted June 16 2012)

(Online publication July 17 2012)

Key words

  • Epidemiology;
  • influenza;
  • pneumonia;
  • public health;
  • surveillance system