1241. Community Acquired Pneumonia (CAP) in adults hospitalized with ARI during the 2014-2015 Influenza Season: Participant characteristics and viral etiologies
Session: Poster Abstract Session: Clinical Infectious Diseases: Respiratory Infections
Friday, October 28, 2016
Room: Poster Hall
Background: Few studies have characterized the frequency of respiratory viruses associated with community acquired pneumonia (CAP). We used data and specimens from a test-negative study of influenza vaccine effectiveness to compare hospitalized adults with and without diagnoses of CAP and examine the frequency of respiratory viruses.

Methods: Adults hospitalized with acute respiratory illness (ARI) were prospectively enrolled from two Michigan hospitals during the 2014-2015 influenza season. CAP cases were defined by ICD-9 codes (480-487.0). Patients were characterized by demographics, self-reported frailty, Charlson Comorbidity Index (CCI) score, influenza and pneumococcal vaccination, and clinical outcomes. Respiratory specimens were tested for influenza and respiratory syncytial virus (RSV) by RT-PCR. Clinical multiplex RT-PCR testing for other respiratory pathogens were available for a subset of enrollees.

Results: 224 (36%) of 624 adults hospitalized with ARI had ICD-9 codes consistent with CAP. These patients were older (p < 0.001), had higher CCI scores (p = 0.002), and had more immunosuppressive disorders (p=0.005) and malignancies (p=0.02) than those without CAP. Patients with CAP were less likely to be frail (p = 0.046) or morbidly obese (p=0.01). CAP patients were more likely to have received influenza vaccine (p=0.003), but not pneumococcal vaccine. CAP patients had longer hospitalizations, (mean difference 0.5 days, p < 0.001) and were more likely discharged to another facility (OR 2.2 95%CI 1.2-4.3). Influenza A(H3N2) was more frequently detected in non-CAP patients (19%) than those with CAP (10%). The frequency of RSV infection was similar for both groups (9% and 8%). Those with CAP were more likely to be tested clinically than those without (OR 2.0 95%CI 1.3-3.2). Human Metapneumovirus (hMPV), rhinovirus (HRV), and parainfluenza viruses (PIV) were similarly frequent in CAP patients who underwent clinical testing: 7/110 (6.4%), 8/110 (7.3%), and 8/110 (7.3%) respectively; all were detected more frequently in CAP patients, but differences were not statistically significant.

Conclusion: Patients with CAP were less healthy and had more severe clinical outcomes than non-CAP patients. Among those with CAP, influenza was the most commonly identified viral pathogen, with RSV, HRV, hMPV and PIV also associated with a substantial number of cases.

Ryan E. Malosh, PhD1, Caroline K. Cheng, MS1, Emily T. Martin, MPH, PhD2, Jill M. Ferdinands, PhD, MSc3, Alicia M. Fry, MD, MPH4 and Arnold S. Monto, MD, FIDSA1, (1)Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, (2)Pharmacy Practice, Wayne State University, Detroit, MI, (3)Battelle Memorial Institute, Atlanta, GA, (4)Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA

Disclosures:

R. E. Malosh, None

C. K. Cheng, None

E. T. Martin, None

J. M. Ferdinands, None

A. M. Fry, None

A. S. Monto, Sanofi Pasteur: Consultant and Grant Investigator , Consulting fee and Grant recipient
GSK: Consultant , Consulting fee
Novavax: Consultant , Consulting fee

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