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Influenza in adults admitted to Canadian hospitals: data from two seasons

Abstract number: O125

McGeer A., Gravel D., Taylor G., Weir C., Frenette C., Vayalumkal J., Wong A., Moore D., Michaud S., Amihod B.

Objective: Seasonal influenza (flu) remains a cause of substantial morbidity and mortality. Antiviral treatment should be considered for all hospitalised patients with influenza. To better understand the epidemiology and burden of illness within the hospital sector in Canada and the current use of antiviral therapy, we carried out a multihospital survey of virologically confirmed flu in hospitalised adults.

Methods: CNISP is a network of largely teaching hospitals across Canada that collaborates to collect data on infections in hospitalised patients. During two consecutive years (2006/2007 and 2007/2008) hospitals within CNISP identified inpatients >16 years who had virologically confirmed flu. Case patient charts were reviewed to capture demographic and clinical data and to determine whether flu was community (CA) or hospital acquired (HA). Cases were reviewed at 30 days to determine outcomes. Deaths at 30 days were reviewed to determine whether flu was a main or contributing cause.

Results: Fifteen (06/07) and 11 (07/08) hospitals were recruited from the CNISP network. 532 virologically confirmed cases of flu were found, 182 in 06/07 (95% flu A) and 358 in 07/08 (56% flu A). Mean patient age was 67 years, 52% were male. There was documentation of patient vaccination that season in 29%. Incidence of CA flu was 11/10,000 admissions in 06/07 (range by hospital 2 – 23) and 27 in 07/08 (1 – 47). Admitting diagnoses in CA cases were: pneumonia or influenza 48%, exacerbation of COPD 20%, sepsis or fever not otherwise specified 9%, cardiac diagnoses 7%, other diagnoses 16%. 24% of cases were HA, range by hospital 3.9 – 5.4/100,000 patient days. 68% of patients were managed with droplet and contact isolation practices, an N-95 mask was used in 19%. 29% of CA cases but 75% of HA cases received antiviral therapy p < 0.01, almost entirely oseltamivir. 9% of cases were admitted to an ICU; 30-day mortality was 8% with 2.6% attributed to influenza.

Conclusion: There is considerable season-season and hospital-hospital variation in flu in patients in Canadian hospitals. Hospitalised patients CA flu present with a wide spectrum of clinical diagnoses; nearly a quarter of all cases were HA. Few CA cases but most HA cases were treated with antiviral drugs. Attributable 30 day mortality was 2.6%.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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