14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 28.021
Session: Influenza
Date: Wednesday, March 10, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
An analysis of critically ill patients with the novel influenza A (H1N1) virus in Japan
K. Wada 1 , H. Nishiura 2 , A. Kawana 3
1 Kitasato University School of Medicine, Sagamihara, Japan, 2 PRESTO, Japan Science and
Technology Agency, Saitama, Japan, 3 National Defense Medical College, Saitama, Japan
Background: Japan identified its first case of novel influenza A (H1N1) on 9 May 2009, and its
incidence has increased steadily. As of 26 October, 34 deaths have been reported. The aim of
this study was to summarize the clinical findings of critically ill patients in Japan.
Methods: Critically ill patients are defined as confirmed or probable cases who meet one of the
following conditions: a case who (1) was diagnosed with influenza-associated encephalopathy,
(2) was admitted to an intensive care unit (ICU), (3) was intubated or (4) died. We analyzed a
total of 120 cases, including 23 deaths, who developed the disease by 6 October 2009.
Results: Of the 120 cases, those aged < 20 years accounted for 71.7%. All 11 cases aged 65
and older resulted in death, while the proportion of deaths among cases aged < 20 years and
adults aged < 65 years was smaller (5.2% and 34.8%, respectively). The mean (SD) and median
times from onset to hospitalization were 62.8 (40.2) and 48.0 hours, respectively. The mean (SD)
and median times from onset to death for the 23 fatal cases were 160.4 (116.5) and 120.0 hours,
respectively. The timing of antiviral administration did not appear to significantly affect the clinical
course among critically ill patients.
Of the 120 cases, 57 (47.5%) had at least one underlying medical condition. Of the 86 cases
aged < 20 years, 27 (31.4%) had one or more comorbidity, with asthma being the most common
(22.9%). Similarly, of the 34 adult cases, 30 (88.2%) had comorbidities and chronic respiratory
disease (23.5%) was the most common.
Conclusion: First, age below 20 were more frequently reported as critically ill than adults. As the
epidemic progresses further, the age-composition of severe cases may change. Second, the
clinical courses appeared to have been rapid after onset. The time from onset to death in Japan
was shorter than those reported elsewhere. Third, approximately half of the cases were
accompanied by at least one underlying condition, and this proportion was particularly high
among adults.