Predictors and outcomes of respiratory failure among hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan.
OBJECTIVE
The worldwide outbreak of a pandemic influenza A (H1N1) virus began in April 2009. We characterized the clinical features of the hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan and elucidated the risk of those patients for developing respiratory failure.


METHODS
Severe complicated influenza infection is a notifiable disease in Taiwan and the hospitalized pneumonia patients with 2009 H1N1 influenza were reported accordingly. We reviewed the medical records of the eligible cases by September 8, 2009; development of respiratory failure was the primary endpoint.


RESULTS
Of the 96 patients we studied, 22 (23%) developed respiratory failure. Among those, 10 (45%) died and all of the non-respiratory failure patients survived. Age distribution, presence of dyspnea, lymphopenia, leukopenia, PaO(2)/FiO(2) ratio, PaCO(2), SOFA score, infiltration on chest x-ray at admission were different between two groups by univariate analysis. The clinical course was also different, with longer duration from onset of symptoms to use of oseltamivir, longer hospital stay, and more complications during hospitalization in patients with respiratory failure. A multivariate logistic regression showed an association between development of respiratory failure and SOFA score > or = 4 at admission, initial lymphocyte count < or = 800/microL, and the duration from symptom onset to initiation of oseltamivir > 48 h.


CONCLUSIONS
Respiratory failure in patients with 2009 H1N1 influenza leads to poor outcomes, including complications and death. Clinicians could apply the three predictors at admission to identify the high-risk pneumonic patients for developing respiratory failure. Further study is needed to validate the findings of this study in other settings.
Chien
Yu-San
YS
Field Epidemiology Training Program, Centers for Disease Control, Taiwan, ROC.
Su
Chia-Ping
CP
Tsai
Huai-Te
HT
Huang
Angela S
AS
Lien
Chia-En
CE
Hung
Min-Nan
MN
Chuang
Jen-Hsiang
JH
Kuo
Hsu-Sung
HS
Chang
Shan-Chwen
SC
D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000821:virology*; D018655:Lymphocyte Count; D011014:Pneumonia / Q000150:complications* / Q000401:mortality / Q000473:pathology*; D012131:Respiratory Insufficiency / Q000453:epidemiology* / Q000401:mortality; D012720:Severity of Illness Index; D013624:Taiwan; D016896:Treatment Outcome