Abstract
We aimed to study factors influencing outcomes of adults hospitalised for seasonal and pandemic influenza.
Individual-patient data from three Asian cohorts (Hong Kong, Singapore and Beijing; N=2649) were analysed. Adults hospitalised for laboratory-confirmed influenza (prospectively diagnosed) during 2008–2011 were studied. The primary outcome measure was 30-day survival. Multivariate Cox regression models (time-fixed and time-dependent) were used.
Patients had high morbidity (respiratory/nonrespiratory complications in 68.4%, respiratory failure in 48.6%, pneumonia in 40.8% and bacterial superinfections in 10.8%) and mortality (5.9% at 30 days and 6.9% at 60 days). 75.2% received neuraminidase inhibitors (NAI) (73.8% received oseltamivir and 1.4% received peramivir/zanamivir; 44.5% of patients received NAI ≤2 days and 65.5% ≤5 days after onset of illness); 23.1% received systemic corticosteroids. There were fewer deaths among NAI-treated patients (5.3% versus 7.6%; p=0.032). NAI treatment was independently associated with survival (adjusted hazard ratio (HR) 0.28, 95% CI 0.19–0.43), adjusted for treatment-propensity score and patient characteristics. Superinfections increased (adjusted HR 2.18, 95% CI 1.52–3.11) and chronic statin use decreased (adjusted HR 0.44, 95% CI 0.23–0.84) death risks. Best survival was shown when treatment started within ≤2 days (adjusted HR 0.20, 95% CI 0.12–0.32), but there was benefit with treatment within 3–5 days (adjusted HR 0.35, 95% CI 0.21–0.58). Time-dependent analysis showed consistent results of NAI treatment (adjusted HR 0.39, 95% CI 0.27–0.57). Corticosteroids increased superinfection (9.7% versus 2.7%) and deaths when controlled for indications (adjusted HR 1.73, 95% CI 1.14–2.62). Early NAI treatment was associated with shorter length of stay in a subanalysis.
NAI treatment may improve survival of hospitalised influenza patients; benefit is greatest from, but not limited to, treatment started within 2 days of illness. Superinfections and corticosteroids increase mortality. Antiviral and non-antiviral management strategies should be considered.
Abstract
NAI treatment, secondary infections and corticosteroids may impact on survival of hospitalised influenza patients http://ow.ly/ErOsT
Footnotes
This article has supplementary material available from erj.ersjournals.com
Support statement: This project is jointly supported by the Research Fund for the Control of Infectious Diseases (grant CU-11-01-01), Food and Health Bureau of the Hong Kong Special Administrative Region Government; a departmental research fund, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong; and research grants from the National Natural Science Foundation of China (grants 81070005/H0104, 81030032/H19 and 81271840), Beijing. Funding information for this article has been deposited with FundRef.
The views expressed are those of the authors and do not reflect the official policies of the Centers for Disease Control and Prevention.
Conflict of interest: Disclosures can be found alongside the online version of this article at erj.ersjournals.com
- Received September 17, 2014.
- Accepted November 11, 2014.
- Copyright ©ERS 2015