Journal Article

Risk Factors for Severe Illness with 2009 Pandemic Influenza A (H1N1) Virus Infection in China

Hongjie Yu, Zijian Feng, Timothy M. Uyeki, Qiaohong Liao, Lei Zhou, Luzhao Feng, Min Ye, Nijuan Xiang, Yang Huai, Yuan Yuan, Hui Jiang, Yingdong Zheng, Paul Gargiullo, Zhibin Peng, Yunxia Feng, Jiandong Zheng, Cuiling Xu, Yanping Zhang, Yuelong Shu, Zhancheng Gao, Weizhong Yang and Yu Wang

in Clinical Infectious Diseases

Published on behalf of Infectious Diseases Society of America

Volume 52, issue 4, pages 457-465
Published in print February 2011 | ISSN: 1058-4838
Published online February 2011 | e-ISSN: 1537-6591 | DOI: http://dx.doi.org/10.1093/cid/ciq144
Risk Factors for Severe Illness with 2009 Pandemic Influenza A (H1N1) Virus Infection in China

More Like This

Show all results sharing these subjects:

  • Infectious Diseases
  • Immunology
  • Public Health and Epidemiology
  • Microbiology

GO

Show Summary Details

Preview

Background. Data on risk factors for severe outcomes from 2009 pandemic influenza A (H1N1) virus infection are limited outside of developed countries.

Methods. We reviewed medical charts to collect data from patients hospitalized with laboratory-confirmed 2009 H1N1 infection who were identified across China during the period from September 2009 through February 2010, and we analyzed potential risk factors associated with severe illness (defined as illness requiring intensive care unit admission or resulting in death).

Results. Among 9966 case patients, the prevalence of chronic medical conditions (33% vs 14%), pregnancy (15% vs 7%), or obesity (19% vs 14%) was significantly higher in those patients with severe illness than it was in those with less severe disease. In multivariable analyses, among nonpregnant case patients aged ≥2 years, having a chronic medical condition significantly increased the risk of severe outcome among all age groups, and obesity was a risk factor among those <60 years of age. The risk of severe illness among pregnant case patients was significantly higher for those in the second and third trimesters. The risk of severe illness was increased when oseltamivir treatment was initiated ≥5 days after illness onset (odds ratio, 1.42; 95% confidence interval, 1.20–1.67). For persons <60 years of age, the prevalence of obesity among case patients with severe illness was significantly greater than it was among those without severe illness or among the general population.

Conclusions. Risk factors for severe 2009 H1N1 illness in China were similar to those observed in developed countries, but there was a lower prevalence of chronic medical conditions and a lower prevalence of obesity. Obesity was a risk factor among case patients <60 years of age. Early initiation of oseltamivir treatment was most beneficial, and there was an increased risk of severe disease when treatment was started ≥5 days after illness onset.

Journal Article.  5318 words.  Illustrated.

Subjects: Infectious Diseases ; Immunology ; Public Health and Epidemiology ; Microbiology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.