title: [Clinical characteristics of adult influenza inpatients in ten provinces in China and analysis of severe risk factors].
abstract: OBJECTIVE
  To identity the clinical characteristics and severe case risk factors for the adult inpatient cases confirmed of influenza monitored by the sentinel surveillance system for severe acute respiratory infection (SARI) inpatient cases in ten provinces in China.
  
  
  METHODS
  Epidemiology and clinical information surveys were conducted for adult cases (≥ 15 year old) consistent with SARI case definition, who were monitored by SARI sentinel hospitals in ten cities in China from December 2009 to June 2014, with their respiratory tract specimens collected for influenza RNA detection. Adult SARI cases were classified into influenza inpatient group and outpatient group by the detection outcomes, analyzing their demographic information, clinical and epidemiology characteristics respectively, in addition to risk factors for severe inpatient cases.
  
  
  RESULTS
  3 071 adult SARI cases were recruited from ten hospitals, including 240 (7.8%) cases of laboratory-confirmed influenza, most of them being A (H1N1) pdm2009 and A (H3N2) sub-types. Age M of the included influenza cases was 63 year old, 47.1% of them being ≥ 65 seniors. 144 (60.0%) cases of the influenza inpatients suffered from at least one chronic underlying condition, and the proportion of emphysema (7.9%) was higher than non-influenza inpatient cases (3.8%), being statistically significant (χ(2) = 3.963, P = 0.047). 19.4% of the women of childbearing age infected of influenza were in pregnancy, and only 1.1% of the 240 influenza cases had been vaccinated against influenza. The proportion of sore throat and dyspnea found among influenza inpatients was higher than inpatients without influenza. 17.4% of the influenza cases were accepted into ICU for treatment, with no statistical significance with non-influenza inpatient cases (P = 0.160). 23.1% of the influenza inpatients received an antiviral drug therapy, a figure higher than the non-influenza inpatient cases (4.8%) (P < 0.001). 41.5% of the inpatients developed complications, with the proportion of viral pneumonia significantly higher than the non-influenza inpatient cases (P < 0.001). Asthma (RR = 15.200, 95% CI: 1.157-199.633), immunosuppressive diseases (RR = 5.250, 95% CI: 1.255-21.960), pregnancy (RR = 21.000, 95% CI: 1.734-254.275), time interval from onset to admission less 7 days (RR = 1.673, 95% CI: 1.071-2.614) were identified as risk factors of severely-ill influenza cases.
  
  
  CONCLUSIONS
  It was found that adult influenza inpatients were mostly ≥ 65 year old seniors. The influenza vaccination rate among the influenza cases was very low, and antivirus drugs were used less than necessary. In this regard, influenza vaccination was recommended for high risk groups of pregnant women, seniors and chronic disease patients on annual basis, while influenza inpatients were advised to use antiviral drugs as early as possible.
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Gansu Provincial Center for Disease Control and Prevention.
authors.forename: Deshan
authors.initials: D
authors.lastname: Yu
authors.affiliation: Zhuhai Municipal Center for Disease Control and Prevention.
authors.forename: Feng
authors.initials: F
authors.lastname: Ruan
authors.affiliation: Yunnan Provincial Center for Disease Control and Prevention.
authors.forename: Wen
authors.initials: W
authors.lastname: Xu
authors.affiliation: Sichuan Provincial Center for Disease Control and Prevention.
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
authors.affiliation: Fujian Medical University Union Hospital.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Heilongjiang Provincial Center for Disease Control and Prevention.
authors.forename: Kaili
authors.initials: K
authors.lastname: Wang
authors.affiliation: Zhejiang Provincial Center for Disease Control and Prevention.
authors.forename: Shelan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Hunan Provincial Center for Disease Control and Prevention.
authors.forename: Hengjiao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: The Center Hospital of Jinan.
authors.forename: Pingdong
authors.initials: P
authors.lastname: Jia
authors.affiliation: Beijing Municipal Center for Disease Control and Prevention.
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Peng
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Email: fenglz@chinacdc.cn.
authors.forename: Luzhao
authors.initials: L
authors.lastname: Feng
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D000998:Antiviral Agents; D002681:China / Q000453:epidemiology; D005260:Female; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D007251:Influenza, Human / Q000453:epidemiology*; D007297:Inpatients; D010045:Outpatients; D011024:Pneumonia, Viral; D011247:Pregnancy; D012141:Respiratory Tract Infections; D012307:Risk Factors; D018571:Sentinel Surveillance; D014611:Vaccination
chemical_list: D000998:Antiviral Agents