title: A clinical prediction rule for diagnosing human infections with avian influenza A(H7N9) in a hospital emergency department setting.
abstract: BACKGROUND
  Human infections with avian influenza A(H7N9) virus are associated with severe illness and high mortality. To better inform triage decisions of hospitalization and management, we developed a clinical prediction rule for diagnosing patients with A(H7N9) and determined its predictive performance.
  
  
  METHODS
  Clinical details on presentation of adult patients hospitalized with either A(H7N9)(n = 121) in China from March to May 2013 or other causes of acute respiratory infections (n = 2,603) in Jingzhou City, China from January 2010 through September 2012 were analyzed. A clinical prediction rule was developed using a two-step coefficient-based multivariable logistic regression scoring method and evaluated with internal validation by bootstrapping.
  
  
  RESULTS
  In step 1, predictors for A(H7N9) included male sex, poultry exposure history, and fever, haemoptysis, or shortness of breath on history and physical examination. In step 2, haziness or pneumonic consolidation on chest radiographs and leukopenia were also associated with a higher probability of A(H7N9). The observed risk of A(H7N9) was 0.3% for those assigned to the low-risk group and 2.5%, 4.3%, and 44.0% for tertiles 1 through 3, respectively, in the high-risk group. This prediction rule achieved good model performance, with an optimism-corrected sensitivity of 0.93, a specificity of 0.80, and an area under the receiver-operating characteristic curve of 0.96.
  
  
  CONCLUSIONS
  A simple decision rule based on data readily obtainable in the setting of patients' first clinical presentations from the first wave of the A/H7N9 epidemic in China has been developed. This prediction rule has achieved good model performance in predicting their risk of A(H7N9) infection and should be useful in guiding important clinical and public health decisions in a timely and objective manner. Data to be gathered with its use in the current evolving second wave of the A/H7N9 epidemic in China will help to inform its performance in the field and contribute to its further refinement.
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Liao
authors.forename: Dennis K M
authors.initials: DK
authors.lastname: Ip
authors.forename: Tim K
authors.initials: TK
authors.lastname: Tsang
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Fengfeng
authors.initials: F
authors.lastname: Liu
authors.forename: Jiandong
authors.initials: J
authors.lastname: Zheng
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Peng
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.forename: Yang
authors.initials: Y
authors.lastname: Huai
authors.forename: Eric H Y
authors.initials: EH
authors.lastname: Lau
authors.forename: Luzhao
authors.initials: L
authors.lastname: Feng
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.forename: Hongjie
authors.initials: H
authors.lastname: Yu
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002681:China / Q000453:epidemiology; D016208:Databases, Factual; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011200:Poultry; D011237:Predictive Value of Tests; D012737:Sex Factors
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