Establishing a clinical decision rule of severe acute respiratory syndrome at the emergency department.
OBJECTIVE
In the absence of reliable rapid confirmatory tests during severe acute respiratory syndrome (SARS) endemics, we designed a 2-phase cohort study to establish a scoring system for SARS and to evaluate whether it could improve the sensitivity and specificity of the World Health Organization (WHO) criteria.


METHODS
According to the clinical characteristics and initial laboratory findings of 175 suspected cases defined by the WHO criteria (20 confirmed as cases of SARS) in 3 university teaching hospitals in Taipei between March 1 and April 20, 2003, the scoring system for SARS was designed by multivariate analysis and stepwise logistic regression as the simple arithmetic sum of point values assigned to 7 parameters. We thereafter applied the scoring system for SARS to the consecutive 232 patients (the validation group) who met the WHO criteria of suspected cases from April 21 to May 22, 2003. Final diagnosis of SARS was determined by the results of real-time polymerase chain reaction and paired serum.


RESULTS
The scoring system for SARS was defined as radiographic findings of multilobar or bilateral infiltrates (3 points), sputum monocyte predominance (3 points), lymphocytopenia (2 points), history of exposure (1 point), lactate dehydrogenase more than 450 U/L (1 point), C-reactive protein more than 5.0 mg/dL (1 point), and activated partial prothrombin time more than 40 seconds (1 point). Of the validation group, 60 patients (group A) were confirmed as having cases of SARS, and the other 172 (group B) patients tested negative for SARS. The total points of the scoring system for SARS at initial presentation were significantly higher in the SARS group (median 9; range 6 to 11) than in the non-SARS group (median 4; range 3 to 7; P<.001). At the cutoff value of 6 points, the sensitivity and specificity of the scoring system for SARS in diagnosing SARS were 100% and 93%, respectively. The positive and negative predictive values of the scoring system for SARS were 83% and 100%, respectively.


CONCLUSIONS
The scoring system for SARS can provide a rapid and reliable clinical decision to help emergency physicians detect cases of SARS more accurately in the endemic area.
Wang
Tzong-Luen
TL
Department of Emergency Medicine, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Jang
Tsrang-Neng
TN
Huang
Chien-Hsien
CH
Kao
Shang-Jyh
SJ
Lin
Chor-Ming
CM
Lee
Fang-Niarn
FN
Liu
Cheng-Yao
CY
Chong
Chee-Fah
CF
Lin
Chu-Mei
CM
Dorji
Harnod
H
Teng
Hsueh-Ju
HJ
Chang
Hang
H
D001772:Blood Cell Count; D015331:Cohort Studies; D003661:Decision Support Techniques; D004196:Disease Outbreaks / Q000517:prevention & control; D042241:Early Diagnosis; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D014943:Global Health; D006801:Humans; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D010343:Patient Admission / Q000706:statistics & numerical data; D016133:Polymerase Chain Reaction; D013902:Radiography, Thoracic; D012044:Regression Analysis; D012307:Risk Factors; D012680:Sensitivity and Specificity; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis* / Q000453:epidemiology; D013183:Sputum / Q000166:cytology; D014944:World Health Organization