Validation of a novel severe acute respiratory syndrome scoring system

Study objective In a pilot study conducted during March 14 to April 2, 2003, 2 severe acute respiratory syndrome (SARS) screening scores were developed for predicting SARS among febrile patients presenting to the emergency department (ED). The objective of this study is to validate these scoring systems with a different set of patients. Methods All adult patients with documented fever, measured at home or at the hospital, and presenting to the ED of National Taiwan University Hospital, a 2,400-bed tertiary care teaching hospital in northern Taiwan, were prospectively enrolled. Two previously developed SARS screening scores were applied to all patients. The final diagnosis of SARS was made by the Expert Committee of the Center for Disease Control Taiwan, Republic of China, according to the criteria of Centers for Disease Control and Prevention, Atlanta, GA. Results A total of 239 adult patients, including 117 men and 122 women, were enrolled. Eighty-two patients were finally diagnosed with SARS. Compared with the SARS patients in the derivation cohort, those in the validation cohort were older (44.5±15.9 versus 33.9±15.9 years), more likely to acquire the disease locally (76.8% versus 37.5%), and more likely to have cough before or during fever. For the non-SARS patients, cases in the validation cohort presented with less cough and coryza but more diarrhea. For the 4-item symptom score, the sensitivity reached 96.3% (95% confidence interval [CI] 89.7% to 98.7%) and the specificity 51.6% (95% CI 43.8% to 59.3%). For the 6-item clinical score, the sensitivity reached 92.6% (95% CI 84.8% to 96.6%) and the specificity 71.2% (95% CI 63.6% to 77.7%). When the clinical score was applied to patients with a positive symptom score, the combined sensitivity reached 90.2% (95% CI 82.0% to 95.0%), and the combined specificity reached 80.1% (95% CI 73.2% to 85.6%). Conclusion This prospective study validated the scoring system previously developed by using a different cohort. The scoring systems could be applied to settings where mass screening of SARS is needed during future outbreaks.