Clinical, laboratory, and radiological features indicative of novel coronavirus disease (COVID‐19) in emergency departments: a multicenter case‐control study in Hong Kong

OBJECTIVES: Little is known about the value of routine clinical assessment in identifying patients with coronavirus disease 2019 (COVID‐19) in the emergency department (ED). We aimed to compare the exposure history, signs and symptoms, laboratory, and radiographic features of ED patients who tested positive and negative for COVID‐19. METHODS: This was a case‐control study in 7 EDs in Hong Kong from 20 January to 29 February 2020. Thirty‐seven patients with laboratory‐confirmed COVID‐19 were age‐ and sex‐matched to 111 controls. We compared the groups with univariate analysis and calculated the odds ratio (OR) of having COVID‐19 for each characteristic that was significantly different between the groups with adjustment for age and presumed location of acquiring the infection. RESULTS: There were no significant differences in patient characteristics and reported symptoms between the groups. A positive contact history within 14 days (adjusted OR 37.61, 95% CI: 10.86–130.19), bilateral chest radiograph shadow (adjusted OR 13.19, 95% CI: 4.66–37.35), having prior medical consultation (adjusted OR 7.43, 95% 2.89–19.09), a lower white blood cell count (adjusted OR 1.30, 95% CI: 1.11–1.51), and a lower platelet count (adjusted OR 1.07, 95% CI: 1.01–1.12) were associated with a higher odds of COVID‐19 separately. A higher neutrophil count was associated with a lower odds of COVID‐19 (adjusted OR 0.77, 95% CI: 0.65–0.91). CONCLUSION: This study highlights a number of clinical features that may be useful in identifying high‐risk patients for early testing and isolation while waiting for the test result. Further studies are warranted to verify the findings.