Comparative study on the clinical characteristics of local cases of COVID-19 and imported cases from abroad A retrospective cohort study

It is presently unknown whether imported cases of the 2019 coronavirus disease (COVID-19) have different characteristics when compared with local cases. To compare the clinical characteristics of local cases of COVID-19 in China compared with those imported from abroad. This was a retrospective study of confirmed cases of COVID-19 admitted at the Beijing Ditan Fever Emergency Department between February 29(th), 2020, and March 27(th), 2020. The clinical characteristics of the patients were compared between local and imported cases. Compared with local cases, the imported cases were younger (27.3 +/- 11.7 vs. 43.6 +/- 22.2 years, P < .001), had a shorter interval from disease onset to admission (1.0 (0.0-2.0) vs 4.0 (2.0-7.0) days, P < .001), lower frequencies of case contact (17.4% vs 94.1%, P < .001), fever (39.1% vs 82.4%, P < .001), cough (33.3% vs 51.0%, P = .03), dyspnea (1.9% vs 11.8%, P = .01), fatigue (7.5% vs. 27.5%, P = 0.001), muscle ache (4.7% vs. 25.5%, P < 0.001), and comorbidities (P < .05). The imported cases were less severe than the local cases, with 40.4% versus 5.9% mild cases, 2.8% versus 15.7% severe cases, and no critical cases (P < .001). The length of hospital stay was longer in imported cases than in local cases (32.3 +/- 14.5 vs 21.7 +/- 11.2 days, P < .001). The imported cases showed smaller biochemical perturbations than the local cases. More imported cases had no sign of pneumonia at computed tomography (45.0% vs 14.9%, P = .001), and none had pleural effusion (0% vs 14.9%, P < .001). Compared with local cases, the imported cases of COVID-19 presented with milder disease and less extensive symptoms and signs.