Clinical Features and Outcomes in Imported and Non-Imported Patients with COVID-19 in Chongqing, China: A Retrospective, Multi-Centre, Descriptive Study (preprint)

ABSTRACT

Background: Global outbreak of novel coronavirus 2019 (COVID-19) continues to constitute a public health emergency of international concern. However, few studies have directly compared the differences of clinical features and outcomes between imported and non-imported COVID-19 patients. Methods: In this retrospective, multi-centre, descriptive study, we enrolled 275 patients (53 imported cases and 222 non-imported cases) with laboratory-confirmed COVID-19 from four designated hospitals in Chongqing, China. Epidemiological, demographic, clinical, laboratory, treatment, and outcome data were collected and analyzed. Outcomes were followed up until Mar 1, 2020. Findings: The proportion of asymptomatic patients in the non-imported group was significantly higher than that in the imported group (18.9% vs. 3.8%, p=0.016), and the proportions of symptoms of fever, sore throat and diarrhea in the non-imported group were all lower than those in the imported group (p≤0.048). The imported group had a lower lymphocyte count (1.1×109/L vs. 1.5×10 9 /L, p=0.018), higher neutrophil-to-lymphocyte ratio (NLR) value (2.6 vs. 2.3, p=0.0237), higher proportion of CD4+ T cells reduction (70% vs. 44.6%, p=0.043), longer duration of viral shedding (20 days vs. 18 days, p = 0.0416) than the non-imported group. As to asymptomatic patients in non-imported group, 33.3% had no abnormal chest CT images. They had higher proportion of ground-glass opacity (21.4% vs. 5.6%, p=0.004), lower proportions of bilateral patchy shadowing (7.1% vs. 21%, p=0.027) and multiple manifestations (21.4% vs. 31.3%, p=0.014), higher lymphocyte count (1.6×109/L vs. 1.3×109/L, p=0.003) including both CD4+ (567 vs. 414, p=0.029) and CD8+ (370 vs. 279, p=0.003) T cells than the symptomatic patients in non-imported group. Furthermore, when compared with imported group, asymptomatic group showed higher lymphocyte count (1.6×109/L vs. 1.1×109 /L, p< 0.001) and CD4+ T cells(567 vs.375, p=0.029), while the symptomatic group showed no difference in lymphocyte count, CD4+ or CD8+ T cells (p ≥ 0.0894). Interpretation: In our retrospective study, we found the non-imported group displayed higher lymphocyte count, lower proportion of CD4+ T cells reduction, lower NLR value, shorter duration of viral shedding, but more atypical symptoms and a much higher asymptomatic proportion when compared with imported cases. Our further subgroup analysis suggested that the counts of lymphocyte and CD4+ T cell from non-imported asymptomatic group were higher than those in the imported patients, but there were no difference between non-imported symptomatic and imported patients. Our results indicated that when compared with imported patients, damage to the immune system by SARS-Cov-2 in non-imported patients was milder, and this might be mainly due to its higher asymptomatic proportion. Funding: National Natural Science Foundation of China (No. 81500015). Natural Science Foundation of Chongqing Science and technology bureau (No. cstc2018jcyjAX0115). National Natural Science Foundation of Chongqing (No. cstc2019jcyj‑msxmX0849). The Joint Fund of Science and Health Medicine of Chongqing, China (No. 2019QNXM004).Declaration of Interests The authors declare no competing interests.Ethics Approval Statement This study is approved by Ethics Committees of the four hospitals mentioned above and written informed consent was obtained from each enrolled patient.