Difference of Epidemiological, Clinical Characteristics and Outcomes of Patients with COVID-19: A Comparative Study between Epicenter and Peripheral Areas of Pandemic from China

Abstract

Background: There has been little information on difference of epidemiology, clinical characteristics and outcomes between epicenter and peripheral areas of Covid-19 pandemic. Methods: Based on Sichuan & Wuhan collaboration research group for Covid-19, we established two retrospective cohorts reflecting the epicenter and peripheral area of pandemic. Epidemiology, clinical characteristics and outcomes of patients were compared. Subgroup analyses were also explored. Multivariate regression analyses were used to estimate adjusted odds ratios (aOR) to identify clinical variables associated with outcomes. Findings: Upon data cut-off (March 12, 2020), Wuhan cohort consisted of 710 patients using random sampling, and 474 consecutive cases constituted Sichuan cohort, who included two sub-cohorts with (n=305) and without Wuhan-related exposure (n=169). The cases in Sichuan cohort distinctly peaked behind of Wuhan cohort by 7 days. Sichuan cohort had more upper airway symptoms, while Wuhan cohort is elder, has more lower airway symptoms and comorbidities. The case fatality rate in Sichuan cohort was lower (0.6% vs. 8.3%, P < 0.001). The multivariable regression models indicated Wuhan cohort had higher risk of death (aOR=7.64, p=0.001), ICU admission (aOR=1.66, p=0.031), delayed time from illness onset to hospital and ICU admission (aOR=6.29 and aOR=8.03, both p<0.001) and prolonged duration of viral shedding (aOR=1.64, p=0.006) after adjusting for sex, age, smoking and comorbidities. However, no differences were found between two sub-cohorts in Sichuan. Interpretation: Worse outcomes in the epicenter would be partly explained by delayed time from illness onset to hospital and ICU admission associated with elevated systemic inflammation reflecting organ dysfunction and prolonged duration of virus shedding except for age and comorbidities. It indicates potentially clinical implications of Covid-19 that early supportive care would achieve lower mortality. Funding Statement: This study was supported by the Sichuan Provincial Program for Diagnostic and Treatment of Covid-19 (No. 2020YFS002 and 2020YFS0005), and the National Key Development Plan for Precision Medicine Research (2017YFC091004), and the National Natural Science Foundation of China (No. 81920108002). Declaration of Interests: On behalf of all authors, the corresponding author states that there is no conflict of interest. Ethics Approval Statement: This study was approved by the Institutional Review Board from respective sites (No. 2020-304, 2020-126 and WDRY2020-K068). Written informed consent from each participant was waived for design of a retrospective study.