This retrospective, multi-centered, cohort study included 649 adult (≥18 years old) patients confirmed with COVID-19 who died or were discharged between Dec 29, 2019 and Feb 17, 2020 from 14 hospitals in Hubei Province of China. The 14 hospitals involved in the study are government-designated hospitals to receive and treat the patients with COVID-19, and seven of them were from Wuhan, the outbreak center of COVID-19. According to WHO interim guidance(https://www.who.int/) and Chinese New Coronavirus Infected Pneumonia Diagnosis and Treatment Plan(http://www.nhc.gov.cn/; Trial Version 7), all patients enrolled in this study were classified into general survivor, severe/critical survivor, and non-survivor. The diagnostic criteria of severe/critical are as follows: 1) respiratory distress, respiratory rate ≥ 30 times/min; 2) means oxygen saturation ≤ 93% during the resting state; 3) arterial blood oxygen partial pressure / oxygen concentration ≤ 300mmHg (1mmHg = 0.133kPa); 4) lesions progress > 50% on pulmonary images within 24-48 hours; 5) occurrence of respiratory failure and requirement of mechanical ventilation; 6) shock; 7) requirement of ICU monitoring and treatment for combined organ failure. Patients were discharged from hospitals when they met the following criteria: 1) the body temperature returns to normal for more than three days; 2) respiratory symptoms improve significantly; 3) pulmonary imaging shows a marked improvement in acute exudative lesions; 4) nucleic acid tests of two consecutive (at least one day interval) respiratory specimens are negative.
All data including epidemiological, demographic, clinical and laboratory data, and treatment information, were collected and reviewed by the experienced doctors of every hospital from their hospital's electronic medical record system. These data were then collated, analyzed and interpreted by researchers from the Department of Respiratory and Critical Care Medicine, Tongji Hospital, Huazhong University of Science and Technology. The recorded information is mainly related to the following five aspects: demographic data, medical history, symptoms and signs, laboratory findings and treatment measures, the details as follows:
Signs and symptoms: The main symptoms included cough, fever, and pant. The signs included body temperature, respiratory rate, and heart rate. Additionally, we divided the body temperature into three levels: normal (<37.3℃), low fever (37.3~38℃), and fever (>38℃), to evaluate the body temperature distribution among patients in each group.
Laboratory parameters: Laboratory data were collected throughout the whole hospitalization period, and the main tests included blood routine, and C-reactive protein and biochemical examination.
Therapeutic regimen: The main treatment measures in this study were constituted of medications (corticosteroid, antiviral, and antibacterial), γ-globulin, and respiratory support (mask breathing, non-invasive, invasive, and Extracorporeal membrane oxygenation [ECMO]). We also recorded the use of corticosteroids, including the average daily dosage, duration, and the occasion of use. The injections and oral tablets of methylprednisolone, prednisone acetate, and dexamethasone were mainly used. The corticosteroid values recorded in the study were all calculated and analyzed after conversion to methylprednisolone. Antivirals included lopinavir/ritonavir, oseltamivir, interferon, etc., two or three of which were routinely used. Antibacterials included amoxicillin, ceftazidime, moxifloxacin, linezolid, meropenem, etc., one or two of which were commonly administrated.
Chest radiology: Chest x-rays and/or chest CT were performed for all patients enrolled. This examination revealed that all patients had varying degrees of imaging manifestations related to COVID-19 infection (not shown in this article).
Continuous variables are expressed as mean (SD) if they are normally distributed or median (IQR) if they are not, and categorical variables are expressed as number (%). The Student t test or one-way ANOVA was employed for comparison of continuous data that are normally distributed between these three groups involved; Otherwise, the Mann-Whitney U test or Kruskal-Wallis test was used. To compare the categorical data, we used chi-square test or the Fisher exact test as appropriate. Some variables possibly affecting clinical outcomes (discharged or dead) were included in univariate analysis to screen for potential confounding factors, including ages, gender, any comorbidities, leukocyte count, neutrophil count, lymphocyte count, AST, total bilirubin, urea, creatinine and lactate dehydrogenase, and further Cox regression were processed. Statistical analyses were performed using SPSS (Version 26.0). A two-sided α of less than 0.05 was considered statistically significant.