2.2 Data Collection
The electronic medical records of each patient were extracted and
analyzed by four independent researchers with a standardized data
collection form. Patients’ demographic and baseline characteristics
(including age, sex, exposure history, comorbidities, surgery history
and smoking history), symptomatic and
radiological characteristics
[including signs and symptoms, and chest computed tomography (CT)
results], as well as the laboratory findings on admission (including
complete blood cells counts and percentages, and biochemical
parameters), and follow-up data of laboratory parameters in severe
survived and non-survived patients were obtained and analyzed. The
clinical outcome of each patient (i.e. non-survived, discharged, or
remained in hospital) as of Mar 28th, 2020 (the final
follow-up date) and the intervals of symptoms onset (i.e. the day when
the symptoms were noticed) to hospital admission for each patient were
also recorded.
Information in regards of the disease severity, occurrence of
complications (shock, respiratory failure or acute renal failure),
co-infection status with other pathogens during the hospital stay was
collected. The available chest CT images of each patient were reviewed
by a senior radiologist blinded to the clinical data, in order to
confirm detailed abnormality of radiological characteristics of these
patients. The presence or absence of the three following features was
recorded for each patient: 1) ground-glass opacity (GGO); 2) subpleural
lesions and pleural effusion; 3) affected pulmonary lobe numbers.
The presence of exposure history was defined as any close contact with
patients diagnosed with COVID-19 (for example, familial cluster
occurrence or occupational exposure of healthcare professionals) or has
visited Huanan wet market since December 2019. Severe COVID-19 was
designated, if the patients met one of the following criteria: (a)
respiratory distress with respiratory frequency ≥ 30/min; (b) pulse
oximeter oxygen saturation ≤ 93% at rest; and (c) oxygenation index
(artery partial pressure of oxygen/inspired oxygen fraction,
PaO2/FiO2) ≤ 300 mmHg.