Patients involvement and data collection
All hospitalized patients (n = 40) (admission date from Jan 26th to Feb 23rd 2020) in the first affiliated hospital of Anhui Medical University and the first people's hospital of Chuzhou City were recruited in this study, diagnosed as “COVID-19”according to the diagnostic and treatment guideline of SARS-CoV-2 issued by the Chinese National Health Committee (Version 4-6). The epidemiological risks included: a history of travel to or residence in Wuhan city, China or other cities with continuous transmission of local cases in the last two weeks before symptoms onset; contact with patients with fever or respiratory symptoms from Wuhan city, China or other cities with continuous transmission of local cases in the last two weeks before symptoms onset; or epidemiologically connected to 2019-nCoV infections or clustered onsets.
Demographic information, incubation period (the time delay from infection to illness onset), clinical characteristics (including medical history, comorbidity, surgery history, signs and symptoms), chest computed tomography (CT) scan or X-ray results and laboratory findings of each patient were obtained from the electronical medical record system. The study was performed according to the Declaration of Helsinki and approved by the institutional ethics board of the first affiliated hospital of Anhui Medical University (Quick-PJ 2020-02-12), and all patients signed the informed consent.
The date of disease onset and hospital admission date, as well as the severity of COVID-19 were also recorded. The onset date was defined as the day when any symptoms were noticed by the patients. Severity of COVID-19 was defined according to the diagnostic and treatment guideline of SARS-CoV-2 issued by the Chinese National Health Committee (Version 4-6). The clinical classifications are as follows: (1) mild, with fever, respiratory symptoms, but no pneumonia in CT image. (2) common, with fever, respiratory symptoms, and imaging shows pneumonia. (3) moderate, meet any of the following criteria: 1) Respiratory rate ≥30 beats/min; 2) Pulse Oximeter Oxygen saturation ≤93% at rest; 3) Oxygenation index (artery partial pressure of oxygen fraction, PaO2/FiO2) ≤300mmHg. (4) severe, meet any of the following conditions:1) respiratory failure occurs and requires mechanical ventilation; 2) shock occurs; 3) ICU admission is required for combined organ failure.
Hematology examination, respiratory virus nucleic acid, liver and kidney function, C-reactive protein (CRP), lactate, D-dimer, fibrinogen, inflammatory cytokines ((interleukin(IL)-6, IL-2R, Tumor Necrosis Factor α (TNF-α)), CD4+ and CD8+T lymphocytes counts etc were examined on the hospital admission date and re-examined every 3 to 5 days after treatment.
Patients’ pharyngeal swab specimens were collected for the SARS-CoV-2 viral nucleic acid examination on the hospital admission date and re-examined every other day after the 3 days’ treatment. All medical laboratory data were generated by the clinical laboratory of the first affiliated hospital of Anhui Medical University and the first people's hospital of Chuzhou City.
Chest imaging examination
All patients took the chest CT on the hospital admission date and re-examined every 3 to 5 days after treatment to assess the disease progression and therapeutic effect. Disease progression and therapeutic effect assessed by the CT imaging can be classified into 5 degrees compared with the original CT imaging, -2: pulmonary lesion area increased more than 50%; -1: pulmonary lesion area increased less than 50%; 0: no change; 1: pulmonary lesion area decreased less than 50%; 2: pulmonary lesion area decreased more than 50%.
All patients were treated according to the diagnostic and treatment guideline of SARS-CoV-2 issued by the Chinese National Health Committee (Version 4-6). Antiviral medicine includes α-interferon atomization inhalation (5 million U, twice daily), lopinavir/ritonavir orally (500 mg, twice daily), arbidol orally (0.2 gram, three times a day). Other treatment such as oxygen therapy was administered if the patients had hypoxemia. The patients were re-examined for symptoms, laboratory indexes and chest imaging at indicated times during the treatment period.
The primary target in this study was the SARS-CoV-2 viral shedding time, which was calculated by the date of diagnosis and respiratory nucleic acid convert to negative for two consecutive times at an interval of one day. Meanwhile, we set the cut-off of viral shedding time as 10 days and classified the patients into two groups (group A (less than 10 days) and group B (10 days or more)).
Categorical variables were described as frequencies and percentages, continuous variables were described as means and standard deviations or median and interquartile ranges (IQR). To compare the continuous variables for data of different groups, two-tailed t-test and Mann-Whitney test were used. The frequencies of categorical variables were compared using the chi-square and Fisher’s exact test. Multivariable Logistic analysis was conducted to evaluate the association of demographic, laboratory measurements and nucleic acid conversion time. All statistical analyses were generated using SPSS software version 16 (Statistical Product and Services Solutions). The P value less than 0.05 was considered statistically significant.