Study characteristics
Patient Sampling  Purpose: diagnosis COVID‐19 pneumonia ‐ to identify differences in CT imaging and clinical manifestations between pneumonia patients with and without COVID‐19, and to develop and validate a diagnostic model for COVID‐19 based on radiological semantic and clinical featuresDesign: cross‐sectional multicentre retrospective studyRecruitment:
cases: consecutive patients with COVID‐19 admitted in 5 independent hospitals
controls: at the same period, another 66 consecutive pneumonia patients without COVID‐19 from Meizhou People’s HospitalSample size: n = 136 (cases = 70)Inclusion criteria: patients admitted with COVID‐19 pneumonia (cases) and patients admitted with non‐COVID‐19 pneumonia (controls)Exclusion criteria: not specified for cases except those from 1 hospital (Meizhou), for cases and controls in Meizhou: after chest CT neoplasm, tuberculosis, pulmonary oedema, pulmonary contusion, aspiration pneumonia, bronchitis, any local or systemic treatment before CT scan, normal CT image without epidemiological history
Patient characteristics and setting  Facility cases: pneumonia patients with positive SARS‐CoV‐2 testFacility controls: CT pneumonia patients with consecutive negative RT‐PCRCountry: ChinaDates: 1 January 2020‐8 February 2020Symptoms and severity: pneumonia patients for cases and control; unclear severity of casesDemographics: M/F: cases 41/29, controls 43/23
mean age: cases 42.9 range, 16‐69 years, controls 46.7 range, 0.3‐93 yearsExposure history: data about exposure to epidemic centres collected, but no results in the study nor in appendices
Index tests  Systolic BP
Diastolic BP
Respiration rate
Heart rate
Temperature
Dry cough
Fatigue
Sore throat
Stuffy
Runny nose
Target condition and reference standard(s)  TC: COVID‐19 pneumonia
RS: RT‐PCR and next generation sequencing for SARS‐Cov2
Flow and timing  Time interval not specified
Comparative   
Notes   
Methodological quality
Item   Authors' judgement   Risk of bias   Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?  Yes      
Was a case‐control design avoided?  Yes      
Did the study avoid inappropriate exclusions?  Yes      
Did the study avoid inappropriate inclusions?  No      
Could the selection of patients have introduced bias?     High risk   
Are there concerns that the included patients and setting do not match the review question?        High
DOMAIN 2: Index Test (All tests)
Were the index test results interpreted without knowledge of the results of the reference standard?  Unclear      
If a threshold was used, was it pre‐specified?  No      
Could the conduct or interpretation of the index test have introduced bias?     Unclear risk   
Are there concerns that the index test, its conduct, or interpretation differ from the review question?        Unclear
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?  Yes      
Were the reference standard results interpreted without knowledge of the results of the index tests?  Yes      
Could the reference standard, its conduct, or its interpretation have introduced bias?     Low risk   
Are there concerns that the target condition as defined by the reference standard does not match the question?        Low concern
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?  Unclear      
Did all patients receive the same reference standard?  Yes      
Were all patients included in the analysis?  Yes      
Could the patient flow have introduced bias?     Low risk