Chen X 2020.

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 features Design: cross‐sectional multicentre retrospective study Recruitment: 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 Hospital Sample 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 test Facility controls: CT pneumonia patients with consecutive negative RT‐PCR Country: China Dates: 1 January 2020‐8 February 2020 Symptoms and severity: pneumonia patients for cases and control; unclear severity of cases Demographics: M/F: cases 41/29, controls 43/23 mean age: cases 42.9 range, 16‐69 years, controls 46.7 range, 0.3‐93 years Exposure 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