Barbhaya 2021.

Study characteristics
Patient Sampling	Purpose: diagnosis of SARS‐CoV‐2 infection (mild COVID‐19 disease); to investigate and characterise mild to moderate COVID‐19 and risk factors Design: cross‐sectional cohort study, retrospective data collection Recruitment: patients presenting to a dedicated ambulatory COVID‐19 clinic in Washington DC Sample size: n = 2471 (846) Inclusion criteria: patients from the community and hospital associates; PCR tested, prescreened for symptoms or exposure; decisions for testing made according to CDC guidelines in place at the time of each encounter, most often only if the patient was symptomatic Exclusion criteria: none specified
Patient characteristics and setting	Facility cases: positive SARS‐CoV‐2 test Facility controls: negative SARS‐CoV‐2 test Country: USA Dates: 11 March 2020‐14 June 2020 Symptoms and severity: mild to moderate disease 88.9%, severe disease (= hospitalisation) 11.1% Demographics: mean age cases 43.2 years, controls 43.5 years M%/F%: cases 47.8/52.0, controls 35.5/64.4, 0.1% not specified Exposure history: exposure to patient with COVID‐19 58.7%
Index tests	Anosmia Subjective fever Change in taste Anorexia Objective fever Myalgias Cough Chills Fatigue/malaise Dizziness Headache Nausea Diarrhoea Rhinorrhoea Vomiting Shortness of breath Chest pain Abdominal pain Sore throat Congestion
Target condition and reference standard(s)	TC: SARS‐CoV‐2 infection RS: RT‐PCR for SARS‐CoV‐2 (nasopharyngeal and mid‐turbinate swab)
Flow and timing	Index tests and RS both taken at presentation
Comparative
Notes	Funding: none declared
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Unclear
Did the study avoid inappropriate inclusions?	Unclear
Could the selection of patients have introduced bias?		Unclear risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
DOMAIN 2: Index Test (All tests)
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	No
Could the conduct or interpretation of the index test have introduced bias?		High risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
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?	Unclear
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?	Yes
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