Determining the risk of developing symptomatic COVID-19 infection after attending hospital for radiological examinations: Controlled cohort study

Abstract

OBJECTIVE To determine whether brief attendance for outpatient radiological investigations is associated with increased risk of clinically significant coronavirus disease 2019 (covid-19) infection.DESIGN Observational cohort study with a historical control.SETTING 2 large UK University Hospitals located in Nottingham and Cardiff.PARTICIPANTS All 47,340 patients who attended an outpatient radiology appointment at Nottingham University Hospitals and University Hospital of Wales during the first wave of the pandemic in 2020, and 70,655 patients that comprised the control cohort who attended for outpatient radiology the same period in 2019.MAIN OUTCOME MEASURES The risk of developing clinically significant covid-19 infection within 28-days of attending a radiological examination. Covid-19 infection rates for the 2020 cohort were compared against a control group who attended in 2019.RESULTS 84 positive SARS-CoV-2 tests were temporally associated with 47,340 radiological examinations across two hospitals in 2020. This low infection rate was higher than the 2019 control cohort; OR 2.507 (1.766 – 3.559) and equates to an approximate 1 positive covid-19 infection per 1000 radiology investigations.CONCLUSIONS Our data suggests that attending hospitals for outpatient radiological investigations during the pandemic is associated with a very small absolute risk of acquiring clinically significant covid-19 infection. It is unlikely that this risk is directly attributable to radiology attendance, considering the reasons leading individuals to attend hospitals during the pandemic, the true attributable risk will likely be even lower.TRIAL REGISTRATION ClinicalTrials.gov NCT04544176Competing Interest StatementThe authors have declared no competing interest.Clinical TrialNCT04544176Funding StatementNo specific funding was provided for this study.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:This study was approved by the Health Research Authority (20/HRA/4783) and was not reviewed by a research ethics committee as the research was limited to using previously collected, non-identifiable information.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData sharing: A summary of the data may be provided by application to the corresponding author at nikos.evangelou{at}nottingham.ac.uk subject to the necessary ethical and regulatory approvals by the applicant, and subject to data availability.