Original Article
Tomographic score (RAD-Covid Score) to assess the clinical severity of the novel coronavirus infection

https://doi.org/10.1016/j.bjid.2021.101599Get rights and content
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Abstract

Objectives

The severity of pulmonary Covid-19 infection can be assessed by the pattern and extent of parenchymal involvement observed in computed tomography (CT), and it is important to standardize the analysis through objective, practical, and reproducible systems. We propose a method for stratifying the radiological severity of pulmonary disease, the Radiological Severity Score (RAD-Covid Score), in Covid-19 patients by quantifying infiltrate in chest CT, including assessment of its accuracy in predicting disease severity.

Methods

This retrospective, single-center study analyzed patients with a confirmed diagnosis of Covid-19 infection by real-time reverse-transcriptase polymerase chain reaction, who underwent chest CT at hospital admission between March 6 and April 6, 2020. CT scans were classified as positive, negative, or equivocal, and a radiological severity score (RAD-Covid Score) was assigned. Clinical severity was also assessed upon hospital admission.

Results

658 patients were included. Agreement beyond chance (kappa statistic) for the RAD-Covid Score was almost perfect among observers (0.833), with an overall agreement of 89.5%. The RAD-Covid Score was positively correlated with clinical severity and death, i.e., the higher the RAD-Covid Score, the greater the clinical severity and mortality. This association proved independent of age and comorbidities. Accuracy of this score was 66.9%.

Conclusions

The RAD-Covid Score showed good accuracy in predicting clinical severity at hospital admission and mortality in patients with confirmed Covid-19 infection and was an independent predictor of severity.

Keywords

Covid-19
Chest CT
Infection
Severity
Hospitalization

Abbreviations

CT
computed tomography
rt-PCR
real time polymerase chain reaction
Covid-19
coronavirus disease 2019
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
ICU
intensive care unit
CI
confidence interval
GGO
ground-glass opacities
MDCT
multidetector computed tomography
COPD
chronic obstructive pulmonary disease
CKD
chronic kidney disease

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