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. 2021 Feb;38(2):207-216.
doi: 10.1111/echo.14962. Epub 2021 Jan 24.

The COVID-19 Worsening Score (COWS)-a predictive bedside tool for critical illness

Enrico Boero  1 , Serena Rovida  2 , Annia Schreiber  3   4 , Paola Berchialla  5 , Lorena Charrier  6 , Marta Maria Cravino  7 , Marcella Converso  8 , Paola Gollini  9 , Mattia Puppo  10 , Angela Gravina  7 , Giorgia Fornelli  7 , Giulia Labarile  11 , Santi Sciacca  7 , Tiziana Bove  12 , Dimitrios Karakitsos  13   14   15 , Franco Aprà  16 , Michael Blaivas  14   17 , Luigi Vetrugno  12
Affiliations

The COVID-19 Worsening Score (COWS)-a predictive bedside tool for critical illness

Enrico Boero et al. Echocardiography. 2021 Feb.

Abstract

Objectives: To evaluate the accuracy of a new COVID-19 prognostic score based on lung ultrasound (LUS) and previously validated variables in predicting critical illness.

Methods: We conducted a single-center retrospective cohort development and internal validation study of the COVID-19 Worsening Score (COWS), based on a combination of the previously validated COVID-GRAM score (GRAM) variables and LUS. Adult COVID-19 patients admitted to the emergency department (ED) were enrolled. Ten variables previously identified by GRAM, days from symptom onset, LUS findings, and peripheral oxygen saturation/fraction of inspired oxygen (P/F) ratio were analyzed. LUS score as a single predictor was assessed. We evaluated GRAM model's performance, the impact of adding LUS, and then developed a new model based on the most predictive variables.

Results: Among 274 COVID-19 patients enrolled, 174 developed critical illness. The GRAM score identified 51 patients at high risk of developing critical illness and 132 at low risk. LUS score over 15 (range 0 to 36) was associated with a higher risk ratio of critical illness (RR, 2.05; 95% confidence interval [CI], 1.52-2.77; area under the curve [AUC], 0.63; 95% CI 0.676-0.634). The newly developed COVID-19 Worsening Score relies on five variables to classify high- and low-risk patients with an overall accuracy of 80% and negative predictive value of 93% (95% CI, 87%-98%). Patients scoring more than 0.183 on COWS showed a RR of developing critical illness of 8.07 (95% CI, 4.97-11.1).

Conclusions: COWS accurately identify patients who are unlikely to need intensive care unit (ICU) admission, preserving resources for the remaining high-risk patients.

Keywords: COVID-19; critical care; intensive care; lung sonography; lung ultrasound; prognostic score.

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Conflict of interest statement

MB has participation in EchoNous Inc, Sonosim Inc, Ethos Medical, 410Medical. LV received travel facilities from Cook medical.

Figures

FIGURE 1
FIGURE 1
Diagram of included patients
FIGURE 2
FIGURE 2
GRAM score derived risk groups (on the left) and outcomes (on the right); gray shadows link classification to outcomes and their width is proportional to the number of patients
FIGURE 3
FIGURE 3
Probability of developing critical illness (Y‐axis) according to increasing values of LUS score (X‐axis)
FIGURE 4
FIGURE 4
Distribution curves of the patients who developed critically illness (red dots) and those who had favorable outcomes (green dots). X‐axis: linear predictor; Y‐axis: incremental values of GRAM score (upper panel) and GRAM‐PLUS values (lower panel). LUS: lung ultrasound
FIGURE 5
FIGURE 5
Performance of the COWS in classifying high‐ and low‐risk patients. Red dots indicate patients with adverse outcome. Dashed line refers to the COWS threshold
FIGURE 6
FIGURE 6
Nomogram of COVID‐19 Worsening Score and how to use it
See this image and copyright information in PMC

References

    1. World Health Organization . WHO/Europe | Coronavirus disease (COVID‐19) outbreak ‐ WHO announces COVID‐19 outbreak a pandemic. Accessed April 17, 2020. http://www.euro.who.int/en/health‐topics/health‐emergencies/coronavirus‐...
    1. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395(10223):497‐506. - PMC - PubMed
    1. Wu C, Chen X, Cai Y, et al. Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China. JAMA Intern Med. 2020;180(7):934. - PMC - PubMed
    1. Liang W, Liang H, Ou L, et al. Development and validation of a clinical risk score to predict the occurrence of critical illness in hospitalized patients With COVID‐19. JAMA Intern Med. Published online 2020;180(8):1081–1089. 10.1001/jamainternmed.2020.2033 - DOI - PMC - PubMed
    1. Borghesi A, Maroldi R. COVID‐19 outbreak in Italy: experimental chest X‐ray scoring system for quantifying and monitoring disease progression. Radiol Med. 2020;125(5):509‐513. - PMC - PubMed