External Validation of the CHOD Risk Scale

Study Overview
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Brief Summary
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Severe COVID-19 is associated with a hypercoagulable state, with a high risk of thrombotic phenomena such as pulmonary thromboembolism (PE). Its diagnostic suspicion is complicated, due to the overlap of symptoms of PE with those of COVID-19 itself. Therefore, it is essential to improve PE prediction to optimise the performance of confirmatory imaging tests such as thoracic CT angiography. Early diagnosis has relevant therapeutic implications, as it justifies starting anticoagulant treatment early, with a possible positive impact on the clinical evolution of these patients. The CHOD risk scale has recently been described: the acronym for C-reactive protein concentration, heart rate, oxygen saturation, and D-Dimer levels. Its initial description was carried out in a study in a single hospital centre. proving to be an easy-to-apply tool, useful for predicting the appearance of PE in patients hospitalized for COVID-19. The objective of this study is to carry out an external validation of this scale in patients hospitalized for COVID-19 pneumonia, through an observational, cross-sectional, multicenter, real-life study in patients hospitalized for severe COVID-19 pneumonia, confirmed by objective methods, and showing high D-dimer values. Imaging tests with CT angiography will be performed in patients with elevated D-Dimer, following international clinical practice regulations. Given that they will be consecutive patients, CT angiography will be performed in all patients regardless of the patient's clinical probability of PE as long as they meet the inclusion criteria and none of the exclusion criteria. To calculate the PE predictive power of the CHOD scale in the validation cohort, a methodology similar to that used in the construction cohort will be used, that is, the use of a ROC curve. Taking into account that a similar predictive value (with a maximum error of 5%) between the CHOD scale in the construction cohort and that of this study (validation cohort) will be considered as an adequate external validation, and taking into account a statistical power of 80%, an alpha error of 5% and a maximum loss of patients of 15%, the required sample size is 245 patients. Since 7 centres initially participate, each of which will have to contribute 35 valid consecutive patients for the analysis.

Official Title
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Predicting the Risk of Pulmonary Thromboembolism in Patients Hospitalized for COVID-19 Pneumonia: External Validation of the CHOD Risk Scale.

Conditions
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COVID-19 Pneumonia, Pulmonary Embolism

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnostic confirmation of SARS-CoV-2 infection by positive result in at least one test: Rapid nasopharyngeal smear antigen test. PCR smear or nasopharyngeal aspirate. Sputum PCR. PCR of bronchoalveolar lavage. Positive IgM in the serology for SARS-CoV2 Hospitalization for COVID-19 pneumonia More than 5 days from the date of onset of symptoms (this criterion can be met during hospitalization). Elevated D-dimer, by any of the following criteria: DD> 500 ng/ml; In the case of patients over 50 years of age, the DD cut-off point adjusted for age (age x 10) will be applied. With the DDU measurement, the cut-off point is 250 mg/dl (instead of 500) and the adjustments for age in those over 50 years are made by multiplying the age x 5 (instead of x 10). Exclusion Criteria: Pregnancy. Age <18 years. Hemodynamic instability: SBP <90 mmHg or vasopressors to achieve ≥ 90 mmHg. Contraindication for performing CT angiography: Severe kidney failure (GFR <30) Allergy to iodinated contrasts. Intolerance to decubitus.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| CHOD risk scale value | External validation of the CHOD risk scale (an acronym of C-reactive protein concentration + Heart rate + Oxygen saturation + D-Dimer levels) in patients hospitalized for confirmed COVID-19 pneumonia in the usefulness for the diagnosis of PE. The scale ranges from 0 to 7 points. The probability of incident PE during the hospitalization is low (4.5%) at 0-2 points, moderate (36.8%) at 3-5 points, and high (100%) at 6-7 points. | At least 5 days after the onset of symptoms | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of pulmonary embolism | To establish the frequency of PE in patients hospitalized for COVID-19 pneumonia with elevated D-Dimer, during the time it takes to complete the expected sample of 235 patients. | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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COVID-19, Pulmonary embolism, CT angiography, Screening test