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An optimized D-dimer cut-off value to predict pulmonary thromboembolism in COVID-19 patients
Sophie Y H Engels1, Ilonka H P A A van Veen1, Matthijs Oudkerk2,3
1Department of Pulmonary Medicine, Medisch Spectrum Twente, Enschede, The Netherlands.
Insights
For COVID-19 patients, a D-dimer level below 750 ng/mL safely rules out pulmonary thromboembolism (PTE). This revised threshold reduces computed tomography pulmonary angiography (CTPA) use by 13% while maintaining high sensitivity for PTE detection.
Area of Science:
- Pulmonology
- Hematology
- Infectious Diseases
Background:
- Pulmonary thromboembolism (PTE) is a frequent complication in COVID-19 patients.
- Elevated D-dimer levels in COVID-19 can be non-specific, diminishing its utility as a screening tool for PTE.
- The applicability of conventional D-dimer cut-off values, such as those in the YEARS algorithm, to COVID-19 patients remains uncertain.
Purpose of the Study:
- To determine an optimal D-dimer cut-off value for predicting PTE in hospitalized COVID-19 patients.
- To assess if a D-dimer threshold lower than 500 ng/mL can safely exclude PTE in this population.
- To evaluate the impact of an adjusted D-dimer cut-off on the need for computed tomography pulmonary angiography (CTPA).
Main Methods:
- Retrospective analysis of confirmed COVID-19 patients who underwent CTPA within five days of admission for suspected PTE.
- Logistic regression analyses to identify predictors of PTE, including D-dimer levels.
- Receiver operating characteristic (ROC) curve analysis to determine the optimal D-dimer cut-off value.
Main Results:
- PTE prevalence was 20.4% in the study cohort of 142 patients.
- The optimal D-dimer cut-off value for predicting PTE was identified as 750 ng/mL, with 100% sensitivity and 100% negative predictive value.
- A D-dimer level <750 ng/mL safely excluded PTE, and this threshold reduced the need for CTPA by 13% compared to the YEARS algorithm's 500 ng/mL cut-off, with similar sensitivity.
Conclusions:
- In patients hospitalized with COVID-19, a D-dimer level below 750 ng/mL is a safe threshold for excluding PTE.
- This higher D-dimer cut-off value can decrease the utilization of CTPA in COVID-19 patients with suspected PTE.
- External validation is recommended for the proposed D-dimer cut-off value in future research.
Abstract:
Pulmonary thromboembolism (PTE) is a common complication in coronavirus disease 2019 (COVID-19) patients. Elevated D-dimer levels are observed even in the absence of PTE, reducing its discriminative ability as a screening test. It is unknown whether conventional D-dimer cut-off values, as used in the YEARS algorithm, apply to COVID-19 patients. This study aimed to determine the optimal D-dimer cut-off value to predict PTE in COVID-19 patients. All confirmed COVID-19 patients with a computed tomography pulmonary angiography (CTPA) performed ≤5 days after admission due to suspicion of PTE between March 2020 and February 2021, at Medisch Spectrum Twente, The Netherlands, were retrospectively analyzed. The association between PTE and D-dimer levels prior to CTPA, and other potential predictors, was analyzed using logistic regression analyses. The optimal cut-off value was identified using receiver operating characteristic (ROC) curve analyses. In 142 patients, PTE prevalence was 20.4%. The optimal cut-off value was 750 ng/mL (sensitivity 100%; specificity 19.5%; negative predictive value 100%; positive predictive value 24.2%). In total, 15 of 113 (13%) patients without PTE had a D-dimer level ≥500 and <750 ng/mL. In our population of patients hospitalized with COVID-19, a D-dimer level <750 ng/mL safely excluded PTE. Compared to the YEARS 500 ng/mL cut-off value, 13% fewer patients are in need of a CTPA, with similar sensitivity. Future research is required for external validation.
