d-Dimer and COVID-19

Editor:

In their article published online in Radiology on August 13, 2020, Dr Schalekamp and colleagues described the development of a risk score for patients who are more likely to develop severe coronavirus disease 2019 (COVID-19), with resultant worse outcome (1). In this retrospective analysis, Dr Schalekamp and colleagues point to findings in laboratory and chest radiographic reports combined with medical history and underlying morbidity. Interestingly, the plasma d-dimer values are not mentioned in this report.

Based on a study in Wuhan, and reference 6 in their article, the plasma d-dimer levels were shown to be highly correlated with unfavorable outcomes (2). This was further confirmed by several other studies, summarized in a subsequent report, and included the first prospective data on the use of plasma d-dimer in patients in intensive care and the direct link with development of pulmonary embolism (3). Some of the authors of the present article also reported on the high incidence of vascular thrombotic complications in patients in intensive care (4).

Was plasma d-dimer not available routinely, or was this biomarker not considered? If plasma d-dimer measurements were not considered routinely, this may be a shortcoming for this risk assessment tool given that plasma d-dimer consistently demonstrated high correlation with outcomes and has implications for thrombotic risk management. Alternatively, it would be useful to reassess this risk score by considering plasma d-dimer values, which should probably be performed as part of the prospective validation of the risk score.