Letter to the Editor: “Association of subpleural ground-glass opacities with respiratory failure and RNAemia in COVID-19”
by Furkan Ufuk (email@example.com)Association of subpleural ground-glass opacities with respiratory failure and RNAemia in COVID-19
I read with great interest the article titled “Association of subpleural ground-glass opacities with respiratory failure and RNAemia in COVID-19” by Nagaoka et al . I congratulate the authors for this informative and valuable study. In this article, the authors aimed to assess the relationship between the most common CT pattern in the early phase of SARS-CoV-2 infection and the development of hypoxemic respiratory failure, and compare the accuracy of the CT pattern in predicting outcome to that of a semi-quantitative CT score. Moreover, the authors assessed the relationship between CT pattern and SARS-CoV-2 viral load . I would like to make a few comments on aspects that may affect the results of this study.
First, the current prospective study does not specify the median time between the onset of symptoms and chest CT examination, plasma sampling, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) testing. The timing of chest CT examination, plasma sampling, and RT-qPCR testing in COVID-19 is considered important as it affects the accuracy of the results. Moreover, it has been shown that, serial plasma sampling and viral load can provide important information about the progression and resolution of the infection .
Second, higher D-dimer values have been linked to increased mortality and critical condition in adult COVID-19 patients . One study by Xu et al  showed that COVID-19 patients with RNAemia had high levels of D-dimer and suggested that procoagulation factors could lead to thrombosis in these patients. However, the relationship between D-dimer levels and patient prognosis was not explored in this study.