A team of researchers in China recently examined potential prognostic factors in patients with coronavirus disease 2019 (COVID-19) and identified blood tests that may be useful in assessing patients with COVID-19, according to results published in The Lancet Haematology. Notably, the researchers reported that thrombotic and hemorrhagic events occurred in slightly more than one-third of nonsurvivors in this analysis.

In a retrospective cohort study, researchers examined risk factors and outcomes for 380 patients with COVID-19 who were seen at the Wuhan Union Hospital in China. In this patient cohort, 86 patients had critical disease (median age, 68.0 years), 145 had severe disease (median age, 67.0 years), and 149 had moderate disease (median age, 56.0 years).

Deaths occurred in 14% of the overall study population: 62% of patients with critical disease, 1% of those with severe disease, and in 0 patients with moderate disease.

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Nearly half (49%) of the patients with critical disease had thrombocytopenia (platelet count below 100 x 109/L), compared with incidences of 14% for those with severe disease, and 6% for those with moderate disease (P <.0001). Lymphocyte and eosinophil counts were also reduced in patients with critical disease, compared with those having either severe or moderate disease (P <.0001).

However, significant increases were seen for prothrombin time, D-dimer, and fibrin degradation products as the severity of the disease rose (P <.0001 for each).

The researchers performed multivariate analyses to examine risk factors for death. Thrombocytopenia was associated with an odds ratio (OR) for death of 8.33 (95% CI, 2.56-27.15; P =.00045). An increased ratio of neutrophils to lymphocytes, at or above 9.13, was associated with an OR of 5.39 (95% CI, 1.70-17.13; P =.0042). A prothrombin time of more than 16 seconds was associated with an OR of 4.94 (95% CI, 1.50-16.25; P =.0094). Additionally, a D-dimer above 2 mg/L was associated with an OR of 4.41 (95% CI, 1.06-18.30; P =.041).

Thrombotic and hemorrhagic events occurred in 35% of patients in this study who had died. Sepsis-induced coagulopathy and overt disseminated intravascular coagulation also had become more common events with time in patients who died.

The researchers determined that tests of platelet count, prothrombin time, D-dimer, and neutrophil-to-lymphocyte ratio may be helpful in evaluating the severity of and patient prognosis with COVID-19, and it was recommended that these factors be dynamically monitored.

“In conclusion, coagulopathy is a non-negligible complication and potentially important cause of death in patients with critical COVID-19,” the researchers wrote.


Liao D, Zhou F, Luo L, et al. Haematological characteristics and risk factors in the classification and prognosis evaluation of COVID-19: a retrospective cohort study [published online July 10, 2020]. Lancet Haematol. doi: 10.1016/S2352-3026(20)30217-9