Increased procoagulant platelet levels are predictive of death in COVID-19.

Prior research has identified abnormal platelet procoagulant responses in COVID-19. Coated-platelets, a form of procoagulant platelets, support thrombin formation and are elevated in ischemic stroke patients with increased risk for recurrent infarction. Our goal was to examine changes in coated-platelet levels over the course of COVID-19 infection and determine their association with disease severity, thrombosis, and death. Coated-platelet levels were assayed after admission and repeated weekly in COVID-19 patients, and in COVID-19 negative controls. Receiver operator characteristic (ROC) analysis was used to calculate area under the curve (AUC) values for a model including baseline coated-platelets to predict death. Kaplan–Meier and Cox proportional hazards analysis was used to predict risk for death at 90 days. We enrolled 33 patients (22 with moderate and 11 with severe infection) and 20 controls. Baseline coated-platelet levels were lower among moderate (mean ± SD; 21.3 ± 9.8%) and severe COVID-19 patients (28.5 ± 11.9%) compared to controls (38.1 ± 10.4%, p   33.9% was 40.99 when compared to those with levels ≤ 33.9% (p < 0.0001). Platelet procoagulant potential is transiently decreased in most patients during COVID-19; however, increased baseline platelet procoagulant levels predict death. Defining the mechanisms involved and potential links with aging may yield novel treatment targets.