COVID-19 induces a hyperactive phenotype in circulating platelets
Platelet counts, MPV, Neutrophil counts, and PNRs of patients with severe (n = 34) or nonsevere (n = 20) COVID-19 and hospitalised controls (n = 20). (A) On the day of admission, patients who subsequently developed severe COVID-19 had significantly higher MPV (p = 0.015) and neutrophil counts (p = 0.013) and significantly lower PNR (p = 0.0067) compared to those who did not subsequently develop severe COVID-19. (B) On day 7 of hospitalisation, nonsevere COVID-19 patients had a significantly higher platelet count compared to severe COVID-19 patients on the day of transfer to intensive care (p = 0.014). Boxplots represent the data median (line inside the box) and the IQR (outline of the box) together with data maximum and data minimum (whiskers) and individual observations (see individual data in S1 Data). Statistical analysis was performed using a two-tailed t test, and p-values were adjusted for multiple comparisons using a Holm–Bonferroni post hoc test. COVID-19, Coronavirus Disease 2019; IQR, interquartile range; MPV, mean platelet volume; PNR, platelet-to-neutrophil ratio.