Inflammatory and thrombotic parameters associated with the COVID-19 course in Poland (SARSTer study)

PURPOSE: The aim of the study was to assess the coagulation and inflammatory markers connected with severe course of COVID-19 and no clinical improvement. MATERIAL AND METHODS: The study population included 2590 adult patients, diagnosed with COVID-19, selected from the SARSTer national database - an ongoing project led by the Polish Association of Epidemiologists and Infectiologists and supported by the Medical Research Agency. Clinical and laboratory parameters, such as C-reactive protein (CRP), white blood cells (WBCs), neutrophil and lymphocyte count, procalcitonin, ferritin, interleukin-6 (IL-6), D-dimer concentration and platelet (PLT) count were analyzed before and after treatment (remdesivir, tocilizumab, dexamethasone, anticoagulants). RESULTS: Significant differences between patients with mild and severe course of the disease were observed in all examined parameters before treatment (p ​< ​0.05). After treatment only ferritin concentration did not differ significantly. In patients with pulmonary embolism, CRP concentration, neutrophil count, D-dimer and IL-6 concentration were significantly higher than in patients without embolism (p ​< ​0.05). The significant differences between the groups with and without fatal outcome were observed within all analyzed parameters. Significant differences in all examined parameters before treatment were observed between patients with and without clinical improvement (p ​< ​0.05). Multivariate logistic regression showed that no clinical improvement was associated with: IL-6>100 ​pg/ml (OR-2.14), D-dimer concentration over 1000 ​ng/ml (OR-1.62) and PLT count below 150,000/μl (OR-1.57). CONCLUSIONS: Severe course of the disease is associated with lower PLT and lymphocyte count, higher D-dimer, CRP, neutrophil count and IL-6 concentration. The best predictors of no clinical improvement in COVID-19 are: IL-6>100 ​pg/ml, D-dimer>1000 ​ng/ml and PLT<150,000/μl.