The predictive value of coagulation parameters for the course of disease in COVID-19 patients

Introduction COVID-19 is a systemic disease associated with a high incidence of thrombotic complications. In this study we aimed to identify coagulation parameters as predictors of mortality in hospitalized patients with severe COVID-19 infection.

Method We conducted a non-interventional, national, monocentric observational study of patients treated for COVID infection at the ICU at Frankfurt University Hospital. A total of 410 patients were enrolled in the study between April 1, 2020 and December 31, 2021. Patients had to be 18 years or older and the diagnosis was confirmed by COVID real-time PCR. Coagulation parameters were analysed once on admission to the clinic and 5 to 8 days later.

Variables studied included thromboplastin time, aPTT, fibrinogen, D-dimers, antithrombin, hs-troponin, all coagulation factors and vWF antigen, protein C and protein S. Data was also collected on age, sex, comorbidities, medication, and invasive ventilation, ECMO therapy and dialysis. In order to compare patients regarding their general disease status, the SAPS-II and the Horovitz index were determined at the beginning and end of the observation period.

Univariate and multivariate logistic regression models were then used to screen coagulation parameters for association with mortality in critically ill COVID patients.

Results The arithmetic mean age of patients was 60.9 (± 14.7) years, with 76.1% being male. Of 410 patients, 259 (63.2%) received invasive ventilation, 95 (23.2%) received ECMO therapy and 105 (25.6%) received renal replacement therapy. The median inpatient length of stay was 16 (IQR: 10-29) days and ICU length of stay was 12 (IQR: 6-25) days. 176 patients (43%) died because of their COVID disease, 234 (57%) were discharged home or to other facilities for further treatment.

In univariate logistic regression, increased age (OR= 1,029, 95%-CI [1,013-1,1,044]), higher SAPS-II (OR= 1,031, 95%-CI [1,018-1,045]), fibrinogen (OR= 1,002, 95%-CI [1,001-1,003]), FVIII (OR= 1,004, 95%-CI [1,001-1,007]) and vWF antigen (OR= 1,005, 95%-CI [1,003-1,007]) as well as lower antithrombin (OR= 0,981, 95%-CI [0,971-0,991]), FII (OR= 0,983, 95%-CI [0,972-0,993]), FXIII (OR= 0,992, 95%-CI [0,986-0,999]), Horovitz index at admission (OR= 0,994, 95%-CI [0,990-0,997]) and decreased protein C activity (OR= 0,989, 95%-CI [0,982-0,996]) were associated with increased mortality.

In the final multivariate regression analysis with backward elimination, low antithrombin activity (OR= 0.987, 95%-CI [0.974-1.000]), high vWF antigen levels (OR= 1.004, 95%-CI [1.002-1.007]) and a low Horovitz index (OR= 0.993, 95%-CI [0.989-0.997]) were identified as independent predictive factors for increased mortality.

Conclusion In the study of 410 COVID patients requiring intensive care, the Horovitz index, antithrombin activity and vWF antigen on hospital admission were identified as independent predictors of mortality.

Publication History

Article published online:
20 February 2023