Researchers have found a high risk of deep vein thrombosis or venous thromboembolism (VTE) and pulmonary embolism in hospitalised patients suffering from COVID-19.

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Deep vein thrombosis is a serious condition that occurs when a blood clot forms in a vein located deep inside your body. This condition is serious because blood clots can loosen and lodge in the lungs.While hospitalised patients at general wards have a VTE risk between five and 11 percent, the risk of developing deep vein thrombosis or pulmonary embolism in critically ill patients is 18 to 28 percent, the study, published in the journal Research and Practice in Thrombosis and Haemostasis, reported. "From the beginning of the COVID-19 pandemic, studies reported an increased rate of thrombosis and pulmonary embolism in patients with COVID-19," said study author Cihan Ay from the Medical University of Vienna in Austria. "Our study now offers a better understanding of the underlying risk and, therefore, aids in individual treatment decisions based on accurate risk assessment for the different patient groups," Ay added.

For the findings, the research team assessed a total of 5,951 studies published in the field of VTE in COVID-19. Of those, 86 studies were found eligible for inclusion and reported rates of thrombosis and pulmonary embolism in COVID-19 patients. After excluding additional studies due to underlying risk of bias in a structured assessment, 66 studies (28,173 patients) were found eligible to perform a meta-analysis to provide a robust estimate on risk of VTE in COVID-19. The main findings are as follows: the overall VTE risk in hospitalized patients with COVID-19 is 14 percent, despite rigorous thromboprophylaxis regimens in most studies. Further, high heterogeneity in VTE rates was found between different patient subgroups. The rate was highest in patients admitted to intensive care units, with 23 percent of patients suffering VTE.

Patients admitted to general wards suffered VTE in 8 percent of the cases. These findings underline the high risk of VTE in COVID-19 patients.In addition, the authors specifically focused on estimating the risk of potentially life-threatening pulmonary embolism. "This risk is considerably higher than in other comparable serious medical illnesses and ranges between 10 and 18 percent in COVID-19 patients requiring intensive care. In addition, the exploratory analysis revealed that patients who developed deep vein thrombosis or pulmonary embolism during hospitalization had significantly higher D-dimer concentrations at admission, a laboratory parameter that indicates an activated coagulation system. These findings underscore the strong impact of COVID-19 on the blood-clotting system.