Reacción a "Reactions to the study quantifying the risk of developing thrombosis following covid-19"

It is an important, retrospective study, looking at the medical records of more than a million patients, very well matched with people who did not have covid-19 as a control. Such a large number of patients almost makes up for the drawback of not being a randomised study, which was not possible. The results confirm what we already sensed. They show that covid-19 increases the risk of venous thrombosis - we know that it also increases the risk of arterial thrombosis, but this study focuses on venous thrombosis, and finds that 70 days after severe covid-19 the risk of venous thrombosis is much higher. It is also noted that this effect is clearly attributable to covid-19 and not to other factors. 

The authors have also studied the risk of pulmonary embolism, and find that it is much higher even six months after severe covid-19 has been overcome. Pulmonary embolism is found to be very important and is not directly related to venous thrombosis. The pathophysiology of this pulmonary embolism is not exactly the same as what we usually know, but is related to the development of the cytokine storm, and the stimulation of anticoagulation that occurs with covid-19.

The third effect studied is bleeding, and again a higher risk is detected after severe covid-19 or ICU admission.

The risk of suffering these effects is higher in patients who underwent covid-19 in the first wave, which is to be expected since we then had fewer tools to manage the disease. 

This result shows the benefit of anticoagulant thromboprophylaxis in patients with covid 19, although it is not estimated how long after the acute phase of the disease it is necessary to maintain this treatment. This is highly relevant for future management of the disease.