Study finds low risk of thromboembolism after hospital discharge for COVID-19

DG Alerts

A study published in Thrombosis Research found that the risk of thromboembolism among patients with coronavirus disease 2019 (COVID-19) who were hospitalised and then discharged was low.

Of 140 patients discharged from a non-intensive care unit (ICU) ward, only 1 (0.71%) patient developed a pulmonary embolism 9 days after discharge. Of 35 patients who were discharged from a COVID-19 rehabilitation ward, no thromboembolic events were observed.

“[This] suggests that even if acutely infected patients with COVID-19 have a high incidence of thromboembolic complications, the risk diminishes quickly after the acute phase,” wrote Alex Bourguignon, MD, Centre Hospitalier Universitaire de Montréal, Montréal, Quebec, and colleagues.

The researchers scrutinised data from 454 hospitalised patients with COVID-19 from March 2020 to June 27, 2020. Of the patients, 285 were admitted to a non-ICU ward (median age, 72 years), 78 were admitted to the ICU at some point in their stay (median age, 63 years), and 91 were admitted to a COVID-19 rehabilitation ward (median age, 86 years) from various institutions in the city. Thromboprophylaxis was administered to 91.2%, 96.2%, and 88% of patients, respectively.

Among non-ICU hospitalised patients, the incidence of arterial and venous thrombotic complications was 2.5% (7 events) and 1.8% (5 events), respectively, after a median length of stay of 10 days (interquartile range [IQR], 5-22 days). Of the patients with arterial complications, 6 were strokes, with 2 as a presenting feature of the infection, and the other was an acute coronary syndrome, also as a presenting feature. Meanwhile, all venous thromboembolisms (VTEs) reported were pulmonary embolisms.

In the ICU population, the incidence of arterial complications was 3.9% (3 events) and the incidence of venous thrombotic complications was 21% (16 events), after a median stay of 18 days (IQR, 10-43 days). Of the arterial complications, 2 were strokes and 1was an aortic thrombus — all present at admission. Of the thrombotic complications, 87.5% were pulmonary embolisms; the other 2 events were catheter-related thrombosis. The researchers found no impact of thromboprophylaxis dose on the incidence of thrombotic events among this high-risk population, noting that 26% had a thromboembolic complication even though 68% were either treated with intermediate-dose thromboprophylaxis or were on full anticoagulation therapy.

For the inpatient rehabilitation cohort, only 1 (1.1%) patient was found to have a pulmonary embolism.

The researchers did not find a statistically significant association between the type of thromboprophylaxis and the incidence of thrombosis in the ICU group.

“Some 38% of patients that were fully anticoagulated presented a thrombotic event — a higher proportion than with standard and intermediate dose thromboprophylaxis,” the authors wrote. “We think this could represent an ‘impending doom’ bias, with patients presenting with more worrisome clinical and laboratory features being treated more aggressively. These data suggest that this population should not systematically require prolonged thromboprophylaxis until prospective randomised trials are performed in this setting.”