In a recent study of patients with COVID-19, patients who also had myeloproliferative neoplasms (MPNs) showed a greater risk of arterial thrombosis than patients without MPNs did. However, patients with or without MPNs had similar risks of venous thromboembolism (VTE), bleeding, and death. The study results were published in the journal Research & Practice in Thrombosis & Haemostasis.

COVID-19 is associated with an increased thrombosis risk. Patients with MPNs may possess certain mutations that are also linked to thrombosis, and MPNs are linked to arterial and venous thrombotic complications. “Given the increased propensity of thrombosis and prognostic significance of thrombosis in both COVID-19 and MPNs, defining the risk of thrombotic complications in this patient population is clinically relevant,” the study investigators wrote in their report.

The researchers conducted a retrospective cohort analysis of the electronic health records of patients within the Mass General Brigham health system who had tested positive for SARS-CoV-2 infection by polymerase chain reaction analysis between March 1, 2020 and January 1, 2021. Cohorts included patients who had MPNs and those without MPNs.

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The study investigators gathered data on patient and clinical characteristics and evaluated multiple outcomes. These included arterial thrombosis, VTE, all-cause mortality, and International Society on Thrombosis and Haemostasis (ISTH) major and clinically relevant nonmajor bleeding at 90 days.

There were 44 patients in the MPN cohort and 1114 patients in the non-MPN cohort. Patients with MPNs experienced arterial thrombosis at a rate of 7%, compared with 1% among patients without MPNs (P =.03).

VTE occurred in 7% of patients with MPNs, compared with 5% of patients without MPNs (P =.73). ISTH major and clinically relevant nonmajor bleeding events were reported in 7% of patients with MPNs and in 2% of patients without MPNs (P =.06). All-cause mortality rates were also similar, with fatalities occurring in 9% of patients on the MPN cohort and 6% of the patients in the non-MPN cohort (P =.32).

In terms of patient characteristics, patients of the MPN cohort tended to be older and more often had cardiovascular morbidities. With adjustments for age, the researchers performed a time-to-event analysis that showed the risk of AT being higher with MPNs than without MPNs (subdivision hazard ratio, 3.95; 95% CI, 1.09-14.39). Risks of VTE, bleeding, or death did not appear to be higher with MPNs.

The study investigators concluded that in patients with COVID-19, the presence of an MPN was associated with an increased risk of arterial thrombosis, but not higher risks of VTE, bleeding, or death, compared with the absence of an MPN. However, they also noted the sample size was small and suggested larger studies are necessary for confirmation of the study’s results.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Leiva O, Campia U, Snyder J, et al. Patients with myeloproliferative neoplasms and COVID-19 have increased rates of arterial thrombosis. Res Pract Thromb Haemost. 2022;6(5):e12752. doi:10.1002/rth2.12752