Study findings suggest that patients with BCRABL-negative myeloproliferative neoplasms (MPNs) are at increased risk of bleeding events while on antiplatelet or anticoagulation therapies. The study findings were published in the European Journal of Haematology.

BCRABL-negative MPNs include polycythemia vera, essential thrombocythemia, and myelofibrosis. Patients with these conditions are at an increased risk of thromboembolic events as well as a tendency toward a greater risk of bleeding events, which can complicate the use of anticoagulation. However, the researchers noted that bleeding complications in patients with MPNs are not fully understood. Therefore, they undertook this analysis to elucidate bleeding risks and tendencies in patients with MPNs receiving antiplatelet and anticoagulation therapies.

In this real-world, retrospective study, 829 patients with MPNs were evaluated at a single center in Germany. The study was noninterventional, and the goal was to examine the frequency, risk factors, and types of bleeding events in patients with MPNs.

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Patients were followed for a median 5.5 years (range, 0.1 to 35.6). The incidence of a first bleed was 2.29% per patient/year, with first MPN-associated bleeding events occurring in 17.2% of patients in this study. These occurred at a median 4.1 years (range, 0.1 to 27.6) after MPN diagnosis. Nearly one-third (32.9%) of first bleeding events were major bleeding events, for an overall rate of 5.7% for major bleeding in this population. A fatality related to bleeding occurred in 1 patient.

Treatment with an antiplatelet therapy was associated with most of the bleeding events, reflecting 60.1% of patients who experienced bleeding. Another 20.3% of patients with bleeding events were receiving anticoagulants, and 19.6% of patients with bleeding events received no anticoagulants. During the first bleeding event, 42.7% of the patients with bleeding events were receiving cytoreductive therapy.

Independent predictors of higher bleeding risk, as determined by multivariate analysis, included use of anticoagulation therapy (hazard ratio [HR], 4.06; 95% CI, 2.32-7.09) or use of antiplatelet therapy (HR, 2.31; 95% CI, 1.43-3.71). Age, sex, and mutational status were not factors associated with bleeding risk. MPN subtypes did not show significant differences in terms of bleeding risk.

These findings reveal that patients with MPNs undergoing antiplatelet or anticoagulation therapy have a higher risk of bleeding complications but without an apparent increase in bleeding-related mortality while on these agents.

“Therefore, concerns about bleeding should still not be a reason to refrain from guideline-tailored primary prophylactic anticoagulation or to prematurely discontinue secondary prophylaxis in MPN patients,” the researchers concluded. “Ultimately, the indication for anticoagulation in MPN must be made carefully at the beginning and reviewed over the course of the disease.”


Wille K, Huenerbein K, Jagenberg E, et al. Bleeding complications in bcr-abl-negative myeloproliferative neoplasms (MPN): a retrospective single-center study of 829 MPN patients. Eur J Haematol. Published online October 31, 2021. doi:10.1111/ejh.13721