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. 2025 Jun 10;9(11):2783-2793.
doi: 10.1182/bloodadvances.2025016247.

Thrombosis, major bleeding, and mortality in 1079 patients with myelofibrosis: a matched population-based study

Anneli Enblom Larsson  1 , Henrik Renlund  2 , Björn Andréasson  3 , Henrik Holmberg  4 , Maria Liljeholm  5 , Anders Själander  1
Affiliations

Thrombosis, major bleeding, and mortality in 1079 patients with myelofibrosis: a matched population-based study

Anneli Enblom Larsson et al. Blood Adv. .

Abstract

Bleeding and thrombotic events are known complications in myeloproliferative neoplasms (MPNs), but few studies have exclusively focused on patients with myelofibrosis (MF). In this nationwide population-based study, we assessed the frequency of major bleeding, thrombotic events, and all-cause mortality in 1079 patients diagnosed with MF and 5395 matched controls using multiple Swedish health care registers. Major bleeding, arterial, and venous events were seen at a rate of 2.55, 2.59, and 1.06 events per 100 years, respectively, in patients with MF. Compared to controls, the rates of bleedings, arterial events, venous events, and mortality were increased, with hazard ratios of 3.78 (95% confidence interval [CI], 2.98-4.79; P < .001), 1.73 (95% CI, 1.40-2.12; P < .001), 2.75 (95% CI, 1.93-3.90; P < .001), and 3.92 (95% CI, 3.50-4.40; P < .001), respectively. Patients treated with JAK inhibitors (JAKis) had higher rates of major bleeding (5.33), arterial events (4.67), and venous events (1.56) than patients with no ongoing symptom-directed therapy (rates, 2.32, 2.15, and 0.79) or hydroxyurea (rates, 2.05, 2.35, and 1.27, respectively). The use of JAKis or low-molecular-weight heparin, previous arterial or venous events, and older age were identified as independent risk factors for new arterial or venous events. A previous venous event, higher leukocyte count at diagnosis, and ongoing JAKi treatment were associated with an increased risk of major bleeding. This study shows that patients with MF have higher rates of thromboembolic events and major bleeding than described in other MPNs, and thromboembolic complications and major bleeding diverge in the different treatment groups.

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Conflict of interest statement

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Figures

None
Graphical abstract
Figure 1.
Figure 1.
Kaplan-Meier curves for the different outcomes in all patients with MF, PMF, and SMF. Cases are marked as red lines, and controls are marked in blue. Shaded areas represent 95% CIs.
Figure 2.
Figure 2.
Forest plot illustrating risk factors for major bleeding and arterial or venous event in MF. The model is adjusted for age, sex, presence of JAK2 V617F mutation, levels of Hb, WBC count, platelet count, previous thrombotic event or bleeding, symptom-directed therapy, and antithrombotic treatment. DOACs, direct oral anticoagulants; ESA, erythropoietin-stimulating agent; IMiDs, immunomodulatory drugs; LMWH, low-molecular weight heparin, VTE, venous thromboembolism.
See this image and copyright information in PMC

References

    1. Arber DA, Orazi A, Hasserjian R, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016;127(20):2391–2405. - PubMed
    1. Guglielmelli P, Pacilli A, Rotunno G, et al. Presentation and outcome of patients with 2016 WHO diagnosis of prefibrotic and overt primary myelofibrosis. Blood. 2017;129(24):3227–3236. - PubMed
    1. Lindgren M, Andréasson B, Samuelsson J, et al. Survival and risk of vascular complications in myelofibrosis—a population-based study from the Swedish MPN Group. Eur J Haematol. 2022;109(4):336–342. - PubMed
    1. Hultcrantz M, Wilkes SR, Kristinsson SY, et al. Risk and cause of death in patients diagnosed with myeloproliferative neoplasms in Sweden between 1973 and 2005: a population-based study. J Clin Oncol. 2015;33(20):2288–2295. - PubMed
    1. Hernández-Boluda JC, Pastor-Galán I, Arellano-Rodrigo E, et al. Predictors of thrombosis and bleeding in 1613 myelofibrosis patients from the Spanish registry of myelofibrosis. Br J Haematol. 2022;199(4):529–538. - PubMed