New Data Proves Role of Thrombosis in Patients with MPNs

New research published in Annals of Internal Medicine shows that the rate of arterial and venous thrombosis was significant in patients with myeloproliferative neoplasms (MPNs).

MPNs include a variety of blood disorders, like myelofibrosis, polycythemia vera, and essential thrombocytosis, and patients with them have been reported to be at increased risk for thrombotic events. Pharmacologic treatment can stabilize the blood counts, but they generally provide only partial symptom improvement. Until recently, no population-based study has estimated the excess risk with matched control participants.

Malin Hultcrantz, M.D., PhD and colleagues, in an effort to address the gap in knowledge, evaluated data from 9,429 patients — 46% of whom were male – diagnosed with MPNs who reported to the Swedish Cancer Register between 1987 and 2009, and matched them to 35,820 control participants and compared their rates of arterial and venous thrombosis. Median age of study participants was 72 years, and a mong them, 3,001 had polycythemia vera, 3,462 had essential thrombocythemia, 1,488 had PMF, and 1,478 had MPN unclassifiable.

Follow-up of this population-based study, “Risk for Arterial and Venous Thrombosis in Patients With Myeloproliferative Neoplasms” was conducted up to 2010.

Results from the study showed that patients with MPNs had hazard ratios (HRs) for arterial thrombosis of 3 at 3 months, 2 at 1 year and 1.5 at 5 years versus match controls. These patients also had HRs for venous thrombosis at 9.7 at 3 months, 4.7 at 1 year and 3.2 at 5 years versus match controls. The decrease in HR for thrombotic after diagnosis was likely due to effective treatment of the underlying MPN. The HR for venous thrombosis was lower in patients diagnosed during more recent calendar periods, according to the researchers.

"These results are encouraging, and we believe that further refinement of risk scoring systems (such as by including time since MPN diagnosis and biomarkers); rethinking of recommendations for younger patients with MPNs; and emerging, more effective treatments will further improve outcomes for patients with MPNs," Hultcrantz's group wrote.

A second article, “Shedding New Light on the Magnitude of Thrombosis Risk in Patients With Myeloproliferative Neoplasms,” was also published in Annals of Internal Medicine this week, and Alison Moliterno, MD, and Elizabeth Ratchford, MD, both of Johns Hopkins University School of Medicine in Baltimore, concluded that the findings by Hulcrantz and colleagues expose the extent of arterial and venous thrombosis risk in patients with MPNs.

“MPNs exhibit marked variability in disease presentation and outcomes, especially with regard to thrombotic events,” they wrote.

“Care of patients with [MPNs] should include aggressive treatment of traditional risk factors to reduce risk for arterial and venous thrombosis, regardless of age; adoption of dietary and lifestyle habits that reduce inflammation; and consideration of combined anticoagulant, antiplatelet, and anti-inflammatory treatment strategies.”

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References:

1. Hultcrantz M, Bjorkholm, M, Abresch RT, Dickman P. Risk for Arterial and Venous Thrombosis in Patients With Myeloproliferative Neoplasms: A Population-Based Cohort Study. Annals of Internal Medicine. 2018. doi: 10.7326/M17-0028
2. Moliterno A, Ratchford E. Shedding New Light on the Magnitude of Thrombosis Risk in Patients With Myeloproliferative Neoplasms. Annals of Internal Medicine. 2018. doi: 10.7326/M17-3153