PB1451 - Development of Occult Myeloproliferative Neoplasm in Patients with Venous Thromboembolism and JAK2 Positive Mutation: A Systematic Review

Background: JAK2-positive myeloproliferative neoplasms (MPN), such as polycythemia vera and essential thrombocythemia, are commonly associated with atypical site thromboembolism (TE). Given this common association, patients presenting with atypical thromboses often have JAK2 testing done, even without cell count changes that would suggest an MPN. The clinical relevance of JAK2 positivity in these patients and the risk of progression to MPN is unclear.

Aims: Perform a systematic review assessing progression to MPN in patients with TE and JAK2 mutations.

Methods: A comprehensive search of MEDLINE, EMBASE, and CENTRAL was completed from inception to October 2023. Studies were screened independently and in duplicate at abstract and full-text levels. Any English language study assessing patients with venous TE, JAK2, and MPN status was included. Two reviewers independently and in duplicate extracted data, including baseline characteristics, details of thrombosis events, JAK2 mutation status, MPN status, and intervention details.

Results: Of the 2951 titles screened, 49 studies were included, with a total of 6940 patients. Of these patients, 760 (10.9%) were JAK2 positive, of which 429 (56.4%) did not meet the diagnostic criteria for MPN. JAK2 mutation was prevalent in patients with Budd-Chiari Syndrome (19%, 119/623). 36 studies followed patients after an initial thrombosis event for a median of 48 months. Of 429 patients who were initially JAK2 positive and MPN negative, 92 patients (21.4%) progressed to MPN at an average of 43.7 months. There was limited information on anticoagulation regimens or rates of recurrent TE.

Conclusion(s): There is a high rate of progression to MPN in patients with JAK2 mutation positivity and thrombosis, demonstrating the importance of close monitoring for disease progression in this population. Further studies are required to investigate the optimal population to test, anticoagulation duration, and initiation of MPN modifying therapy.