patient care perspectives

Nonadherence to Cytoreductive and/or Antithrombotic Therapy in Patients With Polycythemia Vera

by Katherine Walsh, MD, FACP


Patients with polycythemia vera (PV) who are nonadherent to cytoreductive and/or antithrombotic therapy are at an increased risk of thrombotic events and disease progression. Nonadherence is associated with both patient- and disease-related factors, and monitoring treatment adherence is an important aspect of the treatment of patients with PV.

Expert Commentary

Katherine Walsh, MD, FACP

Associate Professor of Clinical Internal Medicine
Division of Hematology
The James Cancer Hospital and Solove Research Institute
The Ohio State University Comprehensive Cancer Center
Columbus, OH

“Patients with no symptoms may be less likely to adhere to their treatment regimens, and these individuals require counseling and education regarding the importance of adherence.” 

Katherine Walsh, MD, FACP

In my experience, nonadherence tends to be more common in patients who are taking cytoreductive or aspirin therapy for the prevention of complications only. That is, patients with no symptoms may be less likely to adhere to their treatment regimens, and these individuals require counseling and education regarding the importance of adherence. Patient preference does factor into treatment choice and subsequent adherence, but most of these discussions occur at the start of therapy, when we are reviewing treatment options and selecting a plan that will work with the patient’s schedule and lifestyle. In their 2018 prospective OUEST study, Le Calloch et al reported that approximately 30% of patients with PV were nonadherent with either low-dose aspirin or cytoreductive therapy, or both. The most common reason for nonadherence was simple forgetfulness—not medication side effects or the perception that hydroxyurea may increase the risk of transformation to leukemia—followed by difficulty in maintaining the treatment during holidays and travel. Interestingly, having other chronic health problems such as diabetes was associated with a lower rate of nonadherence and having a previous thrombotic event did not seem to have a significant impact on adherence in this study. The latter finding may reflect the patients not fully understanding the link between not taking their medications and having thrombotic events, as suggested by the authors. To me, this underscores the importance of talking to our patients about the benefits of consistency. Those with PV can generally expect to live a long life with their diagnosis. I think that an important area of potential impact, in terms of patient education, is having the discussion that consistent therapeutic pressure provides the best chance for favorable outcomes.


Kurtin S, Lyle L. The role of advanced practitioners in optimizing clinical management and support of patients with polycythemia vera. J Adv Pract Oncol. 2018;9(1):56-66.

Le Calloch R, Lacut K, Le Gall-Ianotto C, et al. Non-adherence to treatment with cytoreductive and/or antithrombotic drugs is frequent and associated with an increased risk of complications in patients with polycythemia vera or essential thrombocythemia (OUEST study). Haematologica. 2018;103(4):607-613.

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