Study Summary: Real-World Adherence to Cytoreductive Treatment in Polycythemia Vera Is Low

Study Takeaways

• Patients with polycythemia vera have a higher risk for mortality than people in the general population.
• Clinical practice guidelines recommend use of cytoreductive therapy for patients with high-risk polycythemia vera to reduce risk for thrombotic complications.
• Despite available clinical practice guidelines for polycythemia vera, many high-risk patients are not receiving cytoreductive medications and may be unnecessarily at risk for complications.

Background

Polycythemia vera (PV) is a myeloproliferative disorder characterized predominantly by excessive production of normal red blood cells (erythrocytosis). The mortality risk in affected patients is higher than in the general population, mostly due to greater risks for thrombosis, cardiovascular disease, and hematologic transformation. PV also negatively affects patients’ quality of life, due to disease-related chronic symptoms, including fatigue, abdominal discomfort, and bone pain.¹

The main goal of treating PV is to prevent thrombotic complications. Professional organizations have issued treatment guidelines that stratify patients according to whether they have a low or high risk for thrombosis. For low-risk patients, management is based on use of aspirin therapy and phlebotomy to maintain a hematocrit value of less than 45%. For high-risk patients (those 60 years or older and/or have a history of thrombotic events), guidelines recommend using cytoreductive therapy in addition to aspirin and phlebotomy. In their study, Paranagama and colleagues sought to investigate real-world adherence to cytoreductive therapies among patients with PV, based on guideline recommendations.¹

Study Design

The researchers conducted a noninterventional, retrospective analysis, using claims data from the Truven Health Marketscan database. They stratified patients according to their PV risk status, enrolling those who were 18 years or older and living in the United States with at least 2 nondiagnostic claims for PV. Individuals with claims for either secondary polycythemia or conditions such as myelodysplastic syndrome, myelofibrosis, or acute myelogenous leukemia were excluded from the study. ¹

The researchers chose January 1, 2013, as the study’s index date. Because this date was approximately 2 years after the European LeukemiaNet guidelines for PV were released, Paranagama and colleagues identified it as a point by which clinicians may reasonably have been expected to have adopted the recommendations. The preindex period extended from January 1, 2012, to December 31, 2012, and the postindex period extended from January 1, 2013, to December 31, 2014.¹

Results

A total of 2856 patients with PV were enrolled in this study, 1823 of whom were stratified as high risk and 1033 as low risk. Patients had a mean age of 62.5 years, and most (65.9%) were men. Preindex comorbidities, such as hypertension and congestive heart failure, occurred more commonly in high-risk patients than among low-risk patients. During the preindex period of the study, just 36.5% of high-risk patients (n = 666) and 15.5% of low-risk patients (n = 160) received cytoreductive therapy. The most common cytoreductive therapies used in these 2 patient groups across the preindex period were hydroxyurea (94.7% of high-risk patients and 87.5% of low-risk patients), anagrelide (7.4% and 11.9%, respectively), and interferon (1.7% and 4.4%, respectively). ¹

During the postindex period, 6.7% of patients with PV who had not received cytoreductive therapy before the index date started cytoreductive medications. Of these patients, 74.1% were high risk and 25.9% were low risk. During this period, these 2 groups of patients most commonly received hydroxyurea (97.0% of high-risk patients and 91.4% of low-risk patients), anagrelide (4.0% and 2.9%, respectively), and interferon (2.0% and 8.6%, respectively). ¹

The results indicated that less than half of high-risk patients (42.0%) and less than one-fifth of low-risk patients (18.9%) received cytoreductive medications during the study periods. ¹

Conclusion

Although guidelines recommend use of cytoreductive therapy for patients with high-risk PV, this study highlights that many of these patients are not receiving this treatment and may be unnecessarily at risk for additional cardiovascular complications. Because patients with PV have a greater risk for mortality than individuals in the general population, Paranagama and colleagues suggested that many of those with high-risk disease would benefit if clinicians were to adjust treatment plans to follow guideline recommendations. The researchers concluded that to enhance clinical outcomes in this patient population, clinicians need education to improve their awareness of available guidelines for PV.¹

Reference

Paranagama D, Colucci P, Evans KA, Bonafede M, Parasuraman S. Are patients with high-risk polycythemia vera receiving cytoreductive medications? a retrospective analysis of real-world data. Exp Hematol Oncol. 2018;7:16. doi: 10.1186/s40164-018-0107-8.