Quality of life issues in patients with essential thrombocythemia and polycythemia vera

Essential thrombocythemia and polycythemia vera are both chronic progressive myeloproliferative disorders of insidious onset. If the excessive production of red cells and/or platelets is controlled, patients with these disorders may have prolonged survival. However, the clinical course of these patients can be complicated by a variety of events, including thrombotic episodes, bleeding episodes, arthropathies, pruritus, weakness, weight loss, neurologic impairment, erythromelalgia, fever, abdominal pain, and the life-threatening consequences of progression to myelofibrosis and/or acute leukemia. Effective control of hematopoiesis by phlebotomy or a variety of therapeutic agents has resulted in a reduction or elimination of many of these clinical events, but has not altered the evolution to myelofibrosis or acute leukemia. Use of each of these therapeutic strategies is also associated with a range of adverse events. Monitoring overall survival or a reduction in the frequency of clinical events has previously served as a means of assessing the results of these therapeutic interventions. Quality-of-life instruments have not been applied in a systematic fashion to the evaluation of outcomes in patients with these chronic myeloproliferative disorders. Quality-of-life assessments evaluate not only the state of well-being of a patient that results from an assessment of the individual's ability to perform everyday activities, which are reflective of physical, psychological, and social well-being, but also patient satisfaction with the control of disease and/or treatment-related symptoms. Quality-of-life instruments have been used to assess the clinical course of patients suffering from a variety of disorders, ranging from cancer to renal failure to chronic fatigue syndrome. Information about quality-of-life outcomes can contribute to the evaluation of variations in dose and timing of administration of therapeutic agents. It is possible that the side effects of a particular therapy may outweigh the disease regression achieved with a particular therapy. In the future, quality-of-life instruments may prove useful in prospectively evaluating therapeutic end points in patients with essential thrombocythemia and polycythemia vera.