The impact of phlebotomy and hydroxyurea on survival and risk of thrombosis among older patients with polycythemia vera

Abstract

Current guidelines recommend therapeutic phlebotomy for all polycythemia vera (PV) patients and additional cytoreductive therapy (eg, hydroxyurea [HU]) for high-risk PV patients. Little is known about the impact of these therapies in the real-world setting. We conducted a retrospective cohort study of older adults diagnosed with PV from 2007 to 2013 using the linked Surveillance, Epidemiology, and End Results-Medicare database. Multivariable Cox proportional hazards models were used to assess the effect of phlebotomy and HU on overall survival (OS) and the occurrence of thrombotic events. Of 820 PV patients (median age=77 years), 16.3% received neither phlebotomy nor HU, 23.0% were managed with phlebotomy only, 19.6% with HU only, and 41.1% with both treatments. After a median follow-up of 2.83 years, 37.2% (n=305) of the patients died. Phlebotomy (yes/no; hazard ratio [HR]=0.65; 95% confidence interval [CI], 0.51-0.81; P