Thromboembolic events, major bleeding and mortality in essential thrombocythaemia and polycythaemia vera-A matched nationwide population-based study.

Thromboembolic events and bleeding are known complications in essential thrombocythaemia (ET) and polycythaemia vera (PV). Using multiple Swedish health care registers, we assessed the rate of arterial and venous events, major bleeding, all-cause stroke and all-cause mortality in ET and PV compared to matched controls. For each patient with ET (n = 3141) and PV (n = 2604), five matched controls were randomly selected. In total, 327 and 405 arterial or venous events were seen in the group of ET and PV patients respectively. Compared to corresponding controls, the rate of venous thromboembolism, major bleeding and all-cause mortality per 100 treatment years was significantly increased among both ET (0.63, 0.79 and 3.70) and PV patients (0.94, 1.20 and 4.80). The PV patients also displayed a significantly higher rate of arterial events and all-cause stroke compared to controls. When dividing the cohort into age groups, we found a significantly higher rate of arterial and venous events in all age groups of PV patients, and the rate of all-cause mortality was significantly higher in both ET and PV patients in all ages above the age of 50. This study confirms that PV and ET are diseases truly marked by thromboembolic complications and bleeding.

Survival and risk of vascular complications in myelofibrosis-A population-based study from the Swedish MPN group.

OBJECTIVE: To gain knowledge of underlying risk factors for vascular complications and their impact on life expectancy in myelofibrosis. METHODS: From a cohort of 392 myelofibrosis patients registered in the Swedish MPN registry 58 patients with vascular complications during follow-up were identified. Patients with vascular complications were compared with both 1:1 matched controls and the entire myelofibrosis cohort to explore potential risk factors for vascular complications and their impact on survival. RESULTS: Incidence of vascular complications was 2.8 events per 100 patient-years and the majority of complications were thrombotic. Patients with complications were significantly older and had lower hemoglobin when compared to the entire cohort. In the case-control analysis, no significant risk factor differences were observed. The major cause of death was vascular complications and median survival was significantly impaired in patients with vascular complications (48 months) compared to controls (92 months). Inferior survival in patients with vascular complications was found to be dependent on IPSS risk category in a Cox regression model. CONCLUSION: Vascular complications have a considerable impact on survival in MF. At diagnosis, risk assessment by IPSS does not only predict survival but is also associated with the risk of vascular complications.

A retrospective analysis of the impact of treatments and blood counts on survival and the risk of vascular events during the course of polycythaemia vera.

Vascular and non-vascular complications are common in patients with polycythaemia vera. This retrospective study of 217 patients with polycythaemia vera aimed to determine whether blood counts with respect to different treatments influenced the complication rate and survival. We found that 78 (36%) patients suffered from at least one complication during follow-up. Older age and elevated lactate dehydrogenase at diagnosis were found to be risk factors for vascular complications. When the vascular complication occurred, 41% of the patients with a complication had elevated white blood cells (WBC) compared with 20% of patients without a complication (P = 0·042). Patients treated with hydroxycarbamide (HC; also termed hydroxyurea) experienced significantly fewer vascular complications (11%) than patients treated with phlebotomy only (27%) (P = 0·013). We also found a survival advantage for patients treated with HC, when adjusted for age, gender and time period of diagnosis (Hazard ratio for phlebotomy-treated patients compared to HC-treated patients at 5 years was 2·42, 95% confidence interval 1·03-5·72, P = 0·043). Concerning survival and vascular complications, HC-treated patients who needed at least one phlebotomy per year were not significantly different from HC-treated patients with a low phlebotomy requirement. We conclude that complementary phlebotomy in HC-treated patients in order to maintain the haematocrit, is safe.