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.

Highly reduced survival in essential thrombocythemia and polycythemia vera patients with vascular complications during follow-up

OBJECTIVE

To explore the relative importance of risk factors, treatments, and blood counts for the occurrence of vascular complications and their impact on life expectancy in essential thrombocythemia (ET) and polycythemia vera (PV).

METHODS

Nested case-control study within the Swedish MPN registry. From a cohort of 922 ET patients and 763 PV patients, 71 ET and 81 PV cases with vascular complications were compared with matched controls.

RESULTS

Incidence of vascular complications was 2.0 and 3.4 events per 100 patient-years in ET and PV, respectively. At diagnosis, no significant risk factor differences were observed between cases and controls in neither of the diseases. At the time of vascular event, ET complication cases did not differ significantly from controls but in PV, cases had significantly higher WBCs and were to a lesser extent treated with anti-thrombotic and cytoreductive therapy. Life expectancy was significantly decreased in both ET and PV cases compared with controls.

CONCLUSIONS

The risk of vascular complications is high in both ET and PV, and these complications have a considerable impact on life expectancy. The protective effect of anti-thrombotic and cytoreductive therapy for vascular complications in PV underscores the importance of avoiding undertreatment.