QRISK3 score is predictive of thrombotic risk in patients with myeloproliferative neoplasms.

Thromboembolic events (TE) represent the commonest cause of morbidity and mortality in polycythemia vera (PV) and essential thrombocythaemia (ET). The QRISK3 model is a tool for predicting TE in the general population, with 7.5% recognised as a threshold to identify high-risk patients. We analyzed data of 937 patients (490 ET and 447 PV) with a median follow-up of 85 and 95 months, reporting an occurrence of 52 and 73 TE, respectively. Median QRISK3 scores at diagnosis were higher in conventional high-risk patients in both cohorts (ET; 4.2 in high-risk vs. 2.4 in low-risk, PV; 8.8 vs. 2.8, p < 0.001). During follow-up, a QRISK3 score greater than 7.5%, demonstrated potential to further stratify individuals at high risk of TE, outperforming standard risk assessments in both low and high-risk patients. Using cytoreductive treatment instead of active surveillance in patients with QRISK3 ≥ 7.5% conferred a reduced risk of thrombosis in both cohorts. Of this group, 79.7% with ET and 86.9% with PV, on cytoreductive therapy, remained thrombosis free, compared with 64.1% and 57.1% of those not receiving cytoreductive therapy (p = 0.018/0.034). QRISK3 identifies patients in whom cytoreductive therapies may be indicated, and provides a tool that allows patients to assess, monitor and reduce their cardiovascular risk.