QRISK3 Tool Predicts Thrombotic Events in ET, PV

A risk-assessment tool used to predict the risk of thromboembolic events in the general population can also be used to identify patients with polycythemia vera (PV) and essential thrombocythemia (ET) who would benefit from cytoreductive treatment, a new report has found. The study was published in the journal Leukemia.1

Thrombotic events are the most common cause of morbidity and mortality among people with myeloproliferative neoplasms (MPNs), the authors explained. The risk is due to several factors, they said.

Patients who would be high-risk based on conventional assessments tended to have higher median QRISK3 scores in the study. | Image credit: Eleni - stock.adobe.com

“The hypercoagulable state derives from a complex interplay of factors including endothelial alterations, higher platelet count, and increased blood viscosity, all of which promote thrombus formation,” they wrote.

The risk of thrombotic events in patients with ET and PV has traditionally been estimated using their age and their history of previous thrombotic events. In 2012, a risk-estimation model was developed that also incorporated the presence of the JAK2V617F mutation as an additional risk factor.2

Yet, other potential risk factors, such as concurrent cardiovascular comorbidities, have not yet been incorporated into risk-stratification assessments, the authors said.1

“Despite advancements in stratifying thrombotic risk in the management of MPN patients, existing models do not account for the impact of cardiovascular comorbidities, which play a critical and modifiable role in shaping individual patient risk,” they said.

This led the investigators to wonder whether the QRISK3 score, a tool used to predict thrombotic event risk in the general population, might have utility in the setting of ET and PV.

“It incorporates various clinical and demographic variables, such as age, history of hypertension, atrial fibrillation, and severe mental illness, and high BMI (body mass index), comprehensively evaluating an individual’s risk profile,” they noted.

The authors used the QRISK3 assessment to retrospectively score 490 patients with ET and 447 patients with PV to see whether their scores might correlate with their experience of thrombotic events. At a median follow-up of 85 months for the ET cohort and 95 months for the PV cohort, a total of 52 and 73 thrombotic events had been reported, respectively.

Patients who would be high-risk based on conventional assessments tended to have higher median QRISK3 scores (4.2 among high-risk patients with ET versus 2.4 among low-risk patients; 8.8 among high-risk patients with PV vs 2.8 among low-risk patients [P < .001]).

When the investigators compared QRISK3 scores to conventional risk assessments, they found that using QRISK3 scores above 7.5% was a more effective risk-stratification tool than conventional assessments. A score of 7.5% is the same cutoff used to stratify high and low risk of thrombotic events in the general population, they noted.

Having shown that QRISK3 scores were a meaningful way to predict thrombotic event risk in ET and PV populations, the investigators next looked at the role of intervention.

They found that when patients with QRISK3 scores above 7.5% were given cytoreductive treatment instead of active surveillance, they had lower rates of thrombotic events. Among patients with QRISK3 scores at or above 7.5% who received cytoreductive therapy, 79.7% of patients with ET and 86.9% of patients with PV remained thrombosis-free. Among patients with scores of at least 7.5% who did not undergo cytoreductive treatment, the percentages of patients who remained thrombosis-free were 64.1% in the ET cohort and 57.1% in the PV cohort (P = .018/.034).

Duminuco and colleagues said their data suggest the QRISK3 tool can be a valuable assessment not only at diagnosis but also as a longitudinal risk assessment.

“QRISK3 score appears to be a valid tool that can be applied successfully in PV and ET to help improve thrombotic risk assessment, suggesting the utility of active cytoreductive treatment in high-risk patients,” they concluded.

References

1. Duminuco A, Vaghela R, Virdee S, et al. QRISK3 score is predictive of thrombotic risk in patients with myeloproliferative neoplasms. Leukemia. Published online July 24, 2025. doi:10.1038/s41375-025-02681-9

2. Barbui T, Finazzi G, Carobbio A, et al. Development and validation of an International Prognostic Score of thrombosis in World Health Organization-essential thrombocythemia (IPSET-thrombosis). Blood. 2012;120(26):5128-5252. doi:10.1182/blood-2012-07-444067