An observational study in Polycythemia Secondary and Polycythemia, Primary, sponsored by Hospices Civils de Lyon. Recruiting at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-11-21.
Sponsored by Hospices Civils de Lyon · Observational
Polycythemia (PG) corresponds to an increase in erythrocyte parameters on a blood test. A distinction is usually made between primary and secondary PG. The most common primary PG is Vaquez's disease, a hematological cancer. In Vaquez disease, an increase in hematocrit has been reported to be associated with a logarithmic increase in blood viscosity.
The main complications of primary PGs (especially in Vaquez disease) are thromboembolic complications. In contrast, thromboembolic complications are rarer in secondary PG. In Vaquez disease, a hematocrit ≤ 45% has been defined as the therapeutic goal for significantly reducing thromboembolic risk. However, this has not been established for secondary PGs. All in all, the definition of the 45% threshold is based solely on clinical studies with no obvious biological argument. What's more, simply lowering blood mass through cytoreduction alone does not appear to be sufficient to significantly reduce thromboembolic risk.
To investigator knowledge, there are no studies prospectively evaluating blood viscosity, its determinants and coagulation in different types of polycythemia. Nor are there any data on the direct effect on blood viscosity of the various treatments usually offered.
278 studies on the registry are indexed under Polycythemia Vera; 53 are open to participants now.
This study's planned enrollment of 160 is below the median of 240 across 44 observational studies indexed under Polycythemia Vera.
Browse Polycythemia Vera studies →Hospices Civils de Lyon is the lead sponsor of 1,866 studies on the registry; 448 are open to participants now.
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Patients with polycythemia defined as hematocrit level greater than or equal to 49% in men and 48% in women, whatever the suspected etiology. Primitive and secondary polycythemia are eligible in this observational study. Patients should not have start any cytoreductive therapy prior inclusion.
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Exclusion Criteria:
Patients with polycythemia defined as hematocrit level greater than or equal to 49% in men and 48% in women, whatever the suspected etiology. Primitive and secondary polycythemia are eligible in this observational study. Patients should not have start any cytoreductive therapy prior inclusion.
Whole blood viscosity levels in patients with polycythemia
The investigators expect higher blood viscosity values in polyglobulic patients with symptoms of clinical hyperviscosity than in polyglobulic patients without symptoms of clinical hyperviscosity, but no differences in hematocrit between the two polycythemia groups
Time frame: Baseline
Started Sep 2024 (actual). Primary completion is estimated for Sep 2031, 84 months after the start.
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