Assessing significance of peripheral blood indicators for differential diagnosis and prognosis of thrombotic complications in polycythemia vera and secondary erythrocytosis

The aim of the study ? determining of changes in peripheral blood (PB) in patients with secondary erythrocytosis (SE) and polycythemia vera (PV), detection of discriminatory parameters levels of PB indicators and analyzing of their operating characteristics for differentiation of erythrocytosis and predicting of thrombotic events in patients with PV. Materials and methods. The material for the study was the results of clinical trials of 210 patients with erythrocytosis who underwent differential diagnosis between PV and SE. Results and discussion. The optimal threshold for differential diagnosis of red blood cells content between PV and SE is >6.08?1012/ L, the diagnostic value of the marker equals to the level of a good diagnostic marker (AUC=0.82; 95% CI=0.77-0.87, p <0.0001). Hematocrit threshold is >57.5% with its capacity ? 0.72 (0.66-0.78, p <0.0001), that corresponds to the level of a middle diagnostic marker. The most pathognomonic section of white blood cells (WBC) to differentiate erythrocytosis is >8.9?109/L, and the boundary of marker is consistent with a good level of efficiency (AUC=0.79, 95% CI=0.72-0.84, p<0.0001). The efficiency criterion "platelets >287?109 /L" to differentiate erythrocytosis is 0.90 (0.86-0.94, p <0.0001).The predicting effectiveness of cardiovascular events with help of criterion "hematocrit >55%" and "WBC >12.3?109 /L", according to the AUC (AUC=0.65; 95% CI=0.52-0.79, p=0.021 and AUC=0.66; 95% CI=0.55-0.77, p=0.003, respectively), corresponds to the average power level. Conclusion. Hemoglobin has not confirmed its value for the differential diagnosis between PV and SE. Using other parameters of PB with the aim of differentiating PV and SE is rational, but their discriminatory power levels greatly depend on the group erythrocytosis. In our cohort were obtained the following most appropriate criteria for inclusion of patients in the group of patients with PV: "WBC >8.9?109/L", "red blood cells >6.08?1012/L" and "hematocrit >57.5%". The most significant marker of general clinical blood test to differentiate between PV and SE is "platelets >287?109/L". Hematocrit over 55% and WBC over 12.3?109/L are valuable prognostic markers of thrombosis in PV patients, but their use is appropriate only in a cohort of patients with PV without classical factors of cardiovascular events.