Validation of the triple a model (age, absolute neutrophil count, absolute lymphocyte count) for the prediction of survival and thrombosis in 1000 patients with polycythemia vera.

Standard ELN risk stratification for thrombosis and overall survival (OS) in patients with polycythemia vera (PV) is based on advanced age and history of thrombosis. Recently, the triple A (AAA) risk model was developed for OS prediction in patients with essential thrombocythemia, which, besides rising age, incorporates high (≥8x109/L) absolute neutrophil and low(<1.7 × 109/L) lymphocyte counts. The presented multicenter international study on a large cohort of PV patients validated the findings from prior reports and demonstrated excellent prognostic properties of the triple A model with respect to both thrombosis and survival in PV. Moreover, it revealed that the addition of patient comorbidities (assessed through the Charlson comorbidity index (CCI)) to ELN and triple A score may not help to further refine the survival prognostication of these patients. Therefore, the triple A score with its simplicity seems to offer excellent balance during the initial risk assessment in PV, implicating its global applicability.