Hematocrit to hemoglobin ratio as a prognostic marker in polycythemia vera

The hematocrit to hemoglobin ratio (HHR) is frequently used in everyday practice to measure hemoconcentration; however, clinical associations of HHR in the context of polycythemia vera (PV) have not been investigated so far.

We retrospectively assessed HHR at the time of diagnosis in 107 PV and 40 secondary polycythemia (SP) patients from three community hospitals.

Median HHR was higher in PV than in SP patients (3.131 vs. 2.975, p = 0.041). Among PV patients, higher HHR correlated with splenomegaly, higher total leukocyte and absolute granulocyte counts, higher red blood cell counts, lower hemoglobin, higher red blood cell distribution width, lower mean corpuscular hemoglobin and lower ferritin levels, whereas in SP patients higher HHR correlated with older age, female sex and lower hemoglobin (p < 0.050 for all analyses). Using the receiver operating curve analysis-defined cut-off points, higher HHR in PV was associated with a shorter time to thrombosis (hazard ratio-HR 5.20, p = 0.022) independently of high-risk disease status (HR 4.48, p = 0.034) and shorter overall survival (HR 6.69, p = 0.009) independently of leukocytosis (HR 4.48, P = 0.034) and the absence of aspirin use (HR 15.53, p < 0.001).

Higher HHR may represent iron deficiency and a stronger clonal myeloproliferation in PV and could provide additional prognostic information to the classical risk assessment.