GSTM1 and polycythemia: Using the data from the Persian Registry Of Cardiovascular Disease/ Heart Failure (PROVE-HF) study, we assessed the association between anemia and polycythemia (Hb < 13 g/dLit, > 16.5 g/dLit in males and < 12 g/dLit, and > 16 g/dLit in females, respectively) and short-term mortality using Cox proportional hazard modeling, with adjustment of clinically relevant variables.