GSTM1 and anemia: The data analyses of the surgical records of 10,571 patients (5370 from 2017 and 5201 from 2018) who underwent surgery yielded the following results: 2953 of the 10,571 (27.93%) cases had anemia (Hb < 12.0 g/dl for women and Hb < 13.0 g/dl for men) (Fig. 1), out of which 879 (29.76%) patients had IDA.