GSTM1 and anemia (phenotype): The only factor that was significantly associated with the specifics of the further investigations was the extent of the baseline anemia (Hb 7.8 g/dL [IQR 6.7–9.6] for the early-explored patients vs 9.6 g/dL [IQR 9.5–10.4] for the late-explored patients; P = 0.01).