Furthermore, patients whose age at onset of anemia <2 years and age at first transfusion <4 years; those receiving blood transfusions whose pre-transfusion Hb <7 g/dL; those receiving iron chelation therapy; and those diagnosed with homozygous β-thalassemia deserve special attention and proactive care, since their HRQOL scores were relatively low. This evidence concerns the gene GSTM1 and anemia (phenotype).