Dialysis patients were slightly younger (66.1 ± 8.9 years vs. 69.5 ± 9.0 years, p = 0.09), had higher prevalence of heart failure (52% vs. 37%), and a greater frequency of anemia (Hb < 10 g/dL: 61% vs. 41%). Here, GSTM1 is linked to anemia (phenotype).