GSTM1 and prediabetes syndrome: By multivariable Cox regression, after adjustment for age, sex, the presence of diabetes/prediabetes, and HF duration, higher baseline Hb concentrations (HR 1.347, 95% CI 1.038-1.746, <i>p</i> = 0.025), and eGFR levels (HR 1.016, 95% CI 1.000-1.033, <i>p</i> = 0.46).