Other predictors of poor response included diabetes, ∆Hbβ = −2.66 (−4.81–−0.51), p = 0.015; total iron infusion dose per kg in the 3rd tertile (>20 mg/kg) ∆Hbβ = −3.04 (−5.49–−0.59), p = 0.015; higher baseline Hb, ∆Hbβ = −3.22 (−3.94–−2.5), p < 0.001; higher baseline MCV, ∆Hbβ = −0.21 (−0.34–−0.08), p = 0.002; and the presence of FID ∆Hbβ = −7.61 (−9.94–−5.29), p < 0.001 (compared to AID). The gene discussed is GSTM1; the disease is diabetes mellitus.