GSTM1 and diabetic kidney disease: A high concentration of Hb was associated with an decreased prevalence of DKD (OR = 0.765; 95% confidence interval [95% CI], 0.650–0.900; p < 0.001), after adjusting for age, sex, BMI, HBA1C, FPG, ALP, UA, and TG levels but a lower fasting C‐peptide, TBIL, and eGFR.