To investigate the association between hemoglobin (Hb) levels and incident diabetic kidney disease (DKD) in patients with type 2 diabetes.

This retrospective cohort study included 1,657 patients with diabetes, without DKD at baseline, recruited from six clinics affiliated with Lee's United Clinic in Taiwan. Demographic data and laboratory results were collected and analyzed. Participants were stratified into quartiles based on their baseline Hb levels. A subgroup analysis was conducted specifically for patients with normal Hb levels (men: Hb ≥ 120 g/l, women: Hb ≥ 110 g/l). Cox regression analysis assessed the relation between Hb levels and incident DKD, adjusting for relevant covariates.

Among the initial cohort, 93 (5.6 %) had anemia at baseline. Over an average follow-up period of 5.7 ± 2.6 years, 594 patients (35.8 %) developed DKD. Cox regression analysis revealed that, after adjusting for multiple variables, compared with patients in the highest quartile of baseline Hb levels (Q4: Hb ≥ 154 g/l), the hazard of DKD was 1.6 times higher in the lowest quartile (Q1: Hb ≤ 130 g/l) HR [95 % CI] 1.58 [1.19;2.21] P < 0.001. In patients with normal Hb levels, Cox regression analysis also revealed that compared to the highest quartile (Q’4, Hb ≥ 154 g/l) the hazard of developing DKD was 1.3 times higher in the lowest quartile (Q’1, Hb ≤ 132 g/l) HR [95 % CI ] 1.29 [1.08;1.72] P = 0.042.

Lower Hb is associated with incident DKD, even in patients with normal Hb levels, independent of other risk factors.