Obesity Does Not Influence Hepcidin and Hemojuvelin Levels in Hemodialysis Patients

Abstract

Background/Aims: Clinical studies have shown increased levels of hepcidin causing functional iron deficiency in obese individuals. This study examined whether obesity contributes to increased hepcidin and hemojuvelin levels in adult hemodialysis patients. Methods: In a case-control design, 37 obese [body mass index (BMI) >30 kg/m²] stable hemodialysis patients and 37 patients with normal BMI (20-25 kg/m²), matched for age, gender and race, who fulfilled a strict set of inclusion and exclusion criteria were included in the study. Serum hepcidin and hemojuvelin, markers of iron status and inflammation, and routine hematological and biochemical variables were measured on samples obtained prior to the midweek hemodialysis session. Results: Obese and nonobese patients (BMI 35.1 ± 3.4 vs. 22.8 ± 1.4 kg/m²; p < 0.001) were similar with regard to basic comorbidities and use of erythropoietin and iron. Levels of hemoglobin, hypochromic red cells and reticulocytes were similar in the two groups. Serum iron and transferrin saturation levels were on the low side and not different between obese and lean individuals; total iron-binding capacity showed a trend towards higher levels in obese patients (48.4 ± 8.3 vs. 44.9 ± 7.4 μmol/l; p = 0.065). Levels of serum ferritin (651 ± 302 vs. 705 ± 327 μg/l; p = 0.46), hepcidin (118.3 ± 67.7 vs. 119.3 ± 78.0 ng/ml; p = 0.95) and hemojuvelin (1.90 ± 1.11 vs. 1.94 ± 1.24 mg/l; p = 0.90) were high but similar between the two groups. Serum hepcidin showed a significant correlation only with ferritin (r = 0.287, p = 0.013). Conclusions: Hepcidin and hemojuvelin levels are already considerably elevated in dialysis patients, but obesity does not have an additional impact. Further studies should examine whether increased weight contributes towards hepcidin elevation in predialysis individuals, in whom there is a lesser burden of systemic inflammation.