Comparison of Oral Iron Supplement Formulations for Normalization of Iron Status Following Roux-EN-y Gastric Bypass Surgery: a Randomized Trial

Abstract

Background The evidence behind recommendations for treatment of iron deficiency (ID) following roux-en-y gastric bypass surgery (RYGB) lacks high quality studies. Setting Academic, United States Objective The objective of the study is to compare the effectiveness of oral iron supplementation using non-heme versus heme iron for treatment of iron deficiency in RYGB patients. Methods In a randomized, single-blind study, women post-RYGB and iron deficient received non-heme iron (FeSO4, 195 mg/day) or heme iron (heme-iron-polypeptide, HIP, 31.5 to 94.5 mg/day) for 8 weeks. Measures of iron status, including blood concentrations of ferritin, soluble transferrin receptor (sTfR), and hemoglobin, were assessed. Results At baseline, the mean ± standard deviation for age, BMI, and years since surgery of the sample was 41.5 ± 6.8 years, 34.4 ± 5.9 kg/m2, and 6.9 ± 3.1 years, respectively; and there were no differences between FeSO4 (N = 6) or HIP (N = 8) groups. Compliance was greater than 94%. The study was stopped early due to statistical and clinical differences between groups. Values before and after FeSO4 supplementation, expressed as least square means (95% CI) were hemoglobin, 10.8 (9.8, 11.9) to 13.0 (11.9, 14.0) g/dL; sTfR, 2111 (1556, 2864) to 1270 (934, 1737) μg/L; ferritin, 4.9 (3.4, 7.2) to 15.5 (10.6, 22.6) μg/L; and sTfR:ferritin ratio, 542 (273, 1086) to 103 (51, 204); all p < 0.0001. With HIP supplementation, no change was observed in any of the iron status biomarkers (all p > 0.05). Conclusions In accordance with recommendations, oral supplementation using FeSO4, but not HIP, was efficacious for treatment of iron deficiency after RYGB.