Background: The aim of this study is to investigate changes in iron metabolism and verify whether biochemical parameters are related to the use of oral iron supplement 10 years after Roux-en-Y gastric bypass.
Methods: This longitudinal retrospective study included 151 patients submitted to Roux-en-Y gastric bypass. The collected data included use of an oral iron supplement, hemoglobin, hematocrit, serum iron, and ferritin. The chi-squared or Fisher's exact test was used to analyze the association between use of iron supplement and nutritional deficiency. The generalized estimating equations (GEEs) analyzed the nutritional deficiencies over time.
Results: Of the study patients with iron-deficiency anemia (n = 15) in the 12-month follow-up, 73.33% (n = 11) were taking an iron supplement, and 26.67% (n = 4) were not (p = 0.0010). The effect of time was significant for hemoglobin, ferritin, iron overload (p < 0.0001), and hematocrit (p = 0.0007). Of the patients who remained in the study until the 120-month follow-up, 37.5 and 45.0% were diagnosed with iron-deficiency anemia, defined as ferritin <15 μg/L and ferritin <30 μg/L, respectively.
Conclusions: Iron-deficiency anemia increased over time even in patients taking oral iron supplements.
Keywords: Gastric bypass; Iron deficiency; Iron-deficiency anemia; Oral iron supplement.