P0726 IMPAIRED INTESTINAL IRON ABSORPTION IN CROHN???S DISEASE CORRELATES WITH DISEASE ACTIVITY AND INFLAMMATORY CYTOKINES

Abstract

Introduction: The anemia of chronic inflammation in Crohn’s disease (CD) is multifactorial, and may be secondary to defective intestinal iron absorption, impaired iron delivery to erythroid precursors, impaired iron release from macrophages, and impaired erythropoietin production. The oral iron absorption test is a simple, minimally invasive method to establish whether oral iron can be absorbed by patients with iron deficiency and inflammatory states. In this study, we have evaluated this test in patients with CD, and correlated iron absorption with disease activity and with markers of systemic inflammation. Methods: Seventeen patients with CD (F=6,M=11) were recruited for this study. The patients were on a combination of medications, including: 5-ASA (N=7), corticosteroids (N= 7), and 6-mercaptopurine/azathioprine (N= 8) and infliximab (N=4). Of the 17 patients, 5 had active CD, as defined by a Pediatric Crohn’s Disease Activity Index (PCDAI) of >30 points. Twelve patients had inactive/mild CD (PCDAI<=30). Patients were admitted to the Children’s Hospital General Clinical Research Center after an overnight fast, and indwelling IV access was established. Baseline bloodwork obtained prior to the study included complete blood count, erythrocyte sedimentation rate, C-reactive protein, serum iron, TIBC, Ferritin, interleukins 1 and 6, and tumor necrosis factor. Oral Ferrous sulfate (1mg/ kg of elemental iron) was then administered. Iron levels were drawn at 1, 2, 3, and 4 hours after the administration of oral iron. The area under the curve (AUC) for iron absorption was calculated as the sum of the areas under the trapezoids formed between time points of serum iron levels. Results: Patients with active CD had markedly impaired iron absorption (mean AUC 154, compared to mean AUC 501 in inactive/mild). Iron absorption (AUC) correlated inversely with PCDAI and IL-6 (Spearman rho = −0.52, p= 0.03), (Table).Table 1: Iron Challenge Test and Inflammatory Markers in Active and Inactive CDConclusion: The oral iron challenge test is a simple method of determining an individual’s ability to absorb supplemental iron. Impaired intestinal iron absorption in CD is a function of disease activity.