Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 21, 2016; 22(35): 7908-7925
Published online Sep 21, 2016. doi: 10.3748/wjg.v22.i35.7908
Anemia and iron deficiency in gastrointestinal and liver conditions
Jürgen Stein, Susan Connor, Garth Virgin, David Eng Hui Ong, Lisandro Pereyra
Jürgen Stein, Interdisciplinary Crohn Colitis Centre Rhein-Main, Frankfurt am Main, Department of Gastroenterology and Clinical Nutrition, DGD Clinics Sachsenhausen, Frankfurt am Main, 60594 Frankfurt, Germany
Susan Connor, Department of Gastroenterology and Hepatology, Liverpool Hospital, South Western Clinical School, University of New South Wales, Liverpool NSW 2170, Australia
Garth Virgin, Vifor Pharma, Flughofstrasse 61, CH-8152 Zurich, Switzerland
David Eng Hui Ong, Division of Gastroenterology and Hepatology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore
Lisandro Pereyra, Servicio de Gastroenterología y Endoscopia, Hospital Alemán, Buenos Aires C1118AAT, Argentina
Author contributions: All authors contributed equally to the literature search and data interpretation; Stein J prepared the draft manuscript; all authors reviewed and approved the manuscript prior to submission.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Jürgen Stein, MD, PhD, Professor, Interdisciplinary Crohn Colitis Centre Rhein-Main, Frankfurt am Main, Department of Gastroenterology and Clinical Nutrition, DGD Clinics, Schulstrasse 31, Frankfurt am Main, 60594 Frankfurt, Germany.
Telephone: +49-69-905597810 Fax: +49-69-905597829
Received: April 6, 2016
Peer-review started: April 6, 2016
First decision: May 12, 2016
Revised: July 18, 2016
Accepted: August 10, 2016
Article in press: August 10, 2016
Published online: September 21, 2016

Iron deficiency anemia (IDA) is associated with a number of pathological gastrointestinal conditions other than inflammatory bowel disease, and also with liver disorders. Different factors such as chronic bleeding, malabsorption and inflammation may contribute to IDA. Although patients with symptoms of anemia are frequently referred to gastroenterologists, the approach to diagnosis and selection of treatment as well as follow-up measures is not standardized and suboptimal. Iron deficiency, even without anemia, can substantially impact physical and cognitive function and reduce quality of life. Therefore, regular iron status assessment and awareness of the clinical consequences of impaired iron status are critical. While the range of options for treatment of IDA is increasing due to the availability of effective and well-tolerated parenteral iron preparations, a comprehensive overview of IDA and its therapy in patients with gastrointestinal conditions is currently lacking. Furthermore, definitions and assessment of iron status lack harmonization and there is a paucity of expert guidelines on this topic. This review summarizes current thinking concerning IDA as a common co-morbidity in specific gastrointestinal and liver disorders, and thus encourages a more unified treatment approach to anemia and iron deficiency, while offering gastroenterologists guidance on treatment options for IDA in everyday clinical practice.

Keywords: Iron deficiency anemia, Gastrointestinal bleeding, Nonsteroidal anti-inflammatory drugs, Gastritis, Infection, Bariatric surgery, Celiac disease, Gastrointestinal neoplasm, Chronic hepatitis, Non-alcoholic fatty liver disease

Core tip: Iron deficiency anemia (IDA) frequently originates in the gastrointestinal (GI) tract and is a common cause of patient referral to gastroenterologists. Guidelines for the management of IDA in GI conditions are lacking. Symptoms such as fatigue and impaired exercise capacity should prompt a diagnostic work-up for anemia (hemoglobin), iron status (transferrin saturation, ferritin) and inflammation (C-reactive protein). Treatment of IDA should aim to restore normal hemoglobin levels, red cell indices and iron status. Intravenous administration is the preferred iron treatment in patients with chronic GI bleeding, patients being unresponsive or intolerant to oral iron and patients requiring rapid hemoglobin correction.