Relationship between anemia and Inflammatory Bowel Disease

September 14, 2022


One of the most prevalent complications among patients with Inflammatory Bowel Disease (IBD) is anemia. Although data vary depending on the studies, it is estimated that between 30% and 50% of these patients suffer from it. This complication manifests itself in the form of chronic fatigue, a symptom that has a significant impact on the quality of life of these patients. In fact, it can weaken the patient as much or more than abdominal pain or diarrhea. In addition, anemia can lead to increased morbidity for the patient, with an increase in the number of transfusions, hospital admissions and the average length of hospital stay1.

Avoiding the consequences of anemia in Inflammatory Bowel Disease is one of the main objectives of the gastroenterologist. In his quest to improve the quality of life of these patients, he focuses on correctly identifying patients with anemia and establishing the most appropriate treatment. In fact, he considers anemia as an important factor in the detection, evolution and treatment of pathologies such as ulcerative colitis2. Some professionals even confer it its own entity.

What is anemia?

Anemia is the decrease in the amount of red blood cells or hemoglobin in the blood. As a result, not enough oxygen is delivered from the lungs to the rest of the body’s tissues and, therefore, the cells do not function properly. In fact, according to the World Health Organization (WHO) anemia is achieved when hemoglobin in the blood is less than 13 g/dL in men and 12 g/dL in women. If the values reach 10 g/dL, it is considered a severe anemia.

In short, anemia arises when more red blood cells are destroyed than the amount the organism creates. Some of the symptoms that may alert the patient to this extraintestinal manifestation are: headache, fatigue, tachycardia, irritability, fragility of hair and nails, nausea, vertigo, tinnitus (buzzing in the ears), dyspnea or decreased cognitive capacity, among others. If you have several of these symptoms, you need to see a doctor for a complete blood count and rule out or confirm anemia.

Causes of anemia in patients with IBD

In a patient with Inflammatory Bowel Disease, several factors or mechanisms that triggeranemia usually coexist. Despite its multifactorial nature, two main causes can be distinguished:

  • First, iron loss: It is known as iron-deficiency anemia and is the main cause of this complication. Its origin is usually due to a hemorrhage through intestinal lesions that passes unnoticed. When you lose blood, you also lose iron and hemoglobin.
  • Second, chronic inflammatory disorders may also be responsible for its appearance. In this case, it is known as anemia of inflammation or of chronic disease. The cytokines or pro-inflammatory cytokines, proteins that are characteristic of IBD outbreaks, cause a failure in the functioning of the bone marrow and less hemoglobin is produced. It often coexists with iron-deficiency anemia.

Other causes of anemia in patients with IBD are: deficiency of vitamins such as  folic acid and vitamin B12;  the action of some medicines such as aminosalicylates or thiopurine derivatives; and hemolytic anemia, more present in patients with ulcerative colitis3.

Knowing the cause in order to establish the best treatment for the anemia in Inflammatory Bowel Disease

The lack or loss of iron in patients with Inflammatory Bowel Disease, however mild, should not be considered an insignificant indicator. Nothing could be further from the truth. It is a symptom of some maladjustment in the treatment of ulcerative colitis or Crohn’s disease.

For example, if an evaluation of the patient shows that the IBD is active, the medication will need to be adjusted to control the outbreaks and, in turn, reverse the anemia.

If the patient suffers from iron-deficiency anemia, the inflammation caused by IBD should first be monitored.  It may even be necessary to modify their treatment. And to treat anemia it is possible to use oral iron supplements, intravenously administered iron or, occasionally, it will be necessary to supplement with folic acid or vitamin B12. An iron rich diet is advisable as a supplement and also to prevent this type of anemia.

  2. Goodnough LT, Nissenson AR. Anemia and its clinical consequences in patients with chronic diseases. Am J Med 2004; 116 (Supl. 7A): 1S-2S
  3. What is ulcerative colitis? – Adacyte

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