Anemia is one of the most frequent extraintestinal manifestations of inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC). It may present as iron deficiency anemia, anemia of chronic disease driven by inflammation, or a combination of both. Although hemoglobin levels are routinely assessed at diagnosis, anemia is often inadequately addressed during the long-term management of these chronic conditions.

A systematic review and meta-analysis published in Clinical Epidemiology and Global Health examined the global prevalence of anemia among patients with IBD. The analysis included 47 studies, of which 36 were included in the meta-analysis. Overall, the dataset comprised 138,577 patients with IBD from 22 countries across five continents.

Global Prevalence

The pooled prevalence of anemia among patients with IBD was estimated at 36.9% (95% CI, 31.1%-42.9%).

Iron deficiency accounted for a prevalence of 32.2% (95% CI, 25.6%-39.1%), while anemia of chronic disease was seen in 8.1% (95% CI, 5.8%-10.7%).

When examined by disease type, the prevalences of CD and UC differed only slightly.

Among patients with CD, the prevalence of anemia was estimated at 39.3% (95% CI, 32.4%-46.3%). Iron deficiency occurred in 25.3% of cases (95% CI, 17.7%-33.7%), and inflammatory anemia in 8.2% (95% CI, 5.8%-11.8%).

In UC, the prevalence of anemia was lower at 32.4% (95% CI, 26.9%-38.2%). Iron deficiency occurred at 34.1% (95% CI, 24.7%-44.1%), while inflammatory anemia was seen in 3.5% (95% CI, 1.5%-6.2%).

Why Anemia Develops in IBD

Iron deficiency anemia in IBD often results from chronic gastrointestinal blood loss, impaired intestinal iron absorption caused by mucosal inflammation, and reduced dietary intake or absorption of nutrients.

Anemia of chronic disease arises from the persistent inflammatory state associated with IBD. Proinflammatory cytokines stimulate the hepatic production of hepcidin, which reduces intestinal iron absorption and restricts iron availability for erythropoiesis.

Because these mechanisms are intrinsic to the disease process, patients with IBD remain at an increased risk for anemia, even during periods of clinical remission.

Monitoring Often Falls Short

Despite its high prevalence, anemia remains under-recognized and under-treated in routine clinical practice.

A review published in Inflammatory Bowel Diseases noted that clinicians frequently overlook anemia in patients with IBD, particularly when it is mild or moderate.

However, persistent anemia may have significant long-term consequences, including impaired functional status and reduced quality of life.

Guidelines from the European Crohn’s and Colitis Organisation recommend regular monitoring of anemia. Hematologic parameters should be assessed every 3 months in patients with active disease and every 6-12 months in those in remission. In practice, adherence to these recommendations is inconsistent.

Therefore, more effective treatments are needed. Intravenous iron therapy can correct iron deficiency and should not be reserved for severe cases.

Fatigue as a Key Symptom

Fatigue is one of the most common manifestations of anemia in patients with IBD. A German review published in Best Practice & Research Clinical Gastroenterology summarized the current evidence on fatigue in these conditions.

According to the study, half of the patients with IBD experience chronic or daily fatigue.

Because fatigue is subjective, clinicians may underestimate its impact. Several validated instruments can help assess fatigue in clinical practice.

The Functional Assessment of Chronic Illness Therapy-Fatigue scale is a 40-item measure that evaluates self-reported fatigue and its effects on daily activities and function. The Multidimensional Fatigue Inventory offers a psychometric approach to fatigue assessment. 

Additionally, the Inflammatory Bowel Disease-Fatigue self-assessment scale is a 35-item validated questionnaire designed to measure the severity and impact of fatigue in individuals with CD or UC.

The authors also proposed a clinical decision pathway to guide the evaluation of fatigue in IBD and identify potential therapeutic interventions.

In summary, these findings highlight the need for systematic screening and proactive management of anemia and fatigue in patients with IBD.

This story was translated from MediQuality, part of the Medscape Professional Network.