Management of iron deficiency anemia in adults: BSG guidelines
UK: The British Society of Gastroenterology has released new guidelines for the management of iron deficiency anemia in adults. The guideline is published in the BMJ journal Gut.
Iron deficiency anemia (IDA) is common, and a major cause of morbidity worldwide. IDA can be caused by a range of GI pathologies including cancer, and so GI investigation on an urgent basis should be considered in adults with a new diagnosis of IDA without obvious explanation.
Anemia is defined as a hemoglobin (Hb) concentration below the lower limit of normal for the relevant population and laboratory performing the test. Iron deficiency should be confirmed by iron studies prior to investigation. Serum ferritin is the single most useful marker of IDA, but other blood tests (eg, transferrin saturation) can be helpful if false-normal ferritin is suspected. A good response to iron therapy (Hb rise ≥10 g/L within a 2-week timeframe) in anemic patients is highly suggestive of absolute iron deficiency, even if the results of iron studies are equivocal.
Recommendations and practice statements are given below
Initial clinical assessment
- Taking a detailed history is recommended, as it may provide important clues as to the cause(s) of IDA in the individual case.
- The authors recommend that initial investigation of confirmed IDA should include urinalysis or urine microscopy, screening for coeliac disease (CD) and in appropriate cases, endoscopic examination of the upper and lower GI tract.
- CD is found in 3%–5% of cases of IDA, and it is recommended that it should be routinely screened for serologically, or on small bowel biopsy at the time of gastroscopy.
- Age, sex, Hb concentration and mean cell volume are all independent predictors of risk of GI cancer in IDA, and need to be considered as part of a holistic risk assessment. It follows that the cancer risk in iron deficiency without anaemia is low.
- There are insufficient grounds at present to recommend faecal immunochemical testing for risk stratification in patients with IDA. The evidence base is evolving rapidly, however, and on that basis, this guidance may therefore change.
- In men and postmenopausal women with newly diagnosed IDA, gastroscopy and colonoscopy should generally be the first-line GI investigations. In those not suitable for colonoscopy, CT colonography is a reasonable alternative.
Follow-up and recurrent data
- Hb levels normalise with iron replacement therapy (IRT) in most cases of IDA, but IDA recurs in a minority of these on long-term follow-up.
Further evaluation of the small bowel
- In those with negative bidirectional endoscopy of acceptable quality and either an inadequate response to IRT or recurrent IDA, further investigation is recommended of the small bowel and renal tract to exclude other causes.
- Capsule endoscopy is recommended as the preferred test for examining the small bowel in IDA because it is highly sensitive for mucosal lesions. CT/MR enterography may be considered in those not suitable, and these are complementary investigations in the assessment of inflammatory and neoplastic disease of the small bowel.
- After a negative capsule endoscopy of acceptable quality, the authors recommend that further GI investigation needs to be considered only if there is ongoing IDA after IRT.
- Long-term IRT may be recommended as an appropriate strategy when the cause of recurrent IDA is unknown or irreversible.
Treatment of IDA
- It is recommended that RT should not be deferred while awaiting investigations for IDA unless colonoscopy is imminent.
- It is recommended that the initial treatment of IDA should be with one tablet per day of ferrous sulphate, fumarate or gluconate. If not tolerated, a reduced dose of one tablet every other day, alternative oral preparations or parenteral iron should be considered.
- Limited transfusion of packed red cells may on occasion be required to treat symptomatic IDA, in which case IRT is still necessary post-transfusion.
- It is recommended that patients should be monitored in the first 4 weeks for an Hb response to oral iron, and treatment should be continued for a period of around 3 months after normalisation of the Hb level, to ensure adequate repletion of the marrow iron stores.
- The authors recommend that parenteral iron should be considered when oral iron is contraindicated, ineffective or not tolerated. This consideration should be at any early stage if oral IRT is judged unlikely to be effective and/or the correction of IDA is particularly urgent.
- There is insufficient evidence to support invasive investigation in non-anaemic iron deficiency unless there are additional indications, but periodic blood count monitoring is suggested.
- After the restoration of Hb and iron stores with IRT, the authors recommend that the blood count should be monitored periodically (perhaps every 6 months initially) to detect recurrent IDA.
Special situations – young women
- IDA is common in young women, and major contributory factors include menstrual losses, pregnancy and poor dietary intake.
- Underlying GI pathology is uncommon in young women with IDA, and so after screening for CD, we recommend that further investigation is warranted only if there are additional clinical features of concern.
- If GI investigation in a pregnant woman is deemed necessary prior to delivery, gastroscopy and (after the first trimester) MR enterography are considered safe in pregnancy.
Special situations – young men
- Confirmed IDA is uncommon in young men, but when found the authors recommend that it warrants the same investigational algorithm as for older people.
Special situations – the elderly
- Iron deficiency is common in the elderly, and is often multifactorial in aetiology.
- It is recommended that the risks and benefits of invasive endoscopic and alternative investigation(s) are carefully considered in those with major comorbidities and/or limited performance status.
Special situations – specific comorbidities
- Functional iron deficiency (FID) is a common contributory factor to the anaemia associated with advanced chronic kidney disease (CKD).
- Iron deficiency is common in chronic heart failure (CHF), and is often multifactorial.
- Parenteral IRT may improve symptoms and quality of life in CHF with FID.
- In the management of iron deficiency associated with CKD or CHF, reference to the appropriate specialist published guidelines is recommended.
- IDA is a common manifestation of IBD, particularly when the disease is active.
- Intolerance and malabsorption of oral IRT can be particular problems in the treatment of IBD-associated IDA, and parenteral IRT may be required.
Special situations – GI surgery
- IDA is common following resection or bypass surgery involving the stomach and/or small bowel, including bariatric surgery
- In new presentations of IDA, the authors recommend that a history of GI or bariatric surgery should not preclude a search for other causes of IDA.
Service considerations
- All service providers are recommended to have clear points of referral and management pathways for patients with IDA.
- To ensure efficient use of resources, the authors recommend that IDA pathways should be delivered by a designated team led by a senior clinician.
- It is recommended that service providers should aim to have an ambulatory care base for the administration of parenteral iron.
Reference:
"British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults," is published in the BMJ journal Gut.
DOI: https://gut.bmj.com/content/early/2021/09/07/gutjnl-2021-325210
