NICE vs BSH: Management of Iron Deficiency Anaemia (2025)
Iron deficiency anaemia (IDA) is a common clinical problem encountered across primary and secondary care in the UK. For clinicians, two key national guidelines inform practice: the National Institute for Health and Care Excellence (NG44, published 2015, updated 2018 & 2022) and the British Society for Haematology (BSH, published 2020). While complementary, they offer distinct perspectives and practical recommendations. This comparison highlights the key similarities and differences to aid clinicians in applying the most appropriate guidance for their clinical context.
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Diagnosis and Assessment
The fundamental approach to diagnosing IDA is consistent, but the guidelines differ in their emphasis on specific tests and diagnostic thresholds.
NICE (NG44)
- Diagnostic Focus: Emphasises a functional, pragmatic approach, particularly relevant to primary care.
- Key Tests: Recommends using a combination of ferritin and other markers. Crucially, it advises that a ferritin level of less than 100 µg/L is consistent with iron deficiency in the presence of anaemia, even if the local laboratory's "normal" range is lower.
- Transferrin Saturation (TSAT): Suggests considering TSAT if ferritin is between 100-300 µg/L to confirm functional iron deficiency, especially in the context of inflammation.
- C-Reactive Protein (CRP): Strongly recommends checking CRP to exclude inflammation as a cause of elevated ferritin.
BSH (2020)
- Diagnostic Focus: Provides a more detailed, haematology-led perspective, often used in secondary care.
- Key Tests: Also prioritises ferritin but provides a more nuanced view. It states that a ferritin level of <30 µg/L is diagnostic of iron deficiency, aligning with many laboratory reference ranges.
- Transferrin Saturation (TSAT): Gives TSAT a more prominent role, recommending it as a useful additional test, with a cut-off of <20% being indicative of absolute or functional iron deficiency.
- Newer Biomarkers: Discusses the potential role of reticulocyte haemoglobin content (Ret-He) and soluble transferrin receptor (sTfR), though these are not yet widely adopted in routine NHS practice.
Key Difference: The most significant practical difference is the ferritin diagnostic threshold. NICE's <100 µg/L is more sensitive, aiming to avoid missing iron deficiency in primary care, whereas BSH's <30 µg/L is more specific, reflecting a classic haematological definition.
Treatment and Iron Replacement
Both guidelines agree on the superiority of oral iron as first-line treatment but diverge on formulation choice, dosing, and the threshold for intravenous (IV) iron.
NICE (NG44)
- First-line: Oral iron supplementation.
- Formulation: Recommends ferrous sulfate (200 mg tablets, containing 65 mg elemental iron), one tablet once or twice daily.
- Dosing: Acknowledges that lower doses (e.g., once daily) may improve tolerance and adherence.
- IV Iron Indications: Advises offering IV iron if oral iron is ineffective, not tolerated, or if the patient has clinically significant inflammatory bowel disease (IBD), chronic kidney disease (CKD), or is undergoing haemodialysis.
BSH (2020)
- First-line: Oral iron supplementation.
- Formulation: Does not specify a preferred salt. It emphasises choosing a preparation with a high elemental iron content and good bioavailability (e.g., ferrous sulfate, fumarate, or gluconate).
- Dosing: Suggests alternate-day dosing may enhance absorption and reduce side effects due to upregulation of hepcidin with daily dosing.
- IV Iron Indications: Has broader criteria for IV iron. It recommends IV iron for patients who are symptomatic and have a Hb <100 g/L, regardless of oral iron tolerance, and for those with heavy bleeding, malabsorption, or prior to major surgery to rapidly replenish stores.
Key Difference: The indications for IV iron are broader in the BSH guideline. BSH is more proactive in using IV iron for symptomatic patients with moderate-severe anaemia to achieve a quicker response, whereas NICE reserves it more for oral iron failure or specific comorbidities.
Special Situations
Heart Failure
- NICE: Its IDA guideline (NG44) predates the strong evidence for IV iron in heart failure. It defers to the chronic heart failure guideline (NG106), which recommends IV ferric carboxymaltose for people with symptomatic chronic heart failure and iron deficiency to improve exercise capacity and symptoms.
- BSH: Explicitly recommends IV iron (ferric carboxymaltose) for patients with heart failure and iron deficiency (ferritin <100 µg/L or ferritin 100-300 µg/L with TSAT <20%) to improve functional status, quality of life, and reduce hospitalisations.
Takeaway: For heart failure patients with IDA, IV iron is strongly recommended by both, with BSH providing the specific diagnostic criteria within its IDA document.
Inflammatory Bowel Disease (IBD) and Chronic Kidney Disease (CKD)
- Both guidelines strongly favour IV iron in these conditions due to functional iron deficiency, inflammation, and poor tolerance/response to oral iron.
- BSH provides more detailed protocols for dosing and monitoring in these patient groups.
Management of Underlying Cause
- Both guidelines are unequivocal: identifying and managing the cause of iron deficiency is paramount.
- NICE: Provides very clear, risk-based pathways for investigating the underlying cause, particularly for gastrointestinal (GI) malignancy. It mandates referral for upper and lower GI investigation for all men and post-menopausal women with confirmed IDA (without a clear cause), and for pre-menopausal women with IDA and any GI symptoms or a strong family history.
- BSH: Also stresses investigation but offers a slightly more flexible approach, acknowledging that in young women with obvious heavy menstrual bleeding, GI investigation may not be immediately necessary if they respond to iron therapy.
Practical Clinical Flow: A Synthesis for UK Practice
A pragmatic approach, blending both guidelines, might look like this:
- Confirm IDA: Microcytic, hypochromic anaemia. Check Ferritin and CRP.
- If ferritin <30 µg/L (BSH cut-off) or <100 µg/L with elevated CRP (NICE approach), IDA is confirmed.
- Investigate the Cause: Adhere to NICE's strong recommendations for GI investigation in appropriate patient groups (all men/post-menopausal women). Do not attribute IDA to a non-GI cause without consideration.
- Initiate Treatment:
- For most: Start oral iron (e.g., Ferrous Sulfate 200mg once daily). Consider BSH's alternate-day dosing if side effects occur.
- Consider IV iron first-line if: Symptomatic with Hb <100 g/L (BSH), or if known IBD/CKD/heart failure (both guidelines).
- Monitor: Check Hb after 2-4 weeks. Expect a rise of >20 g/L.
- Manage Non-Response: If no response, reassess adherence, consider switching oral preparation, or move to IV iron. Re-evaluate the underlying diagnosis.
Frequently Asked Questions (FAQs)
1. Which ferritin threshold should I use in primary care?
Answer: Using the NICE threshold of <100 µg/L is more sensitive and safer in a primary care setting, especially when CRP is checked to rule out confounding inflammation. This helps prevent missed diagnoses.
2. A patient cannot tolerate oral ferrous sulfate. What next?
Answer: First, try strategies like reducing the dose to once daily or switching to an alternate salt (e.g., ferrous fumarate). If intolerance persists, the guidelines support moving to IV iron, with BSH being more proactive in this recommendation.
3. Is IV iron safe for use in the community?
Answer: Yes. Modern IV iron preparations have an excellent safety profile. Many NHS Trusts have established Community IV Iron services, often led by nurses, for stable patients, reducing the need for hospital outpatient attendance.
4. How long should I continue iron treatment after Hb normalises?
Answer: Continue treatment for 3-6 months after Hb normalisation to fully replenish iron stores. Check ferritin to guide therapy, aiming for a level >50 µg/L.
5. How should I manage a pre-menopausal woman with no GI symptoms?
Answer: This is a key area of nuance. NICE recommends GI investigation for all post-menopausal women and men, but for pre-menopausal women, it recommends investigation if there are GI symptoms, a family history of GI cancer, or an unexplained failure to respond to treatment. BSH allows for a trial of iron and menstrual management first in low-risk individuals. A risk-based discussion with the patient is essential.
Source Links
- NICE Guideline NG44 (Iron Deficiency Anaemia): NICE NG44 (Last updated: September 2022)
- BSH Guideline (British Journal of Haematology): Wiley article (BJH): 10.1111/bjh.16501 (Published: 2020)
- NICE Guideline NG106 (Chronic Heart Failure): NICE NG106 (See section on iron deficiency)