NICE vs SIGN: Management of Osteoporosis (2025)

NICE vs SIGN: Management of Osteoporosis (2025) - A Clinical Comparison

This guide provides a detailed, factual comparison of the National Institute for Health and Care Excellence (NICE) and the Scottish Intercollegiate Guidelines Network (SIGN) guidelines for the management of osteoporosis. While both aim to reduce fracture risk, their approaches to assessment, risk calculation, and treatment initiation differ in key areas. Understanding these nuances is essential for UK clinicians applying the correct framework to their patient population.

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Diagnosis and Risk Assessment

The foundation of osteoporosis management is accurate diagnosis and fracture risk stratification. Both guidelines use DXA scan results but differ significantly in their primary risk assessment tool.

NICE Approach

• Primary Tool: QFracture®. NICE recommends using the QFracture® algorithm to assess the 10-year probability of major osteoporotic fracture (hip, spine, wrist, humerus) and hip fracture.
• DXA Scanning: A DXA scan to measure BMD is recommended if the 10-year probability of fracture is at or above an age-specific intervention threshold set by NICE. This means a patient can be recommended for treatment based on QFracture® score alone, even before a DXA scan is performed.
• Diagnosis: Diagnosis is based on a T-score of -2.5 SD or lower at the hip or spine.
• Key Focus: Pragmatic, population-based risk assessment that can be used in primary care without immediate reliance on DXA.

SIGN Approach

• Primary Tool: FRAX®. SIGN recommends using the FRAX® tool (calibrated for the UK) to calculate the 10-year probability of major osteoporotic fracture.
• DXA Scanning: DXA scanning is a central component for both diagnosis and refining the FRAX® assessment. A BMD measurement is often incorporated into the FRAX® calculation to provide a more accurate risk estimate.
• Diagnosis: Aligns with NICE, using a T-score of -2.5 SD or lower.
• Key Focus: A diagnosis-led approach, where BMD measurement is integral to risk evaluation, often leading to a FRAX® calculation that includes the BMD result.

Key Difference: The choice of primary risk engine (QFracture® vs FRAX®) and the role of DXA scanning in the initial assessment pathway. NICE uses QFracture® as a gatekeeper to DXA, while SIGN integrates DXA-enhanced FRAX® more centrally.

Pharmacological Treatment

Both guidelines agree on the first-line use of bisphosphonates but differ in their recommendations for treatment initiation and subsequent options.

NICE Guidance (Technology Appraisals)

• First-line: Generic alendronic acid with vitamin D and calcium supplementation.
• Treatment Initiation: Driven by fracture probability thresholds. NICE sets specific 10-year risk thresholds (based on QFracture®) for initiating treatment in primary prevention (without a prior fragility fracture) and secondary prevention (with a prior fragility fracture).
• Second-line: For those who cannot tolerate oral bisphosphonates, zoledronic acid or denosumab are options. NICE has highly specific criteria for the use of denosumab, romosozumab, and teriparatide, often requiring multiple failed treatments or very high fracture risk.

SIGN Guidance (Consensus-Based)

• First-line: Also recommends oral bisphosphonates (alendronate or risedronate).
• Treatment Initiation: Uses intervention thresholds based on FRAX® 10-year major osteoporotic fracture probability. SIGN recommends intervention when the probability is at or above the level defined for a person of the same age with a prior fracture. This is a nuanced difference from NICE's fixed thresholds.
• Second-line: Offers a broader range of options, including ibandronate and strontium ranelate (under strict conditions), in addition to zoledronic acid and denosumab. The pathway is often presented as a more flexible menu of options based on patient factors.

Key Difference: NICE's approach is driven by its technology appraisals, which are cost-effectiveness models leading to stricter, more defined pathways. SIGN's approach is more clinically focused and offers greater flexibility in second-line choices.

Special Situations

Glucocorticoid-Induced Osteoporosis (GIOP)

• NICE: Provides clear guidance in NG66 and the TA464 update. Recommends risk assessment using the FRAX® tool (with adjustment for steroid dose) and offers specific treatment recommendations based on dose and duration, often starting with alendronic acid.
• SIGN: Also provides detailed guidance, broadly aligning with NICE on the use of FRAX® and bisphosphonates. The practical management is very similar.
• Takeaway: Strong alignment between guidelines for GIOP.

Post-Menopausal Women vs. Men

• Both guidelines address osteoporosis in men, with risk assessment using QFracture® (NICE) or FRAX® (SIGN). Treatment recommendations are similar, with alendronic acid as a first-line option where appropriate.
• Key Consideration: NICE TA464 includes specific guidance on treating men at high risk of fracture.

Practical Clinical Flow: A Comparison

NICE Flow (Simplified)

1. Identify risk factors (age, prior fracture, steroids, etc.).
2. Calculate 10-year fracture risk using QFracture®.
3. If probability is at or above the NICE intervention threshold, offer a DXA scan.
4. If BMD T-score ≤ -2.5 SD, or if the patient meets other criteria (e.g., prior fracture), initiate treatment (typically alendronic acid).
5. Follow up and consider second-line agents if contraindicated or treatment fails.

SIGN Flow (Simplified)

1. Identify risk factors.
2. Calculate 10-year risk using FRAX® (without BMD). If intermediate or high risk, proceed to DXA.
3. Perform DXA scan and recalculate FRAX® score with BMD.
4. If the FRAX® probability meets or exceeds the age-specific intervention threshold, initiate treatment (oral bisphosphonate).
5. Follow up and choose from a wider range of second-line options based on clinical judgement.

Frequently Asked Questions (FAQs)

1. Which risk tool should I use in England? And in Scotland?

Answer: You should follow the national guideline for your country. In England and Wales, use QFracture® as per NICE. In Scotland, use FRAX® as per SIGN. Both tools are validated for the UK population but use different algorithms.

2. Can a patient be treated without a DXA scan?

Answer: Under NICE guidance, yes. If the QFracture® score is very high (above the upper threshold), treatment can be recommended without a DXA scan. SIGN strongly emphasises the role of DXA in confirming diagnosis and refining risk, making treatment without a scan less common in their pathway.

3. What is the first-line treatment for both guidelines?

Answer: Both recommend generic alendronic acid as the first-line oral treatment for most patients, alongside adequate calcium and vitamin D.

4. How do the guidelines differ for denosumab?

Answer: NICE has restrictive criteria for denosumab (e.g., for secondary prevention only when bisphosphonates are contraindicated or not tolerated). SIGN presents it as a broader second-line option. A crucial practical point from both is the warning about the "rebound effect" and the necessity of follow-up and consideration of a bisphosphonate after stopping denosumab.

5. Which guideline is more restrictive?

Answer: NICE guidelines, particularly their Technology Appraisals (TAs), are generally more restrictive due to their foundation in health economic modelling. SIGN guidelines often provide more clinical flexibility and a wider choice of agents, reflecting a more consensus-based, clinical practice-oriented approach.

Source Links

• NICE Guideline NG66: Osteoporosis: assessing the risk of fragility fracture. [https://www.nice.org.uk/guidance/ng66]
• NICE Technology Appraisal TA464: Bisphosphonates for treating osteoporosis. [https://www.nice.org.uk/guidance/ta464]
• NICE Clinical Knowledge Summary (CKS): Osteoporosis. [https://cks.nice.org.uk/topics/osteoporosis/]
• SIGN Guideline 142: Management of osteoporosis and the prevention of fragility fractures. [https://www.sign.ac.uk/media/1420/sign142.pdf]
• QFracture® risk calculator: [https://www.qfracture.org/]
• FRAX® risk calculator (UK): [https://www.sheffield.ac.uk/FRAX/tool.aspx?country=19]