FRAX and NOGG: How UK Doctors Decide Who Gets Osteoporosis Treatment

What is NOGG, and why does it decide your osteoporosis treatment?

NOGG is the National Osteoporosis Guideline Group, and its UK guideline is the layer that converts a FRAX percentage into a recommended action.

NOGG describes itself as "a multidisciplinary group that includes patient representation and professionals involved in the care of people with osteoporosis", set up in 2007 to update earlier guidelines from the Royal College of Physicians. NOGG, About NOGG Its current Clinical guideline for the prevention and treatment of osteoporosis was "Updated December 2024". NOGG, 2024

That is the document behind the decision your GP is really making — a decision the Royal Osteoporosis Society says "is based on national guidance, and the medicines available to treat someone of your age, gender and risk of breaking a bone." Royal Osteoporosis Society

NOGG's account of its own status is specific rather than sweeping: the 2021 guideline "was re-accredited by NICE in October 2021", and its intervention thresholds are "recommended by NICE Quality Standards". NOGG, About NOGG NOGG, 2024 FRAX is the arithmetic; NOGG is the judgement built on top of it.

Who gets a FRAX assessment in the first place?

NOGG's case-finding rule is deliberately wide: "A FRAX assessment should be performed in any postmenopausal woman, or man age ≥50 years, with a clinical risk factor for fragility fracture". NOGG, 2024

Note what the recommendation is for: guiding who needs a scan and who needs treatment or referral, not producing a number for its own sake. The Royal Osteoporosis Society lists the everyday prompts — breaking a bone easily, menopause, steroids, or a medication review. Royal Osteoporosis Society

NOGG also builds in a safety valve, recommending that "clinical judgement is needed when clinical risk exceeds those factors able to be entered into FRAX". NOGG, 2024 The tool does not get the final word. For what actually goes into the calculation, see how a FRAX score is calculated.

What are the intervention threshold and the very high-risk threshold?

They are two lines drawn across the range of possible FRAX results — one for "consider treatment", one for "consider a specialist".

The intervention threshold is not a flat number, and NOGG explains why:

"For men and women, the intervention threshold up to age 70 years is set at a risk equivalent to that of a woman of the same age with a prior fracture, in line with current clinical practice, and therefore rises with age. At age 70 years and above, fixed thresholds are applied." NOGG, 2024

In other words, the threshold was reverse-engineered from something clinicians already did: treat people whose risk matches that of a same-age person who has already broken a bone.

The very high-risk threshold is derived from the first one — "very high risk is identified as a FRAX-based fracture probability that exceeds the intervention threshold by 60%". NOGG, 2024 It is a multiplier, not a separate calculation.

Two further lines sit either side of the intervention threshold. NOGG defines LAT and UAT as "the lower and upper assessment thresholds, respectively, between which a BMD is indicated". NOGG, 2024 Those two decide who gets sent for a scan, rather than who gets treated — which is why the order runs LAT, IT, UAT, VHRT. The UAT applies to a FRAX result calculated without bone density; the intervention threshold is used either way — NOGG states that "the same intervention threshold can be used when fracture risk is assessed with or without BMD". NOGG, 2024

What FRAX percentage actually triggers treatment in the UK?

There is no single figure, because NOGG publishes a different set of numbers for every age. Its 2024 guideline gives them explicitly, as 10-year probabilities:

Age	LAT	IT	UAT	VHRT
50	3.4	7.3	8.8	11.7
55	4.5	9.5	11.4	15.2
60	6.0	12.2	14.6	19.4
65	8.6	16.5	19.8	26.4
70	11.1	20.3	24.4	32.5

NOGG thresholds for 10-year major osteoporotic fracture probability (%), from Table 5 of the 2024 guideline. Without a bone density measurement: below the LAT, lifestyle advice; between LAT and UAT, a scan is indicated; above the UAT, treatment is considered. Once BMD is included — or where a scan is not practical — the intervention threshold (IT) is the line compared against. Above the VHRT, specialist referral is considered. NOGG, 2024

The table stops at 70 because fixed thresholds apply from 70 onwards. NOGG publishes a second, much lower set of values for hip fracture specifically — at age 70, an intervention threshold of 5.4 and a very high-risk threshold of 8.6 — because hip probabilities are smaller numbers throughout and are compared against their own lines, not the major-fracture ones. NOGG, 2024

Why does the pathway send some people for a scan and others straight to treatment?

Because the assessment thresholds and the intervention threshold answer different questions: "do we need more information?" versus "do we treat?"

For those between the two assessment thresholds, NOGG recommends referral for "BMD measurement, if practical. Thereafter, fracture probability should be reassessed using FRAX." NOGG, 2024 That is a loop, not a verdict: measure, recalculate, compare again.

Two branches come off that loop. If a scan is "unavailable, contraindicated, or impractical (e.g., in frail individuals)", treatment should still be offered where there is a history of fragility fracture or risk exceeds the intervention threshold — nobody is stranded waiting for a scan they cannot have. And at the top end the scan changes purpose: people at high and very high risk "should have a DXA if a baseline measurement is needed against which to compare future BMD measurements" — measurement for monitoring, once the decision to treat is effectively made. NOGG, 2024

What makes someone "very high risk", and who sees a specialist?

A FRAX probability above the VHRT is one route in — but NOGG also lists single findings that carry someone there on their own.

NOGG recommends considering "referral of very high-risk patients to an osteoporosis specialist in secondary care, for assessment and consideration of parenteral treatment (some may need first-line anabolic drug treatment, especially those with multiple vertebral fractures)." The indications listed include: NOGG, 2024

• "A recent vertebral fracture [within the last 2 years]"
• "≥2 vertebral fractures [whenever they have occurred]"
• "BMD T-Score ≤-3.5" — see T-scores explained
• "Treatment with high dose glucocorticoids [≥7.5 mg/day of prednisolone or equivalent over 3 months]", which NOGG says warrants urgent referral given rapid bone loss after glucocorticoids are started — see steroids and bone loss
• Multiple clinical risk factors together, "particularly with a recent fragility fracture"

The band exists for a pharmacological reason. NOGG notes that teriparatide, abaloparatide and romosozumab "result in rapid and greater fracture risk reductions than some antiresorptive treatments", which created the need to identify who should be reviewed by a specialist and may benefit from them. NOGG, 2024 See osteoporosis treatment options for where each drug class sits.

It is also not a rare category: NOGG puts the proportion of postmenopausal women at very high risk on this definition at "approximately 6% at age 50-54 to 36% at age 90 years or older". NOGG, 2024

Does the threshold get used again once treatment starts?

Yes — it is not a one-off gate at diagnosis, but the same line you are measured against at review.

NOGG recommends planning "oral bisphosphonates (alendronate, ibandronate and risedronate) for at least 5 years and then re-assess fracture risk" — at least 10 years for defined groups, including those aged 70 or over when treatment started, those with a previous hip or vertebral fracture, and those on oral glucocorticoids at 7.5 mg prednisolone a day or more, or equivalent. Intravenous zoledronate is planned for "at least 3 years", with at least six in a similar list of circumstances. NOGG, 2024 More on the drugs in bisphosphonates for osteoporosis.

At that review point, the rule is the threshold again: "If the FRAX-derived fracture probability exceeds the intervention threshold drug treatment should be continued." NOGG, 2024

One limit comes with it: "FRAX is not recommended as a tool to monitor treatment" — it cannot tell you whether a drug is working, only re-estimate your current risk when a management decision is due. NOGG, 2024

What don't the NOGG thresholds settle?

A threshold comparison is the start of the conversation, not the whole of it. NOGG flags several places where the arithmetic needs help.

• Some risk factors aren't in the calculator. NOGG says arithmetic adjustments to FRAX probabilities can be used "to take account of additional clinical risk factors, such as high dose glucocorticoid use, discordantly low lumbar spine BMD, type 2 diabetes, and a history of falls". NOGG, 2024
• High risk can be reclassified upwards. Frequent falls or very low spine BMD "can also lead to redesignation from high to very high risk of fracture". NOGG, 2024
• The UK model carries a population caveat. NOGG notes "the UK FRAX is calibrated to a majority white population... so that the generated probabilities reflect a predominantly white population." NOGG, 2024