Osteoporosis update: key changes

FRAX recommended for assessing absolute fracture risk.

---

The Osteoporosis prevention, diagnosis and management in postmenopausal women and men over 50 years of age guidelines have been updated to reflect recent evidence, expert consensus, and drug developments.

Professor Peter Wong, rheumatologist and chair of the guidelines review committee talks us through some of the key changes.

FRAX recommended for assessing absolute fracture risk

While the 2017 guidelines suggested using either the Garvan Fracture Risk Calculator (Garvan) or the Fracture Risk Assessment Tool (FRAX) to assess absolute fracture risk in people who do not clearly fit established risk criteria, the new guidelines favour the FRAX.

Professor Wong says GPs wanted clarity on which fracture risk assessment tool to use, and FRAX was chosen “because it’s the most widely used risk calculator in the world, it’s in DXA machines, and the makers have been very responsive to change and are improving it over time.”.

It gives an absolute 10-year risk of major osteoporotic fracture (MOF) and hip fracture as a percentage, which can be easier for patients to understand than relative risk, he adds. The guidelines also note that FRAX was developed with a stronger evidence base.

However, the Garvan may be preferable in people with a high falls risk because it has an input for falls, Professor Wong says.

“At the moment FRAX doesn’t have a falls input, and yet we know that if you don’t fall, you’re probably not going to break anything—so falls is clearly an important risk factor for osteoporotic fractures.”

Refer patients to a specialist if their fracture risk is ‘imminent’ or ‘very high’

The new guidelines recommend that “Patients with a very high and/or imminent fracture risk should be promptly referred to a specialist for consideration of osteoanabolic therapy as first-line treatment.”

Regarding ‘imminent’ risk, we know someone who has had a low trauma fracture is at risk of another one, particularly in the first 24 months afterwards, “so that’s when we need to do something about it,” Professor Wong says.

“We also know that if you don’t have bone-protective therapy starting in the first nine months, you’re probably not going to have it started at all.”

“So we need to get the patient in to have a chat about what can we do to stop the next fracture,” he says.

‘Very high risk’ is an evolving concept with no internationally accepted definition, he adds, although guidelines from various countries share some common criteria.

The new Australian guidelines define someone as being at ‘very high risk’ if they have:

• a T-score ≤ -3.0, and
• they have had a fracture within the previous two years, and/or
• a history of two or more fragility fractures, and/or
• clinical risk factors such as corticosteroid use, low BMI, or recurrent falls, and/or
• FRAX risk of ≥ 30% for MOF or ≥ 4.5% for hip fracture.

You can find a risk assessment, diagnosis and management flow chart on page 13 of the guidelines, also available at Healthy Bones Australia.

Professor Wong suggests referring patients who are at imminent or very high fracture risk to a specialist with expertise in bone health, such as an endocrinologist, a rheumatologist, or a geriatrician.

Osteoanabolic therapy

It’s important to identify people who are at very high risk of fracture because we now have better access to osteoanabolic agents, which may be the most appropriate treatment for them, Professor Wong explains.

The guidelines recommend two osteoanabolic agents – romosozumab and recombinant human parathyroid hormone (teriparatide).

Romosozumab (12-month course) is available as first-line therapy for anyone (man or woman) at very high risk of fracture.

As of 1 November, it is now PBS-listed for first-line treatment of severe established osteoporosis (T-score ≤ 2.5 + symptomatic minimal trauma fracture + ≥ 1 hip or vertebral fracture in last 24 months OR ≥2 fractures, including 1 symptomatic fracture in the last 24 months).

“This is a major update and will allow us to use our most potent bone building agent “up front” in those at high fracture risk,” notes Peter Wong.

Increasing evidence suggests romosozumab is best used as initial therapy in those with severe osteoporosis for its potent anabolic effect, followed by an antiresorptive (bisphosphonate or denosumab therapy), he says.

“We use romosozumab upfront to build new bone and once you’ve built new bone, we should be following up with an antiresorptive to preserve what you’ve got,” he says.

Teriparatide (18-month course) is available for those with severe osteoporosis (T-score ≤ 3.0 + ≥2 minimal trauma fractures) who have sustained a subsequent fracture while on antiresorptive therapy.

Both drugs need to be initiated by a specialist, but continuing scripts can be issued by a GP in collaboration with a specialist.

Denosumab therapy and rebound fracture risk

Another important addition relates to anti-resorptive drug denosumab. The guidelines note denosumab therapy should not be interrupted, and patients should be transitioned onto a bisphosphonate for at least 12 months if it needs to be ceased.

Professor Wong points out that denosumab reversibly blocks osteoclast activity, and cessation of the drug or a late dosage can accelerate bone resorption.

“When those osteoclasts come on again and they start chewing up bone, we know that can sometimes translate to vertebral fractures – sometimes even multiple vertebral fractures,” he says.

“So it’s important to give it every six months and if you are thinking of stopping it, we still don’t have all the answers, but if you follow up with 12 months of an oral or IV bisphosphonate, it seems to reduce the risk of rebound vertebral fractures.”

Professor Wong recommends referring patients to a bone health specialist for help with denosumab cessation.

Vitamin D and calcium

There is good evidence that “adequate calcium intake and vitamin D status are important for long-term maintenance of bone and muscle function”, but low evidence for any benefits of short-term (< 6 years) supplementation for reducing fracture risk, the guidelines note.

However, for older people who are frail or institutionalised, they do advise calcium and vitamin D supplementation, along with adequate protein intake, to prevent fractures.

Professor Wong notes this is a complex area, but the bottom line is that these people will probably benefit from supplementation. However, “if you are a community-dwelling, otherwise healthy and ambulatory elderly person, the value of calcium and vitamin D supplementation is probably not great.”

The guidelines also state that people on osteoporosis treatments should take calcium supplements if their dietary calcium intake is less than 1300 mg per day, and vitamin D supplements if their 25-hydroxyvitamin D level is less than 50 nmol/L.

Key messages: FRAX is the recommended absolute risk calculator, although the Garvan may be preferable in patients with a falls history. Promptly refer patients with a very high and/or imminent fracture risk to a specialist for consideration of osteoanabolic therapy. Denosumab should be given every six months and if ceased, patients should transition onto a bisphosphonate for 12 months. Consider referring to a specialist for help with denosumab cessation. Supplement calcium and vitamin D in frail and institutionalised elderly people, and in people taking osteoporosis treatment if calcium intake and/or serum vitamin D levels are low.

For more on this topic, register for Healthed’s 26 November webcast where Professor Wong will discuss further.

Each webcast earns 2 hours of CPD in the Educational Activity category and 1 hour of CPD in the Reviewing Performance category as well as 1 hour of CPD in the Measuring Outcomes category if you do the optional post-lecture CPD activities, all processed and uploaded to your CPD account on RACGP and ACRRM by Healthed.

Sophia Auld is a medical writer.