Dr Pete Colledge recently got in touch to share his thoughts on osteoporosis and mountain medicine. Here's what he wrote...
"Our population is ageing – it’s old news! By 2041, the UK population is projected to reach 73 million with over a quarter aged 65 or older (1). This will create enormous challenges to our society and necessitate significant changes to the allocation of healthcare resources. Closer to home, there is growing numbers of older men and women venturing into the hills – and good on them! But this change is not just about changing population demographics, it is also a shift in mindset about health and leisure. This month, I met an 80-year-old gentleman in Hathersage scouting a walking route for his rambling club. It was inspirational! Tour operators now offer adventure holidays specifically aimed at older adults. This is a good thing, but does it create previously unforeseen risks and a potential liability for the expedition medic?
Recently, my fit and healthy 70-year-old Dad joined a group of similarly aged walkers on the West Highland Way. During the trip, a fellow female member slipped on a moderate slope and sustained a distal fibular fracture and a hairline fracture of her tibia. Since her injury was not in keeping with the forces involved, a diagnosis of fragility fracture* was made.
The commonest cause of a fragility fracture is osteoporosis. This is defined as a bone mineral density (‘BMD’) T-score that is 2.5 standard deviations (SD) below a group of 30 year olds of the same age and ethnicity. For every SD increase in BMD, annual fracture risk increases by a factor of 1.5 to 2.5. In reality, this means that women with osteoporosis have an annual risk of fracture that rises from 2% at 50 to more than 25% at 80 years of age (2).
The commonest way to measure bone mineral density is with dual energy x ray absorptiometry (DXA or DEXA). The test is non-invasive and takes 10 to 20 minutes. Modern scanners use a dose of radiation that is considerably less than that used for a chest x-ray.
So, could the fractures sustained by my Dad's friend have been predicted and prevented?
It’s an important question to consider. A fracture in the mountains may not only endanger the health of the victim but other members of the team as well. It is also relevant in a wider medical context. Estimates suggest that 536,000 osteoporosis-related fractures occur per year in the UK with a substantial impact on hospital bed occupancy, morbidity and mortality (3,4). The annual cost in Europe is an estimated €37bn, with an expected 25% increase by 2025. At present, osteoporosis accounts for 2% of the overall burden of non-communicable disease (3,5).
Here's what we know...
Fracture Prediction: Whilst BMD is a useful starting point it should not be considered in isolation. Online resources such as the Fracture Risk Assessment Tool (‘FRAX’) use BMD and other variables to calculate a 10-year probability of major osteoporotic fractures such as the spine, hip and upper limb. FRAX is externally validated and often written into GP computer systems and scanning software (6). NICE guidance suggests that all women aged over 65 years and all men over 75 years should be assessed for fracture risk using a validated tool such as FRAX. NICE recommends treatment with oral bisphosphonates where the 10-year probability of osteoporotic fracture is 1% or greater.
The Fracture Risk Assessment Tool (FRAX) developed by the University of Sheffield uses 13 variables to calculate a 10 year probability of osteoporotic fracture. FRAX can be found here. FRAX can underestimate the 10 year risk in patients who have had repeated fractures or those taking long courses of steroids (11).
Fracture Prevention: Weight bearing exercise has consistently been shown to have beneficial effects on BMD. Muscle strengthening is associated with improved confidence and a lower risk of falls (7). Both of these are recommended by the National Osteoporosis Guideline Group (‘NOGG’) in order to prevent fractures (6).
The risk of osteoporosis can also be reduced by addressing risk factors - tobacco smoking, alcohol excess and vitamin D deficiency are all associated with the condition. Drugs such phenytoin, warfarin and proton pump inhibitors such as omeprazole are also thought to increase risk.
Effective pharmacological treatments for osteoporosis also exist – bisphosphonates reduce overall fractures by 35% and vertebral fractures by 50% in those who are treated for 3 years or more. Typically, the number needed to treat is 40 or fewer (8). Furthermore, other bone-forming agents such as teriparatide have shown good clinical efficacy in patients unable to take bisphosphonates (9). Despite this, under 20% of patients who have fragility fractures receive secondary preventative treatment and the majority of patients at high risk of fracture are not on primary prevention. In fact, in the UK and US there is a downward trend in osteoporosis treatment (5). The reasons for this are unclear, however Dr Andy Knight describes the reality that faces a very busy GP,
"Primary risk assessment in our experience is generally opportunistic when we identify risk factors in general consultations and our practise mainly uses a clinical assessment and FRAX (bit cumbersome and limited) and ultimately DEXA, of course. There is no national primary screening programme. Secondary prevention is a bit more systematic but repeated audits over the years in our practise has exposed sub-optimal coverage. In our area we have successfully campaigned for assessment to take place as part of the package in fracture clinic as this catches people before they become distracted by LIFE. This seems to be more successful but no figures yet. I suspect practise varies widely around the country"
Damien Hirst's "Alendronic Acid 70mg". At present, 4 oral bisphosphonates are licensed for treatment of osteoporosis in the UK - alendronic acid, ibandronic acid, risedronate sodium and zoledronic acid. All of the drugs act by reducing bone turnover. They are generally well tolerated however a number of side effects have been reported. These can often be managed by switching to other bisphosphonates or using drugs such as teriparatide.
When dealing with older clients in the mountains it's vital to think about the prediction, prevention and treatment of fractures. As a starting point it makes sense to know your client's fracture risk and ensure that those with osteoporosis are appropriately treated. Whilst treatment reduces risk of fractures it does not eliminate it. Fractures will occur and thought must be given to how these are managed in the mountain environment. Finally, its worth remembering that physical activities should be supported in all age groups and that the outdoors should be enjoyed by all. Let’s support that!
*A fragility fracture occurs from a fall from a standing height or less. Since our skeleton should be able to sustain a fall from this height without sustaining a fracture there is normally an underlying cause, such as osteoporosis, that is responsible.
Thanks Pete for contributing to STDZ!
Dr Pete College is an F3 doctor with a lot of outdoor interests including skiing, climbing and mountaineering. He hopes to move into anaesthetic training. The Peak District and Scotland are his favourite outdoor destinations.
Read Pete's previous post here.
The British Mountain Medicine Society (BMMS) are organising a Science Day in the Peak District on the 13th November 2019. Why not come along? Details can be found here.
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9. Bone HG, Wagman RB, Brandi ML, et al. 10 years of denosumab treatment in postmenopausal women with osteoporosis: results from the phase 3 randomised FREEDOM trial and open-label extension. Lancet Diabetes Endocrinol. 2017;5(7):513-523. doi:10.1016/S2213-8587(17)30138-9
10.Shepstone L, Lenaghan E, Cooper C, et al. Screening in the community to reduce fractures in older women (SCOOP): a randomised controlled trial. The Lancet. 2018;391(10122):741-747. doi:10.1016/S0140-6736(17)32640-5
11.Holloway-Kew KL, Zhang Y, Betson AG, et al. How well do the FRAX (Australia) and Garvan calculators predict incident fractures? Data from the Geelong Osteoporosis Study. Osteoporos Int J Establ Result Coop Eur Found Osteoporos Natl Osteoporos Found USA. July 2019. doi:10.1007/s00198-019-05088-2