Osteoporosis: Shattering the Silence

Although osteoporosis is often described as the ‘silent epidemic’, the alarm bells for a crisis in the management of osteoporotic fractures continue to sound very loudly.

There is currently a high prevalence of osteoporosis and low bone mass in the Irish population, a feature that is set to grow in accordance with our aging population. The consequences of an osteoporotic fracture, particularly a hip fracture, can be bleak, often leading to longer term disability and increased mortality. The challenge of course, is to identify the people at risk, before a fracture occurs, and to implement an appropriate treatment strategy to reduce fracture risk. Given that successful treatment strategies are available, the solution may seem straight-forward. However, current research shows that there is a large treatment gap, with many people at risk not receiving the treatment they need. While there are various factors that contribute to this treatment gap, lack of timely diagnosis is known to play a role.

In the identification of fracture risk, DXA (Dual X-Ray Absorptiometry) is the gold standard for the measurement of bone mass density (BMD) and the diagnosis of osteoporosis. Indeed, BMD, as determined by DXA, is the single best predictor of fracture. However, with limited DXA services, and an aging population, how can we ensure that the ‘correct’ people are referred for DXA, so as to optimise efficiency of resources, while providing care and prevention for the people most at risk? Research shows that DXA is most beneficial when used to target people with known risk factors, such as advancing age, low body weight and use of glucocorticoid medications. Indeed, the International Society for Clinical Densitometry (ISCD) provide very clear guidelines on who should be referred for DXA https://iscd.org/official-positions-2023/. Their position is that all women aged 65 or older, and men aged 70 or older, are appropriate candidates for DXA, as well as certain other cohorts of the population with clinical rationale. However, despite this awareness, a mismatch persists within the system, with many people, sadly, missing the opportunity for appropriate preventative care. Although a national screening programme would provide appropriate and equal access for all, this has not yet materialised for Ireland, despite long-standing calls from academics and clinicians. While Fracture Liaison Services have made immense progress in improving the identification of people at risk of secondary fractures, the ultimate goal is to identify risk earlier and avoid fracture in the first instance.

In the midst of this quandary, research forges ahead to develop useable and innovative approaches for the improved identification of people at risk of osteoporotic fracture. Some of these approaches use predictive algorithms based on known risk factors. The FRAX® fracture risk assessment tool https://frax. shef.ac.uk/FRAX/index.aspx, first launched at the University of Sheffield in 2008, is the best known of these, with its use in Ireland known to have increased between 2011 and 2019. As well as age, sex and weight, it currently includes 8 other risk factors, with the additional option to include BMD, if available, for more accurate predictions. With the more recent launch of FRAXplus®, development is ongoing to refine calculations and to keep apace of emerging research. As many different risk factors for osteoporosis have been identified, accurate prediction of fracture risk is potentially a complex task. However, even simple calculations, such as the Osteoporosis Self Assessment Tool (OST), which considers only age and body weight, have been shown to have high predictive value for use in point-of-care settings. Tools such as these have utility, not only in the clinical decision-making process of referral for DXA, but in and of themselves, for the identification of men and women at various stages of life, who may benefit from evidence-based lifestyle, behavioural, and possibly even appropriate pharmaceutical strategies, to maintain bone mass as they age. Another avenue of research is the potential use of bioimpedance analysis for the estimation of bone mass. Bioimpedance analysis is a safe, relatively low cost and convenient technology. It is non-invasive, and takes less than a minute to provide a body composition assessment with calculated estimates of fat, muscle and even bone mass. While it is well-established to provide reliable and valid calculations of fat and muscle mass, its validity for the estimation of bone mass is less certain. While further research is needed in this area, the concept of being able to quickly provide a full assessment to include an estimate of bone mass, at the same time as the indicators of other conditions associated with body composition, such as obesity, is very appealing. Other point-of-care assessments that can indicate a risk of fracture include functional tests such as handgrip strength, the timed up-and-go test and the one-leg standing test. These functional tests, while often used to assess muscle strength, can also be indicative of bone mass and bone strength, partly due to the close physiological relationship between muscle and bone, but also because they assess aspects of balance and strength, which are critical for the prevention of falls. Indeed, the risk of falling is an aspect of fracture risk that, while influenced by age, bodyweight and other factors, is probably more difficult to quantify than any single physiological or clinical risk factor. Therefore, notwithstanding the importance of good access to DXA, point-of-care assessments such as these have an important complementary role to play in the overall clinical assessment of fracture risk.

So while we await a national screening programme for osteoporosis, researchers and clinicians will continue to strive in various ways, to innovate, to collaborate, and to develop, in order to shatter the silence on this debilitating and life-limiting epidemic. Part of this work is to increase the utility of point-of-care assessments, in order to improve the identification of people at risk of fracture, and ultimately to reduce the risk and improve the quality of life for our aging population and their families.

References available on request.

Written by Dr Louise Horrigan, Lecturer, University of Galway

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