Approach to osteoporosis diagnosis and fracture risk management in primary care

Case description

Mira, a 70-year-old woman, lives alone and has well-managed asthma and hypothyroidism. However, osteoarthritis and social isolation limit her ability to prepare meals, leading to frequently skipped meals. Balance issues make grocery shopping daunting, and she has a fear of falling, especially given 2 prior falls and her mother’s history of hip fracture. She is a lifelong nonsmoker and drinks fewer than 5 alcoholic drinks per week. Mira is 160 cm tall and 70 kg, and her body mass index is 27.3 kg/m².

Sources of information

This review integrates interprofessional clinical expertise with evidence from 3 recent Canadian guidelines (2022-2023) on osteoporosis and fracture prevention.^1-3 Fall risk assessment is informed by systematic reviews, global guidelines, and cohort studies. Nutrition and exercise recommendations for bone health are informed by Osteoporosis Canada and Health Canada. Strength of recommendation and certainty of evidence are included where available (Table 1).^1,4

Main message

The primary goal of osteoporosis screening is to identify individuals at increased risk of fragility fractures. Fragility fractures result from minimal trauma, such as falling from standing height. Major osteoporotic fractures include those of hip, humerus, vertebrae, or distal forearm, but exclude fractures of the hand, foot, and craniofacial bones.¹

All 3 Canadian guidelines recommend fracture risk assessment (Table 2),^1-3,5-8 particularly for females 65 years and older, but differ in age- and sex-based recommendations for those 50 to 65 years and in the application of screening tools.^1-3 Osteoporosis Canada additionally recommends assessment of fall history and signs of undiagnosed vertebral fractures (Table 3).¹

Which screening tools are recommended? The Fracture Risk Assessment Tool (FRAX) and the bone mineral density (BMD) test are both currently endorsed by Canadian guidelines as tools for evaluating fracture risk and guiding clinical decision making. The Osteoporosis Self-Assessment Tool (OST) is not part of discussed guidelines as it predicts the risk of osteoporosis on BMD, not fragility fractures.⁹

In evaluating a FRAX-first screening approach followed by BMD (if indicated) and a meta-analysis of 3 randomized controlled trials (RCTs) and 1 clinical study, with re-estimation using Canadian fracture rates (1995-2005), findings suggest an approximate number needed to screen (NNS) of 250 for hip fractures and 85 for clinical fragility fractures (Figure 1).^2,5 Comparable data for BMD-first screening are lacking.

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Figure 1.

In females 65 years or older, risk assessment–first screening with the Fracture Risk Assessment Tool followed by bone mineral density measurement (if indicated) results in 4 fewer hip fractures and 11.8 fewer clinical fragility fractures per 1000 screened

The FRAX tool assesses fracture risk using 11 clinical factors, including age and sex, and has a Canada-specific version calibrated to the local population. However, it has limitations, as it does not account for fall risk or dose-response relationships for certain factors like prior fractures, prednisone dose, and smoking or alcohol use. (FRAXPlus, a Web-based tool that enhances the standard FRAX, addresses some of these gaps but the basic FRAX tool remains free and suitable for most patients.) Additionally, FRAX does not fully capture the complexities of fracture risk across racial and ethnic groups, further influenced by social determinants of health.^10,11 Since FRAX relies on the femoral neck T-score, it may underestimate fracture risk when the lumbar spine T-score is significantly lower. To address this discrepancy, FRAX can be increased by one-tenth of the calculated value for each 1.0 T-score difference between the lumbar spine and femoral neck.¹²

Osteoporosis is defined by a BMD T-score of 2.5 or more standard deviations below the expected peak bone mass, based on a reference population of healthy adults aged 20 to 30 years, measured at the spine, femoral neck, or hip.¹

How can health care providers screen for fall risk? Preventing fragility fractures necessitates interventions aimed at reducing fall risk. Falls are the primary cause of fractures in older adults in Canada with 20% to 30% of seniors older than 65 years experiencing falls annually.^1,13 However, Canadian guidelines lack comprehensive fall risk assessment and prevention strategies.

Multiple tools exist, including both self-reported measures and performance-based measures. Combining multiple tools with comprehensive health and medication reviews enhances predictive validity, but a history of previous falls continues to serve as a practical and reliable indicator of future risk, offering sensitivities (39% to 68%) and specificities (63% to 82%) comparable to other screening measures.^14,15 Standardized assessments often involve multiple tests, but time, space, and training demands can limit their use in primary care.¹² Table 4 outlines 3 performance-based measures^16-21—the 1-legged stance test, the 30-second sit-to-stand test, and the timed up and go (TUG) test—that while limited in predictive validity, are easily administered and consistently linked to fall risk.^15-17 The inability to stand on 1 leg for 10 seconds indicates balance impairment while under 5 seconds indicates fall risk.¹⁸ A sit-to-stand score below age- and sex-specific averages or a TUG time more than 15 seconds may both indicate elevated fall risk.^19,20

What nutritional interventions support bone health? One-third of adults aged 65 years or older are at nutritional risk, with risk factors including social isolation and female sex.²²

Osteoporosis Canada recommends that postmenopausal females and males aged 50 years or older maintain a balanced diet per Canada’s Food Guide.²³ Health Canada recommends a dietary allowance of 600 IU of vitamin D daily for adults aged 51 to 70 years and 800 IU for those older than 70 years, with a minimum supplement of 400 IU per day alongside a vitamin D–rich diet (conditional, high).^1,24 Measurement of 25-hydroxyvitamin D levels may be indicated in patients initiating pharmacotherapy or those at risk for insufficiency. Risk factors for insufficiency include malabsorption syndromes, limited sun exposure, liver cirrhosis, chronic kidney disease or nephrotic syndrome, parathyroid disorders, and use of medications that affect vitamin D metabolism.^1,25 While the optimal serum 25-hydroxyvitamin D level for bone health remains uncertain, levels 50 nmol/L or higher are generally considered adequate.^1,25

Meeting daily calcium needs through diverse calcium-rich foods is recommended: 1000 mg for males aged 51 to 70 years, and 1200 mg for females older than 50 years and males older than 70 years (conditional, moderate to high).^1,26 Supplementation is advised when dietary intake is inadequate.¹ It is often recommended to consume 20 g to 30 g of protein per meal, though further research is needed to determine optimal intake for bone health.¹

Evidence does not support dietary supplements in reducing fracture risk for individuals without deficiencies, although individuals at risk require a comprehensive assessment. Supplementation of protein, vitamin K, or magnesium beyond balanced dietary intake is not advised.¹

Further research is needed on dietary patterns for fracture prevention, focusing on comprehensive dietary interventions.

What exercise interventions support bone health and fall prevention? Exercise focused on strength and balance training has been shown to decrease the risk of falls and fractures.^14,15 While the effect size varies depending on the type, intensity, and duration of exercise, studies suggest a 20% to 50% reduction in vertebral fractures and a 15% to 25% reduction in nonvertebral fractures.²⁷

Osteoporosis Canada recommends including a variety of physical activities, but prioritizing balance and functional and resistance training at least twice weekly for adults aged 50 years or older. Balance and functional exercises have been shown to reduce risk of falls and fall-related fractures (rate ratio=0.44; 95% confidence interval [CI] 0.25 to 0.76) (strong, moderate).¹ Progressive resistance training targeting major muscle groups can further reduce fall risk and improve physical functioning, quality of life, and bone density (conditional, low).²⁸

Engaging in cardiovascular activities, as per the Canadian 24-Hour Movement Guidelines, should be encouraged for overall health and wellness, but should not exclude balance and resistance training.^1,29 In individuals with a prior spine fracture or high fracture risk, moderate- to high-impact exercise or movements involving rapid, repetitive, sustained, weighted, or end-range spinal flexion or twisting may require modification.¹

What are pharmacologic interventions for osteoporosis and fracture prevention? Pharmacologic therapy is recommended for postmenopausal females and males aged 50 years or older with prior hip or vertebral fracture, 2 or more osteoporotic fractures, 10-year fracture risk 20% or higher, or age 70 years or older with a BMD T-score of −2.5 or less (strong, moderate to high). Pharmacologic therapy is also suggested for postmenopausal females with a 15% to 19.9% 10-year fracture risk or those younger than 70 years with a T score of −2.5 or less (conditional, moderate).¹

Pharmacologic interventions include antiresorptive agents and anabolic agents (Table 5).^1,30-32 Antiresorptive medications slow down the activity of osteoclasts (ie, bone-resorbing cells), while anabolic agents enhance the activity of osteoblasts (ie, bone-building cells).³³ Medications are generally less effective in preventing nonvertebral fractures compared to vertebral fractures (Figure 2).^1,32 However, anabolic agents show greater efficacy in vertebral fracture risk reduction compared to antiresorptive drugs.³⁰

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Figure 2.

Fracture outcomes per 1000 treated: A) Bisphosphonate therapy for 3 years is associated with 20 to 30 fewer vertebral fractures, 10 fewer non-vertebral fractures, and 3 fewer hip fractures. B) Anabolic therapy is associated with 35 fewer vertebral fractures, 8 fewer non-vertebral fractures, and 5 fewer hip fractures (treatment duration varies by agent).

Antiresorptive agents, primarily oral bisphosphonates such as alendronate and risedronate and intravenous zoledronate, are widely prescribed for osteoporosis. Bisphosphonates adhere to bone surfaces, inducing osteoclast inactivation and apoptosis.³³ These agents remain in the bone for extended periods, ensuring prolonged therapeutic effects even after discontinuation.³⁴ Denosumab, another antiresorptive agent, is a monoclonal antibody that inhibits receptor activator of nuclear factor–κB ligand, thereby decreasing osteoclast formation and activity.³⁴ Unlike bisphosphonates, denosumab is not retained long term in the bone. Delayed dosing (>7 months) or abrupt withdrawal may cause rapid bone loss and vertebral fractures. Adherence to therapy intervals and transition to bisphosphonates for 1 to 2 years after treatment course is recommended to manage this risk.^35,36

Anabolic agents stimulate osteoblast activity, promoting new bone formation. Teriparatide, a parathyroid hormone analogue, enhances osteoblast activity mainly at trabecular sites. Romosozumab, a monoclonal antibody targeting sclerostin, boosts osteoblast activity, particularly in vertebral trabecular bone.³⁴ Anabolic therapy is recommended for individuals with a recent severe vertebral fracture (>40% height loss) or multiple vertebral fractures and a T-score of −2.5 or less (females; conditional, high).¹

Selective estrogen receptor modulators have a mild antiresorptive effect, reducing vertebral fracture risk.³⁰ Menopausal hormone therapy can be initiated in females younger than 60 years to manage vasomotor symptoms and postmenopausal osteoporosis.^1,3

Common side effects of pharmacotherapy are outlined in Table 5.^1,30-32 Long-term use of antiresorptive medications, including denosumab, is associated with osteonecrosis of the jaw and atypical femur fractures.^1,37,38 Osteonecrosis, linked to low bone turnover, may occur after major dental procedures, with an incidence of 1 in 10,000 to 1 in 100,000. Atypical femur fractures, affecting the femoral shaft, result from prolonged osteoclast suppression, with a risk lower than 1 in 1000 for less than 5 years of therapy, increasing with longer use.^37,38 Atypical femur fractures are infrequently reported with romosozumab.³⁹

What are the guidelines on BMD monitoring with or without treatment? BMD testing is recommended 3 years after initiating pharmacologic therapy or after completion of therapy.¹ For those not initiating therapy, Osteoporosis Canada recommends retesting after 5 to 10 years for a 10-year fracture risk less than 10%, within 5 years for a 10% to 15% risk, and within 3 years for a risk of 15% or greater.¹ Shorter intervals may be appropriate for secondary osteoporosis or new clinical risk factors like recent fractures.¹ The Canadian Task Force on Preventive Health Care indicates that BMD rescreening within 8 years does not enhance fracture risk prediction.² Both Canadian guidelines indicate that rescreening within 3 years is typically unnecessary.

When should therapy be discontinued or a drug holiday be considered? Osteoporosis Canada recommends a drug holiday after 3 to 6 years of antiresorptive therapy to reduce the risk of rare adverse effects such as atypical femur fractures and osteonecrosis of the jaw, which are associated with long-term, continuous use of these medications. At 6 years, potential harms may outweigh benefits.¹ Optimal denosumab therapy duration remains uncertain, often considered up to 10 years, followed by transition to 1 to 2 years of bisphosphonate therapy to reduce the risk of rebound vertebral fractures upon discontinuation.¹ Fracture risk can be reassessed 3 years post discontinuation of therapy to determine the need for resumption.

Case resolution

Mira meets screening criteria outlined in the discussed guidelines. A Canada-specific FRAX tool without BMD estimates a 15% risk of major osteoporotic fractures and a 4% risk of hip fractures over the next 10 years. Subsequent BMD testing indicates a lumbar spine T-score of −2.5 and a femoral neck T-score of −1.9. Including the femoral neck T-score in the assessment yields similar risks: 16% for major osteoporotic fractures and 3.9% for hip fractures over the next decade.

Clinical assessment did not indicate undiagnosed vertebral fractures. Fall risk evaluation revealed prior falls, impaired balance (5.6 seconds on left leg) and reduced leg strength (8 sit-to-stands in 30 seconds).

To minimize fall and fracture risk, Mira should prioritize balance, functional, and resistance training at least twice weekly, along with individualized assessment for tailored exercise and fall prevention strategies. Nutritional guidance recommends 1200 mg of calcium daily from food sources, 20 g to 30 g of protein per meal, and a vitamin D supplement (400 to 1000 IU/day) in addition to dietary sources. Given undernutrition risk factors, referral to a dietitian for personalized nutritional intervention is recommended.

Pharmacotherapy should be offered, considering intermediate fracture risk based on FRAX assessment, an age of 70 years or older, and T-score of −2.5, as per Osteoporosis Canada and Society of Obstetricians and Gynaecologists of Canada guidelines.

Conclusion

Guidelines recommend that a clinical fracture risk assessment be prioritized for females 65 years or older and initiated with the FRAX tool along with an evaluation of fall risk and signs of vertebral fractures. Shared decision making should guide BMD screening and treatment. Management should include exercise, nutrition, fall prevention, and pharmacotherapy tailored to individual risk (Figure 3).^{1,23,24,26,29}

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Figure 3.

Intervention pyramid for fragility fracture risk reduction: Lifestyle measures for all adults ≥50 years; vitamin D or calcium supplements for those not meeting Health Canada’s recommended dietary allowance; anti-resorptive therapies for moderate-to-high risk patients through shared decision making; and anabolic agents for individuals with severe or multiple vertebral fractures.