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Clinical Pearls & Morning Reports

Posted by Carla Rothaus, MD

Published November 22, 2023

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What pharmacologic therapy is generally recommended as initial treatment for postmenopausal osteoporosis?

Approximately 50% of postmenopausal women will have fragility fractures, which cause pain, disability, and decreased quality of life. After a hip fracture, many women never regain independence and 20% are institutionalized, and the risk of death within 1 year doubles. Read the NEJM Clinical Practice Article here.

Clinical Pearls

Q: How is postmenopausal osteoporosis diagnosed?

A: Postmenopausal osteoporosis is diagnosed on the basis of the occurrence of a fragility fracture (with no associated trauma or with trauma equivalent to falling from a standing height or less) or bone mineral density at the spine, total hip, or femoral neck that is at least 2.5 standard deviations below the mean of that in a young adult reference population (T score of −2.5 or less), as measured with the use of dual-energy x-ray absorptiometry (DXA). Fragility fractures of the spine, hip, forearm, humerus, and pelvis are diagnostic of osteoporosis, even if DXA shows T scores higher than -2.5.

Q: What is the fracture risk assessment tool (FRAX)?

A: Fracture risk can be estimated with the use of FRAX or other validated calculators. FRAX estimates the 10-year probability of major osteoporotic fracture and hip fracture on the basis of clinical risk factors, with or without a measurement of bone mineral density. Many authorities recommend designating patients who have an elevated fracture risk but do not have T scores of −2.5 or less or a fragility fracture as having osteoporosis.

Morning Report Questions

Q: When is treatment for postmenopausal osteoporosis indicated?

A: Pharmacologic interventions are targeted to women at high risk for fracture. Intervention thresholds vary according to different guidelines, but many guidelines recommend treating women who have fragility fractures of the hip or spine, regardless of bone mineral density; those with T scores of −2.5 or less at the lumbar spine, total hip, or femoral neck; and those with high 10-year fracture risk as assessed with the use of FRAX (hip fracture risk of ≥3% or major osteoporotic fracture risk of ≥20%). Findings from randomized, controlled trials support the fracture-risk–reduction efficacy of FDA-approved treatments based on T scores or fracture criteria (or both). Evidence that supports treatment based on FRAX-estimated fracture risk is less robust.

Q: What pharmacologic therapy is generally recommended as initial treatment for postmenopausal osteoporosis?

A: Therapies for postmenopausal osteoporosis act by reducing bone resorption (antiresorptive therapies), stimulating bone formation (anabolic therapies), or both. All pharmacologic approaches reduce vertebral fracture risk, and some reduce the risk of nonvertebral and hip fractures. For women with postmenopausal osteoporosis who are at high risk for fracture, most guidelines recommend bisphosphonates as initial treatment, given their efficacy, safety, convenience, low cost, and enduring effects after discontinuation. Four oral and intravenous bisphosphonates are FDA-approved for postmenopausal osteoporosis. All reduce the risk of vertebral fracture. All but ibandronate reduce the risk of hip and nonvertebral fractures. Long-term use of bisphosphonates has been associated with osteonecrosis of the jaw and atypical femur fractures. Osteonecrosis of the jaw is an area of exposed jaw bone that does not heal within 8 weeks after identification by a health care provider. Atypical femur fractures are low-trauma subtrochanteric or femoral-shaft fractures with specific radiographic criteria. In patients receiving bisphosphonates at doses used for postmenopausal osteoporosis, the estimated risks of osteonecrosis of the jaw and atypical femur fracture are very low.

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