Skeletal disorder of reduced bone strength and increased fracture risk; managed with bone-protective lifestyle and antiresorptive or anabolic therapy.
Also known as: osteoporosis, low bone density, fragility fracture
Overview
Skeletal disorder characterized by compromised bone strength predisposing to fracture. Defined operationally by bone mineral density T-score ≤ -2.5 at the femoral neck, total hip, or lumbar spine, OR by the occurrence of a fragility fracture (low-energy fracture from a fall from standing height or less). T-score between -1.0 and -2.5 is osteopenia (low bone mass).
Epidemiology
Affects ~10 million US adults; estimated 50% of women and 20% of men over 50 will have an osteoporotic fracture in their lifetime. Hip fractures carry ~20-30% 1-year mortality.
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Question 1MusculoskeletalMedium
A 55-year-old postmenopausal woman sustains a distal radius fracture after a fall from standing height. She has no prior fractures and takes no medications that affect bone. Dual-energy x-ray absorptiometry shows a T-score of -2.8 at the femoral neck. Serum calcium and renal function are normal. Which of the following is the most appropriate pharmacologic treatment?
ACalcitonin nasal spray with calcium and vitamin D
BCalcium and vitamin D supplementation alone
CRaloxifene therapy with calcium and vitamin D
DOral bisphosphonate with calcium and vitamin D
Reveal answer & full explanation
Correct answer: D — Oral bisphosphonate with calcium and vitamin D
ACalcitonin nasal spray with calcium and vitamin D
BCalcium and vitamin D supplementation alone
CRaloxifene therapy with calcium and vitamin D
DOral bisphosphonate with calcium and vitamin D✓
Why Oral bisphosphonate with calcium and vitamin D is correct
This woman has osteoporosis by both criteria: a T-score of -2.8 (at or below -2.5) and a low-trauma fragility fracture of the distal radius.
Per current osteoporosis guidance (AACE/Endocrine Society), an oral bisphosphonate such as alendronate or risedronate is first-line therapy and substantially reduces both vertebral and hip fracture risk.
Normal serum calcium and renal function clear the key prerequisites for starting an oral bisphosphonate.
Calcium and vitamin D are co-administered to provide adequate substrate for the antiresorptive effect.
Why the others are wrong
Calcitonin nasal spray with calcium and vitamin D — calcitonin has weak antifracture efficacy (modest vertebral benefit only) and is reserved for patients who cannot take other agents (buzzword-matching a drug approved for postmenopausal osteoporosis without weighing efficacy).
Calcium and vitamin D supplementation alone — supplementation is necessary adjunctive care but is insufficient as sole therapy once osteoporosis or a fragility fracture is established (right-diagnosis-wrong-step).
Raloxifene therapy with calcium and vitamin D — raloxifene is a second-line SERM with no proven hip-fracture reduction and added VTE risk, reserved for when bisphosphonates are unsuitable (confused-with-first-line therapy).
Question 2MusculoskeletalMedium
A 65-year-old woman with osteoporosis has been taking oral alendronate for 5 years. Her most recent lumbar spine T-score is -3.1, she has no history of fragility fracture, and her bone density has been stable. She asks whether she can take a drug holiday. Which of the following is the most appropriate next step?
AContinue alendronate for an additional 5 years
BInitiate a bisphosphonate drug holiday
CRepeat dual-energy X-ray absorptiometry in 5 years
DTransition to raloxifene maintenance therapy
Reveal answer & full explanation
Correct answer: A — Continue alendronate for an additional 5 years
AContinue alendronate for an additional 5 years✓
BInitiate a bisphosphonate drug holiday
CRepeat dual-energy X-ray absorptiometry in 5 years
DTransition to raloxifene maintenance therapy
Why Continue alendronate for an additional 5 years is correct
A T-score of -3.1 places this patient in the high (very high) fracture-risk category regardless of how many treatment years have elapsed; risk—not duration of therapy—drives the holiday decision (ACOG/Endocrine Society/AACE)
For high-risk patients, oral bisphosphonate therapy is continued for a total of up to 10 years (or IV zoledronic acid for up to 6 years) rather than being stopped
A drug holiday is reserved for patients who become low-to-moderate risk after 3-5 years (no fractures and a T-score above -2.5); this patient does not qualify
Continuing therapy maintains fracture protection while fracture risk is reassessed periodically
Why the others are wrong
Initiate a bisphosphonate drug holiday — a holiday is inappropriate at a T-score of -3.1 because residual high fracture risk persists; elapsed treatment years alone do not justify stopping (anchoring on duration)
Repeat dual-energy X-ray absorptiometry in 5 years — deferring reassessment for 5 years while leaving a high-risk patient untreated abandons fracture protection and ignores guideline monitoring intervals (false reassurance)
Transition to raloxifene maintenance therapy — raloxifene reduces vertebral fractures but has never shown hip or nonvertebral fracture benefit, so moving a patient with a T-score of -3.1 onto it downgrades protection rather than maintaining it (wrong-agent-for-risk)
Additional high-yield points
Holiday eligibility hinges on becoming low-to-moderate risk: no hip or vertebral fracture and a T-score above -2.5
Very-high-risk patients (e.g., T-score at or below -3.0, prior fracture) may instead be transitioned to an anabolic agent such as teriparatide or romosozumab
Denosumab must not be stopped without transitioning to another antiresorptive because of rebound vertebral fractures
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Non-modifiable: age >65, female sex, postmenopausal status, white or Asian ancestry, family history of hip fracture, low body weight, prior fragility fracture
Modifiable: tobacco use, excessive alcohol (>3 drinks/day), low calcium and vitamin D intake, sedentary lifestyle
Bone is in continuous turnover via osteoclast-mediated resorption and osteoblast-mediated formation. After peak bone mass (~age 30), resorption progressively exceeds formation. Estrogen withdrawal at menopause sharply increases osteoclast activity. Secondary causes (glucocorticoids, hyperparathyroidism) act through additional mechanisms — direct osteoblast suppression, increased RANKL signaling, and accelerated remodeling. The result is reduced trabecular connectivity and cortical thinning.
Clinical presentation
Symptoms
Asymptomatic until fracture occurs
Vertebral compression fracture: sudden back pain after minor strain, often spontaneous; can be silent
Loss of height >1.5 inches (4 cm) and progressive thoracic kyphosis
Hip, distal radius (Colles), pelvis, or proximal humerus fracture from low-energy fall
Signs / physical exam
Thoracic kyphosis ('dowager hump')
Loss of height
Rib-pelvis distance <2 finger-breadths
Tenderness to percussion over a fractured vertebra
Differential diagnosis
Osteomalacia — Defective mineralization from vitamin D deficiency or hypophosphatemia; bone pain, proximal weakness; low Ca, low phos, elevated alk phos, low 25-OH vitamin D
NOF/BHOF 2022 — Clinician's Guide to Prevention and Treatment of Osteoporosis (Bone Health & Osteoporosis Foundation, 2022)
Endocrine Society 2019/2020 — Pharmacological Management of Osteoporosis in Postmenopausal Women: Endocrine Society Clinical Practice Guideline (Eastell et al., J Clin Endocrinol Metab 2019; 2020 update)
ACR 2017 — ACR Guideline for Prevention and Treatment of Glucocorticoid-Induced Osteoporosis (Buckley et al., Arthritis Rheumatol 2017)
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