Applies FRAX scoring with DXA interpretation and treatment algorithms for bone health. Use when assessing fracture risk, interpreting bone density, or selecting osteoporosis treatment.
Applies FRAX scoring with DXA interpretation and treatment algorithms for bone health.
Osteoporosis affects approximately 10 million Americans, with an additional 44 million having low bone density (osteopenia). It causes over 2 million fractures annually, including 300,000 hip fractures with a 20-30% one-year mortality rate. Despite effective screening (DXA) and treatments that reduce fracture risk by 40-70%, osteoporosis remains severely underdiagnosed and undertreated—fewer than 25% of women who sustain a hip fracture receive osteoporosis treatment within 12 months.
The USPSTF recommends DXA screening for all women ≥65 and younger postmenopausal women with equivalent fracture risk (Grade B). The NOF/AACE/Endocrine Society guidelines provide treatment thresholds based on FRAX scoring and DXA T-scores. This skill structures the complete workflow from screening through treatment selection, monitoring, and drug holiday decisions to close the treatment gap.
USPSTF screening recommendations:
DXA T-score classification (WHO):
| T-score | Classification | Action |
|---|---|---|
| ≥ -1.0 | Normal | Reassess per risk factors; repeat DXA per guideline |
| -1.0 to -2.5 | Osteopenia (low bone mass) | Calculate FRAX; treat if meets treatment threshold |
| ≤ -2.5 | Osteoporosis | Initiate treatment |
| Any T-score + fragility fracture | Severe/established osteoporosis | Initiate treatment regardless of T-score |
DXA interpretation pitfalls:
Calculate 10-year fracture probability at https://frax.shef.ac.uk using:
NOF treatment thresholds (for osteopenia with FRAX):
FRAX limitations:
| Agent | Class | Dosing | Fracture Reduction | Key Considerations |
|---|---|---|---|---|
| Alendronate (Fosamax) | Bisphosphonate | 70mg PO weekly | Spine 44%, hip 40% | Take fasting, upright 30 min, with water only; avoid if eGFR <30-35 |
| Risedronate (Actonel) | Bisphosphonate | 35mg PO weekly or 150mg monthly | Spine 41%, hip 30% | Same administration rules as alendronate |
| Zoledronic acid (Reclast) | IV bisphosphonate | 5mg IV annually | Spine 70%, hip 41% | For patients intolerant of oral; check calcium/vit D before infusion; adequate hydration |
| Denosumab (Prolia) | RANKL inhibitor | 60mg SQ every 6 months | Spine 68%, hip 40% | No renal dose adjustment; MUST NOT be delayed >7 months (rebound vertebral fractures) |
| Teriparatide (Forteo) | PTH(1-34) analog (anabolic) | 20mcg SQ daily | Spine 65%, nonvertebral 35% | Max 2 years; for severe osteoporosis or bisphosphonate failure; avoid if Paget's, bone cancer, or prior radiation |
| Abaloparatide (Tymlos) | PTHrP analog (anabolic) | 80mcg SQ daily | Spine 86%, nonvertebral 43% | Max 2 years; same precautions as teriparatide |
| Romosozumab (Evenity) | Sclerostin inhibitor (anabolic) | 210mg SQ monthly × 12 months | Spine 73%, hip 38% | Black box: increased CV risk; avoid if MI or stroke within 12 months |
Treatment selection framework:
| Nutrient | Daily Recommendation | Source |
|---|---|---|
| Calcium | 1000mg (men 51-70); 1200mg (women >50, men >70) | Dietary preferred; supplement if intake inadequate (calcium carbonate with food; calcium citrate without) |
| Vitamin D | 800-1000 IU daily; may need 2000-4000 IU to achieve 25-OH >30 ng/mL | Cholecalciferol (D3) preferred over D2 |
Lifestyle interventions:
| Treatment Phase | Action | Timing |
|---|---|---|
| On bisphosphonate | Repeat DXA every 2 years; reassess at 3-5 years | DXA at 2 years; treatment review at 3 years (risedronate) or 5 years (alendronate) |
| Drug holiday consideration | After 5 years oral or 3 years IV bisphosphonate if: T-score > -2.5 at femoral neck AND no fractures on treatment | Holiday length 2-3 years; recheck DXA and FRAX; restart if bone loss or fracture |
| On denosumab | NEVER take a drug holiday; discontinuation causes rapid bone loss and rebound vertebral fractures | If stopping, must transition to bisphosphonate (zoledronic acid preferred) |
| Post-anabolic therapy | Transition to antiresorptive (bisphosphonate or denosumab) to maintain gains | Start within 1-2 months of completing anabolic course |
| Monitoring labs | 25-OH vitamin D, calcium annually; bone turnover markers (CTX, P1NP) if assessing treatment response | P1NP suppression confirms bisphosphonate adherence |