Osteoporosis in Postmenopausal Women: Monitoring Initial Therapy with Oral Bisphosphonates
UpToDate algorithm — reviewed with resident
Initial Steps
- Counsel on adherence to bisphosphonates, vitamin D, and calcium
- Educate on secondary causes of bone loss
- Repeat DXA in 1–2 years (sooner if new fracture of spine, hip, or pelvis)
After DXA — Did BMD Decline or New Fragility Fracture of Spine/Hip/Pelvis?
No →
- BMD stable or increased, no new fracture
- Continue same therapy (1–3 years depending on clinical setting)
- Repeat DXA in 1–2 years
Yes →
- Evaluate adherence to therapy
- Assess for malabsorption or GI issues (e.g., poor oral bioavailability)
- Consider secondary causes: hyperparathyroidism, malabsorption, hypogonadism
- Refer to specialist if secondary cause identified
- Repeat DXA in 1–2 years
Does Either Apply? (New fracture of spine/hip/pelvis on oral bisphosphonate OR T-score ≤ −2.5)
Yes →
- Switch to anabolic therapy: teriparatide, abaloparatide, or romosozumab
- Repeat DXA in 1–2 years
No →
- Measure bone turnover marker (e.g., serum CTX) — helps identify malabsorption or poor GI absorption
- If BTM above upper half of reference range, side effects, intolerance, or dosing difficulty:
- Switch to IV zoledronic acid
- Repeat DXA in 1–2 years
- If BTM within acceptable range:
- Continue current oral bisphosphonate
- Repeat DXA in 1–2 years
- If BTM above upper half of reference range, side effects, intolerance, or dosing difficulty: