In a post‑menopausal woman with osteoporosis and no contraindications to estrogen, can menopausal hormone therapy be used as primary treatment, and what regimen and duration are recommended?

Menopausal Hormone Therapy Should NOT Be Used as Primary Treatment for Established Osteoporosis

The American College of Physicians strongly recommends against using menopausal estrogen therapy (with or without progestogen) for the treatment of osteoporosis in postmenopausal women, even when no contraindications exist. 1 Bisphosphonates are the recommended first-line therapy instead. 2

Why MHT Is Not Recommended for Established Osteoporosis

Lack of Fracture Reduction in Women with Established Disease

• Moderate-quality evidence demonstrates that menopausal estrogen treatment did not reduce fracture risk in postmenopausal women with established osteoporosis (defined as T-score ≤ -2.5 or prior fragility fracture). 1
• While earlier studies showed estrogen decreased fracture risk, those trials focused on postmenopausal women with low bone density or general postmenopausal populations—not women with established osteoporosis. 1

Serious Harms That Outweigh Benefits

The harms of MHT are substantial and well-documented:

• 26% increased risk of breast cancer (RR 1.26,95% CI 1.00-1.59) 2, 3
• 41% increased risk of stroke (RR 1.41,95% CI 1.07-1.85) 2, 3
• Increased cardiovascular disease and venous thromboembolism 2, 3
• For every 10,000 women taking estrogen-progestin for 1 year: 7 additional coronary events, 8 more strokes, 8 more pulmonary emboli, and 8 more invasive breast cancers 2

Recommended Treatment Algorithm for Osteoporosis

First-Line Therapy: Bisphosphonates

Bisphosphonates (alendronate, risedronate, or zoledronic acid) are the preferred first-line treatment for postmenopausal women with osteoporosis. 2

• These agents reduce vertebral, nonvertebral, and hip fractures in women with established osteoporosis. 1
• Treatment duration should be 5 years. 1
• Bone density monitoring during the 5-year treatment period is not recommended, as fracture reduction occurs even without BMD increases. 1

Adjunctive Therapy

• Add calcium 1000-1500 mg/day and vitamin D 800-1000 IU/day as supplementation. 2
• Calcium supplementation provides modest additional benefit, particularly at corticocancellous bone sites. 2
• Avoid excessive calcium dosing due to risk of hypercalcemia and kidney stones. 1

Critical Distinction: Prevention vs. Treatment

While MHT may have a role in prevention of bone loss in early postmenopausal women with menopausal symptoms (not the focus of this question), it is explicitly contraindicated as primary treatment once osteoporosis is established. 1, 2, 3

Common Pitfalls to Avoid

• Do not use MHT solely for osteoporosis treatment when safer alternatives exist (bisphosphonates, denosumab, selective estrogen receptor modulators). 3
• Do not extrapolate fracture prevention data from healthy postmenopausal women to those with established osteoporosis—the evidence base differs significantly. 1
• Do not consider raloxifene as first-line therapy despite its bone benefits, as it is associated with serious harms including thromboembolism and does not reduce all fracture types. 1

When MHT Might Be Considered (Not as Primary Osteoporosis Treatment)

MHT should only be considered in the narrow context of women requiring treatment for moderate-to-severe menopausal vasomotor symptoms who also happen to have osteoporosis risk—but even then, it is not the primary osteoporosis treatment. 3 In such cases, bisphosphonates remain the primary bone-directed therapy, with MHT addressing vasomotor symptoms as a separate indication.