When to Treat for Osteoporosis
Pharmacologic treatment should be initiated in postmenopausal women and men over age 50 with any of the following: T-score ≤ -2.5 at the spine, hip, or femoral neck; a history of hip or vertebral fragility fracture regardless of BMD; or osteopenia (T-score -1.0 to -2.5) with FRAX-calculated 10-year probability ≥3% for hip fracture or ≥20% for major osteoporotic fracture. 1, 2
Primary Treatment Indications
1. T-Score Based Diagnosis
- Treat all patients with T-score ≤ -2.5 at the lumbar spine, femoral neck, or total hip, measured by DXA 1, 2
- This threshold applies equally to both men over 50 and postmenopausal women using the same female reference range 1, 2
- FRAX calculation is NOT necessary when T-score is already ≤ -2.5—the diagnosis of osteoporosis is confirmed and treatment is indicated 2
2. Fragility Fracture History
- Any hip fracture with minimal or no trauma mandates treatment, regardless of BMD measurement 1, 3
- Vertebral fractures are diagnostic of osteoporosis even if BMD is in the osteopenic range and warrant treatment 4, 3
- Proximal humerus, pelvis, or distal forearm fractures in patients with osteopenia (T-score -1.0 to -2.5) also indicate treatment 3
- Patients age 50 and older who develop wrist, hip, spine, or proximal humerus fractures with minimal trauma should be treated 1
3. Osteopenia with High FRAX Risk
For patients with osteopenia (T-score between -1.0 and -2.5) without prior fracture, use FRAX to determine treatment need 2, 5:
- Treat if 10-year hip fracture probability ≥3% 1, 2, 5
- Treat if 10-year major osteoporotic fracture probability ≥20% 1, 2, 5
- FRAX integrates clinical risk factors including age, sex, BMI, prior fracture, parental hip fracture history, current smoking, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis causes, and alcohol consumption 1
Special Populations and Circumstances
Glucocorticoid-Induced Osteoporosis
- Lower treatment threshold: T-score ≤ -1.5 (not -2.5) because fractures occur at higher BMD levels in this population 4
- Consider treatment in patients over 65 on long-term glucocorticoids even without DXA, as the vast majority will have T-scores warranting treatment 4
Age-Specific Screening Recommendations
Perform DXA screening in 1:
- All women age ≥65 years
- All men age ≥70 years
- Women <65 years or men <70 years with additional risk factors (estrogen deficiency, maternal hip fracture after age 50, low body weight <127 lb, prolonged amenorrhea, current smoking, height loss, thoracic kyphosis) 1
Treatment Selection Algorithm
First-Line Therapy
- Oral bisphosphonates (alendronate 70 mg weekly) are first-line for most patients 2
- Ensure adequate calcium (1000-1200 mg/day) and vitamin D (600-800 IU/day, targeting 25-OH vitamin D ≥20-30 ng/mL) 2
Alternative Therapies
- Denosumab 60 mg SC every 6 months for patients with renal insufficiency (eGFR <35 mL/min) or those intolerant to oral bisphosphonates 2
- Intravenous bisphosphonates (zoledronic acid) as alternative 1, 2
- Teriparatide or other anabolic agents for very high-risk patients or those failing antiresorptive therapy 1
Critical Pitfalls to Avoid
Do not delay treatment while awaiting complete laboratory workup—initiate calcium and vitamin D supplementation immediately 2. However, before starting bisphosphonates, obtain baseline labs to exclude secondary causes: CBC, calcium, phosphate, creatinine (eGFR), alkaline phosphatase, TSH, and 25-hydroxyvitamin D 2.
Do not use Z-scores for diagnosis in adults over 50—always use T-scores with the female reference range for both sexes 1, 2.
Recognize that most fractures occur in the osteopenic range (not osteoporosis range), making risk assessment tools like FRAX essential for identifying high-risk patients who need treatment despite T-scores above -2.5 6.
Never stop denosumab abruptly without transitioning to another agent, as this increases multiple-fracture risk 5.