Is a postmenopausal woman with a T score of -1.7 on Dual-Energy X-ray Absorptiometry (DEXA) scan at risk for silent fracture or can she wait three years for the next scan?

Risk Assessment for Postmenopausal Woman with T-score of -1.7

A postmenopausal woman with a T-score of -1.7 has osteopenia (low bone mass) and should undergo repeat DEXA scanning in 1-2 years, not 3 years, while implementing non-pharmacological interventions immediately. 1

Understanding the T-score Classification

• A T-score of -1.7 falls within the osteopenia range (between -1.0 and -2.5), which indicates low bone mass but not osteoporosis 2, 1
• This classification means the patient has lower bone density than the young adult reference population but has not yet reached the threshold for osteoporosis diagnosis (T-score ≤ -2.5) 2

Silent Fracture Risk Assessment

The patient is at increased risk for silent (asymptomatic) vertebral fractures and should undergo vertebral fracture assessment (VFA). 2

• VFA is specifically indicated for patients with T-scores less than -1.0 who are postmenopausal women age 70 years or older, have historical height loss >4 cm, have self-reported prior vertebral fracture, or are on chronic glucocorticoid therapy 2
• Approximately 50% of fragility fractures occur in postmenopausal women with T-scores greater than -2.5 (i.e., in the osteopenic range), making fracture risk assessment critical beyond BMD alone 2
• If VFA identifies a vertebral fracture, this would reclassify the patient as having osteoporosis regardless of the T-score, and pharmacologic treatment should be initiated immediately 1, 3

Immediate Non-Pharmacological Management

Implement the following interventions now, not in 3 years: 1

• Weight-bearing exercise regimen to maintain and potentially improve bone density 1
• Calcium supplementation to achieve >1000 mg/day total intake (dietary plus supplements); specifically 1,200 mg/day for postmenopausal women 2, 1
• Vitamin D supplementation 800-1000 IU daily 2, 1
• Smoking cessation if applicable 1
• Limit alcohol consumption 1

Fracture Risk Calculation Required

Calculate the 10-year fracture risk using FRAX or similar algorithm immediately. 1

• FRAX incorporates clinical risk factors beyond BMD alone, including age, prior fracture history, parental hip fracture history, current smoking, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis causes, and alcohol consumption 1
• Pharmacologic treatment should be considered if FRAX shows 10-year risk of major osteoporotic fracture ≥20% or hip fracture risk ≥3%, even with a T-score in the osteopenic range 2
• Treatment should also be considered if the patient has had a low-trauma fracture after age 50, regardless of the T-score 1

Appropriate Monitoring Interval

Repeat DEXA scanning in 1-2 years, not 3 years. 2, 1

• The guideline specifically states repeat scanning every 2 years for patients on aromatase inhibitors with baseline T-score less than -1 SD, and this principle applies to postmenopausal women with osteopenia 2
• For patients with osteopenia at increased risk, 1-2 year follow-up is recommended to assess for progression 1
• Critical pitfall to avoid: Ensure repeat measurements are performed on the same DXA scanner at the same facility using identical positioning and technique, as vendor differences prohibit direct comparison unless cross-calibration has been performed 2, 1
• Compare BMD values (in g/cm²), not T-scores, between scans 2

Additional Risk Factors That Would Trigger Earlier Intervention

Consider pharmacologic therapy now (without waiting for repeat scan) if two or more of the following risk factors are present: 1

• Family history of hip fracture
• Current smoking or history of smoking
• BMI <24
• Oral glucocorticoid use for >6 months

When Pharmacologic Treatment Would Be Indicated

• Immediate treatment: If VFA reveals a vertebral fracture, or if FRAX shows high fracture risk as defined above 2, 1
• First-line therapy: Bisphosphonates (alendronate 70 mg weekly or risedronate 35 mg weekly) 1
• Alternative: Denosumab 60 mg subcutaneously every 6 months if bisphosphonates cannot be tolerated 1

Common Pitfalls to Avoid

• Do not focus solely on the T-score for treatment decisions; fracture risk is a continuum and many fractures occur in patients with osteopenia rather than osteoporosis 2, 1
• Do not wait 3 years for repeat scanning in a postmenopausal woman with osteopenia, as significant bone loss can occur in this timeframe 2, 1
• Do not skip VFA if the patient meets criteria, as identifying a silent vertebral fracture would immediately change management 2
• Do not assume normal BMD elsewhere means low fracture risk; site-specific measurements can vary significantly, and forearm measurements may be warranted in certain populations 4, 5