How should the DEXA scan results (lumbar spine T-score –2.6, left femoral neck T-score –3.2, right femoral neck T-score –2.8, total left –2.8, total right –2.5) and a 5.7% decrease in hip bone density be interpreted in a 71‑year‑old woman?

DEXA Scan Interpretation: Severe Osteoporosis Requiring Immediate Pharmacologic Treatment

This 71-year-old woman has severe osteoporosis with a left femoral neck T-score of –3.2 and concerning bone loss progression (5.7% hip density decrease), meeting criteria for immediate pharmacologic therapy with bisphosphonates as first-line treatment. 1

Diagnostic Classification

Your patient's DEXA results clearly establish severe osteoporosis across multiple skeletal sites:

• Left femoral neck: –3.2 (worst site, diagnostic)
• Right femoral neck: –2.8 (osteoporotic)
• Lumbar spine: –2.6 (osteoporotic)
• Total hip left: –2.8 (osteoporotic)
• Total hip right: –2.5 (osteoporotic threshold)

Any T-score ≤ –2.5 at the lumbar spine, femoral neck, or total hip confirms osteoporosis, and this diagnosis persists even if future scans improve 1, 2. The femoral neck is the WHO-designated reference site, and your patient's left femoral neck at –3.2 places her in the "very low" BMD category (T-score < –3.0), which is specifically identified as a very high fracture risk feature 1.

Critical Concern: Progressive Bone Loss

The 5.7% decrease in hip bone density since the last scan is alarming. This rate of loss exceeds normal measurement variability (least significant change is typically 4-5%) 3, indicating true bone loss rather than measurement error. This progression, combined with already severe osteoporosis, elevates fracture risk substantially.

Common pitfall: Do not dismiss this as "stable osteoporosis" simply because she hasn't fractured yet. The combination of severe BMD deficit and documented progression defines very high fracture risk 1.

Treatment Recommendation: Immediate Pharmacologic Therapy

Pharmacologic therapy is strongly recommended (Grade A evidence) for any patient with T-score ≤ –2.5 1. Your patient exceeds this threshold at multiple sites.

First-Line Treatment: Bisphosphonates

Bisphosphonates should be initiated as first-line therapy 4. Options include:

• Alendronate: 70 mg weekly (oral)
• Risedronate: 35 mg weekly (oral)
• Zoledronic acid: 5 mg annually (IV)

Selection should be based on patient preference and tolerability 4. Oral bisphosphonates require the patient to remain upright for 30 minutes after administration and are contraindicated with esophageal abnormalities 4.

Expected BMD improvements at 2 years: Alendronate increases lumbar spine BMD by ~7% and total hip by ~5%; zoledronic acid shows similar gains 3.

Alternative Considerations

Given her very high fracture risk (T-score < –3.0 plus progressive bone loss), consider:

• Denosumab (60 mg subcutaneous every 6 months): Appropriate for high fracture risk, increases spine BMD by ~8% and hip by ~5% 3, 1
• Anabolic agents (romosozumab, teriparatide): Reserved for very high risk patients, though typically after bisphosphonate failure or in those with prior fractures 1

Critical warning about denosumab: If started, it requires indefinite continuation or transition to bisphosphonate, as discontinuation causes rapid bone loss and rebound fracture risk 1, 5.

Essential Concurrent Interventions

Calcium and Vitamin D Supplementation

At age 71, she requires 4:

• Calcium: 1,200 mg daily
• Vitamin D: 800 IU daily
• Target serum vitamin D level: ≥20 ng/mL (50 nmol/L)

Check her vitamin D level if not recently measured; deficiency is common and impairs treatment response.

Lifestyle Modifications (Grade A-B evidence)

• Weight-bearing and resistance exercises 1
• Balance training to reduce fall risk 1
• Smoking cessation if applicable 1
• Limit alcohol intake 4
• Fall risk assessment and home safety evaluation 1

Evaluate for Secondary Causes

The progressive bone loss warrants evaluation for secondary osteoporosis:

• Complete metabolic panel (calcium, phosphate, creatinine)
• 25-hydroxyvitamin D level
• Thyroid function tests
• Complete blood count
• Consider: celiac screening, serum protein electrophoresis, 24-hour urine calcium if clinically indicated

Monitoring Strategy

Follow-up DEXA in 1-2 years after treatment initiation 3:

• Total hip BMD is preferred for monitoring treatment response (more reliable than spine) 3, 6
• Stable or increasing BMD indicates adequate response 3
• Continued bone loss despite treatment should prompt evaluation for non-adherence or secondary causes 3

Bone turnover markers (CTX, P1NP) at 3-6 months can assess early treatment response, though BMD remains the primary monitoring tool 3.

Fracture Risk Context

Without treatment, her 10-year fracture probability is likely:

• Hip fracture risk: >4.5% (very high risk threshold) 1
• Major osteoporotic fracture risk: >30% (very high risk threshold) 1

These estimates would be refined using FRAX calculator with her specific clinical risk factors (weight, height, smoking status, prior fractures, family history, etc.) 1.

Bilateral Hip Measurement Note

The bilateral hip measurements were appropriate. Diagnosis should be based on the lowest T-score from either hip (in this case, left femoral neck –3.2), not the mean 6. Approximately 2-3% of patients have clinically significant differences between hips that affect diagnosis 7, 8, 6.