What does a DEXA (Dual-Energy X-ray Absorptiometry) scan with a T score of -2.3 in the spine indicate in an older adult, and what is the recommended management?

DEXA T-Score of -2.3 in the Spine: Diagnosis and Management

A T-score of -2.3 in the spine indicates osteopenia (low bone mass), not osteoporosis, and requires fracture risk assessment using FRAX before deciding on pharmacologic treatment. 1

Diagnostic Classification

• Osteopenia is defined as a T-score between -1.0 and -2.5, placing your result of -2.3 squarely in this category according to WHO classification 1, 2
• This is not osteoporosis, which requires a T-score ≤ -2.5 3, 2
• Approximately 50% of fragility fractures occur in patients with osteopenia, so this diagnosis still carries significant fracture risk 1
• The diagnosis should be based on the lowest T-score at any recommended site (spine, femoral neck, or total hip) 4

Critical Risk Assessment Required Before Treatment

You must calculate the 10-year fracture probability using FRAX before making any treatment decisions 1. This tool incorporates:

• Age and gender 1
• BMI (height and weight) 1
• Hip BMD measurement 1
• Family history of hip fracture 1
• Current smoking status 1
• Glucocorticoid use 1
• Rheumatoid arthritis 1
• Personal history of fragility fracture after age 50 1

Treatment Decision Algorithm

Initiate Pharmacologic Therapy If:

• 10-year hip fracture probability ≥ 3% OR 10-year major osteoporotic fracture probability ≥ 20% 1
• Personal history of fragility fracture after age 50, regardless of FRAX score 1
• Glucocorticoid therapy ≥ 7.5 mg prednisone equivalent/day for ≥ 3 months (note: glucocorticoid-induced osteoporosis causes fractures at higher BMD levels, so treatment should be considered at T-score < -1.5) 2
• Two or more additional risk factors, even if FRAX thresholds are not quite met—use clinical judgment 1

Do NOT Automatically Prescribe Medication:

• Avoid prescribing osteoporosis medication based solely on T-score -2.3 without FRAX calculation 1
• Treatment decisions exist on a continuum and require incorporation of all risk factors 1

Non-Pharmacologic Management (Universal for All Patients)

All patients with osteopenia should receive 4:

• Calcium supplementation: 1000-1200 mg daily 4
• Vitamin D supplementation: 800-1000 IU daily 4
• Weight-bearing exercise regimen 4
• Fall prevention strategies 4
• Smoking cessation 4
• Limited alcohol consumption 4

Pharmacologic Treatment Options (If Indicated by FRAX)

• Oral bisphosphonates are first-line treatment 2
• Denosumab 60 mg subcutaneously every 6 months is an alternative if bisphosphonates are contraindicated or not tolerated 4
  • Critical warning: Must transition to bisphosphonate if denosumab is discontinued to prevent rebound bone loss 4

Monitoring Strategy

• Repeat DEXA scanning in 1-2 years on the same machine using the same protocol 4, 1
• Compare absolute BMD values (g/cm²), NOT T-scores or Z-scores, between scans to assess change 3, 1
• Changes must exceed the Least Significant Change (LSC) to be considered clinically meaningful 3
• The maximal acceptable LSC for a technologist is 5.3% for the lumbar spine 3

Additional Evaluation Recommended

• Consider Vertebral Fracture Assessment (VFA) imaging at baseline, especially if over age 65, as vertebral fractures are the strongest predictor of future fractures 4, 3
• Evaluate for secondary causes of low bone mass: endocrine disorders, malabsorption, chronic inflammatory disease, untreated premature menopause 2
• Review medications, particularly glucocorticoids 2

Common Pitfalls to Avoid

• Do not skip FRAX calculation—this is the most common error in osteopenia management 1
• Do not use T-scores if the patient is premenopausal or male < 50 years old; use Z-scores instead 3
• Do not ignore VFA imaging—vertebral fractures can occur even with normal or osteopenic BMD 3, 4
• Do not compare T-scores between follow-up scans; always compare absolute BMD values 3, 1
• Recognize that fracture risk exists on a continuum—BMD is only one component of bone strength 1