What is the recommended workup and treatment for an adult patient with suspected bone density deterioration, likely due to inflammatory arthritis or other conditions contributing to bone loss?

Workup for Bone Density Deterioration in Inflammatory Arthritis

All adults with inflammatory arthritis should undergo DXA scanning of the lumbar spine and hip at diagnosis, with additional forearm measurement in rheumatoid arthritis patients to detect early periarticular bone loss. 1, 2

Initial Diagnostic Evaluation

DXA Bone Mineral Density Testing

• Perform DXA at diagnosis of inflammatory arthritis at the lumbar spine and total hip for all adult patients 1
• Add forearm (non-dominant) measurement specifically in rheumatoid arthritis patients, as peripheral bone loss is pathognomonic for this disease and detects juxtaarticular osteoporosis earlier 2, 3
• Use T-score < -2.5 to diagnose osteoporosis in patients over 50 years old 1
• Use Z-score < -2.0 to define "low bone mass" in patients under 50 years 1

Laboratory Assessment

• Measure serum calcium and 25(OH) vitamin D levels at baseline in all patients with active inflammatory disease 1
• Check for vitamin D deficiency (common in 55% of active disease patients), particularly in those requiring glucocorticoids 1
• Assess for secondary causes: thyroid function, parathyroid hormone, gonadal status 1

Vertebral Fracture Assessment

Perform vertebral fracture assessment (VFA) or standard radiography if the patient has 1:

• T-score < -1.0 AND any of the following:
  • Historical height loss > 4 cm
  • Glucocorticoid therapy ≥ 5 mg prednisone daily for ≥ 3 months
  • Self-reported prior vertebral fracture
  • Age ≥ 70 years (women) or ≥ 80 years (men)

Risk Stratification

Calculate FRAX Score (Adults ≥ 40 Years)

• Use FRAX with femoral neck BMD to estimate 10-year fracture probability 1, 4
• For glucocorticoid users taking > 7.5 mg/day prednisone: multiply FRAX major osteoporotic fracture risk by 1.15 and hip fracture risk by 1.2 4
• Very high fracture risk is defined as: prior osteoporotic fracture(s), BMD T-score ≤ -3.5, FRAX 10-year major osteoporotic fracture ≥ 30% or hip ≥ 4.5%, or high-dose glucocorticoids (≥ 30 mg/day for > 30 days) 4

Key Risk Factors in Inflammatory Arthritis

The following factors substantially increase fracture risk beyond classical osteoporosis risk 5, 6:

• High disease activity and inflammation (upregulates RANKL/OPG pathway causing bone loss) 5, 6
• Glucocorticoid use (any dose ≥ 2.5 mg/day for ≥ 3 months) 1
• Disease duration (longer duration correlates with greater bone loss) 3
• Immobility 5

Monitoring Schedule

Repeat DXA Testing

• Every 1-3 years in adults < 40 years with: history of osteoporotic fracture, Z-score < -3, > 10%/year BMD loss, very high-dose glucocorticoids, or other significant risk factors 1
• Every 2-3 years in adults ≥ 40 years whether treated or untreated 1
• Annually in patients with low BMD, osteoporosis, fragility fractures, or those on drugs affecting BMD 1

Clinical Reassessment

Perform clinical fracture risk reassessment every 12 months including 1:

• Glucocorticoid dose, duration, and pattern of use
• Falls assessment
• New fractures
• Height measurement (without shoes) to detect vertebral compression
• Weight and BMI
• Muscle strength testing
• Assessment for spinal tenderness or deformity

Treatment Considerations

Universal Interventions

All patients should receive 1, 4:

• Calcium 1,000-1,200 mg/day
• Vitamin D 600-800 IU/day (higher doses if deficient)
• Weight-bearing exercise
• Smoking cessation
• Alcohol limitation (< 3 units/day)

Pharmacologic Treatment Thresholds

The decision to initiate osteoporosis medication depends on fracture risk stratification, with very high-risk patients (as defined above) warranting immediate treatment with anabolic agents like teriparatide over antiresorptive agents 4. For moderate to high-risk patients, bisphosphonates, denosumab, or zoledronic acid are conditionally recommended 4.

Critical Pitfalls to Avoid

• Do not rely solely on BMD in inflammatory arthritis patients, as vertebral fractures occur even with normal bone density due to altered bone quality from inflammation 1, 5
• Do not skip forearm measurement in rheumatoid arthritis, as it detects pathognomonic peripheral bone loss earlier than spine/hip 2
• Do not underestimate glucocorticoid impact: even low doses (≥ 2.5 mg/day prednisone) for ≥ 3 months significantly increase fracture risk 1
• Male patients are at particularly high risk with glucocorticoid-treated inflammatory arthritis and require aggressive monitoring 3
• Achieving clinical remission with modern DMARDs and biologics can prevent or minimize both local and generalized bone loss 5