Ankylosing Spondylitis and Military Deployment Fitness: Evaluation Criteria

Ankylosing spondylitis (AS) is a chronic axial spondyloarthritis causing inflammatory back pain, progressive spinal fusion, and extra-articular manifestations (uveitis, IBD, psoriasis). Military fitness for deployment depends on functional capacity, not diagnosis alone.

Deployment-Limiting Factors

• Spinal mobility loss: Reduced lumbar flexion, chest expansion <2.5 cm → impaired load-bearing, NBC gear wear.
• Chronic pain/fatigue: Limits rucking, prolonged sitting/standing, sleep in austere conditions.
• Flare unpredictability: Acute inflammation may require evacuation.
• Medication constraints: Biologics (TNFi, IL-17i, JAKi) require cold chain, monitoring, infection risk in deployed settings.
• Comorbidities: Uveitis (vision), IBD (bowel), cardiovascular disease (accelerated atherosclerosis).

Medical Evaluation Board (MEB) / Physical Evaluation Board (PEB)

• Assess: BASDAI, BASFI, ASDAS, spinal imaging (mSASSS), extra-articular status.
• Determine: Fit, fit with limitations (non-deployable), or unfit (disability separation/retirement).
• DoD Instruction 6130.03 and Service-specific guidelines govern retention standards.

Mitigation Strategies

• Optimize disease control pre-deployment (treat-to-target ASDAS <2.1).
• Physical therapy: posture, chest expansion, core strengthening.
• Medication planning: switch to deployable regimen if possible (e.g., sulfasalazine for peripheral arthritis; discuss biologic hold risks).
• Profile (PULHES) assignment reflecting limitations.

Many with well-controlled AS deploy successfully; severe axial fusion or refractory disease usually precludes combat deployment. Early rheumatology-command communication is essential.