Favorable effect of rehabilitation on balance in ankylosing spondylitis: a quasi-randomized controlled clinical trial

Balance impairment is a frequent and undertreated manifestation in ankylosing spondylitis, leading to increased risk of falls and lower quality of life. Our aim was to assess supervised training and home-based rehabilitation efficacy on balance improvement in ankylosing spondylitis subjects on biologic agents. This was a single-blinded, quasi-randomized parallel study in a single outpatient Rehabilitation Clinic of a tertiary referral center. Subjects with ankylosing spondylitis on biologic agents were assigned either to supervised training and home-based rehabilitation program (rehabilitation group) plus educational-behavioral therapy, or to educational-behavioral therapy alone (educational groups). The same therapist provided therapy. Outcome measures were assessed at baseline (T0), end of treatment (T1) and at 7-month follow-up (T2). Rheumatologic outcomes were Bath Ankylosing Spondylitis Metrology Index, Bath Ankylosing Spondylitis Functional Index and Bath Ankylosing Spondylitis Disease Activity Index. Balance parameters (anterior-posterior oscillation, latero-lateral oscillation, sway area, sway density and sway path) were evaluated by stabilometry in a condition of open and closed eyes. Forty-six subjects (36 M, 10 F) were enrolled. Demographic data and clinical status at baseline were comparable between the two groups (22 rehabilitation group, 20 educational group). Primary outcome was sway density that improved both at T1 (SDy: open eyes p = 0.003, closed eyes p = 0.004) and at T2 (SDx: open eyes p = 0.0015, closed eyes p = 0.032). A trend toward improvement in the rehabilitation group rather than in the educational group emerged for balance parameters, especially those measured with closed eyes (0.004 < p < 0.048 at T1 and 0.004 < p < 0.036 at T2). Supervised training and home exercise lead to balance improvement in people with ankylosing spondylitis. Eyes-closed trials show a more marked trend toward improvement, and this may suggest a positive effect of rehabilitation on proprioception.