A Register-Based, Epidemiological Evaluation of Disease Activity and Functional Performance in Ankylosing Spondylitis Patients After Multimodal Spa Therapy in Austria

Abstract Objective Evidence regarding the impact of multimodal treatment on disease activity and functional performance in ankylosing spondylitis (AS) remains scarce. This study aims to evaluate changes in these outcomes after multimodal rehabilitation, using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Functional Index (BASFI). Methods Mixed-effects linear regression was performed on prospectively collected registry data to explore associations between timepoints and BASDAI/BASFI. Predicted linear margins from fixed effects were calculated for each timepoint. Data were derived from AS patients who underwent multimodal rehabilitation and completed questionnaires at baseline (T0), post-intervention (T1), and at 3 (T2), 6 (T3), and 9 (T4) months follow-up. Results Twohundred-fourtynine AS patients were included (52.14 ± 10.20 years; 42.57% female, BMI: 26.64 ± 4.27 kg/m2). Compared to baseline, BASFI/BASDAI improved significantly until 6 and 9 months, respectively. Predicted BASDAI scores at T0, T1, T2 and T3 were 2.99 (95%CI 2.77; 3.21), 2.31 (2.08; 2.53), 2.38 (2.15; 2.61) and 2.69 (2.46; 2.92). At T4 the score was higher than at T0 (3.04 (2.81; 3.28)). Compared to T0, BASDAI score at T1 reflected a clinically relevant change. Predicted BASFI scores at T0, T1, T2, T3 and T4 were 4.09 (3.88; 4.31), 2.71 (2.49; 2.94), 2.83 (2.60; 3.06), 3.24 (3.01; 3.46) and 3.59 (3.36; 3.82). Compared to T0, BASFI scores at T1, T2 and T3 reflected a clinically relevant change. Conclusion Significant improvements in physical functioning and disease activity among AS patients following multimodal rehabilitation were found. Such interventions may serve as a valuable complement to pharmacological treatment. What is really known on this topic Non-pharmacological, multimodal treatment approaches play a key role in treating AS patients by complementing pharmacological treatment regimens. What this study adds To our knowledge this is the first study to evaluate changes in BASFI and BASDAI in context of multimodal spa therapy. Significant improvements in both BASFI and BASDAI up to 9 months after treatment. How this might affect research, practice, or policy The findings may complement the lack of knowledge in context of disease activity and physical performance after multimodal treatment interventions. The study might also emphasize the determination of adequate treatment intervals.