Efficacy of device-based inspiratory muscle training as an adjunct therapy in ankylosing spondylitis patients: A randomized controlled trial

Abstract

Aim: To evaluate the effectiveness of device-based inspiratory muscle training (IMT) compared with conventional exercises (CE) on pulmonary function, disease activity, functional status, mood, and quality of life in patients with ankylosing spondylitis (AS). Methods: This randomized controlled trial included 40 patients with AS who were allocated to receive standard physical therapy supplemented by either CE (n = 20) or IMT using the Respifit-S® device (n = 20). The interventions were performed for 30 minutes daily over 20 days. Outcomes, assessed pre- and post-intervention, included pulmonary function tests (PFTs), chest expansion, the Bath Ankylosing Spondylitis Disease Activity (BASDAI) and Functional (BASFI) Indices, a Visual Analog Scale (VAS) for pain, the Beck Depression Inventory (BDI), and the SF-36 questionnaire. Results: Baseline characteristics were comparable between the groups. Both groups showed significant post-intervention improvements in VAS pain, BASDAI, BASFI, chest expansion, BDI, Peak Expiratory Flow (PEF), and the SF-36 domains of General Health, Pain, and Physical Function (all p<0.05). Compared to the CE group, the IMT group showed significantly greater improvements in chest expansion (p<0.001), BDI scores (p=0.012), and the SF-36 domains of Vitality (p=0.049) and Physical Function (p=0.008). No significant between-group differences were observed for changes in the VAS, BASDAI, BASFI, PEF, or other SF-36 domains. No adverse events occurred. Conclusion: While both conventional exercises and IMT improve clinical outcomes in AS, incorporating device-based IMT provides superior benefits in enhancing chest expansion, alleviating depressive symptoms, and improving specific quality of life domains. IMT represents a valuable adjunctive therapy in the comprehensive management of ankylosing spondylitis.