Spinal Mobility, Vertebral Squaring, Pulmonary Function, Pain, Fatigue, and Quality of Life in Patients With Ankylosing Spondylitis

OBJECTIVE To investigate the relationships between spinal mobility, pulmonary function, structural change of the spine, pain, fatigue, and quality of life (QOL) in patients with ankylosing spondylitis (AS). METHODS Thirty-six patients with AS were recruited. Their spinal mobility was examined through seven physical tests: modified Schober test, lateral bending, chest expansion, occiput to wall, finger to ground, bimalleolar distance, and range of motion (ROM) of the spine. Pulmonary Function Test (PFT) was performed using a spirometer, and vertebral squaring was evaluated through the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). QOL, disease activity, functional capacity, and fatigue were evaluated by SF-36 Health Survey (SF-36), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), and the Multidimensional Assessment of Fatigue (MAF) scale, respectively. Perceived physical condition and degree of pain were assessed using 10 cm visual analogue scale. RESULTS Participants showed reduced spinal mobility, which was negatively correlated with mSASSS. PFT results showed reduced forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) and increased FEV1/FVC. Reduced FEV1 and FVC showed positive correlations with reduced spinal mobility and a negative relationship with mSASSS. Perceived physical condition and degree of pain were both significantly related to the SF-36, BASDAI, BASFI, and MAF scores. CONCLUSION This study shows that both reduced spinal mobility and radiographic changes in the vertebral body may have a predictive value for pulmonary impairment in patients with AS. Likewise, pain and perceived physical condition may play an important role in the QOL, functional capacity, and fatigue level of these patients.