Correlation Among Disease Activity, Musculoskeletal Function, and Quality of Life in Patients with Ankylosing Spondylitis with Mild to Moderate Radiographic Signs

Purpose To examine the relationship among disease activity, musculoskeletal function, and quality of life (QOL) in ankylosing spondylitis (AS) with mild to moderate radiographic signs. For understanding how muscle strength and function associations QOL in AS with different radiographic signs. Methods Fifty-one adults with AS according to their radiographic signs were divided into a sacroiliitis (mild) or a syndesmophytes (moderate) group. Twenty-three healthy adults were enrolled as normal controls. Disease activity were measured with Bath AS Disease Activity Index (BASDAI) and informative marker of laboratory data. Bath AS Functional Index (BASFI), musculoskeletal function, and the Metrology Index (BASMI) were used to measure muscle function. QOL was assessed using the 36-Item Short-Form Health Survey (SF-36). Results Significant differences were observed in BASFI, BASMI, grip strength, and the acceleration pattern in the sit-to-stand (STS) between the AS and the control group. However, no significant difference in QOL was present. Spinal mobility, shoulder proprioception, and immunoglobulin A level differed between the two AS subgroups. Disease activity was significantly correlated with QOL. Grip strength was significantly correlated with QOL subscales, pain, lumbar side flexion, and cervical rotation range; chest expansion was correlated with QOL subscales and cervical rotation. The 2-minute step test scores were significantly correlated with social functioning and prednisolone use. Conclusion The patient had well managed in disease activity with fair QOL. The spinal mobility and proprioception of patients with syndesmophytes were seriously affected. The muscle strength and STS motion pattern were adversely affected by the disease even on the sacroiliitis AS.