Background Ankylosing spondylitis (AS), a chronic rheumatic disease of young adults, is the prototype of the inflammatory arthropathies. Spinal inflammation, the hallmark of AS, causes pain and stiffness leading to progressive spinal deformity and fusion from syndesmophytes and limitation of the spine and rib cage motion. It is reported that clinical picture in females is milder than in men, vertebral changes develop slowly, and the functional ability remains good for a long time.

Objectives The aim of this study was to investigate differences between men and women in AS patients in relation to age at disease onset, spine motion and respiratory index.

Methods This is retrospective study with 47 consecutive AS patients (33 male and 14 female) admitted to Rehabilitation center because of functional limitation. Average age of patients included in this study was 52.5±11.6 years (range 27-78 years). Average age of the men was 52.5± 12.3 years and female 50.6±9.8 years. Average duration of disease was 15±9.4 years in the men and 7.4±5.9 years in female patients. The disease onset was at 39.6±12.9 years (38.2±13.9 years in men and 43±9.7 years in female). Index of sagital motion for cervical, thoracic, lumbosacral spine and respiratory index were measured for all AS patients at admission to hospital. Student’s t test and multivariate logistic regression analysis were used to establish the occurrence of differences between AS patients. Dependent variable was sex and confounders: Index of sagital motion for cervical, thoracic, lumbosacral spine and Respiratory index.

Results Index of sagital motion of cervical spine was average 3.4±3.0 cm, thoracic spine 1.1±1.2 cm, lumbosacral spine 2.0±1.5cm and Respiratory index was 2.0±1.3 cm. Difference for disease onset between men and women with AS was not statistically significant (t=1, 35, p>0.05) although disease onset of men is earlier than in female. Differences of Index of sagital motion for cervical (t=-0.33, p>0.05) thoracic (t=-0.64, p>0.05), lumbosacral spine (t=-1.78, p=0.05) and Respiratory index (t=-1.21, p>0.05) were not statistically significant. Significant predictor of sex differences in AS patients was Index of sagital motion of lumbosacral spine when controlled by other confounders (p=0.017, p<0.05), OR (95 CI) = 4.46.

Conclusions Index of sagital motion of lumbosacral spine was not significantly higher in female AS patients. After adjustment with confounders, it was significant predictor of differences between men and female AS patients. Higher Index of sagital motion of lumbosacral spine was associated with female AS patients. These results can help in analyzing of results of clinical measurements and prediction of functional limitation in patients with AS.

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Disclosure of Interest None Declared