Measurable definitions of ankylosing spondylitis management recommendations are needed for use in observational studies

To evaluate the influence of tumor necrosis factor (TNF) blocker on the radiographic progression in ankylosing spondylitis (AS) patients.A total of 610 patients were recruited. We stratified two groups (TNF blocker naïve and exposure patients). After then, we analyzed the radiographic spinal progression. Univariable and multivariable analyses were performed to identify predictors associated with radiographic progression, which was assessed by...