Objectives: The formation of spinal syndesmophytes is an important outcome measure in ankylosing spondylitis (AS) but the predictors of new syndesmophyte development in female AS patients are unknown. This longitudinal study aimed to assess the rate and predictors of development of new syndesmophytes over a 2-year period in female AS patients.
Method: Clinical and radiographic data were collected at baseline and after 2 years in 67 female AS patients. Spinal radiographs were scored using the Stoke AS Spinal Score (SASSS). Univariate logistic regression analyses were performed to identify predictors associated with new syndesmophyte development.
Results: Eleven (16%) patients had syndesmophytes at baseline. Nine (13.4%) patients had developed new syndesmophytes in their lumbar spines after 2 years. In the univariate logistic regression analyses, older age, longer disease duration, severe sacroiliitis, elevated C-reactive protein (CRP) levels at baseline, and one or more pre-existing syndesmophytes were associated with the occurrence of new syndesmophytes. After adjustment for baseline SASSS, increases in SASSS were statistically significantly higher in patients with elevated baseline CRP levels (p = 0.002) than in patients with normal CRP at baseline.
Conclusions: Older age, longer disease duration, severe sacroiliitis, the baseline presence of syndesmophytes, and elevated levels of CRP are predictors of the development of new syndesmophytes in female AS patients.