Different clinical expression of patients with ankylosing spondylitis according to gender in relation to time since onset of disease. Data from REGISPONSER.

OBJECTIVE: To describe the differential characteristics by gender and time since disease onset in patients diagnosed with ankylosing spondylitis (AS) attending the Spanish rheumatology clinics, including those on the "Spanish Registry of spondyloarthritis" (REGISPONSER), as well as the diagnostic and therapeutic implications that this entails.

PATIENTS AND METHODS: This is a transversal and observational study of 1514 patients with AS selected from 2367 spondyloarthritis cases included in REGISPONSER. For each patient, the demographics, epidemiology, geriatric, clinical, laboratory, radiological, and therapeutic aspects were were evaluated and comprehensively recorded under the aegis of REGISPONSER, constituting the Minimum Basic identifying data for the disease. Physical function was assessed by Bath Ankylosing Spondylitis Functional Index (BASFI). Clinical activity was evaluated using erythrocyte sedimentation rate, C reactive protein and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Each patient underwent pelvic anteroposterior, anteroposterior and lateral lumbar spine as well as lateral cervical spine x rays; they were scored according to the Bath Ankylosing Spondylitis Spine Radiographic Index, which measures structural damage.

RESULTS: Of the 1514 patients screened, 1131 (74.7%) were men. We found significant differences in age at onset of symptoms as well as in the day of inclusion, between the two groups, being lower in men. We also obtained differences in the duration of the disease, which was lower in women. As for the existence of a history of AS among first-degree relatives, family forms were more common among women. The mean BASDAI score was also higher in women, regardless of time since onset of disease. In contrast, the improvement of pain with the use of NSAID's and radiological severity were higher in men, both reaching statistical significance.

CONCLUSIONS: Among the Spanish AS patients, there are some differences in the clinical manifestations, even when the time since onset of disease was controlled; we also found radiological differences by gender; men showing more structural damage, while women were more active. These data suggest that the phenotype of AS differs between genders. This can influence the subsequent diagnostic approach and therapeutic decisions.