Although female patients with ankylosing spondylitis score worse on disease activity than male patients and improvement in disease activity is comparable, male patients show more radiographic progression during treatment with TNF-α inhibitors

Abstract Background The clinical presentation of ankylosing spondylitis (AS) differs between genders. Our aim was to investigate differences in disease activity, disease outcome and treatment response between male and female AS patients before and after starting tumor necrosis factor (TNF)-α inhibitors in daily clinical practice. Methods Patients from the Groningen Leeuwarden AS (GLAS) cohort who started TNF-α inhibitors and who had visits at baseline and after 3 months and/or 2years of follow-up were included. Results Of 254 included AS patients, 69% were male. At baseline, female patients scored significantly higher on BASDAI, ASDAS, and tender entheses than male patients. In contrast, CRP, swollen joints, and history of extra-articular manifestations were comparable between genders. Women experienced significantly worse physical function and QoL, whereas men showed significantly more kyphosis and spinal radiographic damage. After 3 months and 2years of follow-up, all clinical assessments improved significantly, with comparable mean change scores for female and male patients; mean 2-year change in BASDAI -2.7 vs. -2.7, ASDAS -1.50 vs. -1.68, tender entheses -2.4 vs. -1.4, CRP -8 vs. -8, BASFI -2.2 vs. -2.1 and ASQoL -5 vs. -4, respectively. Radiographic progression was significantly higher in male patients. Female patients switched more frequently to another TNF-α inhibitor during 2years of follow-up (32% vs. 14%). Conclusion Although female patients experienced higher disease activity, worse physical function and quality of life, and switched TNF-α inhibitors more often, clinical improvement during treatment with TNF-α inhibitors was comparable between genders. However, male patients showed more radiographic spinal damage after 2years.