Fewer women than men respond to TNF inhibitors in ankylosing spondylitis
Women with ankylosing spondylitis showed a reduced response to TNF inhibitors compared with men, according to findings published in the Journal of Rheumatology.
“Data on sex differences in ankylosing spondylitis (AS) and particularly on differences concerning response to treatment in male and female patients were scarce and not always consistent,” Adrian Ciurea, MD, of Zurich University Hospital, in Switzerland, told Healio Rheumatology. “We confirm in this large real-life cohort, differences in disease expression between men and women with AS found in previous analyses: Men had more severely impaired spinal mobility and higher CRP levels, while a higher proportion of women presented with peripheral disease [such as arthritis and enthesitis].”
To evaluate this, Ciurea and colleagues conducted a longitudinal analysis of 440 patients from the ongoing Swiss Clinical Quality Management cohort of patients with axial spondyloarthritis, recruited from January 2005 to April 2016.
The researchers determined the proportion of patients who achieved 20% and 40% improvement response, defined by the Assessment of Spondyloarthritis international Society (ASA20 and ASA40). They also calculated Ankylosing Spondylitis Disease Activity Score (ASDAS) improvement and status scores at 1 year. Participants who discontinued TNF inhibitor treatment were considered nonresponders. In addition, ther researchers took particular effort to exclude patients with concurrent fibromyalgia, Ciurea said.
According to the researchers, women had lower mean C-reactive protein levels, better spinal mobility and more peripheral disease at baseline compared to men. By year 1, 52% of women and 63% of men demonstrated an ASAS20 response (OR = 0.63; 95%, CI 0.37-1.07; P = .09). In addition, 18% of women achieved inactive disease status compared with 26% of men (OR = 0.65; 95% CI, 0.32-1.27; P = .22). The differences in response to TNF inhibitors were more pronounced in adjusted analyses for ASAS20 (OR = 0.34; 95% CI, 0.16-0.71; P = .005) and inactive disease status (OR = 0.1; 95% CI, 0.03-0.31; P < .001).
However, there were no differences between the sexes in terms of ASDAS and quality of life, as well as the Bath Ankylosing Spondylitis Disease Activity and Functional indices.
“TNF inhibitors were initiated at the same level of disease burden as assessed by subjective measures of disease activity,” Ciurea said. “Treatment response analyses adjusted for a multitude of factors known to predict response to TNF inhibitors — [such as] HLA-B27, physical function, spinal mobility, CRP, the presence of enthesitis, smoking and BMI — demonstrated however that women with AS show a significantly impaired response to anti-TNF agents in comparison to men. Whether the differences are due to an uncoupling between symptoms and objective signs of inflammation in women will have to be assessed prospectively.” – by Jason Laday
Disclosure: Members of the Swiss Clinical Management Foundation report support from Swiss Society of Rheumatology, AbbVie, Bristol-Myers-Squibb, Janssen-Cilag, Merck Sharp & Dohme, Novartis, Pfizer, Roche, UCB, the Arco Foundation and the Swiss Balgrist Society. The researchers additionally report support from AbbVie and the Stiftung für Rheumaforschung.