Comment on: Tumour necrosis factor inhibitor survival and predictors of response in axial spondyloarthritis—findings from a United Kingdom cohort: reply

Sir, We thank Al Arashi et al. [1] for their interest and comments on our recent report on tumour necrosis factor inhibitor (TNFi) survival and predictors of response in axial spondyloarthritis—findings from a United Kingdom cohort [2].

We did not focus specifically on sex differences in our analysis but have now undertaken further analyses on sex differences in our study population. We found a higher prevalence of acute anterior uveitis (44.9 vs 33.9%, P = 0.03) and family history of SpA (45.2 vs 30.4%, P = 0.02) in females, but not for IBD (females 16.8% vs males 11.9%, P = 0.19) or psoriasis (females 24.3% vs males 19.5%, P = 0.29). This is similar to previous studies, which reported that women are more affected by uveitis in SpA [3] and AS [4].

In our cohort, BASDAI50 response 3–6 months after initiation of index TNFi was achieved by 56 (58.3%) females and 219 (61.5%) males (P = 0.64). Discontinuation rates for index TNFi were higher in females (females n = 56, 37.3%; males n = 168, 33.5%). In addition, females had higher rates of adverse events (44.6 vs 33.9%), and males had a slightly higher proportion of primary non-response (15.5 vs 14.3%) and secondary non-response (20.8 vs 16.1%). None of these differences reached statistical significance.

In conclusion, there are differences between our cohort and those reported by Al Arashi et al. [1]; however, sample sizes are small. Larger prospective studies are required to evaluate sex differences in axSpA.

Funding: No specific funding was received from any funding bodies in the public, commercial or not-for-profit sectors to carry out the work described in this manuscript.

Disclosure statement: F.Y. has received funding to attend congresses and speakers fees from Novartis, Pfizer and AbbVie and has received grants and consultancy from Novartis. K.G. has received research grants, consultancy and speaker fees from AbbVie, Pfizer, Novartis and UCB Pharma. L.H. has received funding for attending congresses from UCB Pharma. C.B. has received training grant from Arthritis Research UK, travel costs to conference from AbbVie and conference fees paid by Pfizer. D.B. has received funding for attending congresses from Pfizer, AbbVie and Chugai, and is on advisory boards for Roche, Chugai and Novartis. R.S. has received speakers fees, consultancy and/or grants from AbbVie, Celgene, Merck Sharp & Dohme, Novartis, Pfizer and UCB Pharma. All other authors have declared no conflicts of interest.