Associations between smoking and extra-axial manifestations and disease severity in axial spondyloarthritis: results from the BSR Biologics Register for Ankylosing Spondylitis (BSRBR-AS)

We are grateful to the staff of the BSRBR-AS register, who are currently Claudia Zabke, Elizabeth Ferguson-Jones, Maureen Heddle, Nafeesa Nazlee and Barry Morris, and to the recruiting staff at the clinical centres, details of which are available at: https://www.abdn.ac.uk/iahs/research/epidemiology/spondyloarthritis. SZ analysed the data and wrote the manuscript, with significant input from all co-authors. GJM and GTJ are Chief Investigator and Deputy Chief Investigator, respectively, on BSRBR-AS and designed the study and oversaw its conduct. In the current project, they discussed results and provided input into drafts of the manuscript. NJG and RJM contributed towards design of the current analysis and drafting of the manuscript. DMH and LED contributed towards statistical analyses and provided input into the manuscript. Funding: The BSRBR-AS is funded by the British Society for Rheumatology (BSR) who have received funding for this from Pfizer, AbbVie and UCB. These companies receive advance copies of manuscripts for comments. They have no input into determining the topics for analysis or work involved in undertaking it. Disclosure statement: The authors have declared no conflicts of interest. Supplementary data Supplementary data are available at Rheumatology online.