Response to ‘Correspondence on 'Tumour necrosis factor inhibitors slow radiographic progression in patients with ankylosing spondylitis: 18-year real-world evidence' by Zhanget al

We thank Zhang et al 1 for their interest in our study, titled “Tumour necrosis factor inhibitors slow radiographic progression in patients with ankylosing spondylitis: 18-year real-world evidence.” We investigated long-term observational data using advanced statistical methods to determine whether changes in radiographic progression are affected by tumour necrosis factor inhibitors (TNFi) in patients with ankylosing spondylitis (AS).2 However, our study did not consider the risk of osteoporosis or vertebral fractures while evaluating the effects of TNFi. There are several studies on bone mineral density (BMD) in patients with AS. Compared with the general population, patients with AS have a lower BMD.3–5 …