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Tumour necrosis factor inhibitors slow radiographic progression in patients with ankylosing spondylitis: 18-year real-world evidence
  1. Bon San Koo1,
  2. Ji Seon Oh2,
  3. Seo Young Park3,
  4. Ji Hui Shin4,
  5. Ga Young Ahn5,
  6. Seunghun Lee6,
  7. Kyung Bin Joo6,
  8. Tae-Hwan Kim4
  1. 1 Department of Internal Medicine, Inje University Seoul Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea
  2. 2 Department of Biomedical Informatics, Asan Medical Center, Seoul, Republic of Korea
  3. 3 Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
  4. 4 Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea
  5. 5 Department of Rheumatology, Department of Internal Medicine, Korea University Guro Hospital, Seoul, Republic of Korea
  6. 6 Department of Radiology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea
  1. Correspondence to Dr Tae-Hwan Kim, Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul 04763, Republic of Korea; thkim{at}


Objectives Tumour necrosis factor inhibitors (TNFis) have been suggested to slow radiographic progression in patients with ankylosing spondylitis. However, limitations such as variations in disease activity, complex drug administration and short follow-up duration make it difficult to determine the effect of TNFis on radiographic progression. The aim of the study was to investigate whether long-term treatment with TNFis can reduce radiographic progression in patients with ankylosing spondylitis using 18-year longitudinal real-world data.

Methods This retrospective study was conducted between January 2001 and December 2018 at a single centre. Among the 1280 patients whose electronic medical records were reviewed, data of 595 patients exposed to TNFis at least once were included. Among them, time intervals of TNFi exposure or non-exposure were determined in 338 patients (‘on the TNFis’ or ‘off the TNFis’ intervals, respectively). The difference in the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) change rate between ‘on the TNFis’ and ‘off the TNFis’ intervals was investigated.

Results We obtained 2364 intervals of 338 patients (1281 ‘on the TNFis’ and 1083 ‘off the TNFis’ intervals). In the marginal structural model for inverse probability of treatment weighting, the change rate of mSASSS significantly decreased with the use of TNFis (β=−0.112, p=0.004), and the adjusted mSASSS changes were 0.848 and 0.960 per year during ‘on the TNFis’ and ‘off the TNFis’ intervals, respectively.

Conclusion Compared with treatment without TNFis, treatment with TNFis slowed radiologic progression significantly.

  • ankylosing spondylitis
  • anti-TNF
  • epidemiology
  • treatment
  • disease activity

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  • Handling editor Josef S Smolen

  • Presented at The results of the study were presented at the American College of Rheumatology Annual Meeting 2019, Atlanta,

    Georgia (8–13 November).

  • Contributors Dr THK had full access to all the data in the study and takes responsibility for the integrity of the data, study supervision and accuracy of the data analysis. All authors participated in the interpretation of data, drafting, revision and approval of the manuscript. BSK, JSO, SYP and THK contributed to the study conception and/or design. BSK, JSO and SYP help in the statistical analysis. JHS, GYA, SL, KBJ and THK provided administrative, technical or material support.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Requirement for informed consent was waived because this study was a retrospective review of electronic medical records.

  • Patient consent for publication Not required.

  • Ethics approval The study design was approved by the appropriate ethics review board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Study protocol and statistical code: Available on request from Dr Park ( Data set: Available on request and signature of a confidentiality agreement from Prof Kim (