May 20, 2014

Post-market drug safety and effectiveness in ankylosing spondylitis (AS)

Query 10-22b: The effects of Disease-Modifying Anti-Rheumatic Drugs (DMARDs) in Ankylosing Spondylitis (AS).

This research was funded by the Drug Safety and Effectiveness Network (DSEN) and conducted by the following investigators: Cristiano S Moura, Walter P Maksymowych, Michal Abrahamowicz, Sasha Bernatsky and the CAN-AIM Team.


  • Ankylosing spondylitis (AS) is serious inflammatory arthritis that requires immune-suppressing treatment to avoid disability. Anti-tumour necrosis factor-α (anti-TNF-α) therapy may provide substantial benefits for AS patients. However, since the drug is a potent immune suppressor, concerns exist regarding infections associated with anti-TNF use in AS.

Study aim:

  • To assess the risk of hospitalized infection among initiators of disease-modifying anti-rheumatic drugs (DMARDs) and/or anti-TNF agents in AS.

Study description:

  • CAN-AIM conducted a population-based cohort study of AS patients in Quebec (QC), focusing on new users of anti-TNF drugs and/or DMARDs between 2001 and 2011.
  • We used Cox proportional hazards regression models with three time-varying drug exposures: current use of DMARDs without anti-TNF, current use of anti-TNF agents alone or in combination with DMARDs (anti-TNF ± DMARDs), and current non-use. The outcome measure was a severe infection defined based on hospitalization discharge diagnoses (primary or non-primary).

Study findings:

  • We found no clear evidence that the risk of hospitalized infection was linked to DMARD and/or anti-TNF drug use.
  • Prior high use of healthcare, corticosteroids, and previous hospitalized infections were associated with higher infection risk in AS. These factors thus represent subsets of individuals with the greatest infection risk.


  • We evaluated the risk of hospitalized infection among initiators of disease-modifying anti-rheumatic drugs (DMARDs) and/or anti-tumour necrosis factor (anti-TNF) agents in ankylosing spondylitis (AS).
  • We did not find clear evidence that AS patients initiating DMARDs and/or anti-TNF agents are at higher risk of hospitalized infection. Because of scarce published literature on the risk of infection in AS patients, our results have important implications for clinicians.

We presented the results at the Canadian Rheumatology Association (CRA) meeting in Quebec City, Quebec in February 2015, and the EUropean League Against Rheumatism (EURLA) meeting in Rome, Italy in June 2015.

Moura et al. Persistence of Anti-TNF and nbDMARD use in a Population-Based Sample of Ankylosing Spondylitis in Quebec. JRheum #40 Canadian Rheumatology Association (CRA) Annual Scientific Meeting. Quebec City, Canada. 4-7 February 2015.

Moura et al. Risk of hospitalized serious infection in spondylitis ankylosing patients using nbDMARD or Anti-TNF.  Ann rheum dis 2015; 74(suppl2): 266. Annual European Congress of Rheumatology EULAR. Rome, Italy. 10-13 June 2015.

Moura C, Rahme E, Maksymowych W, Abrahamowicz M, Bessette L, Bernatsky S. Use of disease-modifying anti-rheumatic or anti-tumour necrosis factor drugs and risk of hospitalized infections in ankylosing spondylitis (AS).  Scandinavian Journal of Rheumatology. 2018 Aug;1-7.

For more information, contact: Autumn Neville, Research Coordinator.