Rethinking the Link between NSAIDs and IBD Flares

This is the 4000th blog post for GutsandGrowth!

S Cohen-Meckelburg et al. American Journal of Gastroenterology 2022: doi:10.14309/ajg.0000000000001932. The association between non-steroidal anti-inflammatory drug use and inflammatory bowel disease exacerbations: a true association or residual bias?

Background: NSAIDs are well-known to cause gastrointestinal injury. While single center studies have suggested that NSAIDs are associated with increased IBD flares, a systemic review of 18 studies found no consistent association between NSAIDs and IBD exacerbation.

This study included 15,705 (44.8%) and 19,326 (55.2%) IBD patients with and without an NSAID exposure.

Key findings:

  • Findings from a Cox proportional hazards model suggest an association between NSAIDs and IBD exacerbation (HR 1.24; 95%CI 1.16-1.33)
  • However, the likelihood of an IBD exacerbation in the NSAID exposed arm preceding NSAID exposure was similar (HR 1.30; 95%CI 1.21-1.39).
  • Those who received NSAIDs were already at increased risk of experiencing a disease flare. And the prior event rate ratio for IBD exacerbation, as determined by dividing the adjusted HR after NSAID exposure by the adjusted HR for pre-NSAID exposure, was 0.95 (95% CI, 0.89 – 1.01).
  • “A self-controlled case series analysis of 3,968 patients who had both an NSAID exposure and IBD exacerbation demonstrated similar exacerbation rates in the 1-year preceding exposure, 2-6 weeks post-exposure, and 6-weeks to 6-months post-exposure, but higher incidence 0-2 weeks post-exposure, suggesting potential confounding by reverse causality.” The self-controlled part of the study allowed patients to serve as their own controls which allowed adjustment for many factors that are difficult to control with retrospective studies.
  • 75% of patients with IBD who were prescribed an NSAID did not have an IBD exacerbation during a mean of 5.9 years of follow-up
  • NSAIDs were commonly used: 36.5% of patients with IBD had received at least one NSAID prescription
  • NSAIDs use was prescribed more frequently in patients with immune targeted therapy (likely a marker for moderate to severe disease)

Discussion points:

  • The estimated prior event ratio of 0.95 suggests that the risk of IBD flares in NSAID-exposed patients preceded the use of NSAIDs. The risk of IBD exacerbation did not increase in the 2 weeks to 6 months after NSAID exposure.
  • The overall association of increased IBD flare is likely related to reverse causation. Patients may take NSAIDs due to arthropathy or other symptoms that may be an early manifestation of a flare.

My take: This study challenges the prevailing view that NSAID use worsen inflammatory bowel disease; it is more likely that IBD exacerbations are due to underlying risk from more severe disease and residual confounding/reverse causality. The study provides reassurance that short-duration use is likely to be well-tolerated in most patients with IBD.

Medscape Gastroenterology (summary of this study): Reassuring Data on NSAIDs in IBD Flares

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