Introduction of anti-TNF therapy has not yielded expected declines in hospitalisation and intestinal resection rates in inflammatory bowel diseases: a population-based interrupted time series study

Objectives To better understand the real-world impact of biologic therapy in persons with Crohn’s disease (CD) and ulcerative colitis (UC), we evaluated the effect of marketplace introduction of infliximab on the population rates of hospitalisations and surgeries and public payer drug costs. Design We used health administrative data to study adult persons with CD and UC living in Ontario, Canada between 1995 and 2012. We used an interrupted time series design with segmented regression analysis to evaluate the impact of infliximab introduction on the rates of IBD-related hospitalisations, intestinal resections and public payer drug costs over 10 years among patients with CD and 5 years among patients with UC, allowing for a 1-year transition. Results Relative to what would have been expected in the absence of infliximab, marketplace introduction of infliximab did not produce significant declines in the rates of CD-related hospitalisations (OR at the last observation quarter 1.06, 95% CI 0.811 to 1.39) or intestinal resections (OR 1.10, 95% CI 0.810 to 1.50), or in the rates of UC-related hospitalisations (OR 1.22, 95% CI 1.07 to 1.39) or colectomies (OR 0.933, 95% CI 0.54 to 1.61). The findings were similar among infliximab users, except that hospitalisation rates declined substantially among UC patients following marketplace introduction of infliximab (OR 0.515, 95% CI 0.342 to 0.777). There was a threefold rise over expected trends in public payer drug cost among patients with CD following infliximab introduction (OR 2.98,95% CI 2.29 to 3.86), suggesting robust market penetration in this group, but no significant change among patients with UC (OR 1.06, 95% CI 0.955 to 1.18). Conclusions Marketplace introduction of infliximab has not yielded anticipated reductions in the population rates of IBD-related hospitalisations or intestinal resections, despite robust market penetration among patients with CD. Misguided use of infliximab in CD patients and underuse of infliximab in UC patients may largely explain our study findings.