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 UC, we evaluated the effect of marketplace introduction of infliximabon the population rates of hospitalisations and surgeries and public payer drug costs. Design We used health administrativedata to study adult persons with CD and UC living in Ontario, Canada between 1995 and 2012. We used an interrupted time seriesdesign with segmented regressionanalysis to evaluate the impact of infliximabintroduction 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 infliximabdid 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 infliximabusers, 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 infliximabintroduction (OR 2.98,95% CI 2.29 to 3.86), suggesting robust market penetrationin this group, but no significant change among patients with UC (OR 1.06, 95% CI 0.955 to 1.18). Conclusions Marketplace introduction of infliximabhas not yielded anticipated reductions in the population rates of IBD-related hospitalisations or intestinal resections, despite robust market penetrationamong patients with CD. Misguided use of infliximabin CD patients and underuse of infliximabin UC patients may largely explain our study findings.