OBJECTIVES:The objective of this study was to contribute long-term safety data for infliximab and other therapies in Crohn's disease (CD).METHODS:We prospectively evaluated CD patients enrolled in the large, observational Crohn's Therapy, Resource, Evaluation, and Assessment Tool registry, established to compare infliximab safety with conventional nonbiological medications in CD.RESULTS:A total of 6,273 patients were enrolled and evaluated on or before 23 February 2010; 3,420 received infliximab (17,712 patient-years; 89.9% received ≥2 infusions) and 2,853 received other-treatments-only (13,251 patient-years). Mean length of patient follow-up was 5.2 years. More infliximab- than other-treatments-only-treated patients had moderate-to-severe (30.6% vs. 10.7%) or severe-to-fulminant (2.5% vs. 0.6%) disease severity (P<0.001). In the year before enrollment, more infliximab- than other-treatments-only-treated patients required surgical intervention (17.4% vs. 13.6%), medical hospitalization (14.2% vs. 8.8%), prednisone (47.8% vs. 31.4%), immunomodulators (52.0% vs. 32.1%), and narcotic analgesics (17.3% vs. 9.1%). Patient mortality was similar for infliximab- and other-treatments-only-treated patients (0.58 vs. 0.59/100 patient-years). In multivariate logistic regression analyses, treatment with prednisone (hazard ratio (HR)=2.14, 95% confidence interval (CI)=1.55, 2.95; P<0.001) or narcotic analgesics (HR=1.79, 95% CI=1.29, 2.48; P<0.001) and age (HR=1.08, 95% CI=1.07, 1.09; P<0.001) were associated with increased mortality risk. Neither infliximab nor immunomodulator treatment was associated with increased mortality risk. Factors independently associated with serious infections included moderate-to-severe disease activity (HR=2.24, 95% CI=1.57, 3.19; P<0.001), narcotic analgesic treatment (HR=1.98, 95% CI=1.44, 2.73; P<0.001), prednisone therapy (HR=1.57, 95% CI=1.17, 2.10; P=0.002), and infliximab treatment (HR=1.43, 95% CI=1.11, 1.84; P=0.006).CONCLUSIONS:Mortality was similar between infliximab- and other-treatments-only-treated CD patients. An increased risk of serious infection with infliximab was observed, although CD severity and use of prednisone or narcotic analgesics carried higher risks.