OP026 Post-operative use of anti-TNFα agents in patients with Crohn's disease and risk of re-operation - a nationwide cohort study
J. Kjeldsen*1, J. Nielsen2, M.D. Larsen2, N. Qvist3, B. Nørgaard2
1University of Southern Denmark, Department of Medical Gastroenterology, Odense University Hospital, and Research Unit of Gastroenterology, Odense , Denmark, 2University of Southern Denmark, Center for Clinical Epidemiology, Odense University Hospital, and Research Unit of Clinical Epidemiology, Institute of Clinical Research,, Odense, Denmark, 3University of Southern Denmark, Department of Surgery, Odense University Hospital, and Research Unit of Surgery, Institute of Clinical Research, Odense, Denmark
“Table: Standardized cancer incidence ratios of patients from the population based IBD-SL cohort, and of medication based sub groups
Up to 80% of patients with Crohn's disease (CD) will at some time require surgery. Surgery is not curative and recurrence is typical. An advantageous role of post-operative anti-tumour necrosis factor-alpha (anti-TNFα) agents has been suggested in observational and small clinical studies. In a nationwide cohort study, we examined the magnitude of risk of reoperation in CD patients treated postoperatively with anti-TNFα agents.
Association between postoperative anti-TNFα agents and reoperation was studied in two cohorts of CD patients undergoing first time operation. Cohort 1: patients not treated with anti-TNFα agents within 6 months before operation; Cohort 2: patients treated with anti-TNFα agents at least once within 6 months before operation. We defined postoperative exposure to anti-TNFα agents as at least one treatment within 6 months after first time operation (exposed cohort), reference cohort was patients not treated with anti-TNFα agents within 6 months after first time operation. Patients were followed from 6 months after first operation until date of reoperation, death, emigration or end of follow-up (5 years). We used Cox proportional-hazards regression to compute crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI). Adjustment was made for age, sex, co-morbidity (Charlson Index), duration of CD, use of immunosuppressive agents within 6 months after operation. Data were retrieved from nationwide Danish health registries.
In cohort 1, patients not treated with anti-TNFα agent before operation (n=2446), only 31 (1.3%) received anti-TNF α agent within 6 months after operation (exposed cohort), 2415 (98.7%) were not treated (reference cohort). Compared to those not treated with anti-TNFα agent after operation, the aHR of reoperation among those treated was 3.14 (1.45-6.81). In cohort 2, patients who were treated with anti-TNFα agent before operation (n=387), 63 (16.3%) were treated with anti-TNFα agent within 6 months after operation (exposed cohort), and 324 (83.7%) were not treated (reference cohort). Compared to those not treated with anti-TNFα agent after operation, the aHR of reoperation among those treated was 1.79 (0.94-3.40).
Postoperative use of anti-TNF α agent was low in anti-TNFα agents naïve patients (1.3%), while 16.3% of the patients pre-operatively exposed to anti-TNFα received this therapy postoperatively. Postoperative anti-TNFα treatment did not reduce the need for subsequent surgery compared to patients not treated. Thus, a reduced rate of surgery after post-operative anti-TNFα treatment could not be documented; however, confounding by indication may contribute to the results obtained.