A82 5-ASA & CHEMOPREVENTION IN IBD: A POPULATION-BASED ANALYSIS

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic, relapsing and remitting inflammatory disease of the gastrointestinal tract. Colorectal cancer (CRC) is a well-documented complication of IBD and is associated with IBD severity, extent and duration. Treatment with 5-aminosalicylic acid (5-ASA) reduces the risk of CRC in IBD. Our objective was to test the association of cumulative exposure to 5-ASA on CRC risk. A retrospective cohort study was performed using a population-based IBD cohort derived from administrative health data in Saskatchewan, Canada. Data were from 1979 to 2011. Exposure to 5-ASA and CRC diagnosis using ICD diagnoses during the study period were examined. CRC rates were compared between 5-ASA exposed/non-exposed groups using chi-square tests; exposure to 5-ASA was evaluated using survival analysis. To account for differences in 5-ASA exposure, propensity scores (PS) based on IBD duration, immunomodulator (IM) and anti-TNF exposure, number of endoscopies, and decade of IBD diagnosis were used to match non-exposed to exposed patients. In the propensity-matched cohorts, we controlled for gender, location (urban/sub-urban/rural), diagnosis and previous corticosteroid use. A dose response survival model was developed in an attempt to control for the duration of 5-ASA. We assumed a 5-ASA dose of 2000 mg/day, and subsequently marked subjects as being “off” treatment if they did not renew a prescription within 30 days of their last prescription. The Kaplan-Meier estimator was used to describe the time-to-event data and Cox proportional hazards regression models were used to test the association of exposure with CRC diagnosis; hazard ratios (HRs) and 95% confidence intervals (95% CIs) were reported. Analyses were stratified by type of IBD (UC, CD). A total of 8821 IBD patients were included in the study, of which 289 (3.3%) developed CRC. In the CRC-free group, 73.9% (n=6307) of patients had exposure to 5-ASA, whereas 61.9% (n=179) had exposure in the CRC group. In the PS-matched cohort, the HR was 2.56 for exposed versus non-exposed individuals (95% CI:[1.9, 3.5]). The risk of CRC diagnosis was higher in the UC sub-group (HR=3.54, 95% CI:[2.3, 5.5]) when compared to the CD population (1.73, 95% CI:[1.1, 2.6]), controlling for gender, location and decade of diagnosis. In our adjusted dose-response model using truncated 5-ASA dosing, the risk of CRC diagnosis was higher in the UC sub-group (HR=2.83, 95% CI:[1.6, 5.1]) when compared to CD (HR=2.17, 95% CI:[1.1, 4.2]). This population-based cohort study suggests a chemo-protective effect of 5-ASA exposure for CRC diagnosis amongst patients with IBD. A larger protective effect was observed amongst UC patients than CD patients. Further data are needed to elucidate the biologic mechanism of CRC reduction. None

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.