P1133 Relative survival and cause-specific mortality of a Chilean Inflammatory Bowel Disease cohort

Abstract

Abstract Background In the past two decades, multiple studies have shown an improvement in outcomes of inflammatory bowel disease (IBD) patients including a decreasing mortality associated with new treatments, surveillance, and healthcare support. There are no large studies in Latin-American countries addressing survival and death causes in IBD patients. We aimed to assess relative survival (RS) and causes of death in Chilean IBD patients. Methods IBD patients treated in a tertiary reference centre (Pontificia Universidad Católica of Chile, Santiago, Chile) since January 1990 were included in a local database. Death certificates were analysed to obtain the date and specific cause of death. The recorded time started on the date of definitive diagnosis and lasted until death or censoring on December 31st, 2020. The survival of IBD patients was compared with the life expectancy of the Chilean general population based on official life tables collected in the Human Mortality Database (www.mortality.org). The RS was computed using the Ederer II method implemented in the RELSURV package of the R software. A RS greater than 1.0 indicates that the analysed cohort has a higher survival than the expected survival of the reference population for the same age, sex and date at which age was coded. Inclusion of 1.0 within 95% CI indicates no difference between observed and expected survival. Data were also expressed graphically as the observed cumulative survival curves over time and the 95% confidence interval (CI) and compared to the reference population. Results We included 1,289 IBD patients with a media age at diagnosis of 35.9±14 years, 40.9% males and a follow-up of 22,525 patients-year. Ulcerative Colitis, Crohn’s disease and IBD unclassified patients comprised 50.2%, 43.1% and 6.7% of the cohort, respectively. A total of 106 patients (8.9%) died during the study period. Compared with the general population, the survival of IBD patients was higher (RS = 1.04; 95% CI: 1.02-1.07) at 20 years of follow-up (Table and Figure). This higher RS in IBD patients was observed in males and females, as well as CD patients and IBD patients older than 40-year-old (Table). The main causes of death in IBD patients were cancer (34%), infections (27.7%) and cardiovascular diseases (21.3%). Conclusion Compared to the general population, a higher long-term survival was observed in this large cohort of Chilean IBD patients. These findings may be due to a closer surveillance of this group of patients. Causes of death mirrored those in previously reported cohorts; therefore, a special care should be pay on their prevention in Latin-American countries as well.