Update on the Prevalence, Incidence, Mortality, and Trends in Treatment of Inflammatory Bowel Disease in a Population-Based Registry in Catalonia Between 2017 and 2023

<b>Background</b>: The prevalence of inflammatory bowel disease (IBD) is increasing worldwide, while the incidence is tending to stabilize. Moreover, the use of biological treatments is increasing; some studies suggest that surgeries and hospitalizations are decreasing instead. <b>Methods</b>: A population-based, retrospective cohort study was conducted using data from the Catalan Health Surveillance System (CHSS). All patients diagnosed with IBD were included between 2017 and 2023. Crude incidence and prevalence rates were calculated for the Catalan population. Data on pharmacological therapy, surgical procedures, hospitalizations, and mortality were analyzed. Trends in age-sex-adjusted rates were also estimated, and logistic regression was used to calculate the adjusted mortality odds ratio (OR). Data for Crohn's disease (CD) and ulcerative colitis (UC) were analyzed separately. <b>Results</b>: The number of prevalent IBD cases rose from 28,752 in 2017 to 41,423 in 2023. Despite incidence rates remaining stable (30.8 in 2017 and 29.9 per 100,000 inhabitants in 2023), prevalence rates increased (386.9 and 510.9 per 100,000 inhabitants, respectively). The use of biologics significantly increased (from 13.5% in 2017 to 21.0% in 2023), particularly ustekinumab and vedolizumab. In parallel, a decline in the use of immunosuppressants was observed. IBD-related surgeries and hospitalizations decreased during the study period, particularly among CD patients. Mortality remained low but was higher among IBD patients compared to the general population. <b>Conclusions</b>: The incidence of IBD in Catalonia has stabilized, while its prevalence continues rising, suggesting a transition to Stage 3 (compounding prevalence). The use of biological treatments is increasing steadily, whereas rates of surgeries and hospitalizations are consistently decreasing.