P1172 Epidemiology and initial presentation of newly diagnosed inflammatory bowel diseases in a Danish population-based inception cohort – results from the IBD Prognosis Study

Abstract

Abstract Background It is unclear whether the incidence of inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), continues to increase. In this study, we aimed to investigate the occurrence and initial disease presentation of IBD in a population-based setting. In addition, we aimed to identify predictors of an early severe disease presentation. Methods The study was conducted as part of IBD Prognosis Study, an ongoing Danish prospective population-based inception cohort study that includes incident patients with IBD according to the Copenhagen Diagnostic Criteria since May 2021, covering the catchment areas of approximately 20% of the Danish population (1.1 million). In this analysis, cutoff for data analysis was in May 2023. Crude incidence rates and European Standard Population (ESP)-adjusted rates were calculated. A multivariable logistical regression model was constructed to identify predictors of a severe disease presentation, defined as the composite need for systemic steroids, immunomodulators, biologics, or IBD-related surgery within three months of disease. Results In total, 554 patients (UC: 344, CD: 210) fulfilled the inclusion criteria, resulting in the following crude incidence rates per 100,000 person-years: IBD 23.4 (95% CI 21.5-25.4), UC 14.0 (12.6-15.6), and CD 8.6 (7.4-9.8). ESP-adjusted rates were: IBD 20.4 (18.2-22.9), UC 11.8 (10.2-13.0), and CD 7.9 (6.5-9.9) (Figure 1). Among patients with UC, 81 (26.3%) and 95 (30.8%) had left-sided or extensive colitis at disease onset, respectively, while 61 (30.3%) and 62 (30.8%) patients with CD had ileal or ileocolonic disease. Stricturing or penetrating CD behaviour was observed in 24 (11.9%) and 11 (5.5%) patients, respectively. A high proportion of patients needed hospitalization (CD: 68 (33.8%), UC: 60 (19.5%), p=0.001) and IBD-related surgery (CD: 21 (10.4%), UC: 10 (3.2%), p=0.004) at the time of diagnosis. In multivariable analysis, a severe disease presentation of UC at the time of diagnosis was associated with left-sided or extensive disease distribution, thrombocytosis, and increased levels of C-reactive protein (CRP) (Table 1). In patients with CD, stricturing, or perianal disease, as well as anemia, levels of albumin, CRP, and calprotectin were predictive of this endpoint (Table 1). Conclusion The incidence of UC and CD in Denmark appears stable compared to historical data from the previous decades.1 The study identified clinical predictors of a severe disease presentation from the time of diagnosis, emphasizing the critical need for early risk stratification and intervention strategies. Reference: 1 Dorn-Rasmussen M et al., J Crohns Colitis. doi: 10.1093/ecco-jcc/jjac138.