P1236Incidence and prevalence of complicated inflammatory bowel disease in Queensland, Australia: a population-based data linkage study

Background Inflammatory bowel disease (IBD), including ulcerative colitis (UC), Crohn’s disease (CD) represents a spectrum of chronic inflammatory conditions affecting the gastrointestinal tract. Whilst some patients experience a benign disease course, others develop complicated IBD characterised by frequent hospitalisations and surgery. The aim of this study is to determine the incidence and prevalence of complicated IBD in Queensland, Australia. Methods Using data from the Queensland Hospital Admitted Patient Data Collection (QHAPDC), this retrospective, population-based, cohort study included all patients admitted to public and private hospitals in the state of Queensland, with an ICD-code of IBD, from 2007-2023. Cases were defined as having IBD if the patient was hospitalised or presented to emergency department, with a diagnosis of IBD, on two separate occasions. Complicated UC was defined by any of the following: colectomy, perforation, toxic megacolon, colorectal cancer or death. Complicated CD was defined by any of the following: intestinal obstruction, intestinal fistulae, intestinal abscess, intestinal perforation, perianal fistulae, perianal abscess, rectovaginal fistulae, anorectal stricture, colorectal cancer or death. After identifying eligible IBD cases, incidence and prevalence rates were calculated and stratified by geographical location and socioeconomic status (SES). Results 22,848 individuals met the definition of IBD, and 5,436 individuals fulfilled the criteria of complicated IBD (805 UC & 4631 CD, 51% female, median age 49, 2.9% aboriginal or Torres Straight Isander). Crude incidence rates for complicated UC and CD were 5.6 and 20.6 per 100,000 person-years. Incidence rates of complicated UC and CD were similar between patients from the highest and lowest socioeconomic deciles (UC: IRR 1.11, p = 1.00; CD: IRR 0.92, p = 1.00), and between those living within and outside metropolitan centres (UC: IRR 0.93, p = 1.00; CD: IRR 0.97, p = 1.00). Crude prevalence rates of complicated UC and CD were 53.1 and 304.7 per 100,000 person-years. The prevalence of complicated UC was not significantly associated with SES (IRR 0.81, p = 0.13) or geographical location (IRR 1.06, p = 0.99). In contrast, complicated CD was more common among patients in the lowest socioeconomic decile (IRR 1.14, p < 0.0001) and those living outside metropolitan areas (IRR 1.08, p < 0.0001). Conclusion Over 15 years, more than half of Queensland CD patients developed intestinal or perianal complications, with higher rates in socioeconomically disadvantaged and non-metropolitan groups. These findings highlight the need for improved access to specialist IBD care in underserved populations to address inequities in disease outcomes. Conflict of interest: Dr. Tambakis, George: No conflict of interest Okano, Satomi: No conflict of interest Hartel, Gunter: No conflict of interest Kumar, Rina: No conflict of interest Goetz, Naeman: No conflict of interest Etchegary, Amirah: No conflict of interest Phillips, Jennifer: No conflict of interest Croft, Anthony: No conflict of interest Valery, Patricia: No conflict of interest Radford-Smith, Graham Lindsay: No conflict of interest Walker, Gareth: No conflict of interest