Clinical Course and Predictors of Biologic Therapy, Hospitalisation and Surgery: A Five‐Year Prospective Study in Newly Diagnosed Inflammatory Bowel Disease

AIMS: This study aimed to describe the characteristics of newly diagnosed inflammatory bowel disease (IBD) patients and to analyse their clinical course within the first 5 years after diagnosis, including the need for surgery, hospitalisations and treatments. METHODS: This prospective and large multicentre incident cohort registry in Spain enrolled adults diagnosed with Crohn's disease (CD), ulcerative colitis (UC) or unclassified IBD (IBD-U) in 2017 and followed them for 5 years. RESULTS: A total of 3301 patients were enrolled: 1526 with CD, 1633 with UC and 142 with IBD-U. Their median age at diagnosis was 43 years (interquartile range 31-56) and approximately 50% were male. Within 5 years post-diagnosis, 30% received biologics or JAK inhibitors (JAKi), 34% were hospitalised at least once and 9% underwent surgery. The cumulative incidence of biologic/JAKi treatment, hospitalisations and surgeries was higher among CD patients. Use of biologics/JAKi correlated with a more aggressive CD phenotype, greater UC extent and younger age at diagnosis. Biologics/JAKi treatment was associated with lower hospitalisation risk in both CD (Hazard ratio [HR] = 0.4, 95% confidence interval [CI] = 0.2-0.6) and UC patients (HR = 0.5, 95% CI = 0.2-0.9). However, it was not associated with the risk of abdominal surgery in CD but was linked to an increased risk of surgery in UC (HR = 11.9, 95% CI = 4.6-30.4). CONCLUSIONS: This large multicentre cohort demonstrated a higher use of biologics/JAKi during the first 5 years after IBD diagnosis than previously reported. Treatment with biologics/JAKi was associated with reduced risk of hospitalisation. However, under current clinical practice patterns, this therapeutic approach did not translate into lower risk of abdominal surgery.