P1182 Risk of surgery in patients with newly diagnosed Crohn's disease is declining along the 21st century

Abstract Background The repertoire of biological medication for Crohn’s disease (CD) has expanded in the past two decades. The impacts of these new therapies on surgery rates are still under investigation. Our aim was to analyse the surgery rates in newly diagnosed CD patients in the biological era in all age groups. Methods Newly diagnosed CD patients were collected from the registry of Social Insurance Institution of Finland and data on surgeries from the Finnish Institute for Health and Welfare. Patients were stratified according to the diagnosis year and the availability of medication to three groups: 2000-2006 (infliximab era), 2007-2013 (anti-TNF era with infliximab and adalimumab available) and 2014-2020 (multiple biologicals available). The subgroups were defined as paediatric (aged 20), adults (aged 20-59), and the elderly (aged ≥60). Results We identified 11,329 newly diagnosed CD patients, of whom 1,959 were operated. The cumulative risk of surgery was 8.2%, 13.8%, and 18.7% in 1, 5, and 10 years postdiagnosis, respectively. Overall, the 1- and 5-year risks were declining (incidence rate ratio (IRR) 0.97, CI 0.96-0.98 and IRR 0.98, CI 0.97-0.99, respectively), yet the 10-year risk showed no change (IRR 0.99, CI 0.98-1.01). The paediatric group (IRR 1.24, CI 1.10-1.39) and the elderly (IRR 1.20, CI 1.07-1.34) had higher risk of surgery compared to the adults. Also, men had higher risk of operation (IRR 1.20, CI 1.10-1.32). Adults had lower operation risk in later eras compared to infliximab era (IRR 0.55, CI 0.49-0.619). However, the paediatric group demonstrated reduction only in the last era (IRR 0.25, CI 0.18-0.34), and the elderly had stable risk (IRR 1.04, CI 0.82-1.31). The most common operation type in the primary operation was ileocecal resection (39%), followed by procedures in colon (32%) and small bowel (23%). Only in the elderly subgroup the most frequent procedure was colon resection (37%), followed by small bowel (32%) and ileocecal procedure (26%). Conclusion The risk of surgery among newly diagnosed CD patients is declining along the 21st century. Risk is also declining in the paediatric population, whereas the risk of the elderly has stayed constant.