Clinical course of ulcerative colitis: Frequent use of biologics and low colectomy rate first year after diagnosis—results from the IBSEN III inception cohort

Summary Background The introduction of biologic therapies and the ‘treat‐to‐target’ treatment strategy may have changed the disease course of ulcerative colitis (UC). Aims To describe the early disease course and disease outcome at 1‐year follow‐up in a population‐based inception cohort of adult patients with newly diagnosed UC. Methods The Inflammatory Bowel Disease in South‐Eastern Norway (IBSEN) III study is a population‐based inception cohort study with prospective follow‐up. Patients newly diagnosed with inflammatory bowel disease during 2017–2019 were included. Patients ≥18 years at diagnosis of UC who attended the 1‐year follow‐up were investigated. We registered clinical, endoscopic and demographic data at diagnosis and 1‐year follow‐up. Results We included 877 patients with UC (median age 36 years (range: 18–84), 45.8% female). At diagnosis, 39.2% presented with proctitis, 24.7% left‐sided colitis and 36.0% extensive colitis. At the 1‐year follow‐up, 13.9% experienced disease progression, and 14.5% had received one or more biologic therapies. The colectomy rate was 0.9%. Steroid‐free clinical remission was observed in 76.6%, and steroid‐free endoscopic remission in 68.7%. Anaemia and initiation of systemic steroid treatment at diagnosis were associated with biologic therapy within the first year after diagnosis. Conclusion In this population‐based inception cohort, colectomy rate in the first year after diagnosis was low, and a high proportion of patients were in remission at 1‐year follow‐up. The use of biologic therapy increases, consistent with findings from previous studies.