Drug utilization of biologic therapy in Crohn's disease and ulcerative colitis: a population-based Danish cohort study 2015-2020.

More than 85% of UC and CD patients initiating biologic therapy had infliximab as their first-line biologic treatment, in accordance with official treatment guidelines. Future studies should explore the higher incidence of treatment discontinuation of adalimumab as the first treatment series.Key summarySeveral biologic therapies are available in the treatment of ulcerative colitis and Crohn's disease.Clinical guidelines stipulate that infliximab should be the first-line biologic therapy.Drug utilization studies comparing biologic therapies head-to-head are sparse.In Denmark, during 2015-2020 infliximab remained the most widely used biologic treatment, with adalimumab being second.One in four patients experienced more than one biologic during the study period.The risk of discontinuation of biologic treatment (and not starting a new biologic) was higher for initiators of adalimumab.Clinical and social background factors available from the registers could not account for the observed risk difference in discontinuation.