Trends in the use of biologicals and their treatment outcomes among patients with inflammatory bowel diseases – a Danish nationwide cohort study

Therapeutic management of inflammatory bowel diseases (IBD) is rapidly evolving, with an expanding armoury of biological drugs at our disposal. However, real-world findings about treatment persistence and the impact of biologicals on surgery remain inconsistent.This study aimed to investigate trends in biological use and surgery rates in a nationwide cohort of biological-naïve IBD patients.Patients with IBD who initiated biological treatment between 2011 and 2018 were identified in the Danish National Patient Registry. Data on use of biologicals, surgeries and healthcare costs were retrieved and analysed for time trends.Between 2011 and 2018, a total of 6,036 IBD (51% ulcerative colitis (UC), 49% Crohn's disease (CD)) patients received biological treatment for the first time. Cumulative use of biologicals increased from 5.0% to 10.8% among UC and 8.9%-14.5% among CD patients. Infliximab remained the most-prescribed first-line biological for UC and CD. Treatment persistence was 44.3% and 16.9% after 1 and 3 years in UC, compared to 59.9% and 33.6% in CD patients. Overall, 32.8% of patients switched to a second biological. Surgery rates decreased in both UC (P = 0.015) and CD (P = 0.008) patients and remained significant for UC in the Cox regression model (P = 0.002). Outpatient and surgical costs also fell among both UC and CD patients.Persistence rates for first-line biologicals among IBD patients were low and one-third switched treatment. Surgery rates and direct costs decreased over time, but whether this is related to the use of biologicals has yet to be determined.