Natural History, Treatment Persistence and Predictors of Treatment Failure in Patients With Ulcerative Colitis on 5-Aminosalicylic Acid: A US Population-Level Cohort Study.

Introduction: Limited data exist on the natural history and treatment persistence in ulcerative colitis (UC) patients on 5-aminosalicylic acid (5-ASA) in the era of biologic agents and small molecules.

Methods: This was a retrospective cohort study utilizing the US Collaborative Network in patients with UC who were initiated on 5-ASA between 2015 and 2019. The 1-, 3-, and 5-year incidence rates of advanced therapy use and colectomy were calculated. Predictors of advanced therapy use and colectomy within 5 years were analyzed and expressed as adjusted odds ratios (aORs) with 95% confidence intervals (CIs) after 1:1 propensity score matching (PSM).

Results: Among 15 177 patients in the UC 5-ASA cohort (mean age 47.2 ± 19.1 years old, 49.2% female and 70.3% White), the 1-, 3- and 5-year incidence of advanced therapy use was 5.37%, 11.56% and 15.8%, respectively. After PSM, age < 40 years old (aOR 1.93, 95% CI, 1.73-2.15), male sex (aOR 1.13, 1.02-1.25), obesity (aOR 1.18, 95% CI, 1.05-1.31), pancolitis (aOR 1.18, 95% CI, 1.03-1.36), steroid use (aOR 1.79, 95% CI, 1.53-2.09), and CRP ≥ 12 mg/L (aOR 1.39, 95% CI, 1.05-1.83) prior to 5-ASA initiation were associated with advanced therapy use within 5 years. The 1-, 3- and 5-year incidence of colectomy was 0.74%, 1.28%, and 1.64% respectively. After PSM, male sex (aOR 1.36, 95% 1.06-1.74), obesity (aOR 1.32, 95% CI, 1.02-1.69), primary sclerosing cholangitis (aOR 2.37, 95% CI, 1.11-5.06), pancolitis (aOR 1.90, 95% CI, 1.29-2.78), and steroid use (aOR 1.96, 95% CI, 1.35-2.84) were associated with colectomy within 5 years.

Conclusion: Our study provides updated estimates of advanced therapy utilization and colectomy as well as predictors of disease progression in patients with UC on 5-ASA in the biologic era.