This study compares the effectiveness and safety of infliximab and adalimumab in biologic-naive patients with ulcerative colitis (UC), in a nationwide register-based propensity score–matched cohort study.

From 1719 adults with UC, between ages 15 and 75 years in Denmark treated with either infliximab or adalimumab as their first biologic agent, we compared rates of all-cause hospitalization, UC-related hospitalization, major abdominal surgery, and serious infections after a variable 2:1 propensity score matching, accounting for baseline clinical characteristics, disease severity, health care utilization, and use of UC-related medications.

As compared with infliximab-treated patients, adalimumab-treated patients had higher rate of all-cause hospitalization (hazard ratio [HR], 1.84; 95% CI, 1.18–2.85) and a trend toward higher rate of UC-related hospitalization (HR, 1.71; 95% CI, 0.95–3.07), particularly in a stratum of patients on concomitant immunomodulator therapy. However, risk of abdominal surgery (HR, 1.35; 95% CI, 0.62–2.94) was not different between the 2 treatment groups. Risk of serious infection requiring hospitalization was significantly higher in adalimumab-treated patients (HR, 5.11; 95% CI, 1.20–21.80).

In this nationwide propensity score matched–cohort study of biologic-naive adults with UC, use of adalimumab as first-line biologic over infliximab was associated with higher risk of hospitalization and serious infections, although risk of surgery was not different. In the absence of head-to-head trials, this evidence may assist patients, health care providers, purchasers, and policy makers to make informed decisions that may improve health care in UC.