Correlation between infliximab trough levels and postoperative endoscopic recurrence in patients with Crohn's disease

Given the high rate of recurrence in Crohn's disease (CD), postoperative maintenance therapy is crucial for preventing disease recurrence. However, the relationship between infliximab trough levels and postoperative endoscopic recurrence in CD patients has been insufficiently evaluated.

This study included consecutive postoperative CD patients treated with infliximab for the prevention of postoperative recurrence, with measurement of infliximab serum trough concentrations and colonoscopy performed within 3 months of sampling. Endoscopic recurrence was defined as a Simple Endoscopic Score for Crohn's Disease (SES-CD) score ≥3 or a Rutgeerts' score ≥2.

The final cohort comprised 137 patients, with 70 in the 'no endoscopic recurrence' group and 67 in the 'endoscopic recurrence' group. Infliximab trough levels were significantly lower in patients with recurrence (3.4 vs. 5.9, P  = 0.001), with an area under the curve of 0.69 and an optimal cutoff value of 3.15 μg/ml. In the subgroup of patients who have undergone ileocolonic resection, the nonrecurrence group showed significantly higher infliximab trough levels (5.8 vs. 2.4, P  = 0.001). In addition, patients with a Rutgeerts' score of 0 had significantly higher trough infliximab levels compared with scores of 2 ( P  = 0.001). Multivariate analysis confirmed that infliximab trough levels were inversely associated with endoscopic recurrence in the overall cohort, and this association remained significant in the ileocolonic resection subgroup.

Our study demonstrates that lower infliximab trough levels are associated with postoperative endoscopic recurrence in CD patients, both in the overall surgical cohort and in the subgroup of patients who underwent ileocolonic resection.