Predictors for Complicated Disease Course after Stepping Down from Combination to Antitumor Necrosis Factor Alpha Monotherapy in Children with Inflammatory Bowel Disease

Objective: Combinations of antitumor necrosis factor alpha (TNFα) and immunomodulators may be indicated in high-risk inflammatory bowel disease patients. Our aims were to compare disease course between children that did and did not step down to anti-TNFα monotherapy and to define risk factors for complicated disease course after stepping down. Methods: A retrospective review of the medical records of consecutive children who were treated with combination therapy. Results: Of 64 children, 32 continued combination therapy while the others stepped down to monotherapy (median duration of 6 months [range 6-10]). Children that stepped down had a trend of lower anti-TNFα levels (median [interquartile range] of 2.4 [1-4.2] μg/mL) compared to those that did not step down (4.5 [2.2-6.23] μg/mL, p = 0.065). Children with Crohn's disease that stepped down had a significantly higher risk for disease exacerbation, hospital admission, and operation (p < 0.025). Univariate analysis revealed that penetrating phenotype, upper gastrointestinal involvement, higher disease activity at diagnosis, and lower anti-TNFα levels under combination therapy were predictors for complicated course after stepping down. Conclusion: Stepping down to anti-TNFα monotherapy may be related to lower anti-TNFα levels and to a more complicated disease course thereafter. Predictors for a complicated course were identified.