Liver enzyme profiles after initiating biological treatment in children with inflammatory bowel diseases.

Objectives: Biological treatments (BTs) are essential in managing pediatric inflammatory bowel diseases (PIBDs). Elevated liver enzymes sometimes succeed BT, yet elucidating studies are scarce. We addressed liver biochemistry after introducing BT and searched for their determinants.

Methods: We identified PIBD patients receiving infliximab, adalimumab, vedolizumab, or ustekinumab at the Children's Hospital, University of Helsinki, Finland, in 2000-2023, and followed their alanine transaminase (ALT) and γ-glutamyl transpeptidase (GT) levels for 24 months. ALT was categorized based on the age- and sex-specific upper limit of normal. We disregarded 46 patients with underlying primary sclerosing cholangitis with/without autoimmune hepatitis (AIH), pretreatment AIH diagnosis, and elevated liver enzymes at the beginning of BT from the analyses.

Results: Of 618 BT episodes in 403 patients, 22.2% exhibited increased ALT or GT (ALT in 117, GT in 4, and both ALT/GT in 16 episodes). Of all ALT elevations (n = 133), 41.4% occurred within the first 3 months. ALT elevation was more common after infliximab (representing 59.5% of BTs) than other BTs (25.9% vs. 14.2%, adjusted odds ratio [OR]: 2.41, 95% confidence interval [CI]: 1.23-4.72). AIH followed 1.5% (n = 9) of BT episodes. Ninety-five percent of ALT elevations resolved within 6 months. Antibiotic exposure (particularly to metronidazole) was associated with ALT elevation in general (adjusted OR: 5.76, 95% CI: 2.40-13.9) and short disease duration before starting BT with notable ALT elevation (adjusted OR: 1.10, 95% CI: 1.01-1.22).

Conclusions: Benign ALT elevation is common within 3 months after starting BT (especially infliximab) and scarcely led to cessation of the treatment. AIH is a rare finding during the first year of BT.