Introduction:
Personalized medicine in inflammatory bowel disease (IBD) aims to achieve maximum effectiveness through rapid induction and maintenance of remission. To achieve this goal, reliable predictors of disease course are needed. The aim of this study was to identify early markers of IBD's poor course understood as the need for anti-tumor necrosis factor (anti-TNFα) treatment.

Material and methods:
We analyzed the clinical, laboratory, radiological and endoscopic data of children with IBD. These parameters were assessed at the time of diagnosis (T0) and 8-12 weeks (T1) after the start of induction therapy. The results of patients who did not require anti-TNFα treatment were compared to children who needed such treatment during the 2-year observation time.

Results:
58.14% of patients with Crohn's disease (CD) and 31.71% of patients with ulcerative colitis (UC) required biological therapy. Patients with CD and UC receiving biological therapy, compared with those without, differed in selected clinical and laboratory parameters both at T0 and T1. In multivariate analysis, the risk of anti-TNFα therapy in patients with CD was associated with the lack of normalization of MCV and PCDAI. In patients with UC higher albumin levels reduced this risk.

Conclusions:
In children with IBD, disease activity and concentrations of selected biochemical parameters assessed within 3 months after diagnosis may be helpful in predicting a poor outcome of CD and UC.