Relationship of faecal calprotectin and long-term outcomes in Finnish patients with Crohn's disease: retrospective multi-centre chart review study.

Background and Aims: A retrospective non-interventional, multi-centre patient chart review study was conducted to investigate the association of faecal calprotectin (FC) 1 year (±2 months) after biological therapy initiation with composite event-free survival (CEFS) consisting of surgical procedures, corticosteroid initiation, treatment failure or dose increase in patients with Crohn's disease (CD). In addition, the correlations of FC and other tests of disease activity were assessed.Materials and methods: Data on Finnish CD patients initiating a biological therapy between 2010 and 2016, were collected. The association of FC and CEFS was analysed with Kaplan-Meier and Cox proportional hazard modelling. The correlations were tested with Pearson's test.Results: Biological therapy was initiated in 186 patients, of which 87 (46.8%) had FC results available at 1 year and 80 had follow-up exceeding 14 months. The characteristics of patients with and without FC results were similar. Patients with elevated FC (>250 µg/g) had a significantly increased risk of experiencing composite event (HR 3.4, 95% CI: 1.3-8.9; p = .013) when compared to patients with normal FC (FC ≤ 100). No such risk was observed in patients with intermediately increased FC level (100 µg/g < FC ≤ 250 µg/g) (HR 2.2 (95% CI: 0.8-6.2; p = .120). FC value had significant positive correlation with CRP, HBI and leukocyte values when measured at similar timepoints.Conclusions: Elevated level of FC approximately 1 year after the initiation of biological therapy was associated with an increased risk of either surgical procedures, corticosteroid initiation, treatment failure or dose increase (i.e. composite outcome) in patients with CD.