Clinical course in Crohn's disease: factors associated with behaviour change and surgery

Background: Crohn’s disease (CD) is a chronic and progressive disease that changes its behaviour over time. Transmural inflammation in CD leads to stricturing and/or penetrating complications. Aim: To evaluate the frequency of long-term progression of CD phenotypes, the need of abdominal surgery, and the main factors associated with these outcomes. Methods: A retrospective study was conducted with a prospective follow-up. Montreal classification was assessed at the moment of the diagnosis and at the end of the follow-up period. Results: Two hundred and ninety patients were included, with mean follow-up duration of nine years. A change in behaviour was observed in 46 patients (15.9%). Ileocolic location (60.9% vs. 45.1%; p = .049), age at diagnosis <16 years (8.7% vs. 2.0%; p = .017), the use of steroids at diagnosis (43.2% vs. 27.0%; p = .031) and shorter exposure time to biological therapy (15.9 months vs 41.3 months; p < .001) were identified as risk factors for phenotype change. Regarding surgery, 70 patients (24.1%) were submitted to abdominal surgery. Smoking habits (41.3% vs. 26.9%; p = .048), stricturing behaviour (50% vs. 18.4%; p < .001), penetrating behaviour 34.8% vs. 7.8%; p < .001), hospitalisations in the first year of diagnosis (52.3% vs. 12.4%; p < .001), and use of steroids at diagnosis (61.4% vs. 23.6%; p < .001) were more frequently seen in patients subjected to surgery. Patients subjected to surgery were less frequently treated with biological therapy (8.7% vs. 23.4%; p < .025). Conclusions: A behaviour progression was observed in about one-sixth of the patients. Progression to a stricturing pattern was the most frequent change in behaviour. Stricturing and penetrating behaviour, higher number of hospitalisations in the first year of diagnosis, use of steroids at diagnosis, smoking status, age at diagnosis