de Barros KSC, et al. – The long–term evolution of patients based on Crohn's disease phenotypes and the main factors correlated with this evolution were evaluated. In around 1/3^rd of patients, clinical behavior altered. A change to stricturing pattern was the most frequent complication. Factors correlated with an unfavorable clinical evolution were disease location, current smoker, immunosuppressive therapy use, hospitalization, and abdominal surgery.

• The authors collected data from 179 patients from a unicentric prospective database.
• They employed Montreal classification.
• They used Kaplan–Meier method to estimate the cumulative probability of complication development and surgery.
• For multivariate analysis, Poisson regression was applied.
• This research was approved by the Local Institutional Review Board.

• There were 54.2% female in this study.
• At diagnosis, mean age: 32.7 (±13.7) years.
• At presentation, behavior: inflammatory 62.0%, stricturing 24.6%, penetrating 13.4%; perianal disease: 31.8%; median follow-up time: 65.2 months (IQR 31.0–108.8).
• At follow-up period end, behavior: inflammatory 43.6%, stricturing 38.0%, penetrating 18.4%; perianal disease: 46.4%.
• In 5, 10, and 20 years, cumulative probability of being complication free: 86.3, 66.4, and 52.2%, respectively.
• In 5, 10, and 20 years, cumulative probability of being surgery free: 87.3, 79.2, and 64.1%, respectively.
• Factors correlated with changes in phenotype or development of complications and perianal disease were L1 and L4 locations, use of immunosuppressive therapy, smoking, number of hospitalization/patient-year, abdominal surgery, age at diagnosis <40 years, and biological therapy.