RESUMEN
The natural history of Crohn's disease is associated with several factors that affect the prognostic of the patients.To determine the most prognostic factors in Crohn's disease, based on a systematic review. methods: Literature review. The most important factors to consider in patients with Crohn's disease are the need for immunosuppressive therapy, the need for intestinal resection and disabling disease. Prognostic factors for these events are ileal involvement, perianal disease and initial treatment by corticosteroid. Other factors such young age, CRP level and smoking status, has not been found in all population-based studies. Protective role of anti-TNF drugs is strongly suggested but need to be confirmed in further studies. In a selected subgroup of patients with Crohn's disease characterized by the presence of these prognostic markers, the "topdown" strategy can be proposed