Subgroups of patients with Crohn's disease have different clinical outcomes.

: Eighty-three patients with long-standing Crohn's disease (CD) were retrospectively reviewed to determine whether natural history and clinical outcome were different and a patient subgroup classification could be reliably adopted. In all patients, the initial anatomical location, the "behavioral pattern," and the operative history of the disease were evaluated. Two different patterns of disease emerged: the first was characterized by a primarily fistulizing or fibrostenotic "behavior" with severe clinical disease and early requirement for surgery; the second was characterized by a primarily inflammatory "behavior" with a less severe disease and less need for surgery. No correlation of these patterns with gender, age at diagnosis, disease duration, smoking habit, and presence of extraintestinal manifestations could be found. The only other factor significantly related to the clinical course of disease was the anatomical location. The occurrence of two distinct CD patient subgroups with different clinical course and prognosis may have important implications in planning prospective trials and adequate therapeutic strategies.