Eighty-three patients with long-standing Crohn's disease (CD) were ret
rospectively reviewed to determine whether natural history and clinica
l outcome were different and a patient subgroup classification could b
e reliably adopted. In all patients, the initial anatomical location,
the ''behavioral pattern,'' and the operative history of the disease w
ere evaluated. Two different patterns of disease emerged: the first wa
s 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'' wit
h a less severe disease and less need for surgery. No correlation of t
hese 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 C
D patient subgroups with different clinical course and prognosis may h
ave important implications in planning prospective trials and adequate
therapeutic strategies.