Utility of IBD classification - Is it helpful from a therapeutic standpoint

The traditional two-part classification into 'Crohn's disease' and 'ulcerative colitis' is no longer sufficient to encompass our current understanding of these inflammatory bowel disorders. Idiopathic ulcerative colitis, for example, follows very different clinical courses ranging from mild treatment-responsive proctitis through severe refractory proctitis to extensive chronic colitis. The situation is even more complex for Crohn's disease. An international Working Team (Rome, 1991) proposed a classification of patients with Crohn's disease into several subgroups based upon anatomical distribution, operative history, and predominant clinical 'behaviour' - namely, inflammatory, fistulizing, or stenotic. Another international Working Group (Vienna, 1998) has now refined this clinical phenotypic classification according to age at onset (less than 40 years versus 40 years and above), anatomical location (distal ileum, colon, ileocolon, proximal gut), and predominant disease behaviour (inflammatory, fistulizing, stenotic). The distributions among these clinical phenotypes have potentially important implications for the therapy, for the design and interpretation of clinical trials, for the understanding of natural history and prognosis and for the study of basic disease mechanisms and etiopathogenesis.