Does the initial location of Crohn's disease have an influence on the time-to-relapse in patients under maintenance treatment with oral mesalamine?

The aim of this study was to determine the possible influence of the initia l location of Crohn's disease (CD) on the time-to-relapse in patients with quiescent CD treated only with oral mesalamine (5-ASA). We divided 74 conse cutive patients in clinical remission into three groups according to the in itial location of CD. Group A consisted of 30 cases with an ileal location; group B, 18 with ileocolonic location; and group C, 26 with a colonic loca tion. The patients entered the study if they were in clinical and endoscopi c remission for at least 3 months. Relapse was defined by CD Activity Index greater than or equal to 150, CD Endoscopic Index of Severity greater than or equal to 4, and by an abnormal increase of C-reactive protein, white bl ood cell count, and erythrocyte sedimentation rate; moreover, if it was con firmed by x-ray and/or endoscopy. Time-to-relapse was defined as the interv al between the date of enrollment and the date of relapse. The patients wit h an ileal location showed a relapse within 5 years, with a time-to-relapse of 1 year in 26% of cases, 2 years in 85%, 3 years in 92%, and 4 years in 96%. The patients with ileocolonic location showed a relapse within 4 years , with time-to-relapse of 1 year in 39% of cases, 2 years in 89%, and 3 yea rs in 94%. The cases with a colonic location showed a relapse within 6 year s, with time-to-relapse of 1 year in 33% of cases, 2 years in 71%, 3 years in 79%, and 4 years in 87%. Surgical treatment was necessary in 37% of the cases with an ileal location, in 44% with ileocolonic location, and 17% wit h a colonic location. In conclusion, even if our data lack a statistical si gnificance, we have found that the initial anatomic involvement is not a va lid parameter to predict the relapse risk in a homogeneous group under cont inuous treatment with oral 5-ASA, although ileocolonic location seems to ha ve a more aggressive course.