Evidence for separate disease phenotypes in intestinal Crohn's disease

Abstract Background This study investigated the hypothesis that separate phenotypes of Crohn's disease exist which display differing patterns of recurrence with a tendency to preservation of phenotype between serial operations. Methods Some 483 abdominal operations (278 patients) were identified from a prospectively compiled database. Patterns of recurrence (reoperation) were analysed by Kaplan–Meier plots and log rank tests according to disease phenotype (perforated, stenosed or ulcerated). Serial operations were analysed by agreement of phenotype and microscopic features of disease using kappa statistics and correlation coefficients. Results There was no significant difference in recurrence according to disease phenotype (median reoperation-free survival time 43·0, 50·2 and 47·9 months for perforated, stenosed and ulcerated types respectively; log rank χ2 = 3·5, P = 0·18). There was poor agreement in phenotype between serial operations (κ = 0·22 for first/second operation and κ = 0·15 for second/third operation) and no significant correlation between pathological features was identified (r between −0·19 and 0·48). Conclusion No evidence was found for the existence of separate disease phenotypes with differing natural histories or underlying pathological characteristics.