Second European evidence-based consensus on the diagnosis and management of ulcerative colitis Part 1: Definitions and diagnosis

### 1.1 Introduction Ulcerative colitis is a lifelong disease arising from an interaction between genetic and environmental factors, observed predominantly in the developed countries of the world. The precise aetiology is unknown and therefore medical therapy to cure the disease is not yet available. Within Europe there is a North–South gradient, but the incidence appears to have increased in Southern and Eastern countries in recent years.1,2 Patients may live with a considerable symptom burden despite medical treatment (66% describe interference with work and 73% with leisure activities3) in the hope that the aetiology of ulcerative colitis will shortly be revealed and a cure emerge. Although this is conceivable in the next decade, clinicians have to advise patients on the basis of information available today. Despite randomised trials there will always be many questions that can only be answered by the exercise of judgement and opinion. This leads to differences in practice between clinicians, which may be brought into sharp relief by differences in emphasis between countries. This Consensus endeavours to address these differences. The Consensus is not meant to supersede the guidelines of different countries (such as those from the UK,4 or Germany,5) which reach broadly the same conclusions since they are, after all, based on the same evidence. Rather, the aim of the Consensus is to promote a European perspective on the management of ulcerative colitis (UC) and its dilemmas. Since the development of guidelines is an expensive and time-consuming process, it may help to avoid duplication of effort in the future. A European Consensus is also considered important because an increasing number of therapeutic trials recruit from Central and Eastern European countries where practice guidelines have yet to be published. This document updates the previous European Consensus on the diagnosis and management of UC, and …