[Activity indices in IBD]

Inflammatory bowel disease (IBD) encompasses two medical conditions, Crohn's disease (CD) and ulcerative colitis (UC). These are chronic idiopathic conditions, marked by recurrent episodes of inflammation of the gastrointestinal tract, interspersed with periods of remission. An important feature of both disorders is that patients vary significantly in their clinical, endoscopic, biochemikal and histologic features. The heterogeneity in disease activity makes objective assessment of disease activity a prerequisite for rationale choice of therapy. At present, a number of activity indices are available for both conditions. These indices may be distinguished in more subjective (clinical), more objective (endoscopic-histological, biochemical) or a combination of the two. All these indices are rather complex and time-consuming; therefore their use is limited to clinical trials. Despite the different indices available, there is no consensus in the literature as to which is the most valid. In everyday clinical practice most gastroenterologists rely on their global clinical judgement, which is less reproducible, but simpler for decision-making in patients treatment. The aim of this article is to provide an overview of the disease activity indices (with a focus on the most frequently used), with analysis of their utilities, strengths and limitations.