Course of disease in patients with microscopic colitis - a European prospective incident cohort study.

BACKGROUND AND AIMS The disease course of microscopic colitis (MC) is considered chronic but benign. However, this assumption is based on mainly retrospective studies, reporting on incomplete follow-up of selective cohorts. Systematic, prospective and unbiased data to inform patients and health care professionals on the expected course of the disease and real-life response to therapy are warranted. METHODS A prospective, pan-European, multi-center, web-based registry was established. Incident cases of MC were included. Data on patient characteristics, symptoms, treatment and quality of life were systematically registered at baseline and during real-time follow-up. Four disease course phenotypes were discriminated and described. RESULTS Among 381 cases with complete 1-year follow-up, 49% had a chronic active or relapsing disease course, 40% achieved sustained remission after treatment and 11% had a quiescent course. In general, symptoms and quality of life improved after 3 months of follow-up. A relapsing or chronic active disease course was associated with significantly more symptoms and impaired quality of life after 1 year. CONCLUSIONS A minority of MC patients follow a quiescent disease course with spontaneous clinical improvement, whereas the majority suffers a chronic active or relapsing disease course during the first year after diagnosis, with persisting symptoms accompanied by a significantly impaired quality of life.