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.