Microscopic colitis or functional bowel disease with diarrhea: a French prospective multicenter study

To describe the characteristics of a cohort of patients with microscopic colitis (MC; lymphocytic (LC) or collagenous (CC) colitis) and to compare them with patients with functional bowel disorder with diarrhea (FBD-D).

Between September 2010 and June 2012, patients fulfilling the following inclusion criteria were prospectively included in 26 centers in France: (i) having at least three bowel movements daily with change in stool consistency; (ii) duration of abnormal bowel habit >4 weeks; and (iii) normal or near-normal colonoscopy. Each patient underwent a colonoscopy and colonic biopsies. We compared the demographic, clinical, biological, and etiological characteristic of patients with MC (CC and LC) with those of control patients with FBD-D.

A total of 433 patients were included: 129 with MC (87 LC and 42 CC), 23 with another organic disease, and 278 with FDB-D, including patients with diarrhea and abdominal pain who met the criteria of Rome III (irritable bowel syndrome with diarrhea) and patients with functional diarrhea without abdominal pain. Logistic regression analysis identified the following independent predictors of MC: age >50 years (odds ratio (OR)=3.1, 95% confidence interval (CI)=1.6-5.9), presence of nocturnal stools (OR=2, 95% CI=1.1-3.9), weight loss (OR=2.5, 95% CI=1.3-4.7), duration of diarrhea <12 months (OR=2.0, 95% CI=1.1-3.5), recent introduction of new drugs (OR=3.7, 95% CI=2.1-6.6; P<0.0001), and the presence of a known autoimmune disorder (OR=5.5, 95% CI=2.5-12).

Age >50 years, the presence of nocturnal stools, weight loss, the introduction of a new drug, and the presence of a known autoimmune disease increase the probability of MC and thus the indication for colonoscopy with biopsies.