Microscopic colitis ups IBD risk

Patients with microscopic colitis suffer from an excess risk of inflammatory bowel diseases (IBDs), a recent study has shown.

Researchers conducted a prospective cohort study of 13,957 microscopic colitis patients (mean age, 60.9 years; 72 percent female) who were then matched to five general population controls (n=66,820) and unaffected siblings (n=13,943). The primary outcome was a diagnosis of Crohn’s disease (CD) or ulcerative colitis (UC).

Over an average follow-up of 7.6 years, 108 microscopic colitis patients developed CD and 323 developed UC, with an average time to diagnosis of 3.3 and 3.2 years, respectively. In comparison, only 108 and 94 population controls reported the corresponding IBD.

Multivariable models verified that the risk of CD (adjusted hazard ratio [HR], 12.6, 95 percent confidence interval [CI], 8.8–18.1) and UC (adjusted HR, 17.3, 95 percent CI, 13.7–21.8) were both significantly elevated in microscopic colitis patients. The same remained true when IBD was taken as a whole, including unclassified cases (adjusted HR, 16.8, 95 percent CI, 13.9–20.3).

Use of the unaffected siblings as comparators decreased the magnitude of interaction but did not attenuate significance for both CD (adjusted HR, 5.4, 95 percent CI, 3.2–9.2) and UC (adjusted HR, 9.4, 95 percent CI, 6.4–13.8). The primary findings also remained stable in sensitivity analyses according to different timings of diagnoses.

“Future studies should focus on identifying the exact mechanism underlying our observed associations,” the researchers said.