Microscopic Colitis and Risk of Inflammatory Bowel Disease in a Nationwide Cohort Study.

Gastroenterology. 2020 Jan 08;:

Authors: Khalili H, Burke KE, Roelstraete B, Sachs MC, Olén O, Ludvigsson JF

BACKGROUND AND AIMS: Microscopic colitis shares pathogenetic mechanisms with inflammatory bowel disease (IBD). We studied the association between microscopic colitis and risk of incident IBD using data from a nationwide cohort study.
METHODS: We conducted a prospective cohort study of all adults who received a diagnosis of microscopic colitis from 1990 through 2017 in Sweden and risk of incident IBD. Cases of microscopic colitis (n= 13,957) were identified through SNOMED codes from the ESPRESSO study, which included gastrointestinal pathology reports from all of Sweden’s 28 centers. Individuals with microscopic colitis were matched to 5 general population controls (n= 66,820) and to unaffected siblings (n=13,943). Cox regression was used to estimate adjusted hazard ratio (aHRs) and 95% CIs.
RESULTS: Through December of 2017, we identified 323 incident cases of ulcerative colitis (UC) and 108 incident cases of Crohn’s disease (CD) in microscopic colitis patients compared to 94 UC and 42 CD cases in population comparators. Mean times from diagnosis of microscopic colitis to diagnosis of CD was 3.3±3.2 years and to diagnosis of UC was 3.2±3.5 years. In multivariable models, microscopic colitis was associated with an aHR of 12.6 (95%CI 8.8-18.1) for CD, 17.3 (95%CI 13.7-21.8) for UC, and 16.8 (95%CI 13.9-20.3) for IBD. The 10-year absolute excess risk of CD and UC were 0.9 (95% 0.7-1.1) and 2.6 (95% CI 2.2-2.9) percentage points, respectively. In sensitivity analyses, comparing microscopic colitis patients to their unaffected siblings, the aHRs of CD and UC were 5.4 (95%CI 3.2-9.2) and 9.4 (95%CI 6.4-13.8), respectively.
CONCLUSIONS: In a population-based study in Sweden, we found a significant increase in risk of incident IBD among patients with microscopic colitis. Future studies should focus on potential mechanisms underlying these observed associations.

PMID: 31926169 [PubMed – as supplied by publisher]

PubMed Link: https://www.ncbi.nlm.nih.gov/pubmed/31926169?dopt=Abstract