Microscopic Colitis Is Associated With a Reduced Risk of Colorectal Adenoma and Cancer: A Meta-Analysis

Background The study sought to conduct a systematic review and meta-analysis of the risk of colorectal adenoma or cancer in patients with microscopic colitis (MC). Methods A comprehensive literature search of PubMed and EMBASE databases was performed. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated to examine the effect of MC on the risk of colorectal adenoma or cancer. Results Twelve studies reporting the outcomes of 50 795 patients with MC were eligible for this meta-analysis. MC was negatively associated with the risk of colorectal adenoma compared with participants without MC (RR, 0.44; 95% CI, 0.33-0.58; P < .001; I2 = 87.3%). Also, the rate of colorectal cancer was lower in the patients with MC compared with the general population (RR, 0.62; 95% CI, 0.43-0.89; P = .01; I2 = 91.6%). In addition, sensitivity and subgroup analyses indicated that the results were robust. Conclusions The present systematic review indicated that patients with MC may be associated with a lower risk of colorectal adenoma or cancer. The clinical data support the current professional society guideline. A surveillance colonoscopy program is not recommended as standard for patients with MC.

Microbial associations with Microscopic Colitis

BACKGROUND AND OBJECTIVE: Microscopic colitis is a relatively common cause of chronic diarrhea and may be linked to luminal factors. Given the essential role of the microbiome in human gut health, analysis of microbiome changes associated with microscopic colitis could provide insights into the development of the disease. METHODS: We enrolled patients who underwent colonoscopy for diarrhea. An experienced pathologist classified patients as having microscopic colitis (n=52) or controls (n=153). Research biopsies were taken from the ascending and descending colon, and the microbiome was characterized with Illumina sequencing. We analyzed the associations between microscopic colitis and microbiome with a series of increasingly complex models adjusted for a range of demographic and health factors. RESULTS: We found that alpha-diversity was significantly lower in microscopic colitis cases compared to controls in the descending colon microbiome. In the descending colon, a series of models that adjusted for an increasing number of co-variates found taxa significantly associated with microscopic colitis, including Proteobacteria that was enriched in cases and Collinsella enriched in controls. While the alpha-diversity and taxa were not significantly associated with microscopic colitis in the ascending colon microbiome, the inference p-values based on ascending and descending microbiomes were highly correlated. CONCLUSION: Our study demonstrates an altered microbiome in microscopic colitis cases compared to controls. Because both the cases and controls had diarrhea, we have identified candidate taxa that could be mechanistically responsible for the development of microscopic colitis independent of changes to the microbial community caused by diarrhea.

Microscopic colitis and the role of the specialist inflammatory bowel disease nurse: a clinical review

Microscopic colitis (MC) is an inflammatory bowel condition similar to but distinct from classical inflammatory bowel disease (IBD). Unlike ulcerative colitis and Crohn's disease, MC is predominately a self-limiting and treatable condition. It is characterised by colonic inflammation and symptoms of watery, non-bloody diarrhoea, alongside abdominal pain and weight loss, causing anxiety, fatigue and reduced quality of life. The prevalence of MC is 119 per 100 000 population and growing. Its aetiology and pathophysiology are poorly understood, but it is likely multifactorial, and possible risk factors include smoking and certain medications and autoimmune conditions. Diagnosis relies on endoscopic biopsy to identify intraepithelial lymphocytosis. Management and treatment begin with excluding possible risk factors and can include anti-diarrhoeal medications, bile acid binders and budesonide, which is highly effective at inducing and maintaining remission. Refractory disease is rare, but it may require biological medications or even surgery. Disease activity is monitored with the Hjortswang criteria and Microscopic Colitis Disease Activity Index. This narrative clinical review draws on recent guidelines and study data to explore the uncertain role of the clinical nurse specialist in caring for these patients.