PROTON-PUMP INHIBITORS ARE ASSOCIATED WITH AN INCREASED RISK OF MICROSCOPIC COLITIS: A POPULATION-BASED STUDY AND REVIEW OF THE LITERATURE.

Background: Microscopic colitis is a relatively new diagnosis that was first described in the 1980s. Patients usually present with chronic watery and non-bloody diarrhea and are typically characterized by an unremarkable gross appearance of the colon on lower endoscopy while having evidence of lymphocytic infiltration of the lamina propria and the epithelium on histology. Two subtypes have been described in the literature: Collagenous colitis, with marked thickening of the subepithelial layer, and Lymphocytic colitis. Multiple risk factors such as female gender, older age and celiac disease have been associated with this entity. A few studies have found an association between microscopic colitis and proton-pump inhibitor (PPI). The aim of our study was to evaluate the risk of developing microscopic colitis and its subtypes for patients who are on PPI therapy.

Methods: A validated multicenter and research platform database of more than 360 hospitals from 26 different healthcare systems across the United States from 1999 to September 2022 was utilized to construct this study. Patients aged 18 years and above were included. Individuals who have been diagnosed with any autoimmune disease have been excluded. A multivariate regression analysis was performed to assess risk of developing microscopic, lymphocytic, and collagenous colitis by accounting for potential confounders including female gender, smoking history, and the use of proton pump inhibitor, nonsteroidal anti-inflammatory drugs, and selective serotonin receptor inhibitors. A two-sided P value <0.05 was considered as statistically significant, and all statistical analyses were performed using R version 4.0.2 (R Foundation for Statistical Computing, Vienna, Austria, 2008).

Results: 78,256,749 individuals were screened in the database and 69,315,150 were selected in the final analysis after accounting for inclusion and exclusion criteria. The baseline characteristics of patients with microscopic, lymphocytic, and collagenous colitis is seen in table 1. Using a multivariate regression analysis, the risk of developing microscopic, lymphocytic, and collagenous colitis was calculated and illustrated in table 2.

Discussion: Our study showed that the risk of microscopic colitis, lymphocytic colitis and collagenous colitis was higher in females and smokers. Although medications like SSRI and NSAIDs showed a positive correlation with colitis, the highest likelihood of developing this disease was associated with PPIs. Lansoprazole has been documented to be associated with microscopic colitis as it is believed to inhibit colonic proton pumps, and subsequently promote diarrhea and inflammation. Interestingly, the prevalence of lymphocytic colitis and collagenous colitis was similar in the cohort of patients treated with PPIs, indicating no specific predisposition to either subtype. This study further confirms the risk factors associated with microscopic colitis. It can help guide physicians to recognize and eliminate these risk factors prior to initiating treatment for this disease. Future studies can focus on identifying the incidence of microscopic colitis with the different types of PPIs in the market.