Smoking Out the Relationship Between Ulcerative Colitis and Cigarette Use: Insights From A Propensity Matched Study

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Conference Proceeding

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American Journal of Gastroenterology


Introduction: Ulcerative colitis (UC) is a chronic inflammatory disorder affecting the colon. Previous studies have indicated that smoking can reduce disease activity in UC, and symptoms may worsen upon smoking cessation. In this study, we aimed to analyze smoking trends in UC and investigate the association between smoking and UC-related complications. Methods: We utilized the National Inpatient Sample (NIS) database to create a 1:1 matched cohort of UC patients without a history of smoking. The matching was based on biodemographic and hospital characteristics, as well as 31 Elixhauser comorbidities. We compared UC-related outcomes between the matched cohorts using the Chi-square test for categorical variables and the student’s t-test for continuous variables. Univariate and multivariate linear and logistic regression models were constructed, incorporating known confounders, and variables with a P-value of , 0.2 on univariate analysis. A statistically significant threshold was set at P#0.05. Results: A total of 550,075 patients with UC were identified, of which 59,145 (10.75%) were smokers. After 1:1 matching, we paired 47,975 smoker patients with an equal number of non-smoker patients. Smokers were 13% more likely to have uncomplicated UC. Smoking in UC was associated with a 21% lower mortality rate, a 0.46-day decrease in length of stay (LOS), and a $5,549 reduction in mean inpatient cost (MIC) compared to non-smokers. Smoking was also linked to a 16% lower odds of gastrointestinal (GI) bleeding but a 22% higher odds of intestinal perforation in comparison to non-smokers. Notably, in recent years, there is an increase in all-cause mortality and intestinal perforation related to UC, paralleling the trends in smoking. Conclusion: This study bolsters the idea of a protective effect of smoking on UC, likely because byproducts such as nicotine and carbon monoxide have an immunomodulatory effect on autoantibody production, cytokine formation and leukocyte migration, leading to overall suppressed immunological response. This effect may also be site and tissue specific as some studies show that cigarette smoke may intensify damage in the small intestine but reduce colitis, possibly because caustic components are metabolized earlier in GI tract and specific microbiota and specialized epithelial cells in the colon have differential immune response compared to other parts of GI tract. This may also account for differences in the effect of smoking on UC versus other GI inflammatory diseases like Crohn’s





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American College of Gastroenterology Annual Scientific Meeting, October 20-25, 2023, Vancouver, Canada

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