Bobby Lo, PhD, and colleagues found a significant association between certain classes of antibiotics and increased risk of IBD flare-ups. In a study published in the Journal of Crohn’s and Colitis, Dr. Lo and colleagues created two nested case-control cohorts. They evaluated the first cohort (n=15,636) for IBD-related hospitalization risk and the second cohort (n=5,178) for high-dose systemic steroid exposure. Dr. Lo and colleagues used multivariate logistic regression and Extreme Gradient Boosted decision tree machine learning models to analyze risk. Patients had significantly increased risk of flare-ups with antecedent exposure to quinolones (antimycotics for systemic use [ATC]: J01M; OR: 3.04-3.82), antimycotics (ATC: J02A; OR: 1.50-2.30), agents against amoebiasis and protozoal infections (ATC: P01A; OR: 1.95-3.18), intestinal anti-infectives (ATC: A07A; OR: 2.09- 2.32), and beta-lactam antibiotics (ATC: J01C; OR: 1.36). These agents were among the 10 most important variables in the machine learning model, which corroborated the findings with areas under the curve ranging from 0.71-0.85.