Patient Safety and Quality
Background: Clostridium difficile infection (CDI) persists as a health quality concern due to increasing incidence and emergence of different strains thought to be due to the increased antibiotic use by health professionals. Emergency providers are often required to start broad-spectrum antibiotics in severely ill patients without a known source or organism. Known risk factors associated with CDI include recent hospitalization, advanced age, immunosuppression, and chemotherapy exposure, all features that may increase the likelihood of emergency providers administering early broad-spectrum antibiotics. In addition, Type 2 diabetes has also been shown to be an independent risk factor for recurrent CDI. However, previous evidence suggests that metformin administration favorably alters of gut microbiota and may decrease the incidence or duration of CDI. Our a priori hypothesis was that metformin is protective against CDI in our complex, high case mix index patient population.
Methods: We identified, 8450 patients tested for CDI between January 01, 2007 and December 31, 2017 from an urban university hospital. In this retrospective case control study, forty patient clinical and demographic characteristics were compared between those that tested positive and negative for CDI. Fisher test was used for categorical variables and t-test for Gaussian distributed continuous variables, or Wilcoxon rank-sum test for non-Gaussian distributed continuous variables. Logistic regression model was construed to estimate the odds ratio and 95% CI of positive C. difficile test by selected confounders.
Results: Of the patients tested for CDI, 1514 (17.9%) were positive and 6936 (82.1%) were negative. No significant differences were found in gender, age, or race. Patients on metformin had an odds ratio 0.593 (0.460-0.765), which showed significantly to have protective impact from CDI, and a 40% reduction of risk for CDI in diabetic patients. However, in non-diabetic patients, metformin protection was not significant.
Conclusion: We conclude that metformin is protective against CDI in patients with diabetes. These findings may have significant implications for future prophylactic measures for preventing CDI. Further prospective study will be required to determine if prophylactic use of metformin may be beneficial in high-risk patients started on broad-spectrum antibiotics.