Risk of Clostridium difficile Infection in Hospitalized Patients Receiving Metronidazole for a Non-C difficile Infection

BACKGROUND & AIMS: Antibiotics often are given to prevent infections but also constitute a risk factor for Clostridium difficile infection (CDI). Metronidazole is an effective treatment for CDI. We investigated whether prophylactic administration of metronidazole to patients before they receive other antibiotics reduces the risk of CDI. METHODS: We performed a retrospective cohort analysis of data collected from 12,026 high-risk patients admitted to Cleveland Clinic Foundation Hospitals from 2008 through 2012. High-risk patients were defined as age 55 or older who received a broad-spectrum antibiotic (piperacillin-tazobactam or ciprofloxacin) and a gastric acid suppressant (a proton pump inhibitor or a histamine-2 receptor blocker) during their hospitalization. Development of CDI was compared between patients who received metronidazole for non-CDI indications before broad-spectrum antibiotics (n = 811) and those who did not (n = 11,215). Logistic regression was used to control for patient demographics and comorbidities. RESULTS: The rate of CDI was 1.4% (n = 11) among the patients who received metronidazole for non-CDI indications and 6.5% (n = 728) among those who did not. This was observed to be an 80% reduction in CDI among patients who received metronidazole (odds ratio, 0.21; 95% confidence interval, 0.11-0.38; P < .001), adjusted for age, sex, and comorbidities. CONCLUSIONS: Based on a retrospective analysis, metronidazole might be used to prevent CDI in certain high-risk patients. Prospective controlled trials are necessary before making further recommendations.