Journal Club 

Quantifying Risk of Clostridioides difficile Infection by Specific Antibiotic Regimens

By Christopher J. Graber, MD, MPH, FIDSA

While Clostridioides difficile infection (CDI) is a known complication of antimicrobial therapy and certain antibiotics and classes of antibiotics (clindamycin, fluoroquinolones, cephalosporins) are classically associated with CDI, data supporting our notions of the strength and magnitude of these associations are surprisingly limited. A recent study published in Clinical Infectious Diseases helps fill in some gaps.

The authors reviewed antibiotic prescription data for nursing home residents aged 66 or older from 2012 to 2017 from the Ontario Drug Benefits database, selecting all days on which residents developed CDI and 0.1% of days in which they did not, excluding resident days in which multiple antibiotics or anti-CDI antibiotics were received within 90 days prior, hospitalization occurred within 30 days prior, or prior CDI occurred within 60 days prior. Logistic random-effects models were used to determine the probability of incident CDI on a given resident day, and CDI risk was calculated for 18 antibiotics for durations between 5 to 14 days.

From 135,851 resident days analyzed among 82,592 unique residents, 1,708 cases of CDI were analyzed. A 7-day course of antibiotics was associated with 1.80x adjusted increased risk of CDI versus no antibiotics (adjusted relative risk [ARR] 95% confidence interval [CI] 1.55-1.97). Among 7-day courses, the highest CDI risk was observed with cefixime (ARR 4.26), clindamycin (ARR 4.04), moxifloxacin (ARR 3.39), and amoxicillin-clavulanate (ARR 2.43). A 14-day course in general was associated with 1.27x increased CDI risk (ARR CI 1.21-1.30) versus a 7-day course, though the strength of the duration-risk association was heterogeneous according to antibiotic. The authors have provided a website in which specific regimens (antibiotic + duration) can be compared.

This work is a very valuable resource that provides us with quantitative CDI risk estimates for one antibiotic regimen versus another. It can be used both on an individual patient level and in planning antimicrobial stewardship interventions on a population level.

(Brown et al. Clin Infect Dis. 2021;72(5):836-44.)