Robust Association Between Antibiotics and C Difficile Infection, Even in Outpatient Settings

Antibiotic exposure is known to raise the risk of Clostridioides difficile infection(CDI). An estimated 30% of outpatient antibiotic prescriptions may be unnecessary, raising the risk of not only C diff infections but antimicrobial resistance as well.

One study, presented at the Society for Healthcare Epidemiology of America Conference 2022 (SHEA), examined the prevalence of community-acquired Clostridioides difficile infection (CA-CDI) among persons without recent hospitalization. To assess the correlation between outpatient antibiotic exposure and risk of CA-CDI, the investigators recruited a 2-year patient cohort from Community-Based Outpatient Clinics (CBOC).

Primary care visits and non-visit antibiotic prescriptions from 2018-2019 were included in the study. Investigators categorized patient characteristics, clinical diagnoses, and antibiotics prescribed for each encounter. They estimated the unadjusted odds ratio of outpatient antibiotics for CA-CDI, and used logistic regression to adjust for additional risk factors.

The final cohort included 884787 patients with clinic visits that fulfilled study criteria. Of these participants, 3533 were prescribed antibiotics and 5 (0.14%) developed CA-CDI. Of the 81254 patients who were not prescribed antibiotics, 15 (0.02%) developed CA-CDI. After adjusting for patient age and comorbidities, the odds ratio of CA-CDI after outpatient antibiotic prescription remained statistically significant.

These findings were presented by Robin Jump, MD, PhD, who concluded that although CA-CDI episodes were infrequent, the odds of CA-CDI were 7-fold higher in outpatients with antibiotic exposure than those without. “Antibiotic stewardship interventions that emphasize adverse events as a result of care provided in the outpatient setting, rather than as events limited to acute care settings, may mitigate CDI risk,” the study authors concluded.

The study, In Veteran Outpatients, Antibiotics Remain Significant Risk Factor for Community-Acquired Clostridiodes difficile Infection,” was presented on April 12 during the Society for Healthcare Epidemiology of America Conference 2022 (SHEA).