Diagnostic Modality of Clostridioides difficile Infection Predicts Treatment Response and Outcomes in Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) patients are at increased risk of developing Clostridioides difficile infection (CDI). Common methods to diagnose CDI involve a combination of tests including the toxin A/B enzyme immunoassay (Toxin) and toxin gene polymerase chain reaction assay (PCR). Disease outcomes in Toxin+ versus Toxin-PCR+ IBD patients remain unclear. Aims: This study aimed to examine the response to antibiotics and risk of IBD therapy escalation in Toxin+ versus Toxin-PCR+ patients. Methods: IBD patients at an academic center with CDI diagnosis based on Toxin+ or Toxin-PCR+ from 2012 to 2017 were identified. Comparisons of response to antibiotics within 30 days and escalation of IBD therapy within 90 days of CDI diagnosis between these two groups were analyzed by Chi-square analysis. Multivariable regression analysis examined factors associated with antibiotic response. Results: Among 92 patients included, 61% had Crohn’s disease and 39% had ulcerative colitis. 70% tested Toxin-PCR+. 60% received vancomycin or fidaxomicin to treat CDI. 82% of Toxin+ patients responded to antibiotics compared to 25% of Toxin-PCR+ patients (p < 0.001). 21% of Toxin+ patients required IBD therapy escalation compared to 63% of Toxin-PCR+ patients (p < 0.001). When adjusted for the types of antibiotics used, IBD subtypes, and immunosuppression status, positivity to Toxin (OR 14.85, CI 4.62–47.72) was the most significant predictor of response to antibiotics. Conclusions: Toxin+ compared to Toxin-PCR+ IBD patients had a significantly higher rate of response to antibiotics and lower chances of requiring IBD therapy escalation. Future outcome studies involving CDI in IBD patients should be stratified by modality of diagnosis.