Risk Factors that Predict the Failure of Multiple Fecal Microbiota Transplantations for Clostridioides difficile Infection.

Background: Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent Clostridioides difficile infection (CDI); however, a small percentage of patients fail to achieve cure even after two FMTs. This high-risk cohort remains poorly understood.

Methods: We performed a multicenter, multinational retrospective review of patients that underwent at least one FMT for a CDI indication at four academic FMT referrals. Patients' data including CDI, FMT, and FMT variables were assessed. The primary outcome was FMT failure after a second FMT defined as persistent diarrhea and positive laboratory test for C. difficile (PCR or toxin) despite a second FMT within 8 weeks of the first FMT. A multivariable logistic regression model was performed to determine predictors of second FMT failure.

Results: A total of 540 patients received at least one FMT during the study period, of which 432 patients had success following the first FMT, 108 had documented failure (25%). Among those who failed the first FMT, 63 patients received a second FMT, of which 36 achieved cure, and 24 had documented failure after the second FMT. Patients that failed the first FMT but did not receive a second FMT and those lost to follow-up were excluded leaving 492 patients included in the analysis. The second FMT failure rate was 4.8% (24/492). Risk factors for second FMT failure identified by multivariable logistic regression included: inpatient status (OR 7.01, 95% CI: 2.37-20.78), the presence of pseudomembranes (OR 3.53, 95% CI: 1.1-11.33), and immunocompromised state (OR 3.56, 95% CI: 1.45-8.72) at the time of first FMT.

Conclusion: This study identifies clinically relevant risk factors predictive of failing a second FMT. Clinicians can use these variables to help identify high-risk patients and provide a better-informed consent regarding the possibility of needing multiple FMTs.