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

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.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.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.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.