Patient Age, Antibiotics, and FMT Donor Influence Recurrent C. Difficile Resolution

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New cohort analysis data provide more context into what factors influence the benefit of FMT in patients with recurrent CDI.

Fecal microbial transplantation (FMT) may be optimally efficacious for treating recurrent C. difficile infection (CDI) in older patients who had not received antibiotics for the disease prior to treatment.1

New data from a cohort analysis by Denmark investigators showed variability in effect of FMT in treated patients with recurrent CDI based on patient demographics, treatment history and iteration of care. The results contribute toward the effort to evidence best-practices of the standard-care FMT regimen in patients with CDI.

Investigators led by Simon M.D. Baunwell, MD, PhD, of the department of hepatology and gastroenterology at Aarhus University Hospital, conducted an analysis to determine the effectiveness of FMT for recurrent CDI, and to validate the determinants for effect. As they noted, FMT’s efficacy for recurrent CDI “varies inexplicably.”

Even factors such as single versus multiple donor has been shown to vary the efficacy of FMT in patients with recurrent CDI—such as shown in another Denmark-based analysis from Aleris-Hamlet Hospitals last year.2

Baunwell and colleagues conducted their cohort analysis using all patients treated with FMT for diagnosed recurrent CDI at their university hospital from October 2018 – June 2020. The team used a statistical process control to evaluate the impact of prospective quality improvement on the efficacy of single treatments of FMT per 10-11 patients.

Investigators sought optimizations of FMT including changes to processing procedures, preparation and clinical application of treatment at standards of 80% effect. Their primary outcome was resolution of recurrent CDI-associated diarrhea at week 8.

FMT was repeated in patients with continued recurrent CDI, and patients were followed for 8 weeks following their latest FMT.

The final analysis included 183 patients with recurrent CDI who received 290 FMT doses. Single FMT achieved diarrhea resolution at 8 weeks in 127 patients (69%; 95% CI, 62 – 76); repeated FMT cumulatively achieved diarrhea resolution in 167 patients (91%; 95% CI, 86 – 95). Single FMT effect varied from 36 – 100% over the period of assessment.

The team reported that in their mixed-effect model, patients >65 years old, those receiving non-recurrent CDI-associated antibiotics at week 1 post-treatment, and FMT donor were associated with treatment effect. They noted, however, that neither increasing the dosages of fecal microbes nor standardizing the process were associated with improved patient outcomes.

“FMT has a high cumulative effectiveness in patients with recurrent CDI following multiple administrations, but the single FMT effect is variable and may be optimized using statistical process control,” investigators concluded. “Optimizing FMT by considering patient age, post-FMT antibiotics, donor and multiple administrations may improve the treatment outcomes.”


  1. Baunwall SMD, Hansen MM, Andreasen SE, et al. Donor, patient age and exposure to antibiotics are associated with the outcome of faecal microbiota transplantation for recurrent Clostridioides difficile infection: A prospective cohort study [published online ahead of print, 2023 Jul 22]. Aliment Pharmacol Ther. 2023;10.1111/apt.17642. doi:10.1111/apt.17642
  2. Walter K. Single-Donor FMT Comparable to Multi-Donor FMT for Recurrent C Difficile. HCPLive. Published February 2, 2022.