Faecal microbiota transplantation (FMT) is currently investigated as a novel treatment option for several chronic diseases related to gut dysbiosis with the strongest evidence for efficacy in the treatment of recurrent Clostridium difficile infection. Although clear reporting of FMT methodology is important to better understand and reproduce studies, reports of the methodological components of FMT interventions in clinical trials vary greatly from publication to publication.

A recent systematic review, led by Dr. Philippe Ravaud from the Centre d’Epidémiologie Clinique at Hôpital Hôtel-Dieu in Paris (France), has examined how all published studies assessing FMT were conducted and reported, particularly focusing on whether the studies adequately described the main methodological components of the FMT intervention.

From 2783 citations retrieved from the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, and Web of Science (from their dates of inception to 31 January 2017), only 85 eligible studies were identified by three independent reviewers according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

Inclusion criteria were clinical studies in humans -regardless of study design- that were published in English and assessed the efficacy or safety of FMT.

The authors divided the key methodological components into 7 items: 1) eligibility criteria for donors, 2) period of collection (the delay between collection and transplantation), 3) type of diluents used, 4) type of stool (fresh or frozen), 5) amount of stool used, 6) number of transplantations performed, and 7) mode of administration. Description of an FMT intervention was considered adequate when all 7 items were reported and inadequate if 1 or more items was not reported.

84% of the published reports found addressed the use of FMT for Clostridium difficile infection or inflammatory bowel disease, of which only 13% were randomized controlled trials. Among the key methodological components of FMT that were not reported were: eligibility criteria for donors (47%), materials used for collecting stools and the period of collection (96%), methods used for conservation of stools (76%), amount and type of stools used, and duration of stool conservation (67%). When methodological components were reported, the methods used for selecting donors and for collecting and preparing stools, and route of administration were heterogeneous among the studies. Besides this, 58% of the published studies did not report an analysis of the gut microbiota composition. These data show that several key methodological components that may be involved in the success of FMT are lacking in reports of human clinical studies assessing the efficacy or safety of the procedure.

In conclusion, important methodological components of FMT interventions, which are necessary to replicate and understand findings about efficacy and safety, are poorly reported. International recommendations for standardizing FMT to facilitate reporting and implementation in clinical practice are needed.



Bafeta A, Yavchitz A, Riveros C, Batista R, Ravaud P. Methods and reporting studies assessing fecal microbiota transplantation: a systematic review. Ann Intern Med. 2017; doi: 10.7326/M16-2810.