Systematic review: the global incidence of faecal microbiota transplantation‐related adverse events from 2000 to 2020

Summary Background Faecal microbiota transplantation (FMT) is an effective treatment in C. difficile infection (CDI) and is currently being investigated in other diseases. There is concern around the safety of FMT and that side effects or complications may be under‐reported in the medical literature. Aim To evaluate the safety of FMT by summarising the overall reported Adverse Events (AEs) over a 20‐year period Methods We searched EMBASE, MEDLINE, and Cochrane Library databases, and CNKI and Wanfang Data from January 2000 to April 2020. All original studies reporting FMT‐related AEs were considered for inclusion. FMT‐related AEs were further classified as delivery‐related or microbiota‐related. Results Based on the inclusion criteria, 129 studies, which included 4241 patients (5688 FMT courses), were finally eligible. The most common indication for FMT was CDI. Overall, FMT‐related AEs were observed in 19% of FMT procedures. The most frequently reported FMT‐related AEs were diarrhoea (10%) and abdominal discomfort/pain/cramping (7%). FMT‐related serious adverse events (SAEs), including infections and deaths, have been reported in 1.4% of patients who underwent FMT (0.99% microbiota‐related SAEs). Four of five FMT‐related deaths were reported in patients receiving FMT via the upper gastrointestinal route. Importantly, all reported FMT‐related SAEs were in patients with mucosal barrier injury. Conclusion Most FMT‐related AEs were mild or moderate and self‐limiting. Although FMT appears to be highly safe, its methodology should be improved to reduce both delivery‐related AEs and, microbiota‐related AEs.