Background: Fecal microbiota transplantation (FMT) is highly effective for treating recurrent Clostridium difficile infection (rCDI). Management protocols are not uniform. The aim of the systematic review and meta-analysis was to assess and compare efficacy of different FMT protocols for recurrent CDI according to route, dose and form.

Method: Various databases were systematically searched from January 2015 to March 2020. Studies with clinical cure of rCDI as primary outcome and provided multiple infusions of FMT if a single infusion did not cure rCDI were included. Primary outcome was assessed using a random effect meta-analysis model with a subgroup analyses comparing different routes and dose. Effect of study design, age, route and form of infusion, year of publication and maximum number infusions assessed using a meta regression.

Results: Thirteen studies included, comprising 686 patients with rCDI treated with FMT. Compared to single infusions, multiple infusions increased efficacy rates overall (73% versus92%). Overall subgroup analysis of route of infusion found the lower gastrointestinal tract more efficient than upper (96%vs 90%). Higher overall dose more efficient; 1-50g vs 51-100g vs 101-150g; (88% vs 97% vs97%). Meta regression found that increase of Dose of FMT per 1 gmincrement, frozen form of FMT and more than 2 infusions, were associated with higher overall efficacy rates (p = 0.019), (p = 0.0002) and (p=0.001) respectively. Frozen feces were associated with higher efficacy rates after a single infusion (p=0.03).

Conclusion: Many infusions, high fecal dosage and frozen form of infusion increases the effectiveness of FMT for rCDI. These findings could be valuable in the creation of effective standardized treatment approaches.