Table 1. Baseline characteristics of the included studies.
| Author (year) | Country | Participants | Case (n) | Age (years) | BMI (kg/m2) | Intervention | Follow up |
|---|---|---|---|---|---|---|---|
| Allegretti (2019) [28] | United Kingdom | Female participants, BMI ≥ 35 kg/m2 without metabolic syndrome | 22: 11 FMT 11 Placebo |
FMT: 44.5±14.4 Placebo: 43.2±13.8 |
FMT: 41.1±5.0 Placebo: 40.4±4.7 |
FMT/ Placebo capsules | 12 weeks |
| Kootte 2017 [29] | Netherlands | Male patients aged 21–69 years with metabolic syndrome | 38: 26 Allogenic FMT 12 Autologous FMT |
Autologous: 54 (49–58) Allogenic: 54 (49–60) |
Autologous: 35.8 (33.1–40.4) Allogenic: 33.8 (32.5–35.7) |
FMT/ autologous FMT was infused through the nasoduodenal tube. | 18 weeks |
| Leong 2020 [30] | New Zealand | Patients aged 14–18 years, BMI ≥ 30 kg/m2 and without chronic diseases. | 87: 42 FMT 45 Placebo |
FMT: 17.3±1.5 Placebo: 17.1±1.4 |
FMT: 38.6±5.9 Placebo: 36.9±4.6 |
FMT/ Placebo capsules | 26 weeks |
| Mocanu 2021 [31] | Canada | Patients aged 18–65 years, BMI ≥ 30 kg/m2 with metabolic syndrome | 61: 29 FMT 32 Placebo |
FMT: 47.3±11.0 Placebo: 48.4±9.6 |
FMT: 46.3±6.6 Placebo: 44.5±7.2 |
FMT/ Placebo capsules coupled with fiber supplementation | 12 weeks |
| Smits (2018) [32] | Netherlands | Male patients aged 21–69 years, BMI ≥ 30 kg/m2 with metabolic syndrome | 20: 10 Allogenic FMT 10 Autologous FMT |
Autologous: 57.7±8.5 Allogenic: 52.3±7.4 |
Autologous: 33.8±4.0 Allogenic: 33.9±3.9 |
FMT/ autologous FMT was infused through the nasoduodenal tube. | 2 weeks |
| Su 2022 [33] | China | Patients aged 41–76 years, with type 2 diabetes | 13: 5 FMT 8 Placebo |
FMT: 57±13.2 Placebo: 60.4±12.0 |
FMT: 25.2±5.0 Placebo: 24.8±3.0 |
received the PPWb formulation only, or coupled with FMT capsules | 90 days |
| Vrieze 2012 [34] | Netherlands | Male patients, BMI ≥ 30 kg/m2 with metabolic syndrome | 18: 9 Allogenic FMT 9 Autologous FMT |
Autologous: 53±3 Allogenic: 47±4 |
Autologous: 35.6±1.5 Allogenic: 35.7±1.5 |
FMT/ autologous FMT was infused through the gastroduodenal tube | 6 weeks |
| Yu 2020 [35] | USA | Patients aged 25–60 years, BMI ≥ 30 kg/m2 and mild to moderate insulin resistancec | 24: 12 FMT 12 Placebo |
FMT: 42.5±8.4 Placebo: 38.5±8.8 |
FMT: 38.8±6.7 Placebo: 41.3±5.1 |
FMT/ Placebo capsules | 12 weeks |
| Groot 2020 [36] | Netherlands | Patients aged 18–35 years with normal BMI, type 1 diabetes | 20: 10 Allogenic FM 10 Autologous FMT |
Autologous: 25.0±3.5 Allogenic: 24.3±5.4 |
Autologous: 23.0±2.0 Allogenic: 21.8±2.5 |
FMT/ autologous FMT was infused through the nasoduodenal tube. | 12 months |
Data are depicted as mean±SD or median (interquartile range), depending on their distribution. BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); FMT, fecal microbiota transplantation.
a. FMT-LF group: FMT and low-fermentable fiber.
b. PPW: diet consisting of probiotics, prebiotics and whole grains.
c. mild to moderate insulin resistance: homeostatic model assessment of insulin resistance (HOMA-IR) between 2.0 and 8.0.