Patients with Clostridium difficile infection who received a single fecal microbiota transplantation using stool from an overweight or obese donor showed no significant changes in their own BMI after treatment, according to new research published in Clinical Gastroenterology and Hepatology.
Investigators concluded that, although stool banks should continue to exclude obese and overweight donors given the evidence linking obesity and metabolic syndrome to the gut microbiome, these findings suggest that using stool from overweight FMT donors, as was previously done among early adopters, may be safe.
“The clinical significance of our findings is that a single FMT, irrespective of the donor weight/BMI, will not change the recipient weight/BMI,” Monika Fischer, MD, MSc, of the department of gastroenterology and hepatology at Indiana University School of Medicine, told Healio Gastroenterology and Liver Disease. “This finding is reassuring in the fact that if a lean/normal weight stool donor is not available, using an otherwise healthy and well-screened overweight/obese donor is okay.”
Fischer and colleagues reviewed data from a randomized clinical trial (n = 103), in which 64% of C. difficile patients received FMT from a normal weight donor and 36% from an overweight donor, and an observational study (n = 70), in which 36% received FMT from a normal weight donor, 43% from an overweight donor and 21% from an obese donor. FMT was administered by colonoscopy or capsule in the RCT, and by colonoscopy only in the observational study, and follow-up periods spanned 48 and 52 weeks, respectively. All treatments were successful.
The investigators found no significant differences between groups in the time trend of BMI changes after FMT. However, they noted that all patients lost weight during their C. difficile infection and subsequently increased BMI after FMT, but this did not exceed their BMI before their infection.
“The weight gain we usually see post-FMT in the majority of patients is simply re-gain of the weight generally lost while being ill with C. diff,” Fischer said.
She and colleagues noted that their results should be interpreted with caution given the limited microbiome analysis performed in the studies, different FMT delivery methods, different study designs, and the association with only a single rather than multiple FMTs.
Though “a bit of a stretch,” Fischer said one could extrapolate from this finding that in the future, “if we want to use FMT from a lean donor for weight loss purposes, one FMT will not do.” – by Adam Leitenberger
Disclosures: Fischer reports she is a research consultant for Finch Therapeutics. Please see the full study for a list of all other authors’ relevant financial disclosures.