Metformin is the broadly accepted the first-line medication for diabetes. Its use, however, is limited by gastrointestinal side effects, which occur in approximately 25% of patients. We performed a cross-sectional study assessing microbiota composition among African Americans (AA) with diabetes with or without metformin intolerance. Participants were stratified into three groups: 1) Intolerant (I) : history of metformin intolerance, not currently on metformin) ; 2) Partially intolerant (PI) : reporting GI symptoms and currently on metformin 3) Tolerant (T) : current metformin use with no GI symptoms. Rectal swab was collected and microbiota analyzed by amplification and sequencing of the V4 region of the 16s rRNA gene.Among 29 participants, mean age 59 ± 11, 58 % female, group I had greatest alpha diversity, followed by T and PI, although differences were not significant (I: 4.9; T: 4.2; PI: 3.9) . Mean difference in alpha diversity for I versus PI were 1.0 (95% CI -0.1, 2.1) and I versus T were 0.7 (95% CI -0.4, 1.8) . Phyla enrichment shown in figure.

Conclusion: This pilot study evaluated the role of microbiota in metformin intolerance among African Americans. We identify differences in alpha diversity and microbiota. Prospective studies are needed to assess the role of microbial diversity and dysbiosis in metformin-related gastrointestinal symptoms.


M.Fayfman: None. S.Srinivasan: None. G.E.Umpierrez: Research Support; AstraZeneca, Dexcom, Inc., Novo Nordisk. G.Blanco: None. A.Gewirtz: None. B.Chassaing: Advisory Panel; Nestlé Health Science, Consultant; Procter & Gamble, Qiagen.



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