Effect of different HbA1c levels on the gut microbiota in patients with type 2 diabetes mellitus

Increasing evidence indicates that the gut microbiota contributes to the development and progression of type 2 diabetes mellitus (T2DM). However, little is known about the effects of different hemoglobin A1c (glycated hemoglobin; HbA1c) levels on the gut microbiota. In the present study, the changes in microbial composition associated with different HbA1c levels in patients with T2DM were investigated. For this purpose, 30 patients with T2DM were randomly divided into three groups according to the HbA1c levels: Group A (HbA1c levels, ≥53 but <75 mmol/mol), group B (HbA1c levels, ≥75 but ≤97 mmol/mol) and group C HbA1c levels, >97.0 mmol/mol). 16S‑rDNA sequencing was performed to analyze the effects of different HbA1c levels on the gut microbiota. The results revealed that the microbial richness and inner diversity of the gut microbiome was slightly increased as the HbA1c levels increased. The Firmicutes/Bacteroidetes ratio was reduced with the increase in blood glucose levels. Collectively, the findings of the present study demonstrated that there was a certain association between the gut microbiome and HbA1c levels in patients with T2DM, indicating that modulating the microbial composition may be a potential strategy for improving glucose homeostasis.