Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota

Growing evidence from metagenome-wide association studies link multiple common disorders to microbial dysbiosis but effects of drug treatment are often not accounted for; here, the authors re-analyse two previous metagenomic studies of type 2 diabetes mellitus patients together with a novel cohort to determine the effects of the widely prescribed antidiabetic drug metformin and highlight the need to distinguish the effects of a disease from the effects of treatment on the gut microbiota.