DPP4 and type 2 diabetes mellitus: Moreover, DPP4 inhibitors significantly reduced glucagon levels compared to other OADs (SMD: -0.35, 95% CI: -0.53 to -0.16, <i>P</i><0.001; I<sup>2</sup> = 66%), and the reduction in glucagon was greater in comparison with insulin secretagogues than in comparison with non-insulin secretagogues (<i>P</i> for subgroup difference =0.03).<h4>Systematic review registration</h4>https://inplasy.com/, identifier INPLASY202280104.<h4>Conclusions</h4>DPP4 inhibitors are effective at reducing the circulating postprandial glucagon level in T2DM patients.