Incretin therapies in the management of patients with type 2 diabetes mellitus and renal impairment.

Renal impairment (RI) is common among patients with type 2 diabetes mellitus (T2DM), and these patients also experience an age-related decline in renal function. At the same time, treatment options are more limited and treatment is more complex, particularly in patients with moderate or severe RI due to contraindications, need for dose adjustment and/or regular monitoring, and side effects, such as fluid retention and hypoglycemia, which are a more serious concern in this patient population. Incretin therapies, consisting of the injectable glucagon-like peptide-1 (GLP-1) receptor agonists and the oral dipeptidyl peptidase-4 (DPP-4) inhibitors, are a promising new class of antihyperglycemic drugs. In the overall population, they improve glycemic control in a glucose-dependent manner and are not likely to cause hypoglycemia, representing a clear advantage in at-risk populations. Data regarding use of these agents in renally impaired patients have started to emerge, and the objective of this article is to provide an overview of the currently available data and the potential role of these novel agents in the management of patients with T2DM and RI. Data for the GLP-1 receptor agonists in patients with moderate or severe RI are still limited, with no trials dedicated to these populations currently published. In addition, their potential to cause gastrointestinal side effects may limit use in patients with RI due to the risk of dehydration and hypovolemia. The use of GLP-1 receptor agonists in patients with moderate or severe RI is therefore, at present, underlying caution and/or restrictions. On the other hand, data from specific trials in patients with moderate or severe RI are now becoming available for most of the DPP-4 inhibitors. These studies demonstrate good efficacy and tolerability of the DPP-4 inhibitors in patients with moderate or severe RI, thus opening a place for these therapies in the treatment of populations with T2DM and RI. Several of the DPP-4 inhibitors are already approved for use in patients with moderate or severe RI, including for those with end-stage renal disease. While discussing the advantages related to their common mechanism of action, this article also describes differences among the DPP-4 inhibitors (eg, related to their pharmacokinetic properties and the available clinical data). In conclusion, while initial data for these new therapies are promising, further experience is needed to fully assess the risk-benefit balance and clinical positioning of these agents in RI populations.