Exploring the effects of DPP-4 inhibitors on the kidney from the bench to clinical trials

Dipeptidyl-peptidase-4 (DPP-4) inhibitors are a relatively new class of non-insulin glucose-lowering agents, belonging to the incretin family, which are able to improve glycemic control with a favorable safety profile, since they are associated with a low risk of hypoglycemia, no weight gain, and good tolerability in patients with chronic renal failure. Some experimental and clinical studies suggest that these drugs may exert significant pleiotropic effects, in particular on chronic kidney disease (CKD) progression, but data from clinical trials are still controversial. In an effort to clarify the effects of DPP-4 inhibitors (DPP-4is) on diabetes-related renal damage, we performed a narrative review of available clinical trials and other experimental studies focusing on renal effects of DPP-4is. Currently, there is no conclusive evidence proving the usefulness of this drug class for improving diabetes-related renal damage. However, our literature review suggests that DPP-4is are safe and well tolerated in type 2 diabetes mellitus (T2DM) patients with CKD. More importantly, results from the reviewed studies indicate that DPP-4 inhibitor therapy may improve two major risk factors for diabetic nephropathy, such as hyperglycemia and albuminuria, resulting in potential renal benefits beyond glycemic control. Despite several limitations, the conclusions of our review corroborate previous evidence on the potential renal benefits of DPP-4is, highlighting the urgent need of future trials adequately powered and designed on hard renal outcomes to ascertain (or contradict) the therapeutic benefit of DPP-4is in T2DM and CKD patients.