The Effect of Dipeptidyl Peptidase-4 Inhibitors on Macrovascular and Microvascular Complications of Diabetes Mellitus: A Systematic Review

BACKGROUND: The World Health Organization estimates that diabetes is the seventh leading cause of death. Uncontrolled diabetes may cause severe consequences such as cardiovascular (CV) events (myocardial infarction, stroke, or CV mortality), lower-extremity amputations, and end-stage renal disease. Microvascular complications include retinopathy, autonomic and peripheral neuropathy, nephropathy, and diabetic ulcers. Major CV outcomes trials that were by the Food and Drug Administration for all new antihyperglycemia medications for patients at high risk for CV events were recently completed for all 4 US-marketed dipeptidyl peptidase-4 (DPP-4) inhibitors. OBJECTIVE: To present a comprehensive review of the clinical trials that evaluate macrovascular and microvascular complications reported with DPP-4 inhibitors in patients with type 2 diabetes mellitus. METHODS: In this review, we analyzed published articles in PubMed and Ovid databases between January 2008 and September 2019 that evaluated the effect of DPP-4 inhibitors on macrovascular and microvascular complications in patients with type 2 diabetes mellitus. RESULTS: A total of 18 studies, which included randomized controlled trials and meta-analyses were assessed. Current evidence demonstrates that the addition of DPP-4 inhibitors to standard antihyperglycemic and CV risk reduction treatment has not shown CV benefit relative to placebo in contrast to recently published studies for other medications within the glucagon-like peptide 1 agonist and sodium-glucose co-transporter 2 inhibitor classes. Notably, the potential risk for heart failure hospitalizations may exist for saxagliptin, and this effect is not extrapolated as a class effect. Based on our review, DPP-4 inhibitors may not influence microvascular complications in patients with diabetes. However, some studies have shown that saxagliptin and linagliptin may slow down the progression of albuminuria in patients with type 2 diabetes mellitus. The overall quality of the studies included in this review was high due to the inclusion of randomized controlled trials and meta-analyses. CONCLUSIONS: DPP-4 inhibitors were found to have a neutral effect on macrovascular and microvascular complications, with the exception of saxagliptin, which may increase the risk for heart failure hospitalizations.