Comparative effects of glucose-lowering agents on endothelial function and arterial stiffness in patients with type 2 diabetes: A network meta-analysis

BACKGROUND AND AIMS

Despite accumulating evidence on the potential of glucose-lowering agents (GLAs) to prevent cardiovascular events, the comparative effects of GLAs on vascular function remain unclear. This study utilized validated indicators such as flow-mediated dilation (FMD; positive value favors) and pulse wave velocity (PWV; negative value favors) to uncover the comparative effects of GLAs on vascular function.

METHODS

Randomized controlled trials (RCTs) comparing the effects of GLAs on FMD or PWV with placebo or other GLAs in patients with type 2 diabetes (T2DM) were searched through PubMed and Embase. The frequentist method of network meta-analysis (NMA) was conducted using a random effects model, and standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated.

RESULTS

The NMA included 38 RCTs with 2,065 patients. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium glucose cotransporter-2 inhibitors (SGLT-2Is) had significantly more positive effects on FMD improvement and PWV reduction than placebo. Thiazolidinedione (TZD) treatment resulted in significantly improved FMD compared to other GLAs as well as placebo (SMD: 1.14; 95% CI: 0.84 to 1.43). Both pioglitazone and rosiglitazone were discovered to have considerably more favorable effects on improving FMD and reducing PWV compared to placebo and other GLAs, as a result of the analysis incorporating each drug in the TZD class. The sensitivity analysis results corroborated the main findings.

CONCLUSIONS

This NMA showed more favorable effects of GLP-1RAs and SGLT-2Is than placebo in improving both arterial stiffness and endothelial function in patients with T2DM. In addition, TZDs showed superior effects in improving endothelial function as compared with the other GLAs and placebo.

Clinical pharmacology of antidiabetic drugs: What can be expected of their use?

The pharmacotherapy of type 2 diabetes mellitus (T2DM) has markedly evolved in the last two decades. Classical antidiabetic agents (sulphonylureas, metformin, insulin) are now in competition with new glucose-lowering medications. Alpha-glucosidase inhibitors and thiazolidinediones (glitazones) were not able to replace older agents, because of insufficient efficacy and/or poor tolerability/safety. In contrast, incretin-based therapies, both dipeptidyl peptidase-4 inhibitors (DPP-4is or gliptins, oral agents) and glucagon-like peptide-1 receptor agonists (GLP-1RAs, subcutaneous injections) are a major breakthrough in the management of T2DM. Because they are not associated with hypoglycaemia and weight gain, DPP-4is tend to replace sulphonylureas as add-on to metformin while GLP-1RAs tend to replace basal insulin therapy after failure of oral therapies. Furthermore, placebo-controlled cardiovascular outcome trials demonstrated neutrality for DPP-4is, but cardiovascular protection for GLP-1RAs in patients with T2DM at high cardiovascular risk. More recently sodium-glucose cotransporter 2 inhibitors (SGLT2is or gliflozins, oral agents) also showed cardiovascular protection, especially a reduction in hospitalization for heart failure, as well as a renal protection in patients with and without T2DM, at high cardiovascular risk, with established heart failure and/or with chronic kidney disease. Thus, GLP-1RAs and SGLT2is are now considered as preferred drugs in T2DM patients with or at high risk of atherosclerotic cardiovascular disease whereas SGLT2is are more specifically recommended in patients with or at risk of heart failure and renal (albuminuric) disease. The management of T2DM is moving from a glucocentric approach to a broader strategy focusing on all risk factors, including overweight/obesity, and to an organ-disease targeted personalized approach.

Evidence-based and tailored medication in type 2 diabetes: a pathway learned from clinical trials

In Japan, the choice of anti-diabetic medication is officially recommended according to the patient’s glycemic condition and disease phenotype, unlike most other regions where metformin is recommended as the first-line medication. There has been an increase in the number of available glucose-lowering agents, making it necessary to select these agents based on ever-improving evidence obtained from clinical trials. For the dipeptidyl peptidase-4 inhibitor class of drugs, nine drugs are currently available on the market in Japan. Although previous cardiovascular outcome trials (CVOTs) demonstrated non-inferiority for both major adverse cardiovascular events (MACEs) and safety for some drugs of the class, the design and results of the CARMELINA trial seemed to be slightly different from earlier trials in that it showed the drugs were safe and partially effective even in patients with renal impairment. Thus, recent CVOTs on newer glucose-lowering agents have mainly focused on the major impacts of individual classes and drugs on clinical outcomes behind their glucose-lowering action. The diverse features of the classes and individual drugs may have also highlighted not only the class-effects, but also the drug-effects of glucose-lowering agents. This will lead to clinical-based evidence and assist with optimum selection of the class and/or drug for tailored medication in patients with type 2 diabetes.