Novel antidiabetic drugs and risk of cardiovascular events in patients without baseline metformin use: a meta-analysis

Aims: To evaluate the effect of sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs) on major cardiovascular events (MACE) in metformin-naïve patients with type 2 diabetes (T2D).

Methods and results: A meta-analysis was performed of randomized controlled clinical trials of GLP-1RAs and SGLT-2 inhibitors on T2D populations, after searching the PubMed/MEDLINE, Embase, and Cochrane Controlled Trials databases. The primary endpoint was MACE. The secondary endpoint, explored in the subgroup of SGLT-2 inhibitors studies, was cardiovascular death or hospitalization for heart failure. A random-effects meta-analysis model was applied. Six eligible trials (three studies of SGLT-2 inhibitors and three trials of GLP-1RAs), including 13 049 patients, were identified and considered eligible for the analyses. The new antidiabetic drugs were associated with a significant reduction in MACE [odds ratio (OR): 0.80, 95% confidence interval: 0.70-0.93; I2: 53%]. The subgroup analysis showed the following findings: GLP-1RAs group, OR: 0.77 (95% confidence interval 0.67-0.88); SGLT-2 inhibitors, OR: 0.85 (95% confidence interval 0.63-1.15). SGLT-2 inhibitors were associated with a significant reduction in hospitalization for heart failure or cardiovascular mortality incidence (OR: 0.67, 95% confidence interval: 0.47-0.95; I2: 78%).

Conclusion: In this meta-analysis, new antidiabetic drugs reduced the incidence of MACE in metformin-naïve T2D patients. The beneficial effect was especially observed in the GLP-1RAs subgroup. The use of SGLT-2 inhibitors was associated with a reduction in cardiovascular death or hospitalization for heart failure. These results support the fact that metformin would not be indispensable to obtain positive cardiovascular effects when new antidiabetic drugs are administered.