Heart failure and type 2 diabetes: From cardiovascular outcome trials, with hope.

An excess risk of heart failure (HF) persists in patients with type 2 diabetes (T2D) despite optimal control of an array of conventional risk factors, including hyperglycaemia. Twelve cardiovascular outcome trials (CVOTs) have been published to date, although none, with the exception of the DECLARE trial with dapagliflozin, has included HF as a primary endpoint. The four trials with dipeptidyl-peptidase inhibitors (DPP-4i) (SAVOR-TIMI 53 with saxagliptin, EXAMINE with alogliptin, TECOS with sitagliptin and CARMELINA with linagliptin) failed to show any significant effect on HF risk in patients with T2D, with the notable exception of saxagliptin which was associated with a 27% increased risk. Five completed CVOTs with the GLP-1 RAs lixisenatide (ELIXA), liraglutide (LEADER), semaglutide (SUSTAIN-6), exenatide once weekly (EXSCEL) and albiglutide (HARMONY) also failed to reveal any significant effect on HF risk. The three trials with sodium glucose co-transporter-2 inhibitors (SGLT-2i) (EMPA-REG OUTCOME with empagliflozin, CANVAS with canagliflozin and DECLARE with dapagliflozin) all revealed a robust and significant reduction in the hazard ratios of hospitalization for HF, from 27% to 35%, which remained consistent, significant and of similar magnitude regardless of the presence of a history of HF or established atherosclerotic cardiovascular disease. There is no association between reductions in HF risk and haemoglobin A1c (A1C) levels, while there is a significant association between reductions in HR for MACE and A1C levels (Spearman's correlation, r = 0.695; P = 0.013). All of the 12 CVOTs completed to date have provided reassurance of the overall cardiovascular safety of the newer anti-hyperglycaemic drugs. At present, the robust, consistent and reproducible reduction of approximately 30% in the risk of HF with SGLT-2i may be considered a class effect. The beneficial effect on MACE outcome observed with the use of some GLP-1RAs and SGLT-2i must be interpreted within the frame of the single trial.