Cardiovascular safety trials of incretin-based drugs: What do they mean?

A Review of Recent Findings on Meal Sequence: An Attractive Dietary Approach to Prevention and Management of Type 2 Diabetes

While adjustment of total energy and nutritional balance is critically important, meal sequence, a relatively simple method of correcting postprandial hyperglycemia, is becoming established as a practical dietary approach for prevention and management of diabetes and obesity. Meal sequence, i.e., consumption of protein and/or fat before carbohydrate, promotes secretion of glucagon-like peptide-1 (GLP-1) from the gut and ameliorates secretions of insulin and glucagon and delays gastric emptying, thereby improving postprandial glucose excursion. GLP-1 is known to suppress appetite by acting on the hypothalamus via the afferent vagus nerve. Thus, enhancement of GLP-1 secretion by meal sequence is expected to reduce body weight. Importantly, consumption of a diet rich in saturated fatty acids such as meat dishes before carbohydrate increases secretions of not only GLP-1 but also glucose-dependent insulinotropic polypeptide (GIP), which promotes energy storage in adipose tissue and may lead to weight gain in the long term. Dietary fiber intake before carbohydrate intake significantly reduces postprandial glucose elevation and may have a weight loss effect, but this dietary strategy does not enhance the secretion of GLP-1. Thus, it is suggested that their combination may have additive effects on postprandial glucose excursion and body weight. Indeed, results of some clinical research supports the idea that ingesting dietary fiber together with meal sequence of protein and/or fat before carbohydrate benefits metabolic conditions of individuals with diabetes and obesity.

Cardioprotective effects of GLP-1(28-36a): A degraded metabolite or GLP-1's better half?

Molecular mechanism underlying glucagon-like peptide-1 exertion of cardioprotective effects in glucagon-like peptide-1 receptor-dependent and -independent manners. Glucagon-like peptide-1 (28-36a) enters coronary artery endothelial cells through macropinocytosis and binds to mitochondrial trifunctional protein-α, shifting substrate utilization to increase adenosine triphosphate production and modulating a adenosine triphosphate-sensor soluble adenylyl cyclase, thereby producing cyclic adenosine monophosphate and activating protein kinase A to exert cytoprotection from oxidative injury.

The journey to understanding incretin systems: Theory, practice and more theory

Accumulating clinical data on incretin-based dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists in the past decade have clearly confirmed their safety and efficacy as antidiabetes drugs. However, the journey to understand the incretin system and its role in health and disease continues.

Practice pearl: liraglutide and cardiovascular and renal events in type 2 diabetes

Review of: Marso S, Daniels G, Brown-Frandsen K, et al. Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med 2016; 375: 311-322. Mann J, Orsted D, Brown-Frandsen K, et al. Liraglutide and Renal Outcomes in Type 2 Diabetes. N Engl J Med 2017; 377: 839-848. This comprehensive research project, LEADER, led to two reports, one focusing on the effect of liraglutide on cardiovascular events, and the second one reporting on the renal effects on the same study population. The study group included 9340 patients with type 2 diabetes. Patients were required to have type 2 diabetes and an age 50 with a previous cardiovascular problem or chronic heart failure, or an age of 60 with at least one cardiovascular risk factor. Patients were randomized to 1.8 mg (or the maximum tolerated dose) of liraglutide, or placebo. The median follow up was 3.8 years. The primary cardiovascular outcome, a combined endpoint of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke, was seen in 13% (608 of 4668 patients) treated with liraglutide versus 14.9 % (694 of 4672 patients) in the placebo patients (HR 0.87; 95% confidence interval [CI] 0.78 to 0.97; P = 0.01 for superiority). Death from cardiovascular disease and death from any cause were also lower in the liraglutide group. The rates for nonfatal myocardial infarction, nonfatal stroke, and hospitalization for heart failure were not significantly reduced. In the renal report, the renal outcome was reduced in the liraglutide versus the placebo group (268 of 4668 versus 337 out of 4672 in the placebo group; HR 0.78; CI 0.67 to 0.92; p = 0.003). This improvement was mainly driven by a lower rate of the new onset of persistent macroalbuminuria in the liraglutide patients (161 vs 215 patients; HR 0.74; 95% CI, 0.60 to 0.91; p = 0.004), while the rates of other renal adverse events were similar in both groups. When taken together these two reports are the first data to show that the glucagon-like peptide 1 (GLP-1) analogue liraglutide can reduce cardiovascular events and halt progression to macroalbuminuria in patients with Type 2 diabetes.

Efficacy and safety of sitagliptin as compared with glimepiride in Japanese patients with type 2 diabetes mellitus aged ≥ 60 years (START-J trial)

The aim of this study was to evaluate the efficacy and safety of sitagliptin administered to elderly patients with type 2 diabetes mellitus (T2DM) for 1 year as compared with glimepiride. Patients aged ≥60 years with T2DM and inadequately controlled blood glucose were randomly assigned to sitagliptin 50 mg once daily or glimepiride 0.5 mg once daily for 52 weeks. The primary efficacy endpoint was the change in glycated haemoglobin (HbA1c) from baseline to week 52. Secondary efficacy endpoints included self-monitored blood glucose and weight. Safety endpoints were adverse events including hypoglycaemia. Administration of sitagliptin or glimepiride to elderly patients with T2DM resulted in a significant decrease in HbA1c change from baseline. At 52 weeks, the least squares mean difference between the treatments was 0.11% (95% confidence interval [CI] -0.02 to 0.24; P = .087) (1.2 mmol/mol [-0.2 to 2.6]). The upper limit of the CI was below the predefined non-inferiority margin (0.3% [3.3 mmol/mol]), demonstrating non-inferiority of sitagliptin to glimepiride for the primary endpoint. Sitagliptin resulted in a significantly lower incidence rate of non-serious hypoglycaemia than glimepiride during the 52 weeks (4.7% vs 16.1%; P = .002); thus, sitagliptin is a useful therapeutic option for elderly patients with T2DM.