The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are released from enteroendocrine cells in response to the presence of nutrients in the small intestines. These homones facilitate glucose regulation by stimulating insulin secretion in a glucose dependent manner while suppressing glucagon secretion. In patients with type 2 diabetes (T2DM), an impaired insulin response to GLP-1 and GIP contributes to hyperglycemia. Dipeptidyl peptidase-4 (DPP-4) inhibitors block the breakdown of GLP-1 and GIP to increase levels of the active hormones. In clinical trials, DPP-4 inhibitors have a modest impact on glycemic control. They are generally well-tolerated, weight neutral and do not increase the risk of hypoglycemia. GLP-1 receptor agonists (GLP-1 RA) are peptide derivatives of either exendin-4 or human GLP-1 designed to resist the activity of DPP-4 and therefore, have a prolonged half-life. In clinical trials, they have demonstrated superior efficacy to many oral antihyperglycemic drugs, improved weight loss and a low risk of hypoglycemia. However, GI adverse events, particularly nausea, vomiting, and diarrhea are seen. Both DPP-4 inhibitors and GLP-1 RAs have demonstrated safety in robust cardiovascular outcome trials, while several GLP-1 RAs have been shown to significantly reduce the risk of major adverse cardiovascular events in persons with T2DM with pre-existing cardiovascular disease (CVD). Several clinical trials have directly compared the efficacy and safety of DPP-4 inhibitors and GLP-1 RAs. These studies have generally demonstrated that the GLP-1 RA provided superior glycemic control and weight loss relative to the DPP-4 inhibitor. Both treatments were associated with a low and comparable incidence of hypoglycemia, but treatment with GLP-1 RAs were invariably associated with a higher incidence of GI adverse events. A few studies have evaluated switching patients from DPP-4 inhibitors to a GLP-1RA and, as expected, improved glycemic control and weight loss are seen following the switch. According to current clinical guidelines, GLP-1RA and DPP-4 inhibitors are both indicated for the glycemic management of patients with T2DM across the spectrum of disease. GLP-1RA may be preferred over DPP-4 inhibitors for many patients because of the greater reductions in hemoglobin A1c and weight loss observed in the clinical trials. Among patients with preexisting CVD, GLP-1 receptor agonists with a proven cardiovascular benefit are indicated as add-on to metformin therapy.

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fractures despite increased body weight and normal or higher bone mineral density. The mechanisms by which T2DM increases skeletal fragility are unclear. It is likely that a combination of factors, including a greater risk of falling, regional osteopenia, and impaired bone quality, contributes to the increased fracture risk. Drugs for the treatment of T2DM may also impact on the risk for fractures. For example, thiazolidinediones accelerate bone loss and increase the risk of fractures, particularly in older women. In contrast, metformin and sulfonylureas do not appear to have a negative effect on bone health and may, in fact, protect against fragility fracture. Animal models indicate a potential role for incretin hormones in bone metabolism, but there are only limited data on the impact of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 agonists on bone health in humans. Animal models also have demonstrated a role for amylin in bone metabolism, but clinical trials in patients with type 1 diabetes with an amylin analog (pramlintide) have not shown a significant impact on bone metabolism. The effects of insulin treatment on fracture risk are inconsistent with some studies showing an increased risk and others showing no effect. Finally, although there is limited information on the latest class of medications for the treatment of T2DM, the sodium-glucose co-transporter-2 inhibitors, these drugs do not seem to increase fracture risk. Because diabetes is an increasingly common chronic condition that can affect patients for many decades, further research into the effects of agents for the treatment of T2DM on bone metabolism is warranted. In this review, the physiological mechanisms and clinical impact of diabetes treatments on bone health and fracture risk in patients with T2DM are described.

Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are emerging as an important therapy to consider for patients with type 2 diabetes (T2D) given this class of treatment’s ability to reduce glycated haemoglobin and their associated weight loss and low risk for hypoglycaemia. Additionally, seven cardiovascular outcomes trials (CVOTs) have been performed in the past 4 years using lixisenatide, liraglutide, semaglutide, exenatide, albiglutide, dulaglutide and oral semaglutide. All have found non-inferiority for cardiovascular outcomes, with many finding superiority of these drugs. These findings have transformed our guidelines on pharmacological treatment of T2D. This review article will discuss GLP-1 RA therapy, review the seven CVOTs reported to date and discuss the implications on current guidelines and therapies going forward.

Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

■ AbstractUntil recently, the pathogenesis of type 2 diabetes mellitus (T2DM) has been conceptualized in terms of the predominant defects in insulin secretion and insulin action. It is now recognized that abnormalities in other hormones also contribute to the development of hyperglycemia. For example, the incretin effect, mediated by glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), is attenuated in T2DM. Intravenous administration of GLP-1 ameliorates hyperglycemia in patients with T2DM, but an extremely short half-life limits its utility as a therapeutic agent. Strategies to leverage the beneficial effects of GLP-1 include GLP-1 receptor agonists or analogs or dipeptidyl peptidase-4 (DPP-4) inhibitors-agents that act by slowing the inactivation of endogenous GLP-1 and GIP. The GLP-1 agonist exenatide has been shown to improve HbA1c and decrease body weight. However, exenatide is limited by its relatively short pharmacologic half-life, various gastrointestinal (GI) side effects, and the development of antibodies. Studies of a long-acting exenatide formulation suggest that it has improved efficacy and also promotes weight loss. Another prospect is liraglutide, a once-daily human GLP-1 analog. In phase 2 studies, liraglutide lowered HbA1c by up to 1.7% and weight by approximately 3 kg, with apparently fewer GI side effects than exenatide. DPP-4 inhibitors such as sitagliptin and vildagliptin result in clinically significant reductions in HbA1c, and are weight neutral with few GI side effects. This review will provide an overview of current and emerging agents that augment the incretin system with a focus on the role of GLP-1 receptor agonists and DPP-4 inhibitors.