GLP-1 receptor agonists and cardiovascular protection: A class effect or not?

Glucagon-like peptide-1 receptor agonists: new strategies and therapeutic targets to treat atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of cardiovascular mortality and is increasingly prevalent in our population. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) can safely and effectively lower glucose levels while concurrently managing the full spectrum of ASCVD risk factors and improving patients' long-term prognosis. Several cardiovascular outcome trials (CVOTs) have been carried out to further investigate the cardiovascular benefits of GLP-1RAs. Analyzing data from CVOTs can provide insights into the pathophysiologic mechanisms by which GLP-1RAs are linked to ASCVD and define the use of GLP-1RAs in clinical practice. Here, we discussed various mechanisms hypothesized in previous animal and preclinical human studies, including blockade of the production of adhesion molecules and inflammatory factors, induction of endothelial cells' synthesis of nitric oxide, protection of mitochondrial function and restriction of oxidative stress, suppression of NOD-like receptor thermal protein domain associated protein three inflammasome, reduction of foam cell formation and macrophage inflammation, and amelioration of vascular smooth muscle cell dysfunction, to help explain the cardiovascular benefits of GLP-1RAs in CVOTs. This paper provides an overview of the clinical research, molecular processes, and possible therapeutic applications of GLP-1RAs in ASCVD, while also addressing current limitations in the literature and suggesting future research directions.

Clinical Features, Cardiovascular Risk Profile, and Therapeutic Trajectories of Patients with Type 2 Diabetes Candidate for Oral Semaglutide Therapy in the Italian Specialist Care

INTRODUCTION

This study aimed to address therapeutic inertia in the management of type 2 diabetes (T2D) by investigating the potential of early treatment with oral semaglutide.

METHODS

A cross-sectional survey was conducted between October 2021 and April 2022 among specialists treating individuals with T2D. A scientific committee designed a data collection form covering demographics, cardiovascular risk, glucose control metrics, ongoing therapies, and physician judgments on treatment appropriateness. Participants completed anonymous patient questionnaires reflecting routine clinical encounters. The preferred therapeutic regimen for each patient was also identified.

RESULTS

The analysis was conducted on 4449 patients initiating oral semaglutide. The population had a relatively short disease duration (42% < 5 years), and a minority (15.6%) had a history of cardiovascular events. Importantly, oral semaglutide was started in subjects with various disease durations and background therapies. Notably, its initiation was accompanied by de-prescription of sulfonylureas, pioglitazone, DPP-4 inhibitors, and insulin. Choice of oral semaglutide was influenced by patient profiles and ongoing glucose-lowering regimens. Factors such as younger age, higher HbA1c, and ongoing SGLT-2 inhibitor therapy drove the choice of oral semaglutide with the aim of improving glycemic control. Projected glycemic effectiveness analysis revealed that oral semaglutide could potentially lead HbA1c to target in > 60% of patients, and more often than sitagliptin or empagliflozin.

CONCLUSION

The study supports the potential of early implementation of oral semaglutide as a strategy to overcome therapeutic inertia and enhance T2D management.

Do SGLT2 inhibitors and GLP-1 receptor agonists modulate differently the risk of stroke ? Discordance between randomised controlled trials and observational studies

Stroke represents a major burden in patients with type 2 diabetes, yet this cerebrovascular complication has been less carefully investigated than the risk of cardiovascular mortality, heart failure and renal disease. Some data suggested that glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert a better protection against stroke than sodium-glucose cotransporter 2 inhibitors (SGLT2is). However, this conclusion was derived from indirect comparisons in absence of any head-to-head randomised controlled trial (RCT). The present comprehensive review compares the effects of SGLT2is versus GLP-1RAs on nonfatal and fatal/nonfatal strokes in network meta-analyses of RCTs (mostly cardiovascular outcome trials) versus placebo, on the one hand, and in real-life observational cohort studies, on the other hand. Whereas network meta-analyses of placebo-controlled RCTs confirm a slight but significant (in 11 out of 13 meta-analyses) higher incidence of stroke in patients treated with SGLT2is compared with those treated with GLP-1RAs, a large majority of retrospective observational cohort studies (19 out of 21) failed to find any significant difference in the risk of stroke between the two pharmacological classes. Available, yet limited, findings suggest that SGLT2is may be more efficacious against haemorrhagic than ischaemic strokes, in patients at risk for atrial fibrillation and in patients with chronic kidney disease.

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.

The use of glucagon-like-peptide-1 receptor agonist in the cardiology practice

The presence of type 2 diabetes confronts the patient with an elevated risk to develop atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), or chronic kidney disease (CKD). Glucose control in itself does not prevent these complications in their entirety. More recently several agents within the class of Sodium-Glucose cotransporter 2 inhibitors (SGLT2-I) and Glucagon-like-peptide-1 receptor agonists (GLP-1RA) have emerged as preferred agents to tackle the residual risk of ASCVD, HF, and CKD in patients with type 2 diabetes. Despite compelling trial data and professional society endorsement, the uptake of these agents in clinical practice is low. Especially GLP-1RA is only used in 8% of eligible candidates with type 2 diabetes and <5% of these prescriptions are attributed to cardiologists. This low uptake amongst cardiologists is related to the unfamiliarity with this class, its initiation, and titration, hesitation regarding simultaneous adjustment of other glucose-lowering agents, the unaccustomedness to prescribing injectable agents, and differential medical priorities. This review aims to offer cardiologists a practical tool for the optimal use of a GLP-1RA in their suitable patients and is focussed on the Belgian field of practice.

Add-on therapy in metformin-treated patients with type 2 diabetes at moderate cardiovascular risk: a nationwide study

BACKGROUND

In randomised clinical trials, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and sodium-glucose cotransporter 2 (SGLT-2) inhibitors reduced cardiovascular events in patients with type 2 diabetes (T2D) at high cardiovascular risk, as compared to standard care. However, data comparing these agents in patients with T2D who are at moderate risk is sparse.

METHODS

From Danish national registries, we included patients with T2D previously on metformin monotherapy, who started an additional glucose-lowering agent [GLP-1 RA, SGLT-2 inhibitor, dipeptidyl peptidase-4 (DPP-4) inhibitor, sulfonylurea (SU), or insulin] in the period 2010-2016. Patients with a history of cardiovascular events [heart failure (HF), myocardial infarction (MI) or stroke] were excluded. Patients were followed for up to 2 years. Cause-specific adjusted Cox regression models were used to compare the risk of hospitalisation for HF, a composite endpoint of major adverse cardiovascular events (MACE) (MI, stroke or cardiovascular death), and all-cause mortality for each add-on therapy. Patients who initiated DPP-4 inhibitors were used as reference.

RESULTS

The study included 46,986 T2D patients with a median age of 61 years and of which 59% were male. The median duration of metformin monotherapy prior to study inclusion was 5.3 years. Add-on therapy was distributed as follows: 13,148 (28%) GLP-1 RAs, 2343 (5%) SGLT-2 inhibitors, 15,426 (33%) DPP-4 inhibitors, 8917 (19%) SUs, and 7152 (15%) insulin. During follow-up, 623 (1.3%, range 0.8-2.1%) patients were hospitalised for HF-hazard ratios (HR) were 1.11 (95% CI 0.89-1.39) for GLP-1 RA, 0.84 (0.52-1.36) for SGLT-2 inhibitors, 0.98 (0.77-1.26) for SU and 1.54 (1.25-1.91) for insulin. The composite MACE endpoint occurred in 1196 (2.5%, range 1.5-3.6%) patients, yielding HRs of 0.82 (0.69-0.97) for GLP-1 RAs, 0.79 (0.56-1.12) for SGLT-2 inhibitors, 1.22 (1.03-1.49) for SU and 1.23 (1.07-1.47) for insulin. 1865 (3.9%, range 1.9-9.0%) died from any cause during follow-up. HRs for all-cause mortality were 0.91 (0.78-1.05) for GLP-1 RAs, 0.79 (0.58-1.07) for SGLT-2 inhibitors, 1.13 (0.99-1.31) for SU and 2.33 (2.08-2.61) for insulin.

CONCLUSION

In a nationwide cohort of metformin-treated T2D patients and no history of cardiovascular events, the addition of either GLP-1 RA or SGLT-2 inhibitor to metformin treatment was associated with a similar risk of hospitalisation for HF and death, and a lower risk of MACE for GLP-1 RA when compared with add-on DPP-4 inhibitors. By contrast, initiation of treatment with SU and insulin were associated with a higher risk of MACE. Additionally, insulin was associated with an increased risk of all-cause mortality and hospitalisation for HF.

SGLT-2 inhibitors and GLP-1 receptor agonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease. A consensus statement by the EURECA-m and the DIABESITY working groups of the ERA-EDTA

Chronic kidney disease (CKD) in patients with diabetes mellitus (DM) is a major problem of public health. Currently, many of these patients experience progression of cardiovascular and renal disease, even when receiving optimal treatment. In previous years, several new drug classes for the treatment of type 2 DM have emerged, including inhibitors of renal sodium-glucose co-transporter-2 (SGLT-2) and glucagon-like peptide-1 (GLP-1) receptor agonists. Apart from reducing glycaemia, these classes were reported to have other beneficial effects for the cardiovascular and renal systems, such as weight loss and blood pressure reduction. Most importantly, in contrast to all previous studies with anti-diabetic agents, a series of recent randomized, placebo-controlled outcome trials showed that SGLT-2 inhibitors and GLP-1 receptor agonists are able to reduce cardiovascular events and all-cause mortality, as well as progression of renal disease, in patients with type 2 DM. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of SGLT-2 inhibitors and GLP-1 analogues, analyses the potential mechanisms involved in these actions and discusses their place in the treatment of patients with CKD and DM.

Series: Implications of the recent CVOTs in type 2 diabetes: Impact on guidelines: The endocrinologist point of view

The management of type 2 diabetes mellitus (T2DM) essentially consists in controlling hyperglycaemia, together with other vascular risk factors, in order to reduce the incidence and severity of diabetic complications. Whereas glucose control using classical glucose-lowering agents (except perhaps metformin) largely fails to reduce cardiovascular disease (CVD), two new pharmacological classes, glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is), have proven their ability to reduce major cardiovascular events in patients with established CVD. Furthermore, SGLT2is reduced the risk of hospitalisation for heart failure and the progression of renal disease. According to the 2018 ADA-EASD consensus report, the choice of a second agent to be added to metformin should now be driven by the presence or not of atherosclerotic CVD, heart failure or renal disease, all conditions that should promote the use of a SGLT2i or a GLP-1 RA with proven efficacy. Thus endocrinologists have to face a new paradigm in the management of T2DM, with a shift from a primary objective of glucose control without inducing hypoglycaemia and weight gain to a goal of cardiovascular and renal protection, largely independent of glucose control. Of note, however, the latter remains crucial to reduce the risk of microangiopathy.

Do GLP-1RAs and SGLT-2is reduce cardiovascular events in black patients with type 2 diabetes? A systematic review and meta-analysis

AIMS

While recent cardiovascular safety trials (CVST) concerning newer diabetes medications included mostly white participants, results are being generalized to all races in recent guidelines. This raises a controversial question regarding the appropriateness of applying CVST data to black patients with type 2 diabetes.

MATERIALS AND METHODS

We searched for randomized trials comparing diabetes medications to placebo in type 2 diabetes and investigated three- or four-point major adverse cardiovascular events (MACE). Data concerning black patients were then extracted. As the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) updated their recommendations for patients with established cardiovascular risk based on the CVST showing cardiovascular benefit, we performed a sensitivity analysis by including those trials only.

RESULTS

A total of 11 trials were included, investigating a glucagon-like peptide-1 receptor agonist (GLP-1RA) in five, a sodium-glucose co-transporter-2 inhibitor (SGLT-2i) in two and dipeptidyl peptidase-4 inhibitors (DPP-4i) in four. Of the 102 416 participants enrolled in the included trials, only 4601 were black (4.5%). Pooled results showed no significant difference in the incidence of MACE among diabetes medications (GLP-1RA, SGLT-2i or DPP-4i) and placebo in black patients with type 2 diabetes (relative risk [RR] [95% CI], 0.94 [0.77,1.16]). Restricting the analysis to different classes of diabetes medication, the results remained non-significant. Restricting the analysis to CVST with significant outcomes, the results remained non-significant (RR [95% CI], 0.97 [0.68,1.39]).

CONCLUSIONS

Given that black patients with type 2 diabetes were not well represented in CVSTs and such trials were underpowered to evaluate racial differences, it remains unclear whether GLP-1RAs or SGLT-2is would reduce cardiovascular risk in such patients, and additional studies targeting black patients are urgently needed.

Beneficial effects of SGLT2 inhibitors on fatty liver in type 2 diabetes: A common comorbidity associated with severe complications

Patients with type 2 diabetes mellitus (T2DM) are exposed to non-alcoholic fatty liver disease (NAFLD), a comorbidity associated with cardiovascular disease and chronic kidney disease, and which may progress to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Sodium-glucose cotransporter type-2 (SGLT2) inhibitors are glucose-lowering agents that improve glucose control while promoting weight loss and lowering serum uric acid levels. These agents may exert cardiovascular and renal protection in T2DM patients with established cardiovascular disease. Recent findings from both randomized controlled trials and open-label studies have also shown that SGLT2 inhibitors are able to reduce fatty liver content, as assessed by different imaging techniques, and improve biological markers of NAFLD, especially serum liver enzymes, in patients with T2DM. In addition, there are emerging data to suggest a mechanism beyond the reduction of hyperglycaemia and body weight, and a potential role for the decrease in low-grade inflammation and oxidative stress associated with SGLT2 inhibitor therapy. This positive effect of SGLT2 inhibitors on NAFLD complements their already well-known effects on cardiovascular and chronic kidney diseases.

Comparative efficacy, safety, and cardiovascular outcomes with once-weekly subcutaneous semaglutide in the treatment of type 2 diabetes: Insights from the SUSTAIN 1-7 trials

In individuals with type 2 diabetes, glycaemic control and cardiovascular risk factor management reduces the likelihood of late-stage diabetic complications. Guidelines recommend treatment goals targeting HbA_1c, body weight, blood pressure, and low-density lipoprotein cholesterol. Development of new treatments for type 2 diabetes requires an understanding of their mechanism and efficacy, as well as their relative effects compared to other treatment choices, plus demonstration of cardiovascular safety. Subcutaneous semaglutide is a glucagon-like peptide-1 receptor agonist currently approved in several countries for once-weekly treatment of type 2 diabetes. Semaglutide works via the incretin pathway, stimulating insulin and inhibiting glucagon secretion from the pancreatic islets, leading to lower blood glucose levels. Semaglutide also decreases energy intake by reducing appetite and food cravings, and lowering relative preference for fatty, energy-dense foods. Semaglutide was evaluated in the SUSTAIN clinical trial programme in over 8000 patients across the spectrum of type 2 diabetes. This review details the efficacy and safety profile of semaglutide in the SUSTAIN 1-5 and 7 trials, and its cardiovascular safety profile in the SUSTAIN 6 trial. Semaglutide consistently demonstrated superior and sustained glycemic control and weight loss vs. all comparators evaluated. In SUSTAIN 6, involving patients at high risk of cardiovascular disease, semaglutide significantly decreased the occurrence of cardiovascular events compared with placebo/standard of care (hazard ratio 0.74, P < 0.001 for non-inferiority). Through a comprehensive phase 3 clinical trial program, we have a detailed understanding of semaglutide's efficacy, safety, cardiovascular effects and comparative role in the treatment of type 2 diabetes.

Effects of glucose-lowering agents on surrogate endpoints and hard clinical renal outcomes in patients with type 2 diabetes

Diabetic kidney disease (DKD) represents an enormous burden in patients with type 2 diabetes mellitus (T2DM). Preclinical studies using most glucose-lowering agents have suggested renal-protective effects, but the proposed mechanisms of renoprotection have yet to be defined, and the promising results from experimental studies remain to be translated into human clinical findings to improve the prognosis of patients at risk of DKD. Also, it is important to distinguish effects on surrogate endpoints, such as decreases in albuminuria and estimated glomerular filtration rate (eGFR), and hard clinical endpoints, such as progression to end-stage renal disease (ESRD) and death from renal causes. Data regarding insulin therapy are surprisingly scarce, and it is nearly impossible to separate the effects of better glucose control from those of insulin per se, whereas favourable preclinical data with metformin, thiazolidinediones and dipeptidyl peptidase (DPP)-4 inhibitors are plentiful, and positive effects have been observed in clinical studies, at least for surrogate endpoints. The most favourable renal results have been reported with glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter type-2 inhibitors (SGLT2is). Significant reductions in both albuminuria and eGFR decline have been reported with these classes of glucose-lowering medications compared with placebo and other glucose-lowering agents. Moreover, in large prospective cardiovascular outcome trials using composite renal outcomes as secondary endpoints, both GLP-1RAs and SGLT2is added to standard care reduced renal outcomes combining persistent macro-albuminuria, doubling of serum creatinine, progression to ESRD and kidney-related death; however, to date, only SGLT2is have been clearly shown to reduce such hard clinical outcomes. Yet, as the renoprotective effects of SGLT2is and GLP-1RAs appear to be independent of glucose-lowering activity, the underlying mechanisms are still a matter of debate. For this reason, further studies with renal outcomes as primary endpoints are now awaited in T2DM patients at high risk of DKD, including trials evaluating the potential add-on benefits of combined GLP-1RA-SGLT2i therapies.

Comparing once-weekly semaglutide to incretin-based therapies in patients with type 2 diabetes: a systematic review and meta-analysis

AIMS

Our aim was to compare once-weekly semaglutide to incretin-based therapies - defined as either dipeptidyl peptidase-4 inhibitors (DPP-4i) or other glucagon-like peptide-1 receptor agonist (GLP-1RA) - in patients with type 2 diabetes.

METHODS

We searched for randomized trials comparing once-weekly semaglutide to other incretin-based therapies in patients with type 2 diabetes. We pooled trials that compared semaglutide to other GLP-1RA together, and those comparing semaglutide to DPP-4i together. The primary outcome was the change in haemoglobin A_1c over time.

RESULTS

Five trials met our inclusion criteria. There was a significantly greater reduction in haemoglobin A_1c favouring semaglutide when compared to other GLP-1RA or DPP-4i [MD (95% CI) = -0.38% (-0.62, -0.15) and -1.14% (-1.53, -0.75) respectively]. There was a significantly greater weight loss favouring semaglutide when compared to other GLP-1RA or DPP-4i [MD (95% CI) = -2.50 kg (-3.91, -1.09) and -3.19 kg (-3.66, -2.72) respectively]. The proportion of patients achieving glycaemic goals and goal weight loss was greater in semaglutide-treated patients when compared to either other GLP-1RA or DPP-4i. However, semaglutide-treated patients had a significantly higher incidence of gastrointestinal side effects.

CONCLUSIONS

While both once-weekly semaglutide and other incretin-based therapies can reduce haemoglobin A_1c, semaglutide causes a more potent haemoglobin A_1c reduction and greater weight loss when compared to other incretin-based therapies. However, this potent effect of semaglutide was associated with a higher incidence of gastrointestinal side effects. Additional studies are needed to determine whether this marked reduction in both haemoglobin A_1c and body weight may translate into improved cardiovascular outcomes.

Cardiovascular outcome studies in type 2 diabetes: Comparison between SGLT2 inhibitors and GLP-1 receptor agonists

Sodium-glucose cotransporter type 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) are two pharmacological classes that have proven their efficacy to reduce major cardiovascular events (MACEs) in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular disease in large prospective cardiovascular outcome trials (CVOTs): EMPA-REG OUTCOME (empagliflozin), CANVAS (canagliflozin), LEADER (liraglutide) and SUSTAIN 6 (semaglutide). Some heterogeneity appears to exist between the various agents within the two pharmacological classes. Whether these positive results could be extrapolated to patients without cardiovascular disease is still unknown. The underlying mechanisms remain a matter of debate but appear to differ between SGLT2is and GLP-1RAs. One crucial question is which patient's characteristics should be taken into account to guide the choice between a SGLT2i or a GLP-1RA according to a personalized approach. Heart failure should encourage the use of a SGLT2i whereas moderate to severe chronic kidney disease should favour the prescription of a GLP-1RA. Despite the results of recent CVOTs, numerous patients who are good candidates for benefiting of these agents do not receive them in clinical practice. Currently, there is a paradigm shift in T2DM management, moving from a primary objective of glucose control to a cardiovascular and renal protection.

Cardiovascular safety of DPP-4 inhibitors compared with sulphonylureas: Results of randomized controlled trials and observational studies

After failure of metformin monotherapy, another glucose-lowering agent should be added to improve glucose control. The clinician has several pharmacological choices, including the addition of a sulphonylurea (SU) or a dipeptidyl peptidase-4 inhibitor (DPP-4i). While the cardiovascular safety of SUs remains a matter of controversy, DPP-4is have proven their non-inferiority vs placebo in recent cardiovascular (CV) outcome trials. In the absence of a head-to-head CV outcome trial-the CAROLINA, comparing linagliptin with glimepiride, is still ongoing-only indirect information can be found in the literature to compare CV outcomes (major CV events, myocardial infarction, ischaemic stroke, CV death and all-cause mortality) in patients with type 2 diabetes mellitus (T2DM) treated with SUs or DPP-4is. Thus, this comprehensive review summarizes the CV outcomes (excluding heart failure) reported in meta-analyses of randomized controlled trials (RCTs) of SUs vs placebo or other glucose-lowering agents, DPP-4is vs placebo or other glucose-lowering agents and SUs vs DPP-4is in phase-II/III studies. Also, the results of observational studies reporting CV events in patients treated with either SUs or DPP-4is have been carefully examined. Overall, the CV safety of SUs appears to be poorer than that of DPP-4is in both RCTs and cohort studies. However, the results are somewhat disparate, and such heterogeneity may be explained by different patient characteristics across studies, but also perhaps by differences between various molecules in each pharmacological class. In particular, some doubt about a class effect affecting SU CV safety has been raised. The results of CAROLINA are expected to shed more light on SU CV concerns, especially compared with DPP-4is.