Cardiovascular Outcome Trials with Glucose-Lowering Drugs

Diabetes and cardiovascular disease in older adults

An aging population combined with a rapidly increasing prevalence of diabetes foreshadows a global epidemic of cardiovascular and kidney disease that threatens to halt improvements in life and health-span and will have particularly severe consequences in older adults. The management of diabetes has been transformed with the recent development of newer anti-hyperglycemic agents that have demonstrated superior efficacy. However, the utility of these drugs extends beyond glycemic control to benefits for managing obesity, cardiovascular disease (CVD), chronic kidney disease, and heart failure. Numerous cardiovascular and kidney outcomes trials of these drugs have played an instrumental role in shaping current guidelines for the management of diabetes and CVD. Older adults with diabetes are diverse in terms of their comorbidities, diabetic complications, and cognitive and functional status. Therefore, there is an unmet need for personalized management of diabetes and CVD in this population. In this review, we provide an overview of the epidemiological burden and management of diabetes and CVD in older adults. We then focus on randomized cardiovascular and kidney outcome trials with anti-hyperglycemic agents to propose an evidence-based approach to the management of diabetes in older adults with high risk of cardiovascular and kidney disease.

The effects of dipeptidyl peptidase-4 inhibitors on cardiac structure and function using cardiac magnetic resonance: a meta-analysis of clinical studies

Objective

The aim of the study was to evaluate the effect of dipeptidyl peptidase-4 inhibitors (DPP4i) on cardiac structure and function by cardiac magnetic resonance (CMR). Research Methods & Procedures: Database including PubMed, Cochrane library, Embase and SinoMed for clinical studies of DPP4i on cardiac structure and function by CMR were searched. Two authors extracted the data and evaluated study quality independently. Mean difference (MD) or standardized MD and 95% confidence intervals (CI) were used for continuous variables. Review Manager 5.3 was used to performed the analysis.

Results

Ten references (nine studies) were included in this meta-analysis. Most of the studies were assessed as well quality by the assessment of methodological quality. For clinical control studies, the merged MD values of △LVEF by fixed-effect model and the pooled effect size in favor of DPP4i was 1.55 (95% CI 0.35 to 2.74, P=0.01). Compared with positive control drugs, DPP4i can significantly improve the LVEF (MD=4.69, 95%CI=2.70 to 6.69), but no such change compared to placebo (MD=-0.20, 95%CI=-1.69 to 1.29). For single-arm studies and partial clinical control studies that reported LVEF values before and after DPP4i treatment, random-effect model was used to combine effect size due to a large heterogeneity (Chi2 = 11.26, P=0.02, I2 = 64%), and the pooled effect size in favor of DPP4i was 2.31 (95% CI 0.01 to 4.62, P=0.05). DPP4i significantly increased the Peak filling rate (PFR) without heterogeneity when the effect sizes of two single-arm studies were combined (MD=31.98, 95% CI 13.69 to 50.27, P=0.0006; heterogeneity test: Chi2 = 0.56, P=0.46, I2 = 0%).

Conclusions

In summary, a possible benefit of DPP4i in cardiac function (as measured by CMR) was found, both including ventricular systolic function and diastolic function.

Incretin mimetics and acute pancreatitis: enemy or innocent bystander?

PURPOSE OF REVIEW

The incretin enhancers and mimetics, including dipeptidyl peptidase-4 (DPP-4) inhibitors, GLP-1 receptor agonists (GLP-1RA) and GLP-1/GIP co-agonists, have become mainstays in the treatment of type 2 diabetes (T2D). Recently, the approval of certain GLP-1RA and GLP-1/GIP co-agonists for the treatment of obesity has broadened their popularity and use. In this review, we summarize the evidence for an association of these drugs with acute pancreatitis and other adverse events of special interest to gastroenterologists.

RECENT FINDINGS

In addition to pancreatic islets, GLP-1 receptors are expressed in the exocrine cells of the pancreas. There is inconsistent evidence for an association of DPP-4 inhibitors, GLP-1RA and co-agonists with risk for acute pancreatitis in individual trials. Meta-analyses of long-term randomized controlled trials indicate a small risk of acute pancreatitis associated with DPP-4 inhibitors but not GLP-1RA or co-agonists. Cholecystitis and cholelithiasis may be more common among those treated with GLP-1RA and GLP-1/GIP co-agonists. There is no evidence that any of these drugs are associated with an increased risk of pancreatic cancer.

SUMMARY

While drugs that leverage the incretin system are increasingly being used for patients with T2D and obesity, caution in warranted in those with a history of pancreatitis and gallbladder disease.

Effects of newer anti-hyperglycemic agents on cardiovascular outcomes in older adults: Systematic review and meta-analysis

AIM

To demonstrate cardiovascular safety of dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1RA), and sodium/glucose cotransporter 2 inhibitors (SGLT-2i) across age-groups.

METHODS

PubMed, Embase and Cochrane were searched for cardiovascular outcome trials (CVOTs) testing newer agents until August 31, 2022 (PROSPERO ID CRD42021260167). Studies with ≥1000 T2D participants enrolled for ≥12 months were included. Random effect models were used to report relative-risk (RR) for three-point major adverse cardiovascular events (3P-MACE) and its components by age subgroups (65 years; 75 years).

RESULTS

For SGLT-2is, five CVOTs (46,969 patients, 45-50 % ≥65 years) were included. SGLT-2is reduced risk of MACE (RR; 0.91 [CI, 0.85-0.98]); cardiovascular death (CV-death) (RR; 0.84 [CI, 0.73-0.96]); and all-cause mortality (ACM) (RR; 0.86 [CI, 0.79-0.93]) with no difference in subgroups <65 or ≥65 years. For GLP-1RAs, nine CVOTs (n = 64,236, 34-75 % ≥65 years) were included. GLP-1RAs reduced risk of MACE (RR; 0.89 [CI, 0.83-0.95]), stroke (RR; 0.86 [CI, 0.76-0.97]) and ACM (RR; 0.90 [CI, 0.83-0.97]) with no significant difference in subgroups <65 or ≥65 years. Additionally, GLP-1RAs reduced risk of MACE (10 %), ACM (12 %) and CV-death (12 %) with no significant difference in subgroups <75 or ≥75 years. Four CVOTs (n = 33,063; 35-58 % ≥65 years) with DPP-4is were included. There were no significant differences in risk for CV outcomes with DPP-4is compared to placebo in any of the age subgroups.

CONCLUSION

The overall cardiovascular safety profile of newer anti-hyperglycemic agents is consistent in older and younger individuals.

Cardiovascular disease management in Australian adults with type 2 diabetes: insights from the CAPTURE study

BACKGROUND

Type 2 diabetes (T2D) is a well-recognised cardiovascular disease (CVD) risk factor, and recent guidelines for the management of T2D include consideration of CVD risk.

AIM

To assess whether contemporary clinical management of Australians with T2D is in accord with recent national and international guidelines.

METHODS

This Australia-specific analysis of the CAPTURE study, a non-interventional, cross-sectional study included adults diagnosed with T2D ≥180 days prior to providing informed consent and visiting primary or specialist care. Main outcome measures were the use of blood glucose-lowering medications (BGLMs), BGLMs with proven cardiovascular benefits and other CVD medications, stratified by CVD status and care setting.

RESULTS

Of 824 Australian participants in the CAPTURE sample, 332 (40.3%) had CVD. Oral BGLMs were used by 83.9% of all participants, most commonly metformin (76.0%), dipeptidyl peptidase-4 inhibitors (28.8%), sodium-glucose cotransporter-2 inhibitors (SGLT2is; 21.8%) and sulfonylureas (21.7%). Insulin was used by 29.2% of participants. BGLMs with proven CV benefit were used by 22.6%; glucagon-like peptide-1 receptor agonists (GLP-1 RAs) were less commonly used than SGLT2is in all CVD groups, but these drug classes were more often prescribed in specialist than primary care (SGLT2is 25.4 vs 20.7%, GLP-1 RAs 3.2 vs 0.8% respectively). Use of non-BGLMs for CVD risk reduction appeared consistent with guidelines.

CONCLUSIONS

Use of BGLMs with CVD benefits appears low in Australia, irrespective of CVD status. This likely reflects the delay in translation of clinical evidence into contemporary care and prescribing restrictions.

Newer Glucose-Lowering Therapies in Older Adults with Type 2 Diabetes

Diabetes is prevalent in older adults and older adults with diabetes are more likely to have multiple comorbidities. It is, therefore, important to personalize diabetes management in this group. Newer glucose-lowering drugs, including dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can be safely used in older patients and are preferred choices in many cases due to their safety, efficacy, and low risk of hypoglycemia.

The cardiovascular benefits of GLP1-RAs are related to their positive effect on glycemic control: A meta-regression analysis

BACKGROUNDS AND AIMS

Glucagon-like-peptides 1 receptor analogues (GLP1-RAs) have gained primacy in the management of type 2 diabetes (T2D).However, in contrast to the CVOT conducted with sodium glucose cotransporter-2 inhibitors (SGLT-2i)there was a significant reduction in glycated haemoglobin (HbA1c) in some of the CVOT with GLP1-RA. The aim of this analysis is to explore the possible association between cardiovascular outcome benefits with GLP1-RA and HbA1c reduction.

METHODS

A Cochrane library based web search yielded 9 eligible citations for this analysis. The analysis was performed using the comprehensive meta-analysis (CMA) software.A meta-regression analysis was performed using HbA1c, weight, and systolic blood pressure reduction as moderators.

RESULT

The meta-regression analysis was conducted on a pooled population of 64,236 patients. There was a significant heterogeneity associated with the MACE benefits (Q = 16.88, I2: 52.59, df = 7, p = 0.03). Among the moderators selected to explain the variance in true effects, HbA1c reduction was significant (Q = 7.00, P=<0.001, R²:1.0). Additional meta-regression analysis using 0.9% reduction of HbA1c from baseline indicated an association with MACE benefit (95% CI -0.23 to -0.02, P = 0.01, R²: 0.98).

CONCLUSION

The MACE benefits associated with GLP1-RAs are dependent on the reduction of HbA1c levels.

Effect of Oral Semaglutide on Cardiovascular Parameters and Their Mechanisms in Patients with Type 2 Diabetes: Rationale and Design of the Semaglutide Anti-Atherosclerotic Mechanisms of Action Study (SAMAS)

INTRODUCTION

Type 2 diabetes (T2D) management has reached a point where not only optimal glycaemic control is necessary, but also additional interventions with proven cardiovascular risk reduction benefit. Subcutaneous semaglutide has been shown to provide cardiovascular protection, but its use may be limited by its injection formulation. To overcome this limitation, an oral semaglutide tablet has been developed, which could potentially be of the same value as its injection counterpart, but in a much wider group of patients with T2D, thereby allowing for broader cardiovascular risk reduction in this vulnerable patient population.

METHODS

A total of 100 consecutive patients with T2D and a disease duration of up to 10 years, without manifest cardiovascular disease, who are treated with metformin (± sulphonylurea) and optimal cardioprotective therapy, will be recruited in a single-blinded, randomized trial named "Semaglutide Anti-atherosclerotic Mechanisms of Action Study (SAMAS)." After 1:1 randomization, patients will receive either oral semaglutide 14 mg daily or placebo for 1 year. The primary outcome comprises changes in atherosclerosis-related structural and functional characteristics of the arterial wall, namely: reduction of the carotid intima-media thickness, improvement of endothelial function and decrease in arterial stiffness. Secondary outcomes are changes in atherogenic small dense low-density lipoproteins, glucose control (HbA1c) and inflammatory markers (hsCRP). Possible correlations between primary endpoints and changes in lipids, HbA1c and high-sensitivity C-reactive protein will be sought.

DISCUSSION

This is the first study to investigate the direct and indirect anti-atherosclerotic mechanisms of oral semaglutide. The results are expected to confirm the position of oral semaglutide in the multifactorial management of T2D with an emphasis on cardiovascular disease prevention.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05147896.

Glucagon-like peptide-1 and beta cell glucose sensitivity - a glucose ramp study in mice

The incretin glucagon-like peptide-1 (GLP-1) is a gut hormone but also locally produced in pancreatic islets. We evaluated effects of GLP-1 on the insulin response to a gradual increase in glucose in mice within physiological levels. We initially developed a glucose ramp technique in mice. Glucose levels were slowly increased by 0.2 mmol/l/min for 40 min under control conditions, during intravenous infusion of GLP-1 and in GLP-1 receptor knockout mice. In control mice, glucose levels increased from 8.5 ± 0.3 to 16.1 ± 0.3 mmol/l over the 40 min, i.e., by 0.22 ± 0.01 mmol/l/min. This resulted in a slow increase in insulin levels by 96 ± 38 pmol/l from the baseline of 319 ± 53 pmol/l. GLP-1 at 0.5 nmol/kg as bolus plus 0.3 nmol/kg/min over 40 min progressively increased this insulin response by 100-fold, to 9.5 ± 0.2 nmol/l (P < 0.001). Higher doses of GLP-1 enhanced the insulin response similarly (1.0 or 3.0 nmol/kg bolus followed by 0.4 or 1.2 nmol/kg/min), whereas a lower dose (0.3 nmol/kg bolus plus 0.15 nmol/kg/min) had no significant effect compared to controls. Moreover, there was no significant difference in insulin responses between controls and GLP-1 receptor knockout mice. Since the increase in glucose levels were standardized, there was no significant difference in glucose levels between the experimental groups. We conclude that the glucose ramp technique is a tool for studies on insulin responses to slow changes in circulating glucose levels in mice. We also conclude that GLP-1 is extraordinarily potent in enhancing the insulin response to a slow increase in glucose levels.