Cardiovascular effects of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists: The P value and beyond

Despite growing awareness of the dangers of a dichotomous interpretation of trial results based on the ‘statistical significance’ of a treatment effect, the uptake of new approaches has been slow in diabetes medicine. We showcase a number of ways to interpret the evidence for a treatment effect applied to the cardiovascular outcome trials of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose co-transporter-2 inhibitors (SGLT-2is): the P value function (or confidence curves), which depicts the treatment effect across the whole spectrum of confidence levels; the counternull value, which is the hazard ratio (i.e. treatment effect size) supported by the same amount of evidence as the null value (i.e. no treatment effect); and the S value, which quantifies the strength of the evidence against the null hypothesis in terms of the number of coin tosses yielding the same side. We show how this approach identifies potential treatment effects, highlights similarities among trials straddling the threshold of statistical significance, and quantifies differences in the strength of the evidence from trials reporting statistically significant results. For example, while REWIND, CANVAS and CREDENCE failed to reach statistical significance at the .05 level for all-cause mortality, their counternull values indicate that reduced death rates by 19%, 24% and 31%, respectively, are supported by the same amount of evidence as that indicating no treatment effect. Moreover, similarities among results emerge in trials of GLP-1RAs (REWIND, EXSCEL and LEADER) lying closely around the threshold of ‘statistical significance’. Lastly, several S values, such as for the primary outcome in HARMONY Outcomes (S value 10.9) and all-cause death in EMPAREG-OUTCOME (S value 15.0), stand out compared with values for other outcomes and other trials, suggesting much larger differences in the evidence between these studies and several others that cluster around the .05 significance threshold. P value functions, counternull values and S values should complement the standard reporting of the treatment effect to help interpret clinical trials and make decisions among competing glucose-lowering medications.     

Preventing all-cause hospitalizations in type 2 diabetes with sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists: A narrative review and proposed clinical approach

Patients with type 2 diabetes (T2D) are at increased risk for hospital admissions, and acute hospitalizations are associated with a worse prognosis. However, outcomes related to all-cause hospital admissions (ACHAs) were often overlooked in trials that demonstrated the cardiovascular and kidney benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs). This review includes a contemporary literature summary of emerging data regarding the effects of SGLT2 inhibitors and GLP-1RAs on ACHAs. The role of SGLT2 inhibitors in preventing ACHAs was shown in exploratory investigations of several randomized controlled trials (RCTs) and was further supported by real-world evidence (RWE). However, the association between GLP-1RA use and lower ACHA risk was mainly shown through RWE, with minimal available RCT data. We also discuss the advantages and challenges of studying ACHAs. Finally, we propose an easily memorized (“ABCDE” acronym) clinical approach to evaluating T2D status and treatment in admitted patients, as they transition from hospital to community care. This systematic approach may assist clinicians in recognizing possible pitfalls in T2D management, thereby preventing subsequent hospitalizations and improving patient prognoses. While acute admission can sometimes be perceived as a management failure, it should also be viewed as an opportunity to take action to prevent the next hospitalization.     

Efficacy and safety of high-dose glucagon-like peptide-1, glucagon-like peptide-1/glucose-dependent insulinotropic peptide,and glucagon-like peptide-1/glucagon receptor agonists in type 2 diabetes

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have become agents of choice for people with type 2 diabetes (T2D) with established cardiovascular disease or in high-risk individuals. With currently available GLP-1 RAs, 51%-79% of subjects achieve an HbA1c target of less than 7.0% and 4%-27% lose 10% of body weight, illustrating the need for more potent agents. Three databases (PubMed, Cochrane, Web of Science) were searched using the MESH terms ‘glucagon-like peptide-1 receptor agonist’, ‘glucagon receptor agonist’, ‘glucose-dependent insulinotropic peptide’, ‘dual or co-agonist’, and ‘tirzepatide’. Quality of papers was scored using PRISMA guidelines. Risk of bias was evaluated using the Cochrane assessment tool. An HbA1c target of less than 7.0% was attained by up to 80% with high-dose GLP-1 RAs and up to 97% with tirzepatide, with even up to 62% of people with T2D reaching an HbA1c of less than 5.7%. A body weight loss of 10% or greater was obtained by up to 50% and up to 69% with high-dose GLP-1 RAs or tirzepatide, respectively. The glucose- and weight-lowering effects of the GLP-1/glucagon RA cotadutide equal those of liraglutide 1.8 mg. Gastrointestinal side effects of high-dose GLP-1 RAs and co-agonists occurred in 30%-70% of patients, mostly arising within the first 2 weeks of the first dose, being mild or moderate in severity, and transient. The development of high-dose GLP-1 RAs and the dual GLP-1/glucose-dependent insulinotropic peptide RA tirzepatide resulted in increasing numbers of people reaching HbA1c and body weight targets, with up to 62% attaining normoglycaemia with 15-mg tirzepatide. Whether this will also translate to better cardiovascular outcomes and affect treatment guidelines remains to be studied.     

All-cause mortality and cardiovascular outcomes with sodium-glucose Co-transporter 2 inhibitors,glucagon-like peptide-1 receptor agonists and with combination therapy in people with type 2 diabetes

Aim

To assess the relationship of sodium-glucose cotransporter-2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor analogues (GLP-1RA) and their combination (SGLT2i + GLP-1RA) with 5-year risk of all-cause mortality, hospitalization and cardiovascular/macrovascular disease in people with type 2 diabetes.

Materials and Methods

Retrospective cohort analysis of 2.2 million people with type 2 diabetes receiving insulin across 85 health care organizations using a global federated health research network. Three intervention cohorts (SGLT2i, GLP-1RA and SGLT2i + GLP-1RA) were compared against a control cohort (no SGLT2i/GLP-1RA). Propensity score matching for age, ischaemic heart disease, sex, hypertension, chronic kidney disease, heart failure and glycated haemoglobin was used to balance cohorts 1:1 (SGLT2i, n = 143 600; GLP-1RA, n = 186 841; SGLT-2i + GLP-1RA, n = 108 504). A sub-analysis comparing combination and monotherapy cohorts was also performed.

Results

The intervention cohorts showed a reduced hazard ratio (HR, 95% confidence interval) over 5 years compared with the control cohort for all-cause mortality (SGLT2i 0.49, 0.48-0.50; GLP-1RA 0.47, 0.46-0.48; combination 0.25, 0.24-0.26), hospitalization (0.73, 0.72-0.74; 0.69, 0.68-0.69; 0.60, 0.59-0.61) and acute myocardial infarct (0.75, 0.72-0.78; 0.70, 0.68-0.73; 0.63, 0.60-0.66), respectively. All other outcomes showed a significant risk reduction in favour of the intervention cohorts. The sub-analysis showed a significant risk reduction in all-cause mortality for combination therapy versus SGLT2i (0.53, 0.50-0.55) and GLP-1RA (0.56, 0.54-0.59).

Conclusions

SGLT2i, GLP-1RAs or combination therapy confers mortality and cardiovascular protection in people with type 2 diabetes over 5 years. Combination therapy was associated with the greatest risk reduction in all-cause mortality versus a propensity matched control cohort. In addition, combination therapy offers a reduction in 5-year all-cause mortality when compared directly against either monotherapy.     

Cardiovascular outcomes trials with glucagon-like peptide-1 receptor agonists: A comparison of study designs,populations and results

Despite treatment advances leading to improved outcomes over the past 2 decades, cardiovascular (CV) disease (CVD) remains the leading cause of morbidity and mortality in people with diabetes. People with type 2 diabetes (T2D) have a 2- to 4-fold increased risk of CVD and CV death. Individuals with T2D have not seen the same improvements in CV morbidity and mortality as those without T2D. Given this, it is important to understand the CV impact of drugs used to treat T2D. In patients with T2D, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have shown a reduction in HbA1c and body weight regardless of their differences in chemical structure and pharmacokinetic variables. Glycaemic efficacy, accompanied by the potential for weight reduction and a low risk of hypoglycaemia, has moved GLP-1 RAs to the first treatment of choice following metformin monotherapy in the latest American Diabetes Association treatment guidelines. Additionally, all GLP-1 RAs have shown CV safety and several have proven CV benefit. GLP-1 RAs have been evaluated in cardiovascular outcomes trials (CVOTs) of varying sizes, designs and patient populations with differing reported effects on CV outcomes. The purpose of this article is to review the completed GLP-1 RA CVOTs with special attention to how their design, size, patient populations and conduct may influence the interpretation of results.     

All-cause mortality in patients with diabetes under glucagon-like peptide-1 agonists: A population-based,open cohort study

AimThe glucagon-like peptide-1 receptor agonist (GLP1a) liraglutide has been described to benefit patients with type 2 diabetes mellitus (T2DM) at high cardiovascular risk. However, there are still uncertainties relating to these cardiovascular benefits: whether they also apply to an unselected diabetic population that includes low-risk patients, represent a class-effect, and could be observed in a real-world setting.MethodsWe conducted a population-based, retrospective open cohort study using data derived from The Health Improvement Network database between Jan 2008 to Sept 2015. Patients with T2DM exposed to GLP1a (n = 8345) were compared to age, gender, body mass index, duration of T2DM and smoking status-matched patients with T2DM unexposed to GLP1a (n = 16,541).ResultsPatients with diabetes receiving GLP1a were significantly less likely to die from any cause compared to matched control patients with diabetes (adjusted incidence rate ratio [aIRR]: 0.64, 95% CI: 0.56–0.74, P-value < 0.0001). Similar findings were observed in low-risk patients (aIRR: 0.64, 95% CI: 0.53–0.76, P -value = 0.0001). No significant difference in the risk of incident CVD was detected in the low-risk patients (aIRR: 0.93, 95% CI: 0.83–1.12). Subgroup analyses suggested that effect is persistent in the elderly or across glycated haemoglobin categories.ConclusionsGLP1a treatment in a real-world setting may confer additional mortality benefit in patients with T2DM irrespective of their baseline CVD risk, age or baseline glycated haemoglobin and was sustained over the observation period.     

Effects of sodium-glucose cotransporter-2 inhibitors on the cardiovascular and renal complications of type 2 diabetes

Sodium-glucose cotransporter-2 inhibitors (SGLT-2is) have been shown to mitigate the risks of cardiovascular (CV) and renal complications in patients with type 2 diabetes (T2D) and CV risk factors or CV disease (CVD). In CV outcomes trials (CVOTs) of patients with T2D and established CVD or multiple CV risk factors, empagliflozin and canagliflozin were associated with significant reductions in the risks of major adverse CV events (MACE), hospitalization for heart failure (HF) and kidney disease progression. In the DECLARE–TIMI 58 study, in which the majority of patients did not have established CVD, dapagliflozin was associated with significant reductions in the composite end point of CV death or hospitalization for HF and was noninferior to placebo with regard to MACE; although patients had relatively good renal function, dapagliflozin also showed renal benefits similar to those seen with empagliflozin and canagliflozin. This article reviews the increased risk of CVD and renal disease in patients with T2D and discusses the potential mechanisms of the cardioprotective and renoprotective effects of SGLT-2i therapy. The observed improvements in CV and renal outcomes with SGLT-2is in CVOTs suggest a class effect in this patient population and have influenced treatment guidelines for the way add-on therapy to metformin is initiated in patients with T2D and high CV risk. The overall cardioprotective and renoprotective effects of SGLT-2is in patients with T2D and high CV risk are most likely attributable to multiple mechanisms, including cardiac, haemodynamic, metabolic, anti-inflammatory and renal effects.     

Injectable semaglutide and reductions in HbA1c and weight in the real world in people switched from alternative glucagon-like peptide-1 receptor agonists

The ABCD semaglutide audit was designed to capture the routine clinical outcomes of people commenced on semaglutide in the UK. Previous work showed differential reductions in HbA1c and weight dependent on previous glucagon-like peptide-1 receptor agonist (GLP-1RA) exposure. The analysis, in this research letter, shows that decreases in HbA1c and weight associated with semaglutide occur irrespective of previous GLP-1RA use. However, HbA1c reductions were less if switched from dulaglutide or liraglutide and weight changes were attenuated if switched from dulaglutide or exenatide, potentially suggesting differing potencies between GLP-1RAs. Dedicated studies with head-to-head comparisons are needed to confirm these findings.     

The dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist tirzepatide improves cardiovascular risk biomarkers in patients with type 2 diabetes: A post hoc analysis

In a phase 2 trial of once-weekly tirzepatide (1, 5, 10, or 15 mg), dulaglutide (1.5 mg), or placebo, the dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist tirzepatide dose-dependently reduced HbA1c and body weight in patients with type 2 diabetes. In this post hoc analysis, inflammation, endothelial dysfunction, and cellular stress biomarkers were measured at baseline, 4, 12, and 26 weeks to evaluate the additional effects of tirzepatide on cardiovascular risk factors. At 26 weeks, tirzepatide 10 and 15 mg decreased YKL-40 (also known as chitinase-3 like-protein-1), intercellular adhesion molecule 1 (ICAM-1), leptin, and growth differentiation factor 15 levels versus baseline, and YKL-40 and leptin levels versus placebo and dulaglutide. Tirzepatide 15 mg also decreased ICAM-1 levels versus placebo and dulaglutide, and high-sensitivity C-reactive protein (hsCRP) levels versus baseline and placebo, but not dulaglutide. GlycA, interleukin 6, vascular cell adhesion molecule 1, and N-terminal-pro hormone B-type natriuretic peptide levels were not significantly changed in any group. YKL-40, hsCRP, and ICAM-1 levels rapidly decreased within 4 weeks of treatment with tirzepatide 10 and 15 mg, whereas the decrease in leptin levels was more gradual and did not plateau by 26 weeks. In this hypothesis-generating exploratory analysis, tirzepatide decreased several biomarkers that have been associated with cardiovascular risk.