Effects of HbA1c and weight reduction on blood pressure in patients with type 2 diabetes mellitus treated with exenatide*

Effect of Hemoglobin A1c Reduction or Weight Reduction on Blood Pressure in Glucagon-Like Peptide-1 Receptor Agonist and Sodium-Glucose Cotransporter-2 Inhibitor Treatment in Type 2 Diabetes Mellitus: A Meta-Analysis

Background Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) have shown their beneficial effects on cardiovascular outcomes and multiple cardiovascular risk factors, including hypertension. However, the mechanism of blood pressure (BP)-lowering effects of these agents has not been elucidated. This study aims to evaluate the effect of hemoglobin A1c reduction or body weight reduction with GLP-1RA treatment and SGLT2i treatment on BP changes in patients with type 2 diabetes mellitus. Methods and Results Studies were identified by a search of MEDLINE, EMBASE, and the Cochrane Central Register until June 2019. Meta-regression analysis was performed to evaluate the association between hemoglobin A1c reduction or body weight reduction and changes of BP. A total of 184 trials were included. Both GLP-1RA and SGLT2i led to significant reductions in systolic BP (weighted mean difference, -2.856 and -4.331 mm Hg, respectively; P<0.001 for both) and diastolic BP (weighted mean difference, -0.898 and -2.279 mm Hg, respectively; P<0.001 for both). For both drug classes, hemoglobin A1c reduction was not independently associated with systolic BP reduction or diastolic BP reduction. In GLP-1RA treatment, weight reduction was positively associated with systolic BP reduction and diastolic BP reduction (β=0.821 and β=0.287, respectively; P<0.001 for both). In SGLT2i treatment, weight loss was significantly associated with systolic BP reduction (β=0.820; P=0.001) but was not associated with diastolic BP reduction. Conclusions Treatment with GLP-1RA and SGLT2i led to significant reductions in BP in patients with type 2 diabetes mellitus. Weight reduction was significantly and independently associated with BP reductions in GLP-1RA treatment and SGLT2i treatment.

Future challenges and therapeutic opportunities in type 2 diabetes: Changing the paradigm of current therapy

Most algorithms for type 2 diabetes mellitus (T2DM) do not recommend treatment escalation until glycated haemoglobin (HbA1c) fails to reach the recommended target of 7% (53 mmol/mol) within approximately 3 months on any treatment regimen ("treat to failure"). Clinical inertia and/or poor adherence to therapy contribute to patients not reaching glycaemic targets when managed according to this paradigm. Clinical inertia exists across the entire spectrum of anti-diabetes therapies, although it is most pronounced when initiating and optimizing insulin therapy. Possible reasons include needle aversion, fear of hypoglycaemia, excessive weight gain and/or the need for increased self-monitoring of blood glucose. Studies have suggested, however, that early intensive insulin therapy in newly diagnosed, symptomatic patients with T2DM with HbA1c >9% (75 mmol/mol) can preserve beta-cell function, thereby modulating the disease process. Furthermore, postprandial plasma glucose is a key component of residual dysglycaemia, evident especially when HbA1c remains above target despite fasting normoglycaemia. Therefore, to achieve near normoglycaemia, additional treatment with prandial insulin or a glucagon-like peptide-1 receptor agonist (GLP-1 RA) is often required. Long- or short-acting GLP-1 RAs offer effective alternatives to basal or prandial insulin in patients inadequately controlled with other therapies or basal insulin alone, respectively. This review highlights the limitations of current algorithms, and proposes an alternative based on the early introduction of insulin therapy and the rationale for the sequential or fixed combination of GLP-1 RAs with insulin ("treat-to-success" paradigm).

Are Ethnic Disparities in HbA1c Levels Explained by Mental Wellbeing? Analysis of Population-Based Data from the Health Survey for England

Aims

It is unclear how ethnic differences in HbA_1c levels are affected by individual variations in mental wellbeing. Thus, the aim of this study was to assess the extent to which HbA_1c disparities between Caucasian and South Asian adults are mediated by various aspects of positive psychological functioning.

Methods

Data from the 2014 Health Survey for England was analysed using bootstrapping methods. A total of 3894 UK residents with HbA_1c data were eligible to participate. Mental wellbeing was assessed using the Warwick-Edinburgh Mental Well-being Scale. To reduce bias BMI, blood pressure, diabetes status, and other factors were treated as covariates.

Results

Ethnicity directly predicted blood sugar control (unadjusted coefficient −2.15; 95% CI −3.64, −0.67), with Caucasians generating lower average HbA_1c levels (37.68 mmol/mol (5.6%)) compared to South Asians (39.87 mmol/mol (5.8%)). This association was mediated by positive mental wellbeing, specifically concerning perceived vigour (unadjusted effect 0.30; 95% CI 0.13, 0.58): South Asians felt more energetic than Caucasians (unadjusted coefficient −0.32; 95% CI −0.49, −0.16), and greater perceived energy predicted lower HbA_1c levels (unadjusted coefficient −0.92; 95% CI −1.29, −0.55). This mediator effect accounted for just over 14% of the HbA_1c variance and was negated after adjusting for BMI.

Conclusions

Caucasian experience better HbA_1c levels compared with their South Asian counterparts. However, this association is partly confounded by individual differences in perceived energy levels, which is implicated in better glycaemic control, and appears to serve a protective function in South Asians.

Long-term changes in cardiovascular risk markers during administration of exenatide twice daily or glimepiride: results from the European exenatide study

OBJECTIVE

The risk of cardiovascular morbidity and mortality is significantly increased in patients with diabetes; thus, it is important to determine whether glucose-lowering therapy affects this risk over time. Changes in cardiovascular risk markers were examined in patients with type 2 diabetes treated with exenatide twice daily (a glucagon-like peptide-1 receptor agonist) or glimepiride (a sulfonylurea) added to metformin in the EURopean EXenAtide (EUREXA) study.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes failing metformin were randomized to add-on exenatide twice daily (n = 515) or glimepiride (n = 514) until treatment failure defined by hemoglobin A1C. Anthropomorphic measures, blood pressure (BP), heart rate, lipids, and high-sensitivity C-reactive protein (hsCRP) over time were evaluated.

RESULTS

Over 36 months, twice-daily exenatide was associated with improved body weight (-3.9 kg), waist circumference (-3.6 cm), systolic/diastolic BP (-2.5/-2.6 mmHg), high-density lipoprotein (HDL)-cholesterol (0.05 mmol/L), triglycerides (-0.2 mmol/L), and hsCRP (-1.7 mg/L). Heart rate did not increase (-0.3 beats/minute), and low-density lipoprotein-cholesterol (0.2 mmol/L) and total cholesterol (0.1 mmol/L) increased slightly. Between-group differences were significantly in favor of exenatide for body weight (P < 0.0001), waist circumference (P < 0.001), systolic BP (P < 0.001), diastolic BP (P = 0.023), HDL-cholesterol (P = 0.001), and hsCRP (P = 0.004). Fewer patients randomized to exenatide twice daily versus glimepiride required the addition of at least one antihypertensive (20.4 vs 26.4%; P = 0.026) or lipid-lowering medication (8.4 vs 12.8%; P = 0.025).

CONCLUSIONS

Add-on exenatide twice daily was associated with significant, sustained improvement in several cardiovascular risk markers in patients with type 2 diabetes versus glimepiride.

CLINICAL TRIAL REGISTRATION

NCT00359762, http://www.ClinicalTrials.gov.

Blood pressure-lowering effects of incretin-based diabetes therapies

Glucagon-like peptide-1 receptor (GLP-1) agonists and dipeptidyl-peptidase-4 (DPP-4) inhibitors are therapies that are used to treat hyperglycemia in patients with type 2 diabetes mellitus. Although both of these medication types primarily lower prandial and fasting blood glucose levels by enhanced GLP-1 receptor signalling, they have distinct mechanisms of action. Whereas DPP-4 inhibitors boost patient levels of endogenously produced GLP-1 (and glucose-dependent insulinotropic peptide) by preventing its metabolism by DPP-4 enzymatic activity, GLP-1 receptor agonists are either synthetic analogues of human GLP-1 or exendin-4 based molecules. They are tailored to resist hydrolysis by DPP-4 activity and to provide longer durability in the circulation compared with native GLP-1. Several roles for incretin-based diabetes therapies beyond the endocrine pancreas and their glycemic-lowering properties have now been described, including attenuation of cardiac myocyte injury and reduction in post-ischemic infarction size after cardiovascular insult. Favourable outcomes have also been observed on systolic blood pressure reduction, postprandial intestinal lipoprotein metabolism, endothelial cell function, modulation of innate immune-mediated inflammation and surrogate markers of renal function. As hypertension is an independent risk factor for premature death in patients with type 2 diabetes, potential favourable extrapancreatic actions, particularly within the heart, blood vessels and kidney, for this drug class are of considerable clinical interest. Herein, we highlight and provide critical appraisal of the clinical data supporting the antihypertensive effects of GLP-1 receptor agonists and DPP-4 inhibitors and link possible mechanisms of action to clinical outcomes reported for this drug class.

The association of the treatment with glucagon-like peptide-1 receptor agonist exenatide or insulin with cardiovascular outcomes in patients with type 2 diabetes: a retrospective observational study

BACKGROUND

To evaluate the association of treatment with glucagon-like peptide-1 (GLP-1) receptor agonist exenatide and/or insulin on macrovascular outcomes in patients with type 2 diabetes (T2DM).

METHODS

We conducted a retrospective longitudinal pharmaco-epidemiological study using large ambulatory care data to evaluate the risks of heart failure (HF), myocardial infarction (MI) and stroke in established T2DM patients who received a first prescription of exenatide twice daily (EBID) or insulin between June 2005 and May 2009, with follow-up data available until December 2012. Three treatment groups were: EBID with oral antidiabetes drugs (OADs) (EBID, n = 2804), insulin with OADs (Insulin, n = 28551), and those who changed medications between EBID and insulin or had combination of EBID and insulin during follow-up, along with OADs (EBID + insulin, n = 7870). Multivariate Cox-regression models were used to evaluate the association of treatment groups with the risks of macrovascular events.

RESULTS

During a median 3.5 years of follow-up, cardiovascular event rates per 1000 person-years were significantly lower for the EBID and EBID + insulin groups compared to the insulin group (HF: 4.4 and 6.1 vs. 17.9; MI: 1.1 and 1.2 vs. 2.5; stroke: 2.4 and 1.8 vs. 6.1). Patients in the EBID/EBID + insulin group had significantly reduced risk of HF, MI and stroke by 61/56%, 50/38% and 52/63% respectively, compared to patients in the insulin group (p < 0.01).

CONCLUSIONS

Treatment with exenatide, with or without concomitant insulin was associated with reduced macrovascular risks compared to insulin; although inherent potential bias in epidemiological studies should be considered.

Retrospective cohort study evaluating exenatide twice daily and long-acting insulin analogs in a Veterans Health Administration population with type 2 diabetes

AIM

This was a retrospective cohort study that evaluated the differences in glycated haemoglobin (HbA1c) and body mass index (BMI) in veterans with type 2 diabetes mellitus (T2DM), prescribed exenatide twice daily (BID) versus long-acting insulin analog (LAIA) two years after initiation in the United States (US) veteran population.

MATERIALS AND METHODS

Patients were included if they were ≥ 18 years old with T2DM, and initiated exenatide BID or LAIA at the Veterans Health Administration between January 1, 2006 and December 31, 2010. Multivariate models were used to evaluate the changes in HbA1c and BMI between groups, controlling for potential confounders. Logistic regression was used to evaluate the odds of achieving ≥ 0.5% HbA1c reduction based on baseline HbA1c stratifications: low,<7%; moderate, 7% to<9%; and high,≥ 9%.

RESULTS

A total of 446 exenatide BID and 51,531 LAIA patients met inclusion/exclusion criteria. On average, exenatide BID patients were significantly older (64 versus 60 years) with a higher BMI (37.8 versus 32.9 kg/m(2)). Baseline HbA1c was 8.2% and 8.8% for exenatide BID and LAIA patients, respectively (P<0.001); otherwise, patients were similar for all other characteristics. Exenatide BID treatment was significantly associated with a 0.32% (95%CI: 0.18-0.47%) greater reduction in HbA1c at two years compared with LAIA. Similar findings were observed for BMI reduction (0.68 kg/m(2); 95%CI: 0.42-0.95 kg/m(2)). Exenatide BID patients with moderate baseline HbA1c had significantly higher odds of achieving ≥ 0.5% HbA1c reduction compared with LAIA patients (OR=1.5; 95%CI: 1.2-2.0).

CONCLUSIONS

Veterans treated with exenatide BID had significantly greater reduction in HbA1c and BMI compared with patients treated with LAIA patients two years after initiation.

Incretin-based therapies: focus on effects beyond glycemic control alone

Type 2 diabetes is associated with a high prevalence of comorbidities resulting from hypertension, dyslipidemia, and hyperglycemia. Inadequate management of these risk factors will eventually result in detrimental health consequences. Thus, the effect of a drug on factors such as weight, cardiovascular (CV) risk factors, and adherence is important to consider. A review was undertaken of the recent medical literature describing the extraglycemic characteristics of the two classes of incretin-based therapies-glucagon-like peptide-1 receptor agonists (GLP-1RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors. PubMed searches were performed to identify published data on incretin therapies that describe their effects on CV risk factors, CV events, and factors related to medication adherence. The maintenance or loss of weight associated with the use of GLP-1RAs and DPP-4 inhibitors is well described in the medical literature. These agents also appear to be associated with a modest decrease in blood pressure and a reduced risk of CV events. In addition, several characteristics of incretin therapies may improve rates of medication adherence, such as generally favorable tolerability profiles (particularly with DPP-4 inhibitors), the availability of formulations that simplify treatment regimens, and a low risk for hypoglycemia. The literature on incretin therapies describes a number of clinical characteristics that are relevant to the management of extraglycemic risk factors. As part of a holistic treatment strategy, these properties constitute important considerations for tailoring therapy to individual patients with type 2 diabetes.

Current issues in GLP-1 receptor agonist therapy for type 2 diabetes

The clinical management of hyperglycemia in patients with type 2 diabetes mellitus (T2DM) is guided not only by published treatment algorithms, but also by consideration of recent evidence and through consultation with colleagues and experts. Recent studies have dramatically increased the amount of information regarding the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs). Topics that may be of particular interest to clinicians who treat T2DM patients include relative glycemic control efficacy of GLP-1 RAs, use of GLP-1 RAs across T2DM progression and in combination with insulin, recent data regarding GLP-1 RA safety, nonglycemic actions of GLP-1 RAs, including weight effects, and impact of GLP-1 RAs on patient quality of life and treatment satisfaction. The following review includes expert consideration of these topics with emphasis on recent, relevant reports to illustrate current perspectives.

Exenatide extended-release: a review of its use in type 2 diabetes mellitus

Subcutaneous exenatide extended-release (ER; Bydureon™; also known as exenatide once weekly), a glucagon-like peptide-1 receptor agonist, provides a convenient, simple, once-weekly regimen that is approved in adult patients with type 2 diabetes as adjunctive monotherapy to diet plus exercise (in the US; not as first-line therapy) and/or as combination therapy with specific oral antihyperglycaemic drugs (OADs) in patients with inadequately controlled type 2 diabetes despite treatment with these OADs (US and Europe). This article reviews the clinical efficacy and tolerability of exenatide ER in the treatment of adult patients with type 2 diabetes and gives a brief overview of its pharmacological properties. In several short-term (24-30 weeks) well designed trials, adjunctive subcutaneously injectable exenatide ER once weekly, as monotherapy or in combination with OADs, significantly improved glycaemic control, bodyweight and some surrogate markers of cardiovascular risk in adult patients with inadequately controlled type 2 diabetes despite diet and exercise and/or treatment with OADs. Furthermore, the beneficial effects of adjunctive exenatide ER therapy were sustained in extension studies of up to 3 years of treatment. Overall, the intensity of glycaemic control with exenatide ER was generally better than that observed with the exenatide immediate-release formulation (twice daily), sitagliptin or insulin glargine. Exenatide ER was shown to be noninferior to metformin in terms of glycaemic efficacy, but did not meet the criteria for noninferiority versus liraglutide. In treatment-naive patients, exenatide ER treatment did not meet noninferiority criteria versus pioglitazone, whereas in treatment-experienced patients, exenatide ER provided better glycaemic control than pioglitazone. Improvements in glycaemic control with exenatide ER and, in general, with other antihyperglycaemic agents were reflected in significant improvements from baseline in treatment satisfaction and health-related quality-of-life measures. Exenatide ER was generally well tolerated in patients participating in these trials, with most treatment-emergent adverse events being of a gastrointestinal nature, of mild to moderate severity, transient and of a similar nature and incidence to those occurring with the exenatide immediate-release formulation. Thus, exenatide ER is a useful option for the treatment of type 2 diabetes, particularly in patients where bodyweight loss is an essential aspect of the individual patient's management.