Differences in glucose tolerance between fixed-dose antihypertensive drug combinations in people with metabolic syndrome

Secondary hypertension: obesity and the metabolic syndrome

The epidemic of obesity in the United States and around the world is intensifying in severity and scope and has been implicated as an underlying mechanism in systemic hypertension. Obese hypertensive individuals characteristically exhibit volume congestion, relative elevation in heart rate, and high cardiac output with concomitant activation of the renin-angiotensin-aldosterone system. When the metabolic syndrome is present, insulin resistance and hyperinsulinemia may contribute to hypertension through diverse mechanisms. Blood pressure can be lowered when weight control measures are successful, using, for example, caloric restriction, aerobic exercise, weight loss drugs, or bariatric surgery. A major clinical challenge resides in converting short-term weight reduction into a sustained benefit. Pharmacotherapy for the obese hypertensive patient may require multiple agents, with an optimal regimen consisting of inhibitors of the renin-angiotensin-aldosterone system, thiazide diuretics, beta-blockers, and calcium channel blockers if needed to attain contemporary blood pressure treatment goals.

Effects of sibutramine plus verapamil sustained release/trandolapril combination on blood pressure and metabolic variables in obese hypertensive patients

OBJECTIVE

The management of obese hypertensive subjects may require the administration of anti-obesity and antihypertensive drugs. Sibutramine use has raised concerns regarding a potential increase in subjects' blood pressure and heart rate. The primary end-points of this study were an evaluation of the effect of sibutramine together with a verapamil sustained release/trandolapril combination tablet versus verapamil sustained release/trandolapril alone on the blood pressure and heart rate in obese hypertensive patients.

RESEARCH DESIGN/METHODS

Patients received a low-fat low-calorie diet and were randomly allocated to open-label verapamil sustained release/trandolapril 180/2 mg (n = 26) or sibutramine 10 mg together with verapamil sustained release/trandolapril 180/2 mg (n = 28) daily for 6 months.

RESULTS

Significant reductions in the subjects' systolic blood pressure and diastolic blood pressure were observed in both groups (p < 0.01 versus baseline). At 6 months a greater fall in blood pressure was observed in the sibutramine/verapamil sustained release/trandolapril group compared with the verapamil sustained release/trandolapril group (systolic blood pressure 21.9 +/- 8.1 versus 15.9 +/- 12.3 mmHg and diastolic blood pressure 15.7 +/- 8.1 versus 9.1 +/- 9.9 mmHg) but this was only significant (p = 0.03) for diastolic blood pressure. The subjects' heart rate did not change significantly in any group. No significant sibutramine-associated attenuation of blood pressure reduction was observed during the study. The sibutramine/verapamil sustained release/trandolapril treatment resulted in significantly greater improvement in the subjects' anthropometric variables, homeostasis model assessment and lipid profiles compared with verapamil sustained release/trandolapril administration. The subjects' small dense low-density lipoprotein cholesterol, high-sensitivity C-reactive protein and visfatin plasma levels were only measured in the sibutramine/verapamil sustained release/trandolapril group (all decreased by p < 0.05 versus baseline).

CONCLUSIONS

The sibutramine/verapamil sustained release/trandolapril combination in obese hypertensive patients significantly reduced their blood pressure and improved their anthropometric and metabolic variables without affecting the heart rate.

Initial combination therapy for rapid and effective control of moderate and severe hypertension

Moderate (grade 2) and severe (grade 3) hypertension are important public health problems associated with high cardiovascular risk. Blood pressure (BP) control becomes more difficult to achieve as hypertension progresses. Therefore, early and effective treatment is essential to prevent hypertensive urgencies and emergencies and reduce cardiovascular risk. Currently, less than 50% of patients being treated for moderate or severe hypertension in the United States achieve their BP goal as recommended by treatment guidelines. This review examines the cardiovascular risk and physician inertia associated with moderate and severe hypertension, and concludes that increased use of initial combination therapy can overcome many of the barriers to effective BP control. Furthermore, initial combination therapy with a renin-angiotensin system (RAS) inhibitor and diuretic has the potential to rapidly and effectively reduce BP across a range of baseline BPs, with a comparable adverse event profile to monotherapy.

Treating hypertension while protecting the vulnerable islet in the cardiometabolic syndrome

Hypertension, a multifactorial-polygenic disease, interacts with multiple environmental stressors and results in functional and structural changes in numerous end organs, including the cardiovascular system. This can result in coronary heart disease, stroke, peripheral vascular disease, congestive heart failure, end-stage renal disease, insulin resistance, and damage to the pancreatic islet. Hypertension is the most important modifiable risk factor for major health problems encountered in clinical practice. Whereas hypertension was once thought to be a medical condition based on discrete blood pressure readings, a new concept has emerged defining hypertension as part of a complex and progressive metabolic and cardiovascular disease, an important part of a cardiometabolic syndrome. The central role of insulin resistance, oxidative stress, endothelial dysfunction, metabolic signaling defects within tissues, and the role of enhanced tissue renin-angiotensin-aldosterone system activity as it relates to hypertension and type 2 diabetes mellitus are emphasized. Additionally, this review focuses on the effect of hypertension on functional and structural changes associated with the vulnerable pancreatic islet. Various classes of antihypertensive drugs are reviewed, especially their roles in delaying or preventing damage to the vulnerable pancreatic islet, and thus delaying the development of type 2 diabetes mellitus.

The metabolic syndrome in hypertension: diagnostic and therapeutic implications

Arterial hypertension is often part of a larger constellation of anthropometric and metabolic abnormalities that includes abdominal (or visceral) obesity, characteristic dyslipidemia (low high-density lipoprotein cholesterol and high triglyceride levels), glucose intolerance, insulin resistance, and hyperuricemia. Using National Cholesterol Education Program Adult Treatment Panel III criteria, prevalence is higher than in the general population and the metabolic syndrome can be found in as many as one third of patients. Among hypertensives with metabolic syndrome, a high prevalence of hypertension-induced target-organ damage and a poor prognostic value has been described. Dietary advice and lifestyle changes should be strongly recommended and prompt pharmacologic treatment is required to control high blood pressure and to reduce risk. The impact of particular antihypertensive drugs on other components of the metabolic syndrome is an important clinical issue with consequences for the success of treatment.

Review: Concomitant calcium entry blockade and inhibition of the renin-angiotensin system: a rational and effective means for treating hypertension

Pharmacological treatment of hypertension is effective in preventing cardiovascular and renal complications. Calcium antagonists (CAs) and blockers of the renin-angiotensin system [angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists (ARBs)] are widely used today to initiate antihypertensive treatment but, when given as monotherapy, do not suffice in most patients to normalise blood pressure (BP). Combining a CA and either an ACE-inhibitor or an ARB considerably increases the antihypertensive efficacy, but not at the expense of a deterioration of tolerability. Several fixed-dose combinations are available (CA + ACE-inhibitors: amlodipine + benazepril, felodipine + ramipril, verapamil + trandolapril; CA + ARB: amlodipine + valsartan). They are expected not only to improve BP control, but also to facilitate long-term adherence with ON antihypertensive therapy, thereby providing renal damage caused by high BP. maximal protection against the cardiovascular and renal damage caused by high BP.

Challenges to the diagnosis, evaluation, treatment, and management of clustered cardiometabolic risk factors

A panel was convened on January 10, 2007, to discuss the challenges to the diagnosis, evaluation, treatment, and management of clustered cardiometabolic risk factors. George Bakris, MD, Professor of Medicine, University of Chicago, Chicago, IL, moderated the panel. Vivian Fonseca, MD, Tulane University Health Science Center, New Orleans, LA, and JoAnne Foody, MD, Harvard School of Medicine, Boston, MA, participated in the discussion. This expert panel discussion was supported by and each author received an honorarium from Merck & Co, Inc, and Sanofi-Aventis for time and effort spent participating in the discussion and reviewing the transcript for important intellectual content before publication. The authors maintained full control of the discussion and the resulting content of this article.

Antihypertensive agents, insulin sensitivity, and new-onset diabetes

The effects of the antihypertensive drugs on carbohydrate metabolism and the development of diabetes have been a major research field for more than two decades. Many clinical studies have investigated the effects of the antihypertensive classes on insulin sensitivity and glycemic control, whereas several observational studies and large outcome trials have examined associations of antihypertensive agents with diabetes incidence. In general, thiazide diuretics and conventional beta blockers decrease insulin sensitivity and increase new-onset diabetes, whereas angiotensin-converting enzyme inhibitors, calcium channel blockers, and angiotensin II receptor blockers have neutral or beneficial effects on these parameters. However, several issues in this field, such as the specific properties of newer agents and the relationship of adverse metabolic outcomes and cardiovascular risk, remain to be fully elucidated. This article presents and evaluates the current knowledge in this important area.

Improving outcomes in diabetes and chronic kidney disease: the basis for Canadian guidelines

The prevalence of diabetes is on the rise in Canada, and there has been a corresponding increase in the rate of micro- and macrovascular complications. Among the worst of these is chronic kidney disease (CKD). It may be diagnosed either through the detection of persistent albuminuria or an estimated glomerular filtration rate that is persistently less than 60 mL/min/1.73 m2. Patients with diabetes and CKD have a lower quality of life and higher health care costs, and face the prospect of end-stage renal disease requiring dialysis. More importantly, this group has an extremely elevated cardiovascular risk and correspondingly reduced survival. Research over several decades has led to two important conclusions. First, progressive worsening of kidney disease is not inevitable in people with diabetes; it can be slowed or even stopped. Second, the elevated cardiovascular risk in this population can be significantly reduced through an aggressive approach to cardiovascular risk factor reduction. These conclusions have prompted Canadian guideline groups, such as the Canadian Diabetes Association and the Canadian Hypertension Education Program, to release clinical practice guidelines that address the management of people with diabetes and CKD. In the present article, the studies that have influenced these Canadian guidelines are examined, and areas in which further research is still required are identified.

Management of hypertension in diabetes mellitus

Overall, approximately 40% of diabetic patients have hypertension at the time of diagnosis of diabetes and a similar percentage may develop hypertension during their follow-up. Factors contributing to this high prevalance of hypertension in diabetes include obesity, old age, insulin resistance, increased extracelluar volume, diabetic nephropathy and increased arterial stiffness. Well-conducted clinical trials that have been completed in the last decade demonstrated a major impact of hypertension on the micro- and macrovascular complications of diabetes and remarkable benefits of its control. Based on this large trial database, the currently accepted level of blood pressure used in diabetes for definition and target of therapy is 130/80 mmHg. Dietary and behavioral lifestyle modifications should be an intergral part of any management regimen. These include weight reduction, low sodium diet, exercise, moderate alcohol intake and smoking cessation. Effective control of blood pressure to target levels is more important than the drug(s) used. Combination drug therapy is needed frequently to achieve a target blood pressure. Although blockers of the renin-angiotensin-aldosterone system seem to have a favorable effect in diabetes, high-level evidence suggests that low-dose thiazide diuretics, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and calcium channel blockers are all good choices, both as initial and add-on therapy. Frequently, more than one drug is needed, and a low-dose thiazide diuretic combined with an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker is a commonly used effective combination. Other drugs that can be added include calcium channel blockers and β-blockers. In certain clinical situations, specific drug classes are indicated. These include angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in the case of diabetic nephropathy, β-blockers in the case of ischemic heart disease, and calcium channel blockers and loop diuretics in the case of advanced renal insufficiency, where the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers carries a significant risk of hyperkalemia.

Incident diabetes in clinical trials of antihypertensive drugs: a network meta-analysis

BACKGROUND

The effect of different classes of antihypertensive drugs on incident diabetes mellitus is controversial because traditional meta-analyses are hindered by heterogeneity across trials and the absence of trials comparing angiotensin-converting-enzyme (ACE) inhibitors with angiotensin-receptor blockers (ARB). We therefore undertook a network meta-analysis, which accounts for both direct and indirect comparisons to assess the effects of antihypertensive agents on incident diabetes.

METHODS

We undertook a systematic review up to Sept 15, 2006, and identified 48 randomised groups of 22 clinical trials with 143,153 participants who did not have diabetes at randomisation and so were eligible for inclusion in our analysis. 17 trials enrolled patients with hypertension, three enrolled high-risk patients, and one enrolled those with heart failure. The main outcome was the proportion of patients who developed diabetes.

FINDINGS

Initial drug therapy used in the trials (and the number of patients with diabetes of the total number at risk) included: an ARB (1189 of 14,185, or 8.38%), ACE inhibitor (1618 of 22,941, or 7.05%), calcium-channel blocker (CCB, 2791 of 38,607, or 7.23%), placebo (1686 of 24,767, or 6.81%), beta blocker (2705 of 35,745, or 7.57%), or diuretic (998 of 18,699, or 5.34%). With an initial diuretic as the standard of comparison (eight groups), the degree of incoherence (a measure of how closely the entire network fits together) was small (omega=0.000017, eight degrees of freedom). The odds ratios were: ARB (five groups) 0.57 (95% CI 0.46-0.72, p<0.0001); ACE inhibitor (eight groups) 0.67 (0.56-0.80, p<0.0001); CCB (nine groups): 0.75 (0.62-0.90, p=0.002); placebo (nine groups) 0.77 (0.63-0.94, p = 0.009); beta blocker (nine groups) 0.90 (0.75-1.09, p=0.30). These estimates changed little in many sensitivity analyses.

INTERPRETATION

The association of antihypertensive drugs with incident diabetes is therefore lowest for ARB and ACE inhibitors followed by CCB and placebo, beta blockers and diuretics in rank order.