Impact of age, race, and obesity on hypertensive mechanisms and therapy

Difference in blood pressure response to ACE-Inhibitor monotherapy between black and white adults with arterial hypertension: a meta-analysis of 13 clinical trials

Background

Among African-Americans adults, arterial hypertension is both more prevalent and associated with more complications than among white adults. Hypertension is also epidemic among black adults in sub-Saharan Africa. The treatment of hypertension among black adults may be complicated by lesser response to certain classes of anti-hypertensive agents.

Methods

We systematically searched literature for clinical trials of ACE-inhibitors among hypertensive adults comparing blood pressure response between whites and blacks. Meta-analysis was performed to determine the difference in systolic and diastolic blood pressure response. Further analysis including meta-regressions, funnel plots, and one-study-removed analyses were performed to investigate possible sources of heterogeneity or bias.

Results

In a meta-analysis of 13 trials providing 17 different patient groups for evaluation, black race was associated with a lesser reduction in systolic (mean difference: 4.6 mmHg (95% CI 3.5-5.7)) and diastolic (mean difference: 2.8 mmHg (95% CI 2.2-3.5)) blood pressure response to ACE-inhibitors, with little heterogeneity. Meta-regression revealed only ACE-inhibitor dosage as a significant source of heterogeneity. There was little evidence of publication bias.

Conclusions

Black race is consistently associated with a clinically significant lesser reduction in both systolic and diastolic blood pressure to ACE-inhibitor therapy in clinical trials in the USA and Europe. In black adults requiring monotherapy for uncomplicated hypertension, drugs other than ACE-inhibitors may be preferred, though the proven benefits of ACE-inhibitors in some sub-groups and the large overlap of response between blacks and whites must be remembered. These data are particularly important for interpretation of clinical drug trials for hypertensive black adults in sub-Saharan Africa and for the development of treatment recommendations in this population.

Does BMI affect the clinical efficacy of proton pump inhibitor therapy in GERD? The case for rabeprazole

BACKGROUND

Increased BMI is associated with a higher risk of gastroesophageal reflux disease.

AIMS

To investigate whether overweight/obesity (BMI≥25 kg/m(2)) affects rabeprazole clinical efficacy versus omeprazole in patients with erosive esophagitis (EE).

PATIENTS AND METHODS

Post-hoc analysis of EE healing rate and symptom response stratified by patient BMI was performed on data from a multicenter, double-blind, randomized, 4-to-8-week trial comparing EE healing with rabeprazole (20 mg daily) and omeprazole (20 mg daily). Analysis of variance, two-sample t-test, Blackwelder's test for equivalence, log-rank, and Cochran-Mantel-Haenszel tests were used to analyze comparisons.

RESULTS

In the two BMI groups (<25 kg/m(2) and ≥25 kg/m(2) respectively), rabeprazole and omeprazole were equally effective for mucosal healing regardless of patient's BMI (N=542, P>0.05). However, in overweight/obese patients, rabeprazole was significantly faster than omeprazole in inducing heartburn relief during the first treatment week (P<0.0001).

CONCLUSIONS

Results of this study show that the clinical efficacy of rabeprazole is maintained in overweight/obese patients with gastroesophageal reflux disease and suggest that this subgroup of patients may derive, from rabeprazole, even greater benefit than lean patients.

Does chocolate reduce blood pressure? A meta-analysis

BACKGROUND

Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals.

METHODS

We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P < 0.05.

RESULTS

Fifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change +/- SE: SBP: -3.2 +/- 1.9 mmHg, P = 0.001; DBP: -2.0 +/- 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 +/- 3.0 mmHg; P = 0.0009; DBP: -2.7 +/- 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 +/- 2.3 mmHg, P = 0.17; DBP: -1.3 +/- 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors for blood pressure outcome.

CONCLUSION

Our meta-analysis suggests that dark chocolate is superior to placebo in reducing systolic hypertension or diastolic prehypertension. Flavanol-rich chocolate did not significantly reduce mean blood pressure below 140 mmHg systolic or 80 mmHg diastolic.

Characteristics of Young-Onset Hypertension Identified by Targeted Screening Performed at a University Health Check-Up

Since the prevalence and clinical characteristics of young-onset hypertension are still to be elucidated, we performed targeted-screening at an annual university health check-up for two consecutive years. Out of 16,464 subjects in 2003 and 17,032 in 2004 that were aged less than 30 years, 22 and 26 students (all males) exhibited high blood pressure (BP), respectively, on three occasions during casual BP measurements at the Tohoku University Health Center (systolic and diastolic BP of 140 and/or 90 mmHg or greater, respectively). These students were asked to measure their BP at home, and 9 subjects in total were diagnosed as having essential hypertension (EH). The remaining students were diagnosed as having white coat hypertension (WCH). In 8 out of 9 EH students, their father and/or mother had also been treated with antihypertensive medication. Adjustment by attendance ratio for each BP measurement suggested that the incidence of EH was around 0.1% and that of hypertension (EH and WCH) was around 0.5% in university students aged less than 25 years, since most of the subjects and hypertensive students were between 18 and 24 years old. Body mass index of the EH, which was more than 25 kg/m2 (overweight), was significantly higher than that with WCH. In conclusion, the combination of repeated casual BP measurements and home BP effectively identified young-onset EH. The clinical parameters indicated that male gender, genetic background, and excessive weight were risk factors for young-onset hypertension.

Treating stage 2 hypertension

The prevalence of hypertension increases with advancing age, due primarily to increases in systolic blood pressure. Systolic hypertension is the most common form of hypertension in individuals over 50 years of age and reflects pathologic decreases in arterial compliance. Systolic blood pressure elevation is a more important risk factor for cardiovascular disease than is diastolic blood pressure elevation. Stage 2 hypertension, defined as blood pressure > or =160/100 mm Hg, is often found in older persons, who are at highest risk for cardiovascular events. In this clinical review, hypertension experts utilize a case study to provide a paradigm for treating older patients with stage 2 hypertension.

Aldosterone and aldosterone antagonism in systemic hypertension

Aldosterone mediates both water and electrolyte balance by acting on the renal mineralocorticoid receptors. Recent experimental studies have also documented the presence of these receptors in other body organs, including the brain, blood vessels, and heart, suggesting that aldosterone plays a larger role in normal physiologic function and in cardiovascular diseases such as systemic hypertension and congestive heart failure (CHF). The nonspecific aldosterone inhibitor spironolactone, and the selective aldosterone inhibitor eplerenone, are both approved for clinical use in treating patients with hypertension and/or symptomatic CHF. Studies have shown that spironolactone lowers blood pressure, improves endothelial function, reduces myocardial hypertrophy and fibrosis, and lowers the incidence of fatal arrhythmias. Eplerenone, which is more specific for the mineralocorticoid receptor, appears to provide all the beneficial effects of spironolactone in hypertensive patients, with the potential to modify many of the side effects related to nonspecific steroid-receptor blockade. Hyperkalemia remains a potential problem with all aldosterone antagonists.

Eplerenone: a selective aldosterone blocker

Recent studies suggest that aldosterone may play a larger role than once appreciated in normal physiologic function and cardiovascular disease. Some of the adverse cardiovascular effects that have been described include cardiac and vascular fibrosis, vascular necrosis and inflammation, impaired endothelial function, reduced fibrinolysis, hypertension, left ventricular hypertrophy (LVH), congestive heart failure, and cardiac arrhythmias. In light of these findings, the ability to block the actions of aldosterone has gained increased therapeutic importance. Eplerenone is a selective aldosterone receptor blocker that displays little interaction with androgen and progesterone receptors. Eplerenone has already been approved for the treatment of systemic hypertension and has been evaluated in numerous hypertension subgroups, including patients with low plasma renin activity; diabetes; LVH; uncontrolled blood pressure while receiving monotherapy with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, calcium channel blockers, or beta-blockers; and in black patients. Results of these trials indicate that eplerenone lowers blood pressure and reduces end-organ damage. Further proof of the therapeutic importance of mineralocorticoid receptor blockade comes from the eplerenone post acute myocardial infarction survival and efficacy study (EPHESUS). In this large-scale clinical outcome trial, eplerenone was shown to reduce total mortality by 15% as well as the combined endpoint of cardiovascular mortality/cardiovascular hospitalization by 13% when administered at a mean of 7.3 days post myocardial infarction to patients with evidence of systolic left ventricular dysfunction and symptoms of heart failure. Eplerenone is well tolerated, with an adverse effect profile comparable to placebo. The advent of selective aldosterone blockers, such as eplerenone, should prove to be of great therapeutic value in hypertension control and prevention of cardiovascular disease and associated end-organ damage.

Response to six classes of antihypertensive medications by body mass index in a randomized controlled trial

Blood pressure increases with increasing body mass index (BMI) and BMI is linearly related to blood pressure in population studies. Obesity has been said to cause resistance to antihypertensive medications. We compared short-term and 1-year blood pressure response by BMI category and weight change with hydrochlorothiazide, atenolol, diltiazem-SR, captopril, clonidine, prazosin, or placebo in 1292 male veterans. Drug doses were titrated to achieve goal diastolic blood pressure <90 mm Hg over 4-8 weeks. Patients who achieved goal blood pressure were maintained for 1 year. BMI did not predict change in systolic, diastolic or pulse pressures during titration for any drug. At 1 year obese patients (BMI >30) were 2.5 times more likely to have diastolic blood pressure controlled by atenolol than normal weight (BMI <27) patients (p=0.01). Only prazosin patients gained weight: 1.7 lb (end-titration, p<0.0001; 1-year, p=0.02). Obesity does not appear to cause resistance to antihypertensive medications.

Aldosterone and aldosterone antagonism in cardiovascular disease: focus on eplerenone (Inspra)

Aldosterone has long been known to mediate water and electrolyte balance by acting on mineralocorticoid receptors in the kidneys. However, recent studies have demonstrated the presence of these receptors in nonclassical locations, including the brain, blood vessels, and the heart. This finding suggests that aldosterone may play a larger role than once appreciated in normal physiologic function and cardiovascular disease. Some of the adverse cardiovascular effects that have been described include cardiac and vascular fibrosis, left ventricular hypertrophy, congestive heart failure, hypertension, endothelial dysfunction, reduced fibrinolysis, and cardiac arrhythmias. In light of these findings, aldosterone receptor blockers have become increasingly more important. This is especially true considering the fact that traditional therapies, such as angiotensin-converting enzyme inhibitors and angiotensin II-receptor blockers, may not be effective in maintaining long-term suppression of aldosterone. Therefore, a great deal of focus has been placed on spironolactone, which has proven to be an effective, albeit nonselective, aldosterone receptor blocker. The Randomized Aldactone Evaluation Study has shown that spironolactone results in a 30% reduction in mortality among patients with severe congestive heart failure. Other studies have shown spironolactone to lower high blood pressure, improve endothelial dysfunction, reduce left ventricular hypertrophy, and lower the incidence of fatal arrhythmias. However, spironolactone, because of its interaction with other steroid receptors, is not without its limitations, which include gynecomastia, breast tenderness, menstrual irregularities, and impotence. As a result, eplerenone (INSPRA), a selective aldosterone blocker, is currently being investigated for its efficacy and side-effect profile compared with spironolactone. Eplerenone has already been approved for the treatment of systemic hypertension, and several clinical trials are currently underway to identify other therapeutic uses for this agent in cardiovascular disease management.

Gender modulates activation of renin-angiotensin and endothelin systems in hypertension and heart failure

Sexual dimorphism may occur during the development of hypertension and congestive heart failure (CHF). Male and female spontaneous hypertension heart failure (SHHF) rats with established hypertension, but before CHF (age 5-8 mo) and during cardiac decompensation leading to CHF (age 18-20 mo in male rats and 22-24 mo in female rats), were studied. At 5-8 mo, male SHHF rats showed early activation of the renin-angiotensin system (RAS), as indicated by increased plasma renin activity (PRA) and higher serum angiotensin-converting enzyme activity compared with female rats. The increase in PRA in female rats was delayed compared with males rats, but it reached comparable levels just before CHF. Urinary endothelin excretion was significantly greater in 5- to 8-mo-old female rats compared with age-matched male rats. Urinary endothelin excretion increased in both male and female rats as CHF developed. Plasma atrial natriuretic peptide (ANP) was comparable at both time points, and both genders showed similar, marked increases as CHF developed. In conclusion, male rats show early activation of the RAS, whereas female rats show early activation of the endothelin vasopressor system. During cardiac decompensation, generalized activation of the RAS, endothelin, and ANP systems occurs and is similar in male and female SHHF rats.

Trends in lifestyle cardiovascular risk factors in women: analysis from the Canadian National Population Health Survey

Cardiovascular disease (CVD) is the leading cause of death and disability among women. The present investigation analyzed data from the National Population Health Survey to examine the prevalence trends of self-reported lifestyle CVD risk factors in adult women. Results indicated an upward prevalence trend in physical activity and high blood pressure, and significant increased prevalence rates in obesity in the lower middle and middle income groups. Logistic regression analysis showed that increased physical activity and advancing age were significant predictors of CVD; age confers more than a one-fold risk for developing heart disease and hypertension. Implications of the study results for nursing practice are discussed.

Antihypertensive effect of low-dose hydrochlorothiazide alone or in combination with quinapril in black patients with mild to moderate hypertension

In this study, using 24-hour ambulatory blood pressure (BP) monitoring, the authors assessed the potential for BP control using hydrochlorothiazide (HCTZ, 12.5 mg daily), given as a monotherapy over 12 months to 49 black South African patients with mild to moderate hypertension (mean day diastolic blood pressure [DBP] > or = 90 and < 115 mmHg). Uncontrolled patients received fixed combination of quinapril/HCTZ 10/12.5, 20/12.5, and 20/25 mg, with dose titration at 3 monthly intervals if BP control was not achieved (day DBP < 90 mmHg). Overall, profound and sustained BP reduction was observed at the end of the study. The 24-hour BP decreased from 151 +/- 14/98 +/- 7 to 136 +/- 15/87 +/- 9 mmHg (p < 0.0001 at end of study vs. baseline); the mean day BP decreased from 155 +/- 14/104 +/- 7 to 140 +/- 15/91 +/- 10 mmHg (p < 0.0001 at end of study vs. baseline). The overall control (mean day DBP < 90 mmHg) and response (decrease in day DBP > or = 10 mmHg) rates were 49% and 61%, respectively. At the end of the study, only 2 patients (4%) remained on treatment with HCTZ. Out of the initial 12 patients controlled on HCTZ at 3 months (12/49, 24%), 5 patients remained controlled at 6 months and only 1 patient at 12 months. In contrast, quinapril/HCTZ combinations maintained their antihypertensive effect up to 9 months, with a significant number of patients (22/49, 45%) requiring the highest dose of the combination (20/25 mg daily). In conclusion, low-dose HCTZ should not be recommended as monotherapy in black patients with mild to moderate hypertension due to the fact that the BP-lowering effect is attenuated already at 6 months of treatment, with most patients requiring the addition of the ACE inhibitor.

Salt and blood pressure responses to calcium antagonism in hypertensive patients

Since salt intake may affect blood pressure response to antihypertensive drugs, an individual's salt-sensitivity status may be an important consideration in the selection of a medication. The purpose of this single-blind study was to assess the impact of salt sensitivity on the antihypertensive effects of isradipine. A total of 21 evaluable hypertensive patients (10 white, 11 black) 35 to 73 years of age (mean 55.9 years) were randomized to a low-salt diet (mean 24-hour urine sodium 100+/-14 mmol) or a high-salt diet (mean 24-hour urine sodium 210+/-22 mmol) for 7 weeks, followed by crossover to the other diet after a 2-week washout period. On each diet regimen, patients received placebo for 2 weeks, followed by optimal titration of isradipine (2.5 to 10 mg BID) for blood pressure control during the last 5 weeks. On the high-salt diet, salt-sensitive hypertensives (mean arterial blood pressure increase > or = 5 mm Hg, n=5) exhibited a systolic/diastolic blood pressure change of -18.7/-19.6 mm Hg from 157.2/102.9 mm Hg after 5 weeks of isradipine treatment, whereas on a low-salt diet, blood pressure change was -6.9/-12.0 mm Hg from 148.7/97.3 mm Hg. Non-salt-sensitive patients (n=16) exhibited a systolic/diastolic blood pressure change of -12.6/-7.6 mm Hg from 155.3/98.6 mm Hg on the high-salt diet and -19.2/-10.9 mm Hg from 161.0/102.6 mm Hg on the low-salt diet after treatment with isradipine. The absolute blood pressure attained in both salt-sensitive and non-salt-sensitive patients was almost identical with isradipine therapy despite variation in dietary salt, although slightly higher doses of isradipine were required in the salt-sensitive group. Consequently, isradipine, and perhaps calcium antagonists in general, manifests a more robust blood pressure-lowering effect in the setting of high sodium intake. This effect does, however, appear to be largely confined to individuals who are salt sensitive.

The impact of ethnicity on response to antihypertensive therapy

The aim of this review is to assess the prevalence of complications and responses to various antihypertensive drug therapies in ethnic minority groups in the United States. In some instances, these comments are extended to responses of citizens in their countries of origin. The incidence of hypertension, mortality from hypertensive heart disease, stroke, and hypertensive renal disease are higher in African Americans. Although some Hispanic Americans have a lesser risk for hypertension, they have a greater risk for other risk factors such as diabetes and dyslipidemia. There is a similar association between income and mortality for both African Americans and Hispanic Americans. When compared to European Americans and other ethnic minorities, African Americans respond less favorably to beta blockers and angiotensin-converting enzyme (ACE) inhibitors. Nevertheless, the observed response in African Americans to ACE inhibitors and beta blockers is clinically significant. The available literature indicates that Asian American responses to calcium antagonists seem to be more favorable than responses to ACE inhibitors and equivalent to their responses to diuretic and beta blocker therapy. Although there are few published studies of drug efficacy in Hispanic Americans, there appears to be no hierarchy in response to the various antihypertensive drug classes. Ethnicity is not an accurate criterion for predicting poor response to any class of antihypertensive therapy. Thus, there is little justification to use racial profiling as a criterion for the avoidance of selected drug classes because of presumed lack of efficacy. Observed differences in the incidence of hypertension and its poor outcomes have led some investigators to postulate that the etiology of hypertension in ethnic minority groups is intrinsically different from whites. Awareness of racial differences in hypertension outcomes evolved in the United States within a historical context that does not fully appreciate that race is often a surrogate for many social and economic factors that influence health status and healthcare delivery. Poor outcomes in ethnic minority groups occur in many diseases, not only hypertension. The goal of ethnicity-related research should be to describe the diversity of disease expression in humans and to target at-risk groups for prevention and early intervention. The use of racial descriptors to explain genetic differences in ethnic groups should take a lesser priority.

Differing mechanisms of action of angiotensin-converting enzyme inhibition in black and white hypertensive patients. The Trandolapril Multicenter Study Group

The antihypertensive effect of the angiotensin-converting enzyme inhibitor trandolapril administered in doses of 1, 2, and 4 mg/d was compared in 207 white patients and 91 black patients with mild to moderate hypertension following a double-blind, randomized, placebo-controlled, parallel study design. Trandolapril is a prodrug that is rapidly hydrolyzed to its active diacid metabolite, trandolaprilat. After 6 weeks of double-blind treatment, trandolapril lowered baseline sitting diastolic pressure in both white and black patients. A comparison of the antihypertensive response of the two populations revealed that the black patients required between two and four times the dose of trandolapril to obtain a response similar to that observed in the white patients. A dose of 1 mg/d trandolapril resulted in a 6.1 mm Hg mean decrease in baseline sitting diastolic pressure for white patients; a similar response (-6.5 mm Hg) was observed in the black patients at 4 mg/d. In contrast to the population differences in blood pressure, the decreases in angiotensin-converting enzyme activity were similar for both populations. An evaluation of trandolaprilat levels revealed that there were no racial differences in the trandolaprilat concentrations required to achieve a given degree of angiotensin-converting enzyme inhibition. Therefore, it appears that the antihypertensive response of black patients is not completely explained by a reduction in angiotensin-converting enzyme activity. The lack of response at a lower dose but increasing response at a higher dose could reflect another vasodepressor activity of trandolapril or just be evidence of reduced sensitivity of high blood pressure in blacks to angiotensin-converting enzyme inhibition.

Prevalence of complications and response to different treatments of hypertension in African Americans and white Americans in the U.S

The aim of this review is to compare the prevalence of complications and response to different treatment for hypertension in African and European Americans. African Americans when compared to European Americans respond less favorably to beta-blockers (BB's) and angiotensin converting enzyme inhibitors (ACEI's). Nevertheless the observed response of African Americans to ACEI's and BB's is significant and these agents are very effective in this subgroup. African American race is not a clinically significant predictor of poor response to any class of antihypertensive therapy and there is little justification to use racial profiling as a criterion for choice of medication. Evidence to restrict or defer usage of BB's and ACEI's in African Americans is lacking. The mortality from hypertensive heart disease, stroke, and the incidence of hypertensive renal disease is higher in African Americans which leads some investigators to postulate that hypertension in African Americans is intrinsically different from whites. They therefore search for a separate etiology and suggest specific approaches to treatment. Awareness of racial differences in hypertension outcomes evolved in the U.S. in an historical context that does not fully appreciate that race is often a surrogate for many social and economic factors that influence health status and health care delivery in the U.S. Poor outcomes in African Americans occur in many diseases including hypertension.

Hypertension in the elderly with a special focus on treatment with angiotensin-converting enzyme inhibitors and calcium antagonists

Age-related changes (e.g., decrease in plasma renin activity and total body potassium, increase in plasma catecholamines, volume depletion) need to be taken into account when selecting an antihypertensive agent for the elderly patient. A number of large scale clinical trials (e.g., Systolic Hypertension in the Elderly Program, Veterans Administration Cooperative Study, European Working Party on High Blood Pressure in the Elderly) have demonstrated that antihypertensive therapy with diuretics substantially reduced cardiovascular mortality and stroke incidence. However, since diuretics, even potassium-sparing agents, may induce hypokalemia, newer antihypertensive agents (angiotensin-converting enzyme [ACE] inhibitors and calcium antagonists) may also be appropriate as first-line monotherapy for this patient population. ACE inhibitors are effective antihypertensive agents and are associated with a lower rate of adverse effects than diuretics, beta blockers, and centrally acting agents. Nevertheless, periodic monitoring of serum potassium, creatinine levels, and renal function is advisable. An important feature of calcium antagonists is that they lower blood pressure with no negative effect on serum lipids or glucose metabolism. Typically, they have few side effects, peripheral edema being the most commonly reported. A recent double-blind randomized study comparing a new sustained release nifedipine formulation and the ACE inhibitor lisinopril found the 2 drugs equivalent in efficacy with no differences in the rate of adverse events.