Influence of race and dietary salt on the antihypertensive efficacy of an angiotensin-converting enzyme inhibitor or a calcium channel antagonist in salt-sensitive hypertensives

The Interaction of Kidneys and Gut in Development of Salt-Sensitive Hypertension

The incidence of salt-sensitive hypertension is quite common and varies between 30-60% in hypertensive patients. Regarding the causal role of high salt intake in the development of salt-sensitive hypertension, recent evidence has demonstrated that the gut through its microbiota plays a significant role in its genesis. Besides the gut, the kidneys also play important role in salt-sensitive hypertension and there is clinical and experimental evidence of an interrelationship between the gut and the kidneys in the development of salt-sensitive hypertension through the so-called "gastro-renal axis." The gut besides being an absorptive organ, it is also a hormonal secretory organ involving the secretion of gastrin, dopamine, norepinephrine, angiotensin, and aldosterone which through their action with the kidneys are involved in the development of salt-sensitive hypertension. In addition, the kidneys exert a protective role against the development of hypertension through the secretion of prostaglandins and their vasodilatory action. To assess the current evidence on the role of high salt intake and the interplay of the gut and kidneys in its development, a Medline search of the English literature was contacted between 2012 and 2022, and 46 pertinent papers were selected. These papers together with collateral literature will be discussed in this review.

Relationship between salt reduction readiness and salt intake in hypertensive patients: a single nonspecialized hypertension clinic case study

This is the first report about the association of readiness for salt reduction with daily salt intake or the salt check sheet score in hypertensive patients at a nonspecialized hypertension clinic. We investigated whether salt reduction readiness as evaluated based on the transtheoretical model (TTM) is associated with estimated daily salt intake or the salt check sheet score. The TTM allows evaluators to easily assess a subject's level of readiness for health-related according to five stages. There was no significant relationship between the TTM stages and estimated daily salt intake. A significant correlation was found between the TTM stages and salt check sheet scores (ρ = -0.409; P  < 0.001). When providing salt reduction guidance to hypertensive patients, it is effective for healthcare professionals to use repeated urine tests and salt check sheets to take a salt reduction approach according to the level of readiness of the patients.

Cost-effectiveness of digital therapeutics for essential hypertension

Hypertension increases the risk of cardiovascular and other diseases. Lifestyle modification is a significant component of nonpharmacological treatments for hypertension. We previously reported the clinical efficacy of digital therapeutics (DTx) in the HERB-DH1 trial. However, there is still a lack of cost-effectiveness assessments evaluating the impact of prescription DTx. This study aimed to analyze the cost-effectiveness of using prescription DTx in treating hypertension. We developed a monthly cycle Markov model and conducted Monte Carlo simulations using the HERB-DH1 trial data to investigate quality-adjusted life-years (QALYs) and the cost of DTx for hypertension plus guideline-based lifestyle modification consultation treatment as usual (TAU), comparing DTx + TAU and TAU-only groups with a lifetime horizon. The model inputs were obtained from the HERB-DH1 trial, published or publicly available data, and expert assumptions. The incremental cost-effectiveness ratio (ICER) per QALY was used as the benchmark for cost-effectiveness. We performed probabilistic sensitivity analyses (PSAs) using the Monte Carlo simulation with two million sets. The DTx + TAU strategy produced 18.778 QALYs and was associated with ¥3,924,075 ($34,122) expected costs, compared with 18.686 QALYs and ¥3,813,358 ($33,160) generated by the TAU-only strategy over a lifetime horizon, resulting in an ICER of ¥1,199,880 ($10,434)/QALY gained for DTx + TAU. The monthly cost and attrition rate of DTx for hypertension have a significant impact on ICERs. In the PSA, the probability of the DTx arm being a cost-effective option was 87.8% at a threshold value of ¥5 million ($43,478)/QALY gained. In conclusion, the DTx + TAU strategy was more cost-effective than the TAU-only strategy.

Sodium Intake as a Cardiovascular Risk Factor: A Narrative Review

While sodium is essential for human homeostasis, current salt consumption far exceeds physiological needs. Strong evidence suggests a direct causal relationship between sodium intake and blood pressure (BP) and a modest reduction in salt consumption is associated with a meaningful reduction in BP in hypertensive as well as normotensive individuals. Moreover, while long-term randomized controlled trials are still lacking, it is reasonable to assume a direct relationship between sodium intake and cardiovascular outcomes. However, a consensus has yet to be reached on the effectiveness, safety and feasibility of sodium intake reduction on an individual level. Beyond indirect BP-mediated effects, detrimental consequences of high sodium intake are manifold and pathways involving vascular damage, oxidative stress, hormonal alterations, the immune system and the gut microbiome have been described. Globally, while individual response to salt intake is variable, sodium should be perceived as a cardiovascular risk factor when consumed in excess. Reduction of sodium intake on a population level thus presents a potential strategy to reduce the burden of cardiovascular disease worldwide. In this review, we provide an update on the consequences of salt intake on human health, focusing on BP and cardiovascular outcomes as well as underlying pathophysiological hypotheses.

Ramipril and Cardiovascular Outcomes in Patients on Maintenance Hemodialysis: The ARCADIA Multicenter Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Renin-angiotensin system (RAS) inhibitors reduce cardiovascular morbidity and mortality in patients with CKD. We evaluated the cardioprotective effects of the angiotensin-converting enzyme inhibitor ramipril in patients on maintenance hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this phase 3, prospective, randomized, open-label, blinded end point, parallel, multicenter trial, we recruited patients on maintenance hemodialysis with hypertension and/or left ventricular hypertrophy from 28 Italian centers. Between July 2009 and February 2014, 140 participants were randomized to ramipril (1.25-10 mg/d) and 129 participants were allocated to non-RAS inhibition therapy, both titrated up to the maximally tolerated dose to achieve predefined target BP values. The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or stroke. Secondary end points included the single components of the primary end point, new-onset or recurrence of atrial fibrillation, hospitalizations for symptomatic fluid overload, thrombosis or stenosis of the arteriovenous fistula, and changes in cardiac mass index. All outcomes were evaluated up to 42 months after randomization.

RESULTS

At comparable BP control, 23 participants on ramipril (16%) and 24 on non-RAS inhibitor therapy (19%) reached the primary composite end point (hazard ratio, 0.93; 95% confidence interval, 0.52 to 1.64; P=0.80). Ramipril reduced cardiac mass index at 1 year of follow-up (between-group difference in change from baseline: -16.3 g/m2; 95% confidence interval, -29.4 to -3.1), but did not significantly affect the other secondary outcomes. Hypotensive episodes were more frequent in participants allocated to ramipril than controls (41% versus 12%). Twenty participants on ramipril and nine controls developed cancer, including six gastrointestinal malignancies on ramipril (four were fatal), compared with none in controls.

CONCLUSIONS

Ramipril did not reduce the risk of major cardiovascular events in patients on maintenance hemodialysis.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

ARCADIA, NCT00985322 and European Union Drug Regulating Authorities Clinical Trials Database number 2008-003529-17.

Salt sensitivity and hypertension

Salt sensitivity refers to the physiological trait present in mammals, including humans, by which the blood pressure (BP) of some members of the population exhibits changes parallel to changes in salt intake. It is commoner in elderly, females, Afro-Americans, patients with chronic kidney disease (CKD) and insulin resistance. Increased salt intake promotes an expansion of extracellular fluid volume and increases cardiac output. Salt-sensitive individuals present an abnormal kidney reaction to salt intake; the kidneys retain most of the salt due to an abnormal over-reactivity of sympathetic nervous system and a blunted suppression of renin-angiotensin axis. Moreover, instead of peripheral vascular resistance falling, salt-sensitive subjects present increased vascular resistance due mainly to impaired nitric oxide synthesis in endothelium. Recent studies have shown that part of the dietary salt loading accumulates in skin. Hypertensive and patients with CKD seem to have more sodium in skin comparing to healthy ones. However, we still have not fully explained the link between skin sodium, BP and salt sensitivity. Finally, although salt sensitivity plays a meaningful role in BP pathophysiology, it cannot be used by the physician in everyday patient's care, mainly due to lack of a simple and practical diagnostic test.

Pharmacology of enalapril in children: a review

Enalapril is an angiotensin-converting enzyme (ACE) inhibitor that is used for the treatment of (paediatric) hypertension, heart failure and chronic kidney diseases. Because its disposition, efficacy and safety differs across the paediatric continuum, data from adults cannot be automatically extrapolated to children. This review highlights paediatric enalapril pharmacokinetic data and demonstrates that these are inadequate to support with certainty an age-related effect on enalapril/enalaprilat pharmacokinetics. In addition, our review shows that evidence to support effective and safe prescribing of enalapril in children is limited, especially in young children and heart failure patients; studies in these groups are either absent or show conflicting results. We provide explanations for observed differences between age groups and indications, and describe areas for future research.

Treating Hypertension in Children With n-of-1 Trials

OBJECTIVES

Clinicians prescribe antihypertensive medication to children with primary hypertension, but without data to define a particular choice as first-line therapy. A one-size-fits-all approach may not be appropriate for these patients. Our aim was to develop a personalized approach to hypertension treatment, using repeated ambulatory blood pressure monitoring (ABPM) in n-of-1 trials (single-patient randomized crossover trials).

METHODS

Children undergoing hypertension management at a single pediatric referral center were offered participation in an n-of-1 trial with repeated ABPM to compare 3 commonly used medications. The medication producing the greatest blood pressure reduction, and without unacceptable side effects, was selected as the preferred therapy for the individual.

RESULTS

Forty-two children agreed to participate; 7 were normotensive without medication; and 3 failed to complete one treatment cycle. Of the remaining 32 patients, lisinopril was preferred for 16, amlodipine for 8, hydrochlorothiazide for 4, and 4 had uncontrolled blood pressure on maximum doses of monotherapy. In conservative Bayesian analyses, the proportion of patients who preferred lisinopril was 49% (95% credible interval [CrI]: 32% to 69%), 24% (95% CrI: 12% to 41%) preferred amlodipine, and 12% (95% CrI: 4% to 26%) preferred hydrochlorothiazide. The preferred therapy for the majority (67%) of African American participants was lisinopril. Unacceptable side effects were reported in 24% of assessments for hydrochlorothiazide, 16% for lisinopril, and 13% for amlodipine.

CONCLUSIONS

No single medication was preferred for more than half of hypertensive children. n of-1 trials with repeated ABPM may promote better informed and individualized decisions in pediatric hypertension management.

Comparative effectiveness of antihypertensive drugs prescribed in Ethiopian healthcare practice: A pilot prospective, randomized, open label study

BACKGROUND

Previous research has been highly suggestive that patients of African ancestry are less responsive to beta-blockers and angiotensin converting enzyme inhibitors. However, clinical practice within Ethiopia has continued to recommend all drugs for treatment of hypertension despite the lack of evidentiary support. Therefore this study aims to compare the effectiveness of the three major antihypertensive drugs currently prescribed in an Ethiopian health care setting to further the potential for evidence based prescribing practices.

METHODS

A prospective, randomized, open label comparative study was used to determine the mean reduction in blood pressure (primary outcome) and assess cardiovascular events (secondary outcomes) among patients receiving one or more of three common antihypertensive drugs (i.e., nifedipine, hydrochlorothiazide, and enalapril) in routine clinical practice between November 2016 and April 2017. Patients were followed for three months. Analysis was based on an intention-to-treat approach. One way analysis of covariance was used to compare the difference in therapeutic effectiveness in reducing blood pressure.

RESULT

A total of 141 patients were randomized to one of three recipient groups-nifedipine (n = 47), enalapril (n = 47) or hydrochlorothiazide (n = 47). Three months after randomization, 44 patients in each group completed the follow-up. Patients randomized to nifedipine had significantly higher mean reduction in systolic blood pressure than those randomized to enalapril(p = 0.003) or hydrochlorothiazide(p = 0.036). The mean reduction in systolic blood pressure was -37.35(CI:-40, -34.2) in the nifedipine group; -30.3(CI: -33.5, -27.1) in patients receiving enalapril; and -32.1(CI:-35, -29.3) in patients assigned hydrochlorothiazide. However, nifedipine did not have a significance difference in reduction of mean diastolic blood pressure compared than those receiving enalapril (p = 0.57) or hydrochlorthiazide (p = 0.99).

CONCLUSION

This study revealed that amongst the three drugs nifedipine was found to be the most effective drug in reduction of systolic blood pressure. Hydrochlorothiazide and enalapril did not show a difference in reduction of mean blood pressure. Further, long term randomized trials are highly recommended to inform revision of Ethiopia-centric hypertension treatment guidelines.

Beta blockers in patients with end-stage renal disease-Evidence-based recommendations

For patients who require hemodialysis, beta blockers offer a simultaneous opportunity and challenge in the treatment of cardiovascular disease. Beta blockers are well supported by data from nondialysis populations and directly mitigate the sympathetic overactivity that links chronic kidney disease with cardiovascular sequelae. However, the evidence supporting their use in patients receiving hemodialysis is sparse and the heterogeneity of the beta blocker class makes it difficult to prescribe these medications with confidence. Despite these limitations, both trial and observational data exist that can help guide the use of these medications. In this review, we outline the reasons to consider beta blockers for patients receiving hemodialysis, discuss the barriers to their use, and provide specific evidence-based recommendations for beta blocker use in patients with heart failure, hypertension, ischemic heart disease and arrhythmia.

Renin-Angiotensin System Inhibitors vs Other Antihypertensives in Hypertensive Blacks: A Meta-Analysis

The purpose of this study was to assess the effects of renin-angiotensin system (RAS) inhibitors vs other antihypertensive agents on cardiovascular outcomes in hypertensive black patients. The authors performed a systematic review and meta-analysis of studies that compared the effects of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) with calcium channel blockers (CCBs), diuretics, and β-blockers in hypertensive black patients on cardiovascular outcomes. A total of 38,983 patients with a mean age of 60 years and mean follow-up of 4 years were included in our meta-analysis. No significant differences were found in all-cause mortality, myocardial infarction, heart failure, and cardiovascular mortality rates among patients treated with RAS inhibitors compared with CCBs, diuretics, and β-blockers. The incidence of stroke was significantly increased in patients treated with RAS inhibitors compared with CCBs (odds ratio, 1.56; 95% confidence interval, 1.31-1.87 [P<.00001]; I2 =0%) and diuretics (odds ratio, 1.59; 95% confidence interval, 1.16-2.17 [P=.004]; I2 =56%) but not β-blockers.

Advances in understanding the renin-angiotensin-aldosterone system (RAAS) in blood pressure control and recent pivotal trials of RAAS blockade in heart failure and diabetic nephropathy

The renin-angiotensin-aldosterone system (RAAS) plays a fundamental role in the physiology of blood pressure control and the pathophysiology of hypertension (HTN) with effects on vascular tone, sodium retention, oxidative stress, fibrosis, sympathetic tone, and inflammation. Fortunately, RAAS blocking agents have been available to treat HTN since the 1970s and newer medications are being developed. In this review, we will (1) examine new anti-hypertensive medications affecting the RAAS, (2) evaluate recent studies that help provide a better understanding of which patients may be more likely to benefit from RAAS blockade, and (3) review three recent pivotal randomized trials that involve newer RAAS blocking agents and inform clinical practice.

Influence of Age and Race on 24-Hour Ambulatory Blood Pressure Responses to Valsartan, Hydrochlorothiazide, and Their Combination: Implications for Clinical Practice

The effects of race and age on 24-hour mean ambulatory systolic blood pressure (maSBP) responses to sequential 4-week periods of angiotensin receptor blocker therapy (valsartan [VAL] 160 mg/d then 320 mg/d and combination VAL/hydrochlorothiazide [HCTZ] 320/12.5 mg/d) were compared in 304 patients with stage 1 or 2 hypertension. There were lesser blood pressure (BP) responses from baseline with VAL monotherapy in black than Caucasian patients (-2.9 and -4.0 mm Hg vs -8.2 and -9.3 mm Hg, respectively; P<.001 each) but VAL/HCTZ BP responses were similar in both groups (-12 vs -15 mm Hg). Participants 65 years and older had lower BP responses with VAL 160 mg/d and 320 mg/d than those younger than 65 years (-2.8 and -4.5 mm Hg vs -6.5 and -7.5 mm Hg, respectively; P<.001) but similar responses to VAL/HCTZ (-14 vs -17 mm Hg). No BP response differences were found between those older than and those younger than 55 years. The authors conclude that: (1) adding low-dose HCTZ (12.5 mg daily) to VAL is more effective than VAL titration, irrespective of age or race, (2) VAL BP efficacy is lower in blacks than Caucasians, and (3) ARB responses are diminished in patients older than 65 years. Guidelines for stage 1 or 2 hypertension that suggest age 55 should determine initial monotherapy choice (eg, ARB vs thiazide diuretic) or that fail to recommend initial ARB-thiazide combination therapy should be reconsidered.

Renal tubular angiotensin converting enzyme is responsible for nitro-L-arginine methyl ester (L-NAME)-induced salt sensitivity

Renal parenchymal injury predisposes to salt-sensitive hypertension, but how this occurs is not known. Here we tested whether renal tubular angiotensin converting enzyme (ACE), the main site of kidney ACE expression, is central to the development of salt sensitivity in this setting. Two mouse models were used: it-ACE mice in which ACE expression is selectively eliminated from renal tubular epithelial cells; and ACE 3/9 mice, a compound heterozygous mouse model that makes ACE only in renal tubular epithelium from the ACE 9 allele, and in liver hepatocytes from the ACE 3 allele. Salt sensitivity was induced using a post L-NAME salt challenge. While both wild-type and ACE 3/9 mice developed arterial hypertension following three weeks of high salt administration, it-ACE mice remained normotensive with low levels of renal angiotensin II. These mice displayed increased sodium excretion, lower sodium accumulation, and an exaggerated reduction in distal sodium transporters. Thus, in mice with renal injury induced by L-NAME pretreatment, renal tubular epithelial ACE, and not ACE expression by renal endothelium, lung, brain, or plasma, is essential for renal angiotensin II accumulation and salt-sensitive hypertension.

Systematic review: antihypertensive drug therapy in patients of African and South Asian ethnicity

Despite the large differences in the epidemiology of hypertension across Europe, treatment strategies are similar for national populations of white European descent. However, hypertensive patients of African or South Asian ethnicity may require ethnic-specific approaches, as these population subgroups tend to have higher blood pressure at an earlier age that is more difficult to control, a higher occurrence of diabetes, and more target organ damage with earlier cardiovascular mortality. Therefore, we systematically reviewed the evidence on antihypertensive drug treatment in South Asian and African ethnicity patients. We used the Cochrane systematic review methodology to retrieve trials in electronic databases including CENTRAL, PubMed, and Embase from their inception through November 2015; and with handsearch. We retrieved 4596 reports that yielded 35 trials with 7 classes of antihypertensive drugs in 25,540 African ethnicity patients. Aside from the well-known blood pressure efficacy of calcium channel blockers and diuretics, with lesser effect of ACE inhibitors and beta-blockers, nebivolol was not more effective than placebo in reducing systolic blood pressure levels. Trials with morbidity and mortality outcomes indicated that lisinopril and losartan-based therapy were associated with a greater incidence of stroke and sudden death. Furthermore, 1581 reports yielded 16 randomized controlled trials with blood pressure outcomes in 1719 South Asian hypertensive patients. In contrast with the studies in African ethnicity patients, there were no significant differences in blood pressure lowering efficacy between drugs, and no trials available with mortality outcomes. In conclusion, in patients of African ethnicity, treatment initiated with ACE inhibitor or angiotensin II receptor blocker monotherapy was associated with adverse cardiovascular outcomes. We found no evidence of different efficacy of antihypertensive drugs in South Asians, but there is a need for trials with morbidity and mortality outcomes. Screening for cardiovascular risk at a younger age, treating hypertension at lower thresholds, and new delivery models to find, treat and follow hypertensives in the community may help reduce the excess cardiovascular mortality in these high-risk groups.

Assessment and management of hypertension in transplant patients

Hypertension in renal transplant recipients is common and ranges from 50% to 80% in adult recipients and from 47% to 82% in pediatric recipients. Cardiovascular morbidity and mortality and shortened allograft survival are important consequences of inadequate control of hypertension. In this review, we examine the epidemiology, pathophysiology, and management considerations of post-transplant hypertension. Donor and recipient factors, acute and chronic allograft injury, and immunosuppressive medications may each explain some of the pathophysiology of post-transplant hypertension. As observed in other patient cohorts, renal artery stenosis and adrenal causes of hypertension may be important contributing factors. Notably, BP treatment goals for renal transplant recipients remain an enigma because there are no adequate randomized controlled trials to support a benefit from targeting lower BP levels on graft and patient survival. The potential for drug-drug interactions and altered pharmacokinetics and pharmacodynamics of the different antihypertensive medications need to be carefully considered. To date, no specific antihypertensive medications have been shown to be more effective than others at improving either patient or graft survival. Identifying the underlying pathophysiology and subsequent individualization of treatment goals are important for improving long-term patient and graft outcomes in these patients.

Recent advances in the management of resistant hypertension

And suddenly, following the preliminary results of renal denervation and carotid baroreceptor stimulation, a big interest in resistant hypertension rose, and all interventionists, many of them with no previous experience with hypertension, fell in love with hypertension and especially resistant hypertension. In the European Society of Hypertension/International Society of Hypertension (ESH/ISH) 2014 Joint Hypertension meeting in Athens, there were no more than four to five sessions related to resistant hypertension and renal denervation, while in the 2014 EuroPCR meeting there were more than 60 renal denervation sessions! In light of the growing scientific interest in the treatment of this patient group, an update on the treatment available and some concerns regarding the definition and treatment of resistant hypertension is presented.

Hypertension in hemodialysis patients treated with atenolol or lisinopril: a randomized controlled trial

BACKGROUND

The purpose of this study was to determine among maintenance hemodialysis patients with echocardiographic left ventricular hypertrophy and hypertension whether in comparison with a β-blocker-based antihypertensive therapy, an angiotensin converting enzyme-inhibitor-based antihypertensive therapy causes a greater regression of left ventricular hypertrophy.

METHODS

Subjects were randomly assigned to either open-label lisinopril (n = 100) or atenolol (n = 100) each administered three times per week after dialysis. Monthly monitored home blood pressure (BP) was controlled to <140/90 mmHg with medications, dry weight adjustment and sodium restriction. The primary outcome was the change in left ventricular mass index (LVMI) from baseline to 12 months.

RESULTS

At baseline, 44-h ambulatory BP was similar in the atenolol (151.5/87.1 mmHg) and lisinopril groups, and improved similarly over time in both groups. However, monthly measured home BP was consistently higher in the lisinopril group despite the need for both a greater number of antihypertensive agents and a greater reduction in dry weight. An independent data safety monitoring board recommended termination because of cardiovascular safety. Serious cardiovascular events in the atenolol group occurred in 16 subjects, who had 20 events, and in the lisinopril group in 28 subjects, who had 43 events {incidence rate ratio (IRR) 2.36 [95% confidence interval (95% CI) 1.36-4.23, P = 0.001]}. Combined serious adverse events of myocardial infarction, stroke and hospitalization for heart failure or cardiovascular death in the atenolol group occurred in 10 subjects, who had 11 events and in the lisinopril group in 17 subjects, who had 23 events (IRR 2.29, P = 0.021). Hospitalizations for heart failure were worse in the lisinopril group (IRR 3.13, P = 0.021). All-cause hospitalizations were higher in the lisinopril group [IRR 1.61 (95% CI 1.18-2.19, P = 0.002)]. LVMI improved with time; no difference between drugs was noted.

CONCLUSIONS

Among maintenance dialysis patients with hypertension and left ventricular hypertrophy, atenolol-based antihypertensive therapy may be superior to lisinopril-based therapy in preventing cardiovascular morbidity and all-cause hospitalizations. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases; ClinicalTrials.gov number: NCT00582114).

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.

Why do hypertensive patients of African ancestry respond better to calcium blockers and diuretics than to ACE inhibitors and β-adrenergic blockers? A systematic review

BACKGROUND

Clinicians are encouraged to take an individualized approach when treating hypertension in patients of African ancestry, but little is known about why the individual patient may respond well to calcium blockers and diuretics, but generally has an attenuated response to drugs inhibiting the renin-angiotensin system and to β-adrenergic blockers. Therefore, we systematically reviewed the factors associated with the differential drug response of patients of African ancestry to antihypertensive drug therapy.

METHODS

Using the methodology of the systematic reviews narrative synthesis approach, we sought for published or unpublished studies that could explain the differential clinical efficacy of antihypertensive drugs in patients of African ancestry. PUBMED, EMBASE, LILACS, African Index Medicus and the Food and Drug Administration and European Medicines Agency databases were searched without language restriction from their inception through June 2012.

RESULTS

We retrieved 3,763 papers, and included 72 reports that mainly considered the 4 major classes of antihypertensive drugs, calcium blockers, diuretics, drugs that interfere with the renin-angiotensin system and β-adrenergic blockers. Pharmacokinetics, plasma renin and genetic polymorphisms did not well predict the response of patients of African ancestry to antihypertensive drugs. An emerging view that low nitric oxide and high creatine kinase may explain individual responses to antihypertensive drugs unites previous observations, but currently clinical data are very limited.

CONCLUSION

Available data are inconclusive regarding why patients of African ancestry display the typical response to antihypertensive drugs. In lieu of biochemical or pharmacogenomic parameters, self-defined African ancestry seems the best available predictor of individual responses to antihypertensive drugs.

Association between dietary sodium and potassium intake with chronic kidney disease in US adults: a cross-sectional study

BACKGROUND/AIMS

Clinical guidelines recommend a diet low in sodium and high in potassium to reduce blood pressure and cardiovascular events. Little is known about the relationship between dietary sodium and potassium intake and chronic kidney disease (CKD).

METHODS

13,917 participants from the National Health and Nutrition Examination Survey (2001-2006) were examined. Sodium and potassium intake were calculated from 24-hour recall and evaluated in quartiles. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) or eGFR ≥60 ml/min/1.73 m(2) with albuminuria (>30 mg/g creatinine).

RESULTS

The mean (SE) age and eGFR of participants were 45.0 ± 0.4 years and 88.0 ± 0.60 ml/min/1.73 m(2), respectively. 2,333 (14.2%) had CKD: 1,146 (7.3%) had an eGFR <60 ml/min/1.73 m(2) and 1,514 (8.4%) had an eGFR ≥60 ml/min/1.73 m(2) and albuminuria. After adjustment for age, sex, race, BMI, diabetes, hypertension, cardiovascular disease and congestive heart failure, subjects in the highest quartile of sodium intake had lower odds of CKD compared to subjects in the lowest quartile (adjusted OR: 0.79; 95% CI: 0.66-0.96; p < 0.016). Compared to the highest quartile, the odds of CKD increased 44% for participants in the lowest quartile of potassium intake (adjusted OR: 1.44; 95% CI: 1.16-1.79; p = 0.0011).

CONCLUSIONS

Higher intake of sodium and potassium is associated with lower odds of CKD among US adults. These results should be corroborated through longitudinal studies and clinical trials designed specifically to examine the effects of dietary sodium and potassium intake on kidney disease and its progression.

Effect of longer-term modest salt reduction on blood pressure

BACKGROUND

A reduction in salt intake lowers blood pressure (BP) and, thereby, reduces cardiovascular risk. A recent meta-analysis by Graudal implied that salt reduction had adverse effects on hormones and lipids which might mitigate any benefit that occurs with BP reduction. However, Graudal's meta-analysis included a large number of very short-term trials with a large change in salt intake, and such studies are irrelevant to the public health recommendations for a longer-term modest reduction in salt intake. We have updated our Cochrane meta-analysis.

OBJECTIVES

To assess (1) the effect of a longer-term modest reduction in salt intake (i.e. of public health relevance) on BP and whether there was a dose-response relationship; (2) the effect on BP by sex and ethnic group; (3) the effect on plasma renin activity, aldosterone, noradrenaline, adrenaline, cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides.

SEARCH METHODS

We searched MEDLINE, EMBASE, Cochrane Hypertension Group Specialised Register, Cochrane Central Register of Controlled Trials, and reference list of relevant articles.

SELECTION CRITERIA

We included randomised trials with a modest reduction in salt intake and duration of at least 4 weeks.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers. Random effects meta-analyses, subgroup analyses and meta-regression were performed.

MAIN RESULTS

Thirty-four trials (3230 participants) were included. Meta-analysis showed that the mean change in urinary sodium (reduced salt vs usual salt) was -75 mmol/24-h (equivalent to a reduction of 4.4 g/d salt), the mean change in BP was -4.18 mmHg (95% CI: -5.18 to -3.18, I (2)=75%) for systolic and -2.06 mmHg (95% CI: -2.67 to -1.45, I (2)=68%) for diastolic BP. Meta-regression showed that age, ethnic group, BP status (hypertensive or normotensive) and the change in 24-h urinary sodium were all significantly associated with the fall in systolic BP, explaining 68% of the variance between studies. A 100 mmol reduction in 24 hour urinary sodium (6 g/day salt) was associated with a fall in systolic BP of 5.8 mmHg (95%CI: 2.5 to 9.2, P=0.001) after adjusting for age, ethnic group and BP status. For diastolic BP, age, ethnic group, BP status and the change in 24-h urinary sodium explained 41% of the variance between studies. Meta-analysis by subgroup showed that, in hypertensives, the mean effect was -5.39 mmHg (95% CI: -6.62 to -4.15, I (2)=61%) for systolic and -2.82 mmHg (95% CI: -3.54 to -2.11, I (2)=52%) for diastolic BP. In normotensives, the mean effect was -2.42 mmHg (95% CI: -3.56 to -1.29, I (2)=66%) for systolic and -1.00 mmHg (95% CI: -1.85 to -0.15, I (2)=66%) for diastolic BP. Further subgroup analysis showed that the decrease in systolic BP was significant in both whites and blacks, men and women. Meta-analysis of hormone and lipid data showed that the mean effect was 0.26 ng/ml/hr (95% CI: 0.17 to 0.36, I (2)=70%) for plasma renin activity, 73.20 pmol/l (95% CI: 44.92 to 101.48, I (2)=62%) for aldosterone, 31.67 pg/ml (95% CI: 6.57 to 56.77, I (2)=5%) for noradrenaline, 6.70 pg/ml (95% CI: -0.25 to 13.64, I (2)=12%) for adrenaline, 0.05 mmol/l (95% CI: -0.02 to 0.11, I (2)=0%) for cholesterol, 0.05 mmol/l (95% CI: -0.01 to 0.12, I (2)=0%) for LDL, -0.02 mmol/l (95% CI: -0.06 to 0.01, I (2)=16%) for HDL, and 0.04 mmol/l (95% CI: -0.02 to 0.09, I (2)=0%) for triglycerides.

AUTHORS' CONCLUSIONS

A modest reduction in salt intake for 4 or more weeks causes significant and, from a population viewpoint, important falls in BP in both hypertensive and normotensive individuals, irrespective of sex and ethnic group. With salt reduction, there is a small physiological increase in plasma renin activity, aldosterone and noradrenaline. There is no significant change in lipid levels. These results provide further strong support for a reduction in population salt intake. This will likely lower population BP and, thereby, reduce cardiovascular disease. Additionally, our analysis demonstrates a significant association between the reduction in 24-h urinary sodium and the fall in systolic BP, indicating the greater the reduction in salt intake, the greater the fall in systolic BP. The current recommendations to reduce salt intake from 9-12 to 5-6 g/d will have a major effect on BP, but are not ideal. A further reduction to 3 g/d will have a greater effect and should become the long term target for population salt intake.

Salt sensitivity: a review with a focus on non-Hispanic blacks and Hispanics

The purpose of this review is to summarize the available information regarding salt sensitivity particularly as it relates to non-Hispanic blacks and Hispanics and to clarify possible etiologies, especially those that might shed light on potential treatment options. In non-Hispanic blacks, there is evidence that endothelial dysfunction, reduced potassium intake, decreased urinary kallikrein excretion, upregulation of sodium channel activity, dysfunction in atrial natriuretic peptide (ANP) production, and APOL1 gene nephropathy risk variants may cause or contribute to salt sensitivity. Supported treatment avenues include diets high in potassium and soybean protein, the components of which stimulate nitric oxide production. Racial heterogeneity complicates the study of salt sensitivity in Hispanic populations. Caribbean Hispanics, who have a higher proportion of African ancestry, may respond to commonly prescribed anti-hypertensive agents in a way that is characteristic of non-Hispanic black hypertensives. The low-renin hypertensive phenotype commonly seen in non-Hispanic blacks has been linked to salt sensitivity and may indicate an increased risk for salt sensitivity in a portion of the Hispanic population. In conclusion, increased morbidity and mortality associated with salt sensitivity mandates further studies evaluating the efficacy of tailored dietary and pharmacologic treatment in non-Hispanic blacks and determining the prevalence of low renin hypertension and salt sensitivity within the various subgroups of Hispanic Americans.

Epidemiology and management of hypertension in the Hispanic population: a review of the available literature

Hispanics are the fastest growing ethnic minority in the USA. Among Hispanics, lack of hypertension awareness and lack of effective blood pressure (BP) control are problematic, as are higher incidence rates of hypertension-related co-morbidities compared with non-Hispanic populations. Moreover, there are currently no hypertension treatment guidelines that address the unique characteristics of this ethnic group. This article discusses ethnic differences in hypertension and cardiovascular risk factors and reviews the literature on the efficacy of antihypertensive agents in Hispanic patients, with a focus on the role of renin-angiotensin-aldosterone system (RAAS) inhibition in the management of hypertension in these patients. Hypertension in Hispanic patients can be challenging to manage, in part because this population has a higher prevalence of obesity, diabetes, and metabolic syndrome compared with non-Hispanic whites. The presence of these co-morbidities suggests that RAAS-inhibitor-based therapies may be particularly beneficial in this population. However, few studies have evaluated the efficacy of antihypertensive treatments in Hispanic patients. Two outcomes studies in hypertensive patients have shown the benefits of treating Hispanic patients with antihypertensive therapy and included RAAS inhibitors as part of the treatment regimen. In addition, BP-lowering trials have shown the antihypertensive efficacy of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and direct renin inhibitors, although data on the latter are more limited. Additional studies are needed to more thoroughly evaluate the effects of RAAS inhibitors (and other drug classes) on outcomes and BP lowering in the Hispanic hypertensive population.

Long-term antihypertensive efficacy of losartan/hydrochlorothiazide combination therapy on home blood pressure control

Angiotensin receptor blocker (ARB)/hydrochlorothiazide (HCTZ) combination therapy has been shown to produce a prompt reduction in clinic blood pressure (BP) without serious adverse effects; however, long-term antihypertensive efficacy on home BP has not been fully investigated. In this open-label multicenter observational study, a total of 151 hypertensive patients uncontrolled with antihypertensive regimens including standard dose of ARBs were switched to the fixed-dose combination of losartan (50 mg)/HCTZ (12.5 mg) (mean age 66.9 ± 9.5 years, 51% male, 19% with diabetes mellitus, and 57% with dyslipidemia). After 3 months, losartan/HCTZ treatment significantly reduced mean home systolic BP/diastolic BP from a baseline level of 153 ± 11/85 ± 9 mm Hg to 136 ± 12/77 ± 10 mm Hg (P < .001) and mean clinic BP from 158 ± 9/87 ± 9 to 136 ± 12/77 ± 10 (P < .001), which were maintained through the study period of 12 months (132 ± 11/75 ± 9 and 136 ± 12/77 ± 10; home and clinic BP at 12 months, respectively, P < .001). Furthermore, younger patients (< 65 years) receiving ARB monotherapy at the start of the study showed a significantly greater reduction in home BP, but not in clinic BP, compared with elderly patients (≥ 65 years). In conclusion, losartan/HCTZ combination therapy exerted a 1-year long-term efficacy on home BP as well as clinic BP. In patients uncontrolled with ARB monotherapy, the antihypertensive efficacy on home BP is more pronounced in younger patients compared with that in elderly patients.

Combined aliskiren-amlodipine treatment for hypertension in African Americans: clinical science and management issues

While it may seem at first that antihypertensive drug combinations run counter to the desire to 'personalize' the management of hypertension, the best combinations have predictable efficacy in different individuals and subpopulations. Race is probably not a valid surrogate for clinically meaningful genetic variation or guide to therapy. Most guidelines suggest similar blood pressure goals for different races but drug treatment recommendations have diverged. In the United States, race is not considered to be a major factor in drug choice, but in England and other countries, initial therapy with renin-angiotensin system blocking drugs is not recommended in Blacks. In this review we: (1) examine new trends in race-based research; (2) emphasize the weaknesses of race-based treatment recommendations; and (3) explore the effects of a new combination, renin inhibition (aliskiren) and amlodipine, in African Americans.

Effects of high- and low-sodium diets on ambulatory blood pressure in patients with hypertension receiving aliskiren

Dietary sodium reduction and, as necessary, pharmacologic treatment are recommended for hypertension management. This prospective, randomized, open-label, blinded-end point, multicenter, crossover study investigated the effect of dietary sodium intake on mean ambulatory systolic blood pressure (maSBP) in patients with hypertension receiving aliskiren 300 mg once daily. Following a 2- to 4-week washout period, patients were randomized to a high- (≥ 200 mmol/d) or low- (≤ 100 mmol/d) sodium diet and were started on aliskiren, 300 mg/d. After 4 weeks, patients were crossed over to the alternate diet for an additional 4 weeks. The primary efficacy variable was change in maSBP between diets. During treatment with aliskiren, maSBP was significantly lower with the low-sodium diet compared with the high-sodium diet (least squares mean difference, 9.4 mm Hg; 95% CI, 7.5-11.4; P < .0001). The percentage of patients achieving a maSBP response to aliskiren (<130 mm Hg or a ≥ 20-mm Hg reduction from baseline) was greater with the low- (76.5%) versus the high-sodium diet (42.6%; P < .0001). Overall, 40.9% patients had ≥ 1 adverse event and the rates were similar between groups. In this study, aliskiren was well tolerated and a low-sodium diet accentuated its antihypertensive effect.

Ethnic differences in blood pressure response to first and second-line antihypertensive therapies in patients randomized in the ASCOT Trial

BACKGROUND

Some studies suggest that blood pressure (BP)-lowering effects of commonly used antihypertensive drugs differ among ethnic groups. However, differences in the response to second-line therapy have not been studied extensively.

METHODS

In the BP-lowering arm of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT-BPLA), BP levels of European (n = 4,368), African (203), and South-Asian- (132) origin patients on unchanged monotherapy (atenolol or amlodipine) and/or on second-line therapy (added thiazide or perindopril) were compared. Interaction between ethnicity and BP responses (defined as end BP minus start of therapy BP) to both first- and second-line therapies were assessed in regression models after accounting for age, sex, and several other potential confounders.

RESULTS

BP response to atenolol and amlodipine monotherapy differed among the three ethnic groups (interaction test P = 0.05). Among those allocated atenolol monotherapy, black patients were significantly less responsive (mean systolic BP (SBP) difference +1.7 (95% confidence interval: -1.1 to 4.6) mm Hg) compared to white patients (referent). In contrast, BP response to amlodipine monotherapy did not differ significantly by ethnic group. BP responses to the addition of second-line therapy also differed significantly by ethnic group (interaction test P = 0.004). On adding a diuretic to atenolol, BP lowering was similar among blacks and South-Asians as compared to whites (referent). However, on addition of perindopril to amlodipine, BP responses differed significantly: compared to whites (SBP difference -1.7 (-2.8 to -0.7) mm Hg), black patients had a lesser response (SBP difference 0.8 (-2.5 to 4.2) mm Hg) and South-Asians had a greater response (SBP difference -6.2 (-10.2 to -2.2) mm Hg).

CONCLUSIONS

We found important differences in BP responses among ethnic groups to both first- and second-line antihypertensive therapies.

Antihypertensive effects of double the maximum dose of valsartan in African-American patients with type 2 diabetes mellitus and albuminuria

OBJECTIVE

The blood pressure (BP)-lowering response to renin-angiotensin-aldosterone system blockade in hypertensive African-Americans is typically less than in whites. To determine whether higher than conventional doses of renin-angiotensin-aldosterone system blockade can improve BP reduction in African-American patients.

METHODS

Hypertensive patients with type 2 diabetes and albuminuria were enrolled: 110 African-Americans (BP = 150/87 mmHg, aged 57.5 +/- 11 years) and 281 non-African-Americans (BP = 151/89 mmHg, aged 57.7 +/- 11 years). All patients received valsartan 160 mg once daily in the morning for 4 weeks, following which patients were randomized to receive one of three valsartan doses: 160, 320 or 640 mg/day (2x, maximal recommended dose) for 26 weeks. If at week 6, target BP (<130/80 mmHg) was not achieved, then other add-on antihypertensives were allowed.

RESULTS

The predominant BP (DeltaSBP/DeltaDBP) reduction was observed within 4 weeks and was lesser in African-Americans (7.8 +/- 15/4.5 +/- 9 mmHg) than non-African-Americans (8.9 +/- 14/6.6 +/- 1 mmHg, P < 0.05). Greater reduction in urinary albumin excretion was observed with higher doses (320 or 640 mg); however, the responses were similar between African-Americans and non-African-Americans. Use of add-on antihypertensives was higher in African-American (56%) vs. non-African-American patients (36%) with a similar rate across the three valsartan doses. From week 4-26, reduction in BP was lesser (P < 0.05) for African-American than non-African-American patients at the160-mg dose but not with 320 and 640-mg doses.

CONCLUSION

In African-American patients, a lower BP reduction response was observed to conventional doses of valsartan than non-African-American patients, but at 640 mg, a higher response was observed in African-American patients than in non-African-American patients.

CYP3A4 and CYP3A5 polymorphisms and blood pressure response to amlodipine among African-American men and women with early hypertensive renal disease

PURPOSE

To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164).

METHODS

Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of < or =107 mm Hg by CYP3A4 (A-392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response.

RESULTS

Women randomized to a usual MAP goal with an A allele at CYP3A4 A-392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20-9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17-3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response.

CONCLUSIONS

Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study.

Concepts guiding therapy for hypertension in children

Increasing attention has been focused on identifying children with prehypertension and hypertension (HTN). Obesity and low birthweight are two risk factors that predispose children to develop HTN during their childhood years or later as adults. Early onset of pre-HTN and HTN increases the lifetime risk for cardiovascular sequelae. Lifestyle modification should be part of the initial recommendations for management of all hypertensive children. In those children requiring pharmacologic therapy, the choice of medication should be guided by the etiology of HTN, the needs of the child and the risk and benefit profiles of the various drug classes. The long-term impact of antihypertensive therapy in children is not known. Concerns regarding the effects of HTN and its treatment on cognitive function are of particular importance in the growing child and warrant further study. Ongoing investigations that offer promise for innovative therapeutic approaches in the future are discussed.

Clinical characteristics and outcomes in hypertensive patients of Hispanic descent

In the United States, patients of Hispanic descent have higher rates of hypertension-related morbidity and mortality than patients from other ethnic groups even though the prevalence of hypertension among Hispanics is lower. This discrepancy likely reflects lower rates of hypertension awareness and control among Hispanics as well as a higher prevalence of diabetes mellitus and other cardiovascular risk factors in this population. Although available data suggest that patients of Hispanic descent who receive antihypertensive therapy experience responses and treatment benefits similar to those achieved by other ethnic groups, clinical trials of antihypertensive therapy have typically enrolled only small numbers of Hispanic patients. Agents targeting the renin-angiotensin system, namely angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, may be particularly useful in the Hispanic population given the ability of these drugs to protect against hypertension-related and diabetes-related end-organ damage independent of their blood pressure-lowering effects.

The role of anemia management in improving outcomes for African-Americans with chronic kidney disease

Chronic kidney disease (CKD) is a serious threat to African-American public health. In this population CKD progresses to end-stage renal disease (ESRD) at quadruple the rate in Caucasians. Factors fueling progression to ESRD include diabetes and hypertension, which show high prevalences and accelerated renal damage in African- Americans, as well as possible nutritional, socioeconomic, and genetic factors. Anemia, a common and deleterious complication of CKD, is more prevalent and severe in African-American than Caucasian patients at each stage of the disease. Proactive management of diabetes, hypertension, anemia, and other complications throughout the course of CKD can prevent or delay disease progression and alleviate the burden of ESRD for the African-American community. Currently, African-Americans with CKD are less likely than Caucasian patients to receive anemia treatment before and after the onset of dialysis. Although African-Americans often require higher doses of erythropoiesis-stimulating agents, this may result from late treatment initiation, lower hemoglobin levels, or the presence of comorbidities such as diabetes and inflammation, although racial differences in response cannot be excluded. This review explores racial-specific challenges and potential solutions in renal anemia management to improve outcomes in African-American patients.

Dietary salt restriction and blood pressure in clinical trials

Dietary salt has long been recognized as a major factor affecting blood pressure such that sodium intake is a component of lifestyle modification guidelines for control of high blood pressure. These recommendations are based on results from epidemiologic observational studies and clinical trials of various sodium diets among normotensives and hypertensives. Nonetheless, results from the different studies vary such that specific recommendations regarding sodium intake are difficult to interpret. The results from several recent major trials indicated greater associations of blood pressure and sodium intake than earlier studies as well as meta-analyses of numerous clinical trials. The studies of sodium intake and blood pressures are complicated by measurements of intake, salt sensitivity, hypertension treatment, effects of sodium independent of blood pressure, and length of interventions. Limitations in the methodology of different studies have reduced the value of the results to provide specific and reliable sodium intake levels essential for clinical and lifestyle guidelines.

Salt: its role in chronic kidney disease

Few controversies in medicine have such a long history as that of whether salt is identifiably dangerous or not dangerous. The most common reported association between excess dietary salt intake and clinical outcome has been in the field of hypertension, but dietary sodium intake mediates effects that go far beyond, and are independent of, extracellular fluid expansion and elevation in blood pressure. For nephrologists, clinical trials that demonstrate no negative outcome of a high salt diet in the general population are thus not particularly assuasive, because patients with chronic kidney disease (CKD) represent an entity that is by no means comparable to the general population. This review takes a look at the challenges associated with salt balance in CKD patients (particularly at K/DOQI stage 5), followed by a summary of current concepts believed to play a part in salt-mediated pathophysiology, and the conclusion, based on the present state of scientific knowledge, that it appears advisable to advocate low dietary salt intake in this patient population.

Risk-based classification of hypertension and the role of combination therapy

The recognition of a continuous relationship between elevated blood pressure (BP) and cardiovascular risk has influenced national and international guidelines for the classification, prevention, and management of hypertension. The most recent report (2003) of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure uses BP thresholds to define categories of normal, prehypertension, and hypertension. A new definition proposed by the Hypertension Writing Group in 2005 offers an approach to diagnosis and management based on global or total risk. Thus, even in the absence of sustained elevations in BP, patients may have a moderate to high risk of vascular events due to the presence of additional cardiovascular risk factors, disease markers, and target organ damage. The 2007 European guidelines continue to classify hypertension based on cutoffs while also placing emphasis on multivariate formulations for cardiovascular risk assessment and goals of therapy. All 3 sets of guidelines acknowledge the necessity of using > or =2 antihypertensive agents to attain BP goals in many patients.

WITHDRAWN: Effect of antihypertensive drugs on mortality, morbidity and blood pressure in blacks

BACKGROUND

Black people have a greater prevalence of elevated blood pressure leading to excess morbidity and mortality.

OBJECTIVES

To systematically review the effects of different antihypertensive drugs on mortality, morbidity and blood pressure black adults with elevated blood pressure.

SEARCH STRATEGY

Medline, Embase, LILACS, African Index Medicus, the Cochrane Library November 2003; Pubmed September 2003 to March 2004. Searches were conducted without language restriction.

SELECTION CRITERIA

Randomised controlled trials of drugs versus placebo (blood pressure outcomes) or versus placebo or other drugs (morbidity and mortality outcomes).

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data unblinded. Disagreements were resolved by discussion. Authors were contacted twice to obtain missing information.

MAIN RESULTS

Full reports or abstracts from more than 2900 references of papers yielded 30 trials considering 53 interventions with 8 classes of antihypertensive drugs in 20,006 black patients from Africa, the Caribbean, and the United States of America, aged 18 to >80 years. In one large trial the main morbidity and mortality outcomes did not differ significantly between initial treatment drug classes when drugs were added to reach goal blood pressures. However, the comparison ACE Inhibitors vs diuretic favoured the diuretic for stroke 1.40 [1.17 to 1.68]; combined CHD 1.15 [1.02 to 1.30] and combined CVD 1.19 [1.09 to 1.30] and the comparison alpha blocker vs diuretic favoured the diuretic for combined CVD 1.40 [1.25 to 1.57]. In addition, all comparisons for heart failure favoured diuretic (1.47 [1.24 to 1.74] vs calcium blocker; 1.32 [1.11 to 1.58] vs ACE Inhibitor; and 2.18 [1.73 to 2.74] vs alpha blocker. The results also showed a greater occurrence of diabetes with diuretics. No significant differences were detected between placebo and beta adrenergic blockers in the reduction of systolic blood pressure (weighted mean difference [95% CI], -3.52 [-7.50 to 0.46] mm Hg). In addition, ACE inhibitors did not significantly differ from placebo in achievement of goal diastolic blood pressure (risk difference [95% CI], 5% [-10% to 21%]). Calcium blockers, diuretics, centrally acting agents, alpha adrenergic blockers and angiotensin II antagonists were all more effective than placebo in reducing blood pressure in the pooled analyses. Only calcium blockers remained effective in all prespecified subgroups, including baseline diastolic blood pressure >109 mm Hg.

AUTHORS' CONCLUSIONS

When first-line drugs from different classes are compared in the treatment of black people, there is no evidence of differential effects on most mortality and morbidity outcomes. Those morbidity differences that were found favoured diuretics. Drugs differ in their ability to reduce blood pressure in black people. Calcium blockers were the only drug class that reduced blood pressure in all subgroups of black people including those with severe hypertension. Beta-blockers, angiotensin receptor blocker, alpha blockers and ACE Inhibitors were least good at reducing blood pressure in black adults.

Targeting mechanisms of hypertensive vascular disease with dual calcium channel and renin-angiotensin system blockade

Patients with hypertension, particularly those with diabetes mellitus, are at heightened risk for cardiovascular and renal disease. Accumulated evidence indicates that the majority of hypertensive patients at high risk will require more than one antihypertensive agent to reach their blood pressure (BP) target. A reasonable strategy is to use agents with complementary mechanisms of action to enhance BP-lowering efficacy and prevent target organ damage. In experimental models, the combination of a calcium channel blocker (CCB) with an agent that blocks the renin-angiotensin system (RAS), an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker, improves measures of endothelial function, inflammation, ventricular remodelling and renal function to a greater degree than these classes given as monotherapy. In clinical trials, calcium channel/RAS blockade combination therapy has been shown to provide greater BP reductions and improve renal function in patients with diabetic and nondiabetic renal disease earlier and to a greater extent than monotherapy. In addition, dual calcium channel/RAS blockade increases arterial compliance, arterial distensibility and flow-mediated vasodilation. Expanding upon extensive research on the benefits of calcium channel blockade and RAS blockade for the prevention of vascular events and preclinical and clinical trial evidence suggests added effects of combination therapy by targeting the underlying mechanisms of hypertensive vascular disease.

Dietary Salt, Blood Pressure, and Microalbuminuria

The relationship between dietary salt, blood pressure, and risk for cardiovascular disease has been debated for decades. Microalbuminuria is a biomarker for both cardiovascular and kidney disease. The presence of microalbuminuria correlates directly with the risk for myocardial infarction and stroke and indicates individuals at risk for the development of progressive kidney disease. Since patients with the metabolic syndrome, diabetes, or chronic kidney disease often are blood pressure salt sensitive, and it is well known that increasing dietary salt may offset both the antihypertensive and antiproteinuric effects of renin-angiotensin system blocking drugs, physicians must consider increased salt intake as a potential modifiable risk factor for progression of chronic kidney disease and possibly even cardiovascular disease.

Racial differences are seen in blood pressure response to fosinopril in hypertensive children

BACKGROUND

Few antihypertensive therapies have been systematically studied in children and dosages for many agents are either extrapolated from adult studies or obtained from small homogenous pediatric populations. It is well established that adult patients of different races show disparate response to angiotensin-converting enzyme (ACE) inhibitors, however no such studies have been performed in children.

METHODS

Two hundred fifty three children ages 6-16 with hypertension or with high normal blood pressure with an associated medical condition requiring antihypertensive therapy were enrolled at 78 clinical sites in the US, Russia, and Israel in a double blind study to evaluate the efficacy of fosinopril compared to placebo.

RESULTS

The racial composition of the cohort included 60.1% white (152/253), 20.6% black (52/253), 13.8% Hispanic (35/253), 2.0% Asian (5/253), 0.4% Native American (1/253), and 3.2% (8/253) children classified as other or of mixed race. After adjusting for baseline blood pressure and body surface area (BSA) there was no significant dose response seen in non-black patients. Non-blacks randomized to the low, medium, and high dosages of fosinopril all had a mean decrease of 12 mm Hg in their sequential systolic BP (SBP). Blacks, however, demonstrated a significant dose response to fosinopril; those who received the low dosage had a 5 mm Hg decrease in SBP, and those who received the high dosage had a mean 13 mm Hg decrease in SBP.

CONCLUSIONS

Fosinopril was effective in treating hypertension, but black children required a higher dose per body weight in order to achieve adequate control. This suggests that black children treated with fosinopril for hypertension on average require higher doses to achieve adequate systolic blood pressure control that non-black children.

Salt Handling and Hypertension

The kidney plays a central role in our ability to maintain an appropriate sodium balance, which is critical for the determination of blood pressure. The kidney's capacity for salt conservation may not be widely appreciated, and in general we consume vastly more salt than we need. Here we consider the socioeconomics of salt consumption, outline current knowledge of renal salt handling at the molecular level, describe some of the disease entities associated with abnormal sodium handling, give an overview of some of the animal models and their relevance to human disease, and examine the evidence that lowering our salt intake can help combat hypertension and cardiovascular disease.