Combination Therapy With Renin-Angiotensin-Aldosterone Receptor Blockers for Hypertension: How Far Have We Come?

Response surface analyses of antihypertensive effects of angiotensin receptor blockers and amlodipine or hydrochlorothiazide combination therapy in patients with essential hypertension

While previous studies have examined the dose-response characteristics of certain antihypertensive drugs alone or in combination, response surface analysis for combination therapies involving angiotensin receptor blockers (ARBs) and either amlodipine (AML) or hydrochlorothiazide (HCT) has not been explored, particularly in the context of low-dose combinations. The objectives of present study were to generate useful dose-response information for the combination of ARB/AML or ARB/HCT and to predict the blood pressure lowering effects of combination therapies compared to monotherapies. We reviewed the New Drug Application data of combination drugs of ARB/AML and ARB/HCT. Data on systolic blood pressure (SBP), from studies conducted using a factorial dose-response design over a period of 8-12 weeks, were used. The placebo-subtracted SBP change was used for analysis. Response surface analyses of the collected data were conducted using a polynomial regression model. For ARB/AML combination, the quadratic polynomial regression model containing two linear terms, two quadratic terms, and one interaction term was best fitted to the naïve pooled data. Meanwhile, for ARB/HCT combination, the best-fitted model was a quadratic model that included two linear terms and two quadratic terms. The 1/2-dose combination of these medications, compared to each monotherapy, resulted in predicted SBP reductions that were 8-30% greater. The ratio of the estimated antihypertensive effects of the combination to the expected additive effects of each component ranged from 82% to 100% of the expected effect. These results can provide a rationale for developing lower-dose combinations of ARB/AML or ARB/HCT and assist in designing clinical trials.

Recent Developments in Drug Targets and Combination Therapy for the Clinical Management of Hypertension

Raised blood pressure is the most common complication worldwide that may lead to atherosclerosis and ischemic heart disease. Unhealthy lifestyles, smoking, alcohol consumption, junk food, and genetic disorders are some of the causes of hypertension. To treat this condition, numerous antihypertensive medications are available, either alone or in combination, that work via various mechanisms of action. Combinational therapy provides a certain advantage over monotherapy in the sense that it acts in multi mechanism mode and minimal drug amount is required to elicit the desired therapeutic effect. Such therapy is given to patients with systolic blood pressure greater than 20 mmHg and/or diastolic blood pressure exceeding 10 mmHg beyond the normal range, as well as those suffering from severe cardiovascular disease. The selection of antihypertensive medications, such as calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and low-dose diuretics, hinges on their ability to manage blood pressure effectively and reduce cardiovascular disease risks. This review provides insights into the diverse monotherapy and combination therapy approaches used for elevated blood pressure management. In addition, it offers an analysis of combination therapy versus monotherapy and discusses the current status of these therapies, from researchbased findings to clinical trials.

Hypertension Canada's 2020 Comprehensive Guidelines for the Prevention, Diagnosis, Risk Assessment, and Treatment of Hypertension in Adults and Children

Hypertension Canada's 2020 guidelines for the prevention, diagnosis, risk assessment, and treatment of hypertension in adults and children provide comprehensive, evidence-based guidance for health care professionals and patients. Hypertension Canada develops the guidelines using rigourous methodology, carefully mitigating the risk of bias in our process. All draft recommendations undergo critical review by expert methodologists without conflict to ensure quality. Our guideline panel is diverse, including multiple health professional groups (nurses, pharmacy, academics, and physicians), and worked in concert with experts in primary care and implementation to ensure optimal usability. The 2020 guidelines include new guidance on the management of resistant hypertension and the management of hypertension in women planning pregnancy.

Retinal Neurovascular Impairment in Patients with Essential Hypertension: An Optical Coherence Tomography Angiography Study

Purpose

To investigate retinal neurovascular structural changes in patients with essential hypertension.

Methods

This observational cross-sectional study consisted of 199 right eyes from 169 nondiabetic essential hypertensive patients, divided into groups as follows: group A, 113 patients with hypertensive retinopathy (HTNR); group B, 56 patients without HTNR; and a control group of 30 healthy subjects. Peripapillary retinal nerve fiber layer (RNFL), radial peripapillary segmented (RPC), ganglion cell–inner plexiform layer (GC-IPL), and superficial (SVP) and deep (DVP) vascular plexus density at the macula (6 × 6 mm²) were measured by optical coherence tomography angiography (OCTA).

Results

DVP density was significantly reduced in groups A and B compared to the control group (group A DVP, P = 0.001; group B DVP P = 0.002). GC-IPL, RNFL thickness, and RPC and SVP density in group A were significantly decreased compared to the control group or group B (all P < 0.05). In hypertensive patients, GC-IPL and RNFL thickness were negatively correlated with severity of HTNR (GC-IPL, r = –0.331, P < 0.001; RNFL, r = –0.583, P < 0.001) and level of home blood pressure monitoring (HBPM) (GC-IPL, r = –0.160, P = 0.050; RNFL, r = –0.282, P = 0.001) and were positively correlated with SVP (GC-IPL, r = 0.267, P = 0.002; RNFL, r = 0.361, P < 0.001) and RPC density (GC-IPL, r = 0.298, P < 0.001; RNFL, r = 0.663, P < 0.001). Among subjects with grade 2 or 3 retinopathy, the superior RNFL was significantly thinner in patients with high HBPM level than in those with normal HBPM level (grade 2, P = 0.016; grade 3, P = 0.006).

Conclusions

Reduction of retinal vessel density and RNFL thickness is observed in patients with HTNR and is inversely associated with level of HBPM.

Combining angiotensin receptor blockers with chlorthalidone or hydrochlorothiazide - which is the better alternative? A meta-analysis

BACKGROUND

Hypertension is a disease with significant clinical and socio-economic consequences. The reduction in cardiovascular mortality and morbidity in patients treated for hypertension is directly related to the magnitude of blood pressure reduction. Diuretics have proven useful for the prevention of cardiovascular complications in addition to a long history of safety and efficacy. The main aim for this meta-analysis is to compare the efficacy of the combination of angiotensin receptor blocker (ARB) and chlorthalidone (CTLD) to the combination of ARB and hydrochlorothiazide (HCTZ) in patients with hypertension.

METHODS

A comprehensive literature search was conducted through electronic databases PubMed, MEDLINE, Scopus, PsyInfo, Cochrane, eLIBRARY.ru, http://ClinicalTrials.gov and http://www.clinicaltrialsregister.eu in July 2020 to identify studies that investigate the effect of the combination of angiotensin receptor blocker with chlorthalidone or hydrochlorothiazide on the systolic and diastolic blood pressure in patients with hypertension. Changes in systolic and diastolic blood pressure (BP) expressed as a weighted mean difference (WMD) were our primary outcomes. The random-effects method was chosen as the primary analysis and results were presented with a 95% confidence interval (CI). Sensitivity analysis was performed and bias was assessed.

RESULTS

Our search returned 2745 titles. Of them, 51 full-text articles remained to be subjected to assessment. Comparisons of ARB/HCTZ versus ARB showed changes in BP of -6.89 (-8.09, -5.69) mmHg for systolic BP and - 3.67 (-4.15, -3.19) mmHg for diastolic BP. For the ARB/CTLD versus ARB/HCTZ comparison changes were - 6.30 (-7.30, -5.29) mmHg for systolic BP and - 3.57 (-4.17, 2.98) mmHg for diastolic BP.

CONCLUSION

Our analysis suggests a small but significant favor for CTLD in blood pressure control when compared to HCTZ. We believe it should be considered as a valuable alternative for HCTZ and an option for fixed dose combinations with an ARB although further research is required.

Comparison of effects between calcium channel blocker and diuretics in combination with angiotensin II receptor blocker on 24-h central blood pressure and vascular hemodynamic parameters in hypertensive patients: study design for a multicenter, double-blinded, active-controlled, phase 4, randomized trial

Background

Hypertension is a risk factor for coronary heart disease and stroke, and is one of the leading causes of death. Although over a billion people are affected worldwide, only half of them receive adequate treatment. Current guidelines on antihypertensive treatment recommend combination therapy for patients not responding to monotherapy, but as the number of pills increase, patient compliance tends to decrease. As a result, fixed-dose combination drugs with different antihypertensive agents have been developed and widely used in recent years. CCBs have been shown to be better at reducing central blood pressure and arterial stiffness than diuretics. Recent studies have reported that central blood pressure and arterial stiffness are associated with cardiovascular outcomes. This trial aims to compare the efficacy of combination of calcium channel blocker (CCB) or thiazide diuretic with an angiotensin receptor blocker (ARB).

Methods

This is a multicenter, double-blinded, active-controlled, phase 4, randomized trial, comparing the antihypertensive effects of losartan/amlodipine and losartan/hydrochlorothiazide in patients unresponsive to treatment with losartan. The primary endpoint is changes in mean sitting systolic blood pressure (msSBP) after 4 weeks of treatment. Secondary endpoints are changes in msSBP, mean 24-h ambulatory mobile blood pressure, mean 24-h ambulatory mobile central SBP, mean 24-h ambulatory carotid-femoral pulse wave velocity, ambulatory augmentation index, and microalbuminuria/proteinuria after 20 weeks of treatment. The sample size will be 119 patients for each group in order to confer enough power to test for non-inferiority regarding the primary outcome.

Conclusion

The investigators aim to prove that combination of a CCB with ARB shows non-inferiority in lowering blood pressure compared with a combination of thiazide diuretic and ARB. We also hope to distinguish the subset of patients that are more responsive to certain types of combination drugs. The results of this study should aid physicians in selecting appropriate combination regimens to treat hypertension in certain populations.

Trial registration

ClinicalTrials.gov NCT02294539. Registered 12 November 2014.

Comparison of long-term safety of fixed-dose combinations azilsartan medoxomil/chlorthalidone vs olmesartan medoxomil/hydrochlorothiazide

This 52-week, randomized, open-label study evaluated long-term safety/tolerability of fixed-dose combination azilsartan medoxomil/chlorthalidone (AZL-M/CLD) vs fixed-dose combination olmesartan medoxomil/hydrochlorothiazide (OLM/HCTZ) in patients with essential hypertension (stage 2; clinic systolic blood pressure 160-190 mm Hg). Initial AZL-M/CLD 40/12.5 mg/d (n=418) or OLM/HCTZ 20/12.5 mg/d (n=419) could be uptitrated during weeks 4 to 52 (AZL-M/CLD to 80/25 mg; OLM/HCTZ to 40/25 mg [United States] or 20/25 mg [Europe]) to meet blood pressure targets. Treatment-emergent adverse events/serious adverse events occurred in 78.5%/5.7% of patients taking AZL-M/CLD vs 76.4%/6.2% taking OLM/HCTZ. The most frequent adverse events were dizziness (16.3% vs 12.6%), blood creatinine increase (21.5% vs 8.6%), headache (7.4% vs 11.0%), and nasopharyngitis (12.2% vs 11.5%). Hypokalemia was uncommon (1.0% vs 0.7%). Greater blood pressure reductions with AZL-M/CLD by week 2 were maintained throughout the study, despite less uptitration (32.3% vs 48.9% with OLM/HCTZ). Fixed-dose combination AZL-M/CLD showed an encouraging benefit-risk profile when used per standard clinical practice in a titrate-to-target strategy.

Safety and tolerability of azilsartan medoxomil in subjects with essential hypertension: a one-year, phase 3, open-label study

This 56-week phase 3, open-label, treat-to-target study, involving 2 consecutive, non-randomized cohorts, evaluated the safety and tolerability of azilsartan medoxomil (AZL-M) in essential hypertension (mean baseline blood pressure [BP] 152/100 mmHg). All subjects (n = 669) initiated AZL-M 40 mg QD, force-titrated to 80 mg QD at week 4, if tolerated. From week 8, subjects could receive additional medications, starting with chlorthalidone (CLD) 25 mg QD (Cohort 1) or hydrochlorothiazide (HCTZ) 12.5–25 mg QD (Cohort 2), if required, to reach BP targets. Adverse events (AEs) were reported in 75.9% of subjects overall in the two cohorts (73.8% Cohort 1, 78.5% Cohort 2). The most common AEs were dizziness (14.3%), headache (9.9%) and fatigue (7.2%). Transient serum creatinine elevations were more frequent with add-on CLD. Clinic systolic/diastolic BP (observed cases at week 56) decreased by 25.2/18.4 mmHg (Cohort 1) and 24.2/17.9 mmHg (Cohort 2). These results demonstrate that AZL-M is well tolerated over the long term and provides stable BP improvements when used in a treat-to-target BP approach with thiazide-type diuretics.

Safety, tolerability, and efficacy of azilsartan medoxomil with or without chlorthalidone during and after 8 months of treatment for hypertension

A phase 3, 26‐week, open‐label, titrate‐to‐target study (n=418) assessed the safety of azilsartan medoxomil (AZL‐M) alone and with chlorthalidone (CLD), followed by a 6‐week, double‐blind, placebo‐controlled reversal phase with change in clinic diastolic blood pressure (DBP) as the primary endpoint. Target blood pressure (BP) was <140/90 mm Hg (<130/80 mm Hg with diabetes/chronic kidney disease). AZL‐M was initiated at 40 mg once a day (QD), force‐titrated to 80 mg at week 4. CLD 25 mg QD could be added (weeks 8–22), if required, to reach target, followed by additional antihypertensives from week 12. At the end of the open‐label phase, mean change in systolic BP (SBP)/DBP from baseline was −23/−16 mm Hg. The most common adverse events, irrespective of treatment, were dizziness (8.9%) and headache (7.2%). Serious AEs were reported in eight patients (1.9%). Consecutive creatinine elevations ≥50% with values exceeding the upper limit of normal (ULN) were reported in nine (2.2%) patients. All returned to below the 50% threshold; most also returned to below the ULN after drug discontinuation. Mean DBP was maintained through the reversal phase in patients receiving AZL‐M, but increased with placebo (difference: −7.8 mm Hg, 95% confidence interval, −9.8 to −5.8; P<.001). AZL‐M alone or with CLD showed good long‐term safety and stable BP improvements in a titrate‐to‐target approach. BP improvements caused by AZL‐M therapy were safely reversible upon AZL‐M withdrawal.

Improved blood pressure control associated with a large-scale hypertension program

IMPORTANCE

Hypertension control for large populations remains a major challenge.

OBJECTIVE

To describe a large-scale hypertension program in Northern California and to compare rates of hypertension control in that program with statewide and national estimates.

DESIGN, SETTING, AND PATIENTS

The Kaiser Permanente Northern California (KPNC) hypertension program included a multifaceted approach to blood pressure control. Patients identified as having hypertension within an integrated health care delivery system in Northern California from 2001-2009 were included. The comparison group comprised insured patients in California between 2006-2009 who were included in the Healthcare Effectiveness Data and Information Set (HEDIS) commercial measurement by California health insurance plans participating in the National Committee for Quality Assurance (NCQA) quality measure reporting process. A secondary comparison group was included to obtain the reported national mean NCQA HEDIS commercial rates of hypertension control between 2001-2009 from health plans that participated in the NCQA HEDIS quality measure reporting process.

MAIN OUTCOMES AND MEASURES

Hypertension control as defined by NCQA HEDIS.

RESULTS

The KPNC hypertension registry included 349,937 patients when established in 2001 and increased to 652,763 by 2009. The NCQA HEDIS commercial measurement for hypertension control within KPNC increased from 43.6% (95% CI, 39.4%-48.6%) to 80.4% (95% CI, 75.6%-84.4%) during the study period (P < .001 for trend). In contrast, the national mean NCQA HEDIS commercial measurement increased from 55.4% to 64.1%. California mean NCQA HEDIS commercial rates of hypertension were similar to those reported nationally from 2006-2009 (63.4% to 69.4%).

CONCLUSIONS AND RELEVANCE

Among adults diagnosed with hypertension, implementation of a large-scale hypertension program was associated with a significant increase in hypertension control compared with state and national control rates. Key elements of the program included a comprehensive hypertension registry, development and sharing of performance metrics, evidence-based guidelines, medical assistant visits for blood pressure measurement, and single-pill combination pharmacotherapy.

Combination therapy as first-line treatment for hypertension

Systemic hypertension is a long-term risk factor for the development of atherosclerotic vascular disease and when uncontrolled is a short-term trigger of acute vascular events such as acute coronary syndromes and stroke. Thus, rapid reduction in BP is desirable. Patients at high risk for vascular disease, such as those with diabetes mellitus, have aggressive goal BP targets because studies have shown that achieving these targets reduces events. Given the dual goals in high-risk patients of reducing BP quickly and to aggressively low targets, the classic 'step therapy' of one drug titrated at a time to reduce BP is inadequate. Combination therapy with at least two potent medications makes more sense, and manufacturers are now increasing their offerings of single-pill combinations for hypertension. Combination pills are popular with patients and increase compliance with therapy. Many believe that renin-angiotensin aldosterone system (RAAS) blockers are the cornerstone of hypertension treatment in patients at high risk for vascular disease. The newer combination pills include a RAAS blocker and diuretics or a long-acting calcium channel antagonist (CCA). Recent studies have shown that a RAAS blocker plus a dihydropyridine CCA is superior to older diuretic-based combinations for preventing cardiovascular events. These considerations support a new approach to the higher risk hypertensive patient: effective doses of RAAS blocker/CCA combination pills to rapidly lower BP to <130/80 mmHg.

Receptor tyrosine kinase Ephb6 regulates vascular smooth muscle contractility and modulates blood pressure in concert with sex hormones

Eph kinases constitute the largest receptor tyrosine kinase family, and their ligands, ephrins (Efns), are also cell surface molecules. Our study is the first to assess the role of Ephb6 in blood pressure (BP) regulation. We observed that EphB6 and all three of its Efnb ligands were expressed on vascular smooth muscle cells (VSMC) in mice. We discovered that small arteries from castrated Ephb6 gene KO males showed increased contractility, RhoA activation, and constitutive myosin light chain phosphorylation ex vivo compared with their WT counterparts. Consistent with this finding, castrated Ephb6 KO mice presented heightened BP compared with castrated WT controls. In vitro experiments in VSMC revealed that cross-linking Efnbs but not Ephb6 resulted in reduced VSMC contractions, suggesting that reverse signaling through Efnbs was responsible for the observed BP phenotype. The reverse signaling was mediated by an adaptor protein Grip1. Additional experiments demonstrated decreased 24-h urine catecholamines in male Ephb6 KO mice, probably as a compensatory feedback mechanism to keep their BP in the normal range. After castration, however, such compensation was abolished in Ephb6 KO mice and was likely the reason why BP increased overtly in these animals. It suggests that Ephb6 has a target in the nervous/endocrine system in addition to VSMC, regulating a testosterone-dependent catecholamine compensatory mechanism. Our study discloses that Ephs and Efns, in concert with testosterone, play a critical role in regulating small artery contractility and BP.

Hydrochlorothiazide versus calcium channel blockers: what is the best add-on to a renin-angiotensin system blocker for treating hypertension in patients with renal disease?

Hypertension remains an important problem that increases the risk of cardiovascular disease and is a leading cause of mortality worldwide. Achieving long-term control of arterial hypertension, which has an estimated prevalence of 28% in the US adult population, would translate into a significant reduction in cardiovascular events. Specific causes can be identified and treated for certain forms of secondary hypertension, but often it is multifactorial. Therefore, it makes sense to attain blood pressure control by addressing more than one pressor mechanism. Several clinical studies have demonstrated that combination antihypertensive therapy is more effective than monotherapy, and a review of currently published data suggests that approximately 75% of hypertensive individuals will require some form of combination therapy to achieve target blood pressure (BP) goals. To this end, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of Blood Pressure (JNC 7) has recommended that antihypertensive therapy should start with two drugs when a patient presents with systolic blood pressure (SBP) more than 20 mm Hg above target levels, diastolic blood pressure (DBP) more than 10 mm Hg above target levels, or both. This review attempts to analyze the current evidence in published medical literature to answer the question of whether hydrochlorothiazide or a calcium channel blocker is a better add-on to a renin-angiotensin system blocker for treating hypertension in patients with renal disease.

Comparison of the antihypertensive efficacy of irbesartan/HCTZ and valsartan/HCTZ combination therapy: impact of age and gender

This analysis aimed to explore whether low-dose irbesartan/hydrochlorothiazide (HCTZ) has superior blood pressure (BP)-lowering efficacy over low-dose valsartan/HCTZ in the elderly and across both genders. This is a post-hoc analysis of data from a multicenter, parallel group, open-label, blinded-endpoint study in patients with hypertension uncontrolled with HCTZ monotherapy. The reduction in systolic BP (SBP)/diastolic BP (DBP) and rate of BP control achieved following 8 weeks of treatment with irbesartan/HCTZ 150/12.5 mg or valsartan/HCTZ 80/12.5 mg were analyzed for older (≥65 years) vs. younger (<65 years) patients and for men vs. women. Blood pressure measurements were by home BP monitoring (HBPM). In the age and gender subgroups, both treatments significantly decreased home SBP and DBP (p < 0.0001). The reduction in home SBP and DBP was numerically greater with irbesartan/HCTZ compared to valsartan/HCTZ for all subgroups: the difference in DBP was significant for all except the elderly (p < 0.05), and the difference in SBP was significant in the elderly and in men (p < 0.03). In all subgroups, more patients achieved BP control (HBPM ≤135/85 mmHg) in the irbesartan/HCTZ arm (range 45%-58%) than in the valsartan/HCTZ arm (range, 23%-39%; p < 0.02). Both combination therapies were well tolerated and safety parameters were similar in both age and gender subgroups. More patients with mild or moderate hypertension, uncontrolled in HCTZ monotherapy alone, had their BP controlled with irbesartan/HCTZ 150/12.5 mg than with valsartan/HCTZ 80/12.5 mg, irrespective of age or gender.

Combination therapy in hypertension: An update

Meticulous control of blood pressure is required in patients with hypertension to produce the maximum reduction in clinical cardiovascular end points, especially in patients with comorbidities like diabetes mellitus where more aggressive blood pressure lowering might be beneficial. Recent clinical trials suggest that the approach of using monotherapy for the control of hypertension is not likely to be successful in most patients. Combination therapy may be theoretically favored by the fact that multiple factors contribute to hypertension, and achieving control of blood pressure with single agent acting through one particular mechanism may not be possible. Regimens can either be fixed dose combinations or drugs added sequentially one after other. Combining the drugs makes them available in a convenient dosing format, lower the dose of individual component, thus, reducing the side effects and improving compliance. Classes of antihypertensive agents which have been commonly used are angiotensin receptor blockers, thiazide diuretics, beta and alpha blockers, calcium antagonists and angiotensin-converting enzyme inhibitors. Thiazide diuretics and calcium channel blockers are effective, as well as combinations that include renin-angiotensin-aldosterone system blockers, in reducing BP. The majority of currently available fixed-dose combinations are diuretic-based. Combinations may be individualized according to the presence of comorbidities like diabetes mellitus, chronic renal failure, heart failure, thyroid disorders and for special population groups like elderly and pregnant females.

Reno-prevention vs. reno-protection: a critical re-appraisal of the evidence-base from the large RAAS blockade trials after ONTARGET--a call for more circumspection

The ACEI, captopril was introduced into clinical medicine in the early 1970s for hypertension. Other ACEIs and the ARBs were introduced subsequently. Following several RAAS blockade trials, we now have an expanded set of clinical indications for these agents. Despite the escalated use of these agents, we continue to experience an unexplained epidemic of ESRD/CKD/ARF. There are concerns regarding potential iatrogenic renal failure arising from these agents. A case, it would appear, of unintended consequences. Our publication of several reports on the previously unrecognized syndrome of late onset renal failure from angiotensin blockade (LORFFAB) in 2008 adds to this evolving literature. At the same time, some recent reports have questioned the veracity of claims of superior reno-protection with these agents beyond BP lowering. A post hoc analysis of a subset of patients in the MICRO-HOPE cohort suggested that a previously unrecognized greater 24-h BP lowering achieved in the ramipril arm vs placebo could explain the reported benefits of the ACEI. These doubts and concerns became heightened by the results of the ONTARGET study. Our critical re-appraisal of the large RAAS blockade trials revealed design flaws and protocol contradictions that further these doubts and concerns. We conclude that these agents be used more judiciously, with better monitoring of kidney function. Treating physicians must consider drug discontinuation in selected patients. We also support temporary withdrawal of these agents before major surgical procedures, contrast media administration and during acute illness. Such preventative measures (reno-prevention) would enhance the benefits of reno-protection with RAAS blockade.