A systematic review and meta-analysis of aliskiren and angiotension receptor blockers in the management of essential hypertension

Renin inhibitors versus angiotensin receptor blockers for primary hypertension

BACKGROUND

Renin inhibitors, which inhibit the first and rate-limiting step in the renin angiotensin system (RAS), are thought to be more effective than other RAS inhibitors in blocking the RAS. Previous meta-analyses have shown that renin inhibitors have a favourable tolerability profile in people with mild-to-moderate hypertension and a blood-pressure-lowering magnitude that is similar to that of angiotensin receptor blockers (ARBs). ARBs inhibit the RAS by interfering with the binding of angiotensin II with its receptors. ARBs are widely prescribed and recommended as first-line therapy by some hypertension guidelines. However, a drug's efficacy in lowering blood pressure cannot be considered as a definitive indicator of its effectiveness in reducing mortality and morbidity. The benefits and harms of renin inhibitors compared to ARBs in treating hypertension are unknown.

OBJECTIVES

To evaluate the benefits and harms of renin inhibitors compared to angiotensin receptor blockers in people with primary hypertension.

SEARCH METHODS

On 26 January 2024, the Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials: Cochrane Hypertension's Specialised Register, Cochrane Central Register of Controlled Trials, Ovid MEDLINE, and Ovid Embase. The World Health Organization International Clinical Trials Registry Platform and the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) were also searched for ongoing trials. We contacted authors of relevant papers regarding further published and unpublished work and checked the bibliographies of included studies and relevant systematic reviews. The searches had no language restrictions.

SELECTION CRITERIA

We included randomised, double-blind, parallel-design clinical trials comparing renin inhibitors and ARBs for people with primary hypertension. Studies recruiting people with proven secondary hypertension were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the included trials, evaluated the risks of bias using the RoB 1 tool, and entered the data for analysis. We reported dichotomous outcomes as a risk ratio (RR) with a 95% confidence interval (CI) and continuous variables as mean difference (MD) with a 95% CI. The primary outcomes were all-cause mortality, total cardiovascular events, end-stage renal disease (ESRD), withdrawal due to adverse effects (WDAE), serious adverse events (SAE), and adverse events. The secondary outcomes were fatal and non-fatal myocardial infarction, fatal and non-fatal stroke, fatal heart failure or hospitalisation for heart failure, systolic and diastolic blood pressure (SBP and DBP), and heart rate. We used the GRADE approach to rate our confidence in the evidence.

MAIN RESULTS

We included 11 double-blind RCTs involving 6780 participants with mild primary hypertension and without cardiovascular complications (mean age range 52 to 59 years), with a mean follow-up ranging from four weeks to nine months. Risk of bias was low or unclear for most domains except for other bias, which was high risk for 10 of the 11 trials due to industry funding. All the studies compared aliskiren, the only marketed molecule in the class of renin inhibitors, with an ARB. The ARB comparator was losartan in four trials, valsartan in three trials, irbesartan in three trials, and telmisartan in one trial. There were very limited or no data on cardiovascular outcomes and ESRD. There may be little to no difference between renin inhibitors and ARBs in all-cause mortality (RR 0.35, 95% CI 0.07 to 1.64; 3 studies, 1932 participants; low-certainty evidence). There is probably little to no difference between renin inhibitors and ARBs in WDAE (RR 0.71, 95% CI 0.49 to 1.02; 9 studies, 4634 participants; moderate-certainty evidence), SAE (RR 0.75, 95% CI 0.45 to 1.27; 6 studies, 3283 participants; moderate-certainty evidence), and adverse events (RR 0.98, 95% CI 0.90 to 1.06; 10 studies, 4722 participants; moderate-certainty evidence). There is probably little to no difference between renin inhibitors and ARBs in lowering SBP (MD -0.25 mmHg, 95% CI -1.05 to 0.56; 10 studies, 4222 participants; moderate-certainty evidence) and there may be little to no difference in lowering DBP (MD 0.25 mmHg, 95% CI -0.14 to 0.64; 10 studies, 4222 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

The available RCT evidence suggests little to no difference between renin inhibitors and ARBs in terms of mortality, SAE, WDAE, adverse events, and blood pressure in people with mild primary hypertension. The evidence was derived from short-term trials with a limited occurrence of morbidity outcomes, leaving any potential differences unknown. Larger RCTs of longer duration with a wider range of participants and a focus on cardiovascular outcomes are needed.

Targeting the renin-angiotensin signaling pathway in COVID-19: Unanswered questions, opportunities, and challenges

The role of the renin-angiotensin signaling (RAS) pathway in COVID-19 has received much attention. A central mechanism for COVID-19 pathophysiology has been proposed: imbalance of angiotensin converting enzymes (ACE)1 and ACE2 (ACE2 being the severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] virus "receptor") that results in tissue injury from angiotensin II (Ang II)-mediated signaling. This mechanism provides a rationale for multiple therapeutic approaches. In parallel, clinical data from retrospective analysis of COVID-19 cohorts has revealed that ACE inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) may be beneficial in COVID-19. These findings have led to the initiation of clinical trials using approved drugs that target the generation (ACEIs) and actions (ARBs) of Ang II. However, treatment of COVID-19 with ACEIs/ARBs poses several challenges. These include choosing appropriate inclusion and exclusion criteria, dose optimization, risk of adverse effects and drug interactions, and verification of target engagement. Other approaches related to the RAS pathway might be considered, for example, inhalational administration of ACEIs/ARBs (to deliver drugs directly to the lungs) and use of compounds with other actions (e.g., activation of ACE2, agonism of MAS1 receptors, β-arrestin-based Angiotensin receptor agonists, and administration of soluble ACE2 or ACE2 peptides). Studies with animal models could test such approaches and assess therapeutic benefit. This Perspective highlights questions whose answers could advance RAS-targeting agents as mechanism-driven ways to blunt tissue injury, morbidity, and mortality of COVID-19.

Clinical efficacy, safety and tolerability of Aliskiren Monotherapy (AM): an umbrella review of systematic reviews

BACKGROUND

Aliskiren is a newly developed drug. Its role in lowering BP has been recognized. However, the role of aliskiren in treating heart and renal diseases are still controversial.

OBJECTIVE

To evaluate the existing evidence about clinical efficacy, safety and tolerability of aliskiren monotherapy (AM).

METHODS

An umbrella review of systematic reviews of interventional studies. We searched Pubmed, Embase and Cochrane Library up to June 2019. Two reviewers applied inclusion criteria to the select potential articles independently. The extract and analyze of accessible data were did by two reviewers independently too. Discrepancies were resolved with discussion or the arbitration of the third author.

RESULTS

Eventually, our review identified 14 eligible studies. Results showed that for essential hypertension patients, aliskiren showed a great superiority over placebo in BP reduction, BP response rate and BP control rate. Aliskiren and placebo, ARBs or ACEIs showed no difference in the number or extent of adverse events. For heart failure patients, AM did not reduce BNP levels (SMD -0.08, - 0.31 to 0.15) or mortality rate (RR 0.76, 0.32 to 1.80), but it decreased NT-proBNP (SMD -0.12, - 0.21 to - 0.03) and PRA levels (SMD 0.52, 0.30 to 0.75), increased PRC levels (SMD -0.66, - 0.8 to - 0.44). For patients who are suffered from hypertension and diabetes and/or nephropathy or albuminuria at the same time, aliskiren produced no significant effects (RR 0.97, 0.81 to 1.16).

CONCLUSION

We found solid evidence to support the benefits of aliskiren in the treatment of essential hypertension, aliskiren can produce significant effects in lowering BP and reliable safety. However, the effects of aliskiren in cardiovascular and renal outcomes were insignificant.

TRIAL REGISTRATION

Study has been registered in PROSPERO (CRD42019142141).

Aliskiren therapy in hypertension and cardiovascular disease: a systematic review and a meta-analysis

The efficacy and safety of aliskiren combination therapy with angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) in patients with hypertension and cardiovascular disease remains attractive attention. We searched the Cochrane Central Register, the Clinical Trials Registry, EMBASE, MEDLINE and PubMed for relevant literatures up to January 2017. A total of 13 randomized controlled trials (RCTs) with 12222 patients were included in this study, and the combined results indicated that aliskiren in combination therapy with ACEIs or ARBs had remarkable effects in reducing systolic blood pressure (SBP) [weighted mean differences (WMD), -4.20; 95% confidential intervals (CI) -5.44 to -2.97; I² , 29.7%] and diastolic blood pressure (DBP: WMD, -2.09; 95% CI -2.90 to -1.27; I² , 0%) when compared with ACEIs or ARBs monotherapy, but with significantly increased the risk of hyperkalaemia [relative risk (RR), 1.45; 95% CI 1.28 to 1.64; I² ,10.6 %] and kidney injury ( RR, 1.92; 95% CI 1.14 to 3.21; I² , 0%). Besides, there was no significant difference in the incidence of major cardiovascular events (RR, 0.95; 95% CI 0.89 to 1.02; I² , 0%) between the combined therapy and ACEIs or ARBs monotherapy. In conclusion, this meta-analysis demonstrated that aliskiren in combination therapy with ACEs/ARBs could control BP effectively, but is associated with increasing risks of hyperkalaemia and kidney injury, and have no benefit in preventing of major cardiovascular events.

Renin Inhibition with Aliskiren: A Decade of Clinical Experience

The renin-angiotensin-aldosterone system (RAAS) plays a key role in the pathophysiology of arterial hypertension as well as in more complex mechanisms of cardiovascular and renal diseases. RAAS-blocking agents like angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers, have long been key components in the treatment of essential hypertension, heart failure, diabetic nephropathy, and chronic kidney disease, showing benefits well beyond blood pressure reduction. Renin blockade as the first step of the RAAS cascade finally became possible in 2007 with the approval of aliskiren, the first orally active direct renin inhibitor available for clinical use and the newest antihypertensive agent on the market. In the last decade, many clinical trials and meta-analyses have been conducted concerning the efficacy and safety of aliskiren in comparison to other antihypertensive agents, as well as the efficacy and potential clinical use of various combinations. Large trials with cardiovascular and renal endpoints attempted to show potential benefits of aliskiren beyond blood pressure lowering, as well as morbidity and mortality outcomes in specific populations such as diabetics, heart failure patients, and post-myocardial infarction individuals. The purpose of this review is to present the currently available data regarding established and future potential clinical uses of aliskiren.

Role of the Renin-Angiotensin-Aldosterone System and Its Pharmacological Inhibitors in Cardiovascular Diseases: Complex and Critical Issues

Hypertension is one of the major risk factor able to promote development and progression of several cardiovascular diseases, including left ventricular hypertrophy and dysfunction, myocardial infarction, stroke, and congestive heart failure. Also, it is one of the major driven of high cardiovascular risk profile in patients with metabolic complications, including obesity, metabolic syndrome and diabetes, as well as in those with renal disease. Thus, effective control of hypertension is a key factor for any preventing strategy aimed at reducing the burden of hypertension-related cardiovascular diseases in the clinical practice. Among various regulatory and contra-regulatory systems involved in the pathogenesis of cardiovascular and renal diseases, renin-angiotensin system (RAS) plays a major role. However, despite the identification of renin and the availability of various assays for measuring its plasma activity, the specific pathophysiological role of RAS has not yet fully characterized. In the last years, however, several notions on the RAS have been improved by the results of large, randomized clinical trials, performed in different clinical settings and in different populations treated with RAS inhibiting drugs, including angiotensin converting enzyme (ACE) inhibitors and antagonists of the AT1 receptor for angiotensin II (ARBs). These findings suggest that the RAS should be considered to have a central role in the pathogenesis of different cardiovascular diseases, for both therapeutic and preventive purposes, without having to measure its level of activation in each patient. The present document will discuss the most critical issues of the pathogenesis of different cardiovascular diseases with a specific focus on RAS blocking agents, including ACE inhibitors and ARBs, in the light of the most recent evidence supporting the use of these drugs in the clinical management of hypertension and hypertension-related cardiovascular diseases.

Exercise is the real polypill

The concept of a "polypill" is receiving growing attention to prevent cardiovascular disease. Yet similar if not overall higher benefits are achievable with regular exercise, a drug-free intervention for which our genome has been haped over evolution. Compared with drugs, exercise is available at low cost and relatively free of adverse effects. We summarize epidemiological evidence on the preventive/therapeutic benefits of exercise and on the main biological mediators involved.

Renin inhibitors and cardiovascular and renal protection: an endless quest?

Renin-angiotensin system (RAS) blockade with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) has become a major therapeutic approach in medicine since the end of the 1970's. Although these molecules were the first RAS blockers to be developed, it would have been physiologically and pharmacologically more pertinent to selectively inhibit renin itself. Indeed, the reaction between renin and its unique substrate, angiotensinogen, is the highly regulated and rate-limiting step of the RAS. The development of direct renin inhibitors (DRI) has been a slow and complex process and the synthesis of the first orally active DRI, aliskiren, was only achieved in the 2000's. Its pharmacological profile in patients with hypertension, diabetic nephropathy or heart failure, in addition to experimental evidence, suggests that aliskiren may be of value for the management of cardiovascular and renal diseases. However, the long-term, randomized, placebo-controlled, morbidity/mortality trial, ALTITUDE, which included 8,600 patients with type 2 diabetes, proteinuria and a high cardiovascular risk already treated with ACE inhibitors or ARBs was terminated in December 2011 because of futility and an increased incidence of serious adverse events in the aliskiren 300 mg arm. Other long-term studies are still ongoing to demonstrate the safety and efficacy of aliskiren to reduce cardiovascular morbidity and mortality in patients with heart failure and in elderly individuals (≥65 years) with systolic blood pressure of 130 to 159 mmHg, no overt cardiovascular disease, and a high cardiovascular risk profile. In the meantime, according to the European Medicines Agency recommendations, aliskiren should not be prescribed to diabetic patients in combination with ACE inhibitors or ARBs.

[Heart failure with preserved ejection fraction: a systemic disorder?]

When the syndrome of heart failure (HF) is due to left ventricular (LV) systolic dysfunction the clinical manifestations and natural history of the syndrome depend primarily on the severity of LV systolic dysfunction. In contrast, when the syndrome is attributed to LV diastolic dysfunction multiple comorbidities are responsible for the clinical manifestations and the natural history of the syndrome. The present review underscores the multifactorial pathogenesis of the syndrome of HF associated with LV diastolic dysfunction that nowadays is more properly referred to as HF with preserved LV ejection fraction (HFpEF) than to diastolic HF. The prognosis is similarly poor whether HF is due to systolic dysfunction or associated with diastolic dysfunction. The cause of death that is commonly non-cardiovascular in HFpEF supports the pathogenic importance of comorbidities in this condition. Hypertension, chronic kidney disease (CKD), diabetes, obesity and sleep disorder breathing are among the most frequent comorbidities in HFpEF. These comorbidities account for the multiple clinical presentations of the syndrome of HFpEF. Limited functional capacity is in HFpEF largely related to the downward spiral between CKD mediated fluid accumulation and LV stiffness as well as altered ventricular-vascular coupling. The diagnosis of HFpEF currently relies on 2D-Doppler echocardiography findings of impaired LV relaxation and increased LV stiffness and to a lesser extent on biomarkers. Owing to both lack of stringent inclusion and exclusion enrollment criteria and mistaken therapeutic target, placebo-controlled randomized therapeutic trials have been so far negative in HFpEF.

Haemodynamic effects of aliskiren in decompensated severe heart failure

Aim: The renin–angiotensin–aldosterone system (RAAS) has dual pathways to angiotensin II production; therefore, multiple blockages may be useful in heart failure. In this study, we evaluated the short-term haemodynamic effects of aliskiren, a direct renin inhibitor, in patients with decompensated severe heart failure who were also taking angiotensin-converting enzyme (ACE) inhibitors.

Materials and methods: A total of 16 patients (14 men, two women, mean age: 60.3 years) were enrolled in the study. The inclusion criteria included hospitalisation due to decompensated heart failure, ACE inhibitor use, and an ejection fraction < 40% (mean: 21.9 ± 6.7%). The exclusion criteria were: creatinine > 2.0 mg/dl, cardiac pacemaker, serum K+ > 5.5 mEq/l, and systolic blood pressure < 70 mmHg. Patients either received 150 mg/d aliskiren for 7 days (aliskiren group, n = 10) or did not receive aliskiren (control group, n = 6). Primary end points were systemic vascular resistance and cardiac index values. Repeated-measures analysis of variance (ANOVA) was used to assess variables before and after intervention. A two-sided p-value < 0.05 was considered statistically significant.

Results: Compared to pre-intervention levels, systemic vascular resistance was reduced by 20.4% in aliskiren patients, but it increased by 2.9% in control patients ( p = 0.038). The cardiac index was not significantly increased by 19.0% in aliskiren patients, but decreased by 8.4% in control patients ( p = 0.127). No differences in the pulmonary capillary or systolic blood pressure values were observed between the groups.

Conclusion: Aliskiren use reduced systemic vascular resistance in patients with decompensated heart failure taking ACE inhibitors.

A current evaluation of the safety of angiotensin receptor blockers and direct renin inhibitors

The safety of angiotensin II receptor blockers (ARBs) for the treatment of hypertension and cardiovascular and renal diseases has been well documented in numerous randomized clinical trials involving thousands of patients. However, recent concerns have surfaced about possible links between ARBs and increased risks of myocardial infarction and cancer. Less is known about the safety of the direct renin inhibitor aliskiren, which was approved as an antihypertensive in 2007. This article provides a detailed review of the safety of ARBs and aliskiren, with an emphasis on the risks of cancer and myocardial infarction associated with ARBs. Safety data were identified by searching PubMed and Food and Drug Administration (FDA) Web sites through April 2011. ARBs are generally well tolerated, with no known class-specific adverse events. The possibility of an increased risk of myocardial infarction associated with ARBs was suggested predominantly because the Valsartan Antihypertensive Long-Term Use Evaluation (VALUE) trial reported a statistically significant increase in the incidence of myocardial infarction with valsartan compared with amlodipine. However, no large-scale, randomized clinical trials published after the VALUE study have shown a statistically significant increase in the incidence of myocardial infarction associated with ARBs compared with placebo or non-ARBs. Meta-analyses examining the risk of cancer associated with ARBs have produced conflicting results, most likely due to the inherent limitations of analyzing heterogeneous data and a lack of published cancer data. An ongoing safety investigation by the FDA has not concluded that ARBs increase the risk of cancer. Pooled safety results from clinical trials indicate that aliskiren is well tolerated, with a safety profile similar to that of placebo. ARBs and aliskiren are well tolerated in patients with hypertension and certain cardiovascular and renal conditions; their benefits outweigh possible safety concerns.