Effect of inhibitors of the renin-angiotensin system and other antihypertensive drugs on renal outcomes: systematic review and meta-analysis

Toward better renoprotection: Lessons from angiotensin receptor blockers

The rising tide of chronic kidney disease (CKD), especially diabetic nephropathy, has become a worldwide catastrophe. However, therapeutic options to prevent or retard the progression of CKD still remain very limited. The understanding of its molecular mechanisms and the delineation of tools able to modify them are thus of critical importance. The discovery that some antihypertensive agents inhibiting the renin-angiotensin system, such as angiotensin II type 1 receptor blockers, protect the kidney opens new therapeutic perspectives. In this article, we focus on their renoprotective actions beyond blood pressure lowering.

The podocyte in health and disease: insights from the mouse

The glomerular filtration barrier consists of the fenestrated endothelium, the glomerular basement membrane and the terminally differentiated visceral epithelial cells known as podocytes. It is now widely accepted that damage to, or originating within, the podocytes is a key event that initiates progression towards sclerosis in many glomerular diseases. A wide variety of strategies have been employed by investigators from many scientific disciplines to study the podocyte. Although invaluable insights have accrued from conventional approaches, including cell culture and biochemical-based methods, many renal researchers continue to rely upon the mouse to address the form and function of the podocyte. This review summarizes how genetic manipulation in the mouse has advanced our understanding of the podocyte in relation to the maintenance of the glomerular filtration barrier in health and disease.

Clinical trials in nephrology: success or failure

PURPOSE OF REVIEW

A large amount of clinical and epidemiologic evidence has been gathered supporting the importance of blood pressure control in reducing chronic kidney disease progression. Suppression of the rennin-angiotensin-aldosterone system should also be considered in any patient with chronic kidney disease, in particular if albuminuria is present.

RECENT FINDINGS

Analysis of renal outcome by estimating glomerular filtration rate in trials primarily devoted to cardiovascular protection in hypertensive patients, in particular the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial trial, has come to question the effectiveness of suppressing the rennin-angiotensin-aldosterone system in controlling blood pressure and thus protecting the kidney in hypertensive patients. This subject is particularly interesting because the existence of an increased cardiovascular risk associated with renal function decline has been demonstrated in many different clinical conditions including arterial hypertension. The increase in global cardiovascular risk accompanying chronic kidney disease would necessitate the use of drugs suppressing the rennin-angiotensin-aldosterone system for cardiovascular protection irrespective of the influence on renal outcome.

SUMMARY

This review includes the most recent data evaluating renal endpoints in clinical trials primarily devoted to renal function as well as those dedicated to arterial hypertension and its cardiovascular consequences.

Blood pressure lowering for the prevention and treatment of diabetic kidney disease

The current pandemic of diabetes mellitus will inevitably be followed by an epidemic of chronic kidney disease. It is anticipated that 25-40% of patients with type 1 diabetes and 5-40% of patients with type 2 diabetes will ultimately develop diabetic kidney disease. The control of blood pressure represents a key component for the prevention and management of diabetic nephropathy. There is a strong epidemiological connection between hypertension in diabetes and adverse outcomes in diabetes. Hypertension is closely linked to insulin resistance as part of the 'metabolic syndrome'. Diabetic nephropathy may lead to hypertension through direct actions on renal sodium handling, vascular compliance and vasomotor function. Recent clinical trials also support the utility of blood pressure reduction in the prevention of diabetic kidney disease. In patients with normoalbuminuria, transition to microalbuminuria can be prevented by blood pressure reduction. This action appears to be significant regardless of whether patients have elevated blood pressure or not. The efficacy of ACE inhibition appears to be greater than that achieved by other agents with a similar degree of blood pressure reduction; although large observational studies suggest the risk of microalbuminuria may be reduced by blood pressure reduction, regardless of modality. In patients with established microalbuminuria, ACE inhibitors and angiotensin receptor antagonists (angiotensin receptor blockers [ARBs]) consistently reduce the risk of progression from microalbuminuria to macroalbuminuria, over and above their antihypertensive actions. The clinical utility of combining these strategies remains to be established. In patients with overt nephropathy, blood pressure reduction is associated with reduced urinary albumin excretion and, subsequently, a reduced risk of renal impairment or end stage renal disease. In addition to actions on systemic blood pressure, it is now clear that ACE inhibitors and ARBs also reduce proteinuria in patients with diabetes. This anti-proteinuric activity is distinct from other antihypertensive agents and diuretics. Although there is a clear physiological rationale for blockade of the renin angiotensin system, which is strongly supported by clinical studies, to achieve the optimal lowering of blood pressure, particularly in the setting of established diabetic renal disease, a number of different antihypertensive agents will always be needed. In the end, the choice of agents should be individualised to achieve the maximal tolerated reduction in blood pressure and albuminuria. Ultimately, no matter how it is achieved, so long as it is achieved, renal risk can be reduced by agents that lower blood pressure and albuminuria.

Hypertension and Kidney Damage

Substantial evidence indicates that hypertension is a major contributor to the development of end-stage renal disease in most patients. However, such risk ranges from being fairly low in essential hypertension to a marked increase in susceptibility to hypertensive injury in patients with chronic kidney disease, including diabetic nephropathy. Studies in experimental animal models using blood pressure radiotelemetry have provided significant insights into the quantitative relationships between blood pressure and renal damage and the importance of protective renal autoregulatory capacity as a determinant of such differences in susceptibility to hypertensive injury. Moreover, such investigations have also emphasized the predominant importance of achieving normotension per se over the selection of particular antihypertensive regimens, including renin-angiotensin system blockade, in slowing the progression of chronic kidney disease.

Prevention of Hypertension with or without Renin-Angiotensin System Inhibition Precludes Nephrin Loss in the Early Stage of Experimental Diabetes Mellitus

BACKGROUND AND AIMS

Several lines of clinical evidence support the concept that the reduction of blood pressure may be useful in the prevention of diabetic kidney disease. In young diabetic spontaneously hypertensive rats (SHR), prevention of hypertension reduces several early renal abnormalities including albuminuria. However, the contribution of nephrin loss to albuminuria in this early stage of experimental diabetes is unknown. Therefore, we investigated whether elevation of albuminuria in young diabetic SHR is associated with nephrin loss, and if prevention of hypertension, with or without inhibition of the renin-angiotensin system, precludes these abnormalities.

METHODS

Diabetes was induced by streptozotocin injection in 4-week-old still normotensive SHR and their genetically normotensive control, Wistar-Kyoto rats. Diabetic SHR were randomized for no treatment, or treatment with captopril, losartan, or triple therapy (hydrochlorothiazide, reserpine and hydralazine) for 20 days.

RESULTS

The increase in systolic blood pressure was equally prevented by all treatments. Albuminuria was higher in diabetic SHR and similarly reduced (p < 0.05) by captopril, losartan, and triple therapy. Glomerular expression of nephrin was significantly reduced in diabetic SHR in comparison with non-diabetic controls. The antihypertensive treatment prevented the reduction in glomerular expression of nephrin.

CONCLUSIONS

These results demonstrate that the loss of nephrin is associated with albuminuria in a model of genetic hypertension and diabetes, and that the prevention of development of hypertension restores nephrin and prevents albuminuria. This finding suggests a crucial role of blood pressure in diabetes as determinant of nephrin expression and albuminuria.

Renoprotective Effect and Cost-Effectiveness of Using Benidipine, a Calcium Channel Blocker, to Lower the Dose of Angiotensin Receptor Blocker in Hypertensive Patients with Albumiuria

In hypertensive patients with chronic renal disease, angiotensin receptor blockers (ARBs) are among the first-line drugs, and calcium channel blockers (CCBs) are recommended as a second line. We examined the effects of two therapeutic strategies using ARBs and benidipine, a CCB, on blood pressure (BP), urinary albumin excretion (UAE), and cost-effectiveness in hypertensive patients with albuminuria. Patients whose BP was 140/90 mmHg or higher despite treatment with low- or medium-dose ARBs were assigned randomly to two groups. In Group A (n=14), the ARB dose was maximized and then benidipine was added until BP targets were reached (<130/85 mmHg). In Group B (n=18), benidipine was administered first and then the ARB dose was increased until BP targets were reached. The BP targets were achieved by ARB alone in 36% of Group A patients and by the addition of benidipine in 83% of Group B patients. Finally, BP decreased in each group, reaching the targets in 93% of Group A patients and 94% of Group B patients after a 4-month therapeutic period. UAE was decreased in both groups after a 4-month therapeutic period compared to the allocation period (-33+/-6% in Group A, -31+/-6% in Group B; p<0.001, respectively). The monthly drug cost was higher (11,426+/-880 vs. 8,955+/-410 yen, p=0.012) and the cost-effectiveness of antihypertensive treatment was lower (p=0.003) in Group A than in Group B. We conclude that the addition of benidipine to low- or medium-dose ARB is, in light of the renal protection and the cost-effectiveness of this approach, a useful therapeutic strategy for controlling BP in hypertensive patients with albuminuria.

Antihypertensive Therapy in the Presence of Proteinuria

The presence of proteinuria is a well-known risk factor for both the progression of renal disease and cardiovascular morbidity and mortality, and decreases in urine protein excretion level were associated with a slower decrease in renal function and decrease in risk of cardiovascular events. Increased blood pressure has a major role in the development of proteinuria in patients with either diabetic or nondiabetic kidney disease, and all recent guidelines recommend a blood pressure goal less than 130/80 mm Hg in patients with proteinuria to achieve maximal renal and cardiovascular protection. Drugs interfering with the renin-angiotensin system, ie, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, should be used as first-line antihypertensive therapy in patients with proteinuria because they seem to have a blood pressure-independent antiproteinuric effect, and if blood pressure levels are still out of goal, a diuretic should be added to this regimen. A combination of an angiotensin-converting enzyme inhibitor with an angiotensin receptor blocker or other classes of medications shown to decrease protein excretion, such as nondihydropyridine calcium antagonists or aldosterone receptor blockers, should be considered to decrease proteinuria further. This review provides an extended summary of current evidence regarding the associations of blood pressure with proteinuria, the rationale for currently recommended blood pressure goals, and the use of various classes of antihypertensive agents in proteinuric patients.

Lost in publication: Half of all renal practice evidence is published in non-renal journals

Physicians often scan a select number of journals to keep up to date with practice evidence for patients with kidney conditions. This raises the question of where relevant studies are published. We performed a bibliometric analysis using 195 renal systematic reviews. Each review used a comprehensive method to identify all primary studies for a focused clinical question relevant to patient care. We compiled all the primary studies included in these reviews, and considered where each study was published. Of the 2779 studies, 1351 (49%) were published in the top 20 journals. Predictably, this list included Transplantation Proceedings (5.9% of studies), Kidney International (5.3%), American Journal of Kidney Diseases (4.7%), Nephrology Dialysis Transplantation (4.3%), Transplantation (4.2%), and Journal of the American Society of Nephrology (2.4%). Ten non-renal journals were also on this list, including New England Journal of Medicine (2.4%), Lancet (2.3%), and Diabetes Care (2.2%). The remaining 1428 (51%) studies were published across other 446 journals. When the disciplines of all journals were considered, 59 were classified as renal or transplant journals (42% of articles). Other specialties included general and internal medicine (16%), endocrinology (diabetes) and metabolism (6.5%), surgery (6.2%), cardiovascular diseases (6.1%), pediatrics (4.3%), and radiology (3.3%). About half of all renal practice evidence is published in non-renal journals. Browsing the top journals is important. However, relevant studies are also scattered across a large range of journals that may not be routinely scanned by busy physicians, and keeping up with this literature requires other continuing education strategies.

Oral renin inhibitors

Use of drugs that inhibit the renin-angiotensin system is an effective way to intervene in the pathogenesis of cardiovascular and renal disorders. The idea of blocking the renin system at its origin by inhibition of renin has existed for more than 30 years. Renin inhibition suppresses the generation of the active peptide angiotensin II. The first generation of orally active renin inhibitors were never used clinically because of low bioavailability and weak blood-pressure-lowering activity. At present, aliskiren is the first non-peptide orally active renin inhibitor to progress to phase-III clinical trials. It might become the first renin inhibitor with indications for the treatment of hypertension and cardiovascular and renal disorders. Novel compounds with improved oral bioavailability, specificity, and efficacy are now in preclinical development. This Review summarises the development of oral renin inhibitors and their pharmacokinetic and pharmacodynamic properties, with a focus on aliskiren.

Angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists for preventing the progression of diabetic kidney disease

BACKGROUND

Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor antagonists (AIIRA) are considered to be equally effective for patients with diabetic kidney disease (DKD), but renal and not mortality outcomes have usually been considered.

OBJECTIVES

To evaluate the benefits and harms ACEi and AIIRA in patients with DKD.

SEARCH STRATEGY

We searched MEDLINE (1966 to December 2005), EMBASE (1980 to December 2005), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library issue 4 2005) and contacted known investigators.

SELECTION CRITERIA

Studies comparing ACEi or AIIRA with placebo or each other in patients with DKD were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and results expressed as relative risk (RR) with 95% confidence intervals (CI). Heterogeneity among studies was explored using the Cochran Q statistic and the I(2) test, subgroup analyses and random effects metaregression.

MAIN RESULTS

Fifty studies (13,215 patients) were identified. Thirty eight compared ACEi with placebo, five compared AIIRA with placebo and seven compared ACEi and AIIRA directly. There was no significant difference in the risk of all-cause mortality for ACEi versus placebo (RR 0.91, 95% CI 0.71 to 1.17) and AIIRA versus placebo (RR 0.99, 95% CI 0.85 to 1.17). A subgroup analysis of studies using full-dose ACEi versus studies using half or less than half the maximum tolerable dose of ACEi showed a significant reduction in the risk of all-cause mortality with the use of full-dose ACEi (RR 0.78, 95% CI 0.61 to 0.98). Baseline mortality rates were similar in the ACEi and AIIRA studies. The effects of ACEi and AIIRA on renal outcomes (ESKD, doubling of creatinine, prevention of progression of micro- to macroalbuminuria, remission of micro- to normoalbuminuria) were similarly beneficial. Reliable estimates of effect of ACEi versus AIIRA could not be obtained from the three studies in which they were compared directly because of their small sample size.

AUTHORS' CONCLUSIONS

Although the survival benefits of ACEi are known for patients with DKD, the relative effects on survival of ACEi with AIIRA are unknown due to the lack of adequate direct comparison studies. In placebo controlled studies, only ACEi (at the maximum tolerable dose, but not lower so-called renal doses) were found to significantly reduce the risk of all-cause mortality. Renal and toxicity profiles of these two classes of agents were not significantly different.

Type 1 angiotensin receptor pharmacology: signaling beyond G proteins

Drugs that inhibit the production of angiotensin II (AngII) or its access to the type 1 angiotensin receptor (AT₁R) are prescribed to alleviate high blood pressure and its cardiovascular complications. Accordingly, much research has focused on the molecular pharmacology of AT₁R activation and signaling. An emerging theme is that the AT₁R generates G protein dependent as well as independent signals and that these transduction systems separately contribute to AT₁R biology in health and disease. Regulatory molecules termed arrestins are central to this process as is the capacity of AT₁R to crosstalk with other receptor systems, such as the widely studied transactivation of growth factor receptors. AT₁R function can also be modulated by polymorphisms in the AGTR gene, which may significantly alter receptor expression and function; a capacity of the receptor to dimerize/oligomerize with altered pharmacology; and by the cellular environment in which the receptor resides. Together, these aspects of the AT₁R “flavour” the response to angiotensin; they may also contribute to disease, determine the efficacy of current drugs and offer a unique opportunity to develop new therapeutics that antagonize only selective facets of AT₁R function.

Diuretics: A modern day treatment option? (Review Article)

The choice of drugs to initiate therapy for the management of hypertension remains contentious and diuretics are central to this controversy. Because most of the major trials involve complex treatment algorithms and allow diverse background treatments, one of the greatest challenges lies in separating out true class-specific effects - for example, separating true class-specific effects of diuretics from those of beta blockers. Despite these difficulties, the evidence confirms that diuretics are at least as effective as the newer first line groups in preventing cardiovascular events. The main area of doubt lies in relation to the risk of renal outcomes and of metabolic outcomes, such as new onset diabetes - where the evidence suggests that drugs that inhibit the renin-angiotensin system may be more protective than all other drug classes. These issues are reflected in the most recent international guidelines, all of which include diuretics among the first-line drugs for the treatment of hypertension, although they do differ on the role of diuretics in the initiation of therapy. Diuretics remain important for treating hypertension, especially in combination with other drug classes. The particular place of diuretics in the rank order of drugs must be tailored to suit the clinical situation in the individual patient. This will vary from a preferred option, as in black patients or elderly patients with systolic hypertension, to a second-line option in patients at high risk of developing new onset diabetes.

End-stage renal disease risk equations for Hong Kong Chinese patients with type 2 diabetes: Hong Kong Diabetes Registry

AIMS/HYPOTHESIS

The objective of the study was to investigate risk factors and develop risk equations for end-stage renal disease (ESRD) in Chinese patients with type 2 diabetes.

SUBJECTS AND METHODS

A prospective cohort of 4,438 patients with type 2 diabetes mellitus and without ESRD (median observation period 2.9 years, interquartile range 1.6-4.1 years) was included in the analysis. The end-point (ESRD) was defined by: (1) death due to diabetes with renal manifestations or renal failure; (2) hospitalisation due to renal failure; (3) estimated GFR (eGFR) <15 ml min(-1) 1.73 m(-2). Cox proportional hazards regression was used to develop risk equations. The data were randomly and evenly divided into the training data for development of the risk equations and the test data for validation. The validation was performed using the area under the receiver operating characteristic curve (aROC), which takes into account follow-up time and censoring.

RESULTS

During the observation period, 159 patients or 12.45 per 1,000 person-years (95% CI 10.52-14.37 per 1,000 person-years) developed ESRD. Known duration of diabetes, systolic blood pressure, log(10) total cholesterol:HDL cholesterol ratio and retinopathy were significant predictors of ESRD. After further adjusting for eGFR, log(10) spot albumin:creatinine ratio (ACR) and haematocrit, only eGFR, haematocrit and log(10) ACR remained as independent predictors of ESRD. The risk equation derived from these three independent predictors had good discrimination, with an aROC of 0.97.

CONCLUSIONS/INTERPRETATION

Estimated GFR, haematocrit and ACR were independent predictors of ESRD and the derived risk equation performed well in Chinese patients with type 2 diabetes.

Increasing incidence of proteinuria and declining incidence of end-stage renal disease in diabetic Pima Indians

The introduction of more efficacious treatments for diabetic kidney disease may slow its progression, but evidence for their effectiveness in populations is sparse. We examined trends in the incidence of clinical proteinuria, defined as a urinary protein-to-creatinine ratio >0.5 g/g, and diabetic end-stage renal disease (ESRD), defined as death from diabetic nephropathy or onset of dialysis, in Pima Indians with type 2 diabetes between 1967 and 2002. The study included 2189 diabetic subjects >/=25 years old. During follow-up, 366 incident cases of proteinuria occurred in the subset of 1715 subjects without proteinuria at baseline. The age-sex-adjusted incidence rate of proteinuria increased from 24.3 cases/1000 person-years (pyrs) (95% confidence interval (CI) 18.7-30.0) in 1967-1978 to 35.4 cases/1000 pyrs (95% CI 28.1-42.8) in 1979-1990 and 38.9 cases/1000 pyrs (95% CI 31.2-46.5) in 1991-2002 (P(trend)<0.0002). In each period, the age-sex-adjusted incidence of proteinuria increased with diabetes duration, but diabetes duration-specific incidence was stable throughout the study period (P=0.8). The age-sex-adjusted incidence of ESRD increased between 1967 and 1990 and declined thereafter. The incidence of proteinuria increased over 36 years in Pima Indians as the proportion of people with diabetes of long duration increased. On the other hand, the incidence of ESRD declined after 1990, coinciding with improved control of blood pressure, hyperglycemia, and perhaps other risk factors.

Anaemia correction in predialysis elderly patients: influence of the antihypertensive therapy on darbepoietin dose

Anaemia and hypertension are common in patients with chronic renal insufficiency. The correction of anaemia with erythropoiesis stimulating agents (ESA) can improve survival and decrease the decline of renal function. Angiotensin converting-enzyme inhibitors (ACEI) and angiotensin II receptor blockers (AIIRA) can also slow the progression of renal failure, but the blockade of the renin-angiotensin system can worsen anaemia. The aim of our study was to assess the impact of antihypertensive therapy (ACEI plus AIIRA) in the requirements of darbepoietin in a group of elderly predialysis patients. We included 71 patients (m = 39, f = 32), mean age of 76.3 years with a mean creatinine clearance of 17.5 ml/min. Patients were divided in two groups according to their antihypertensive therapy: G-I patients under ACEI or AIIRA therapy and G-II normotensive patients or hypertensive patients under antihypertensive drugs other than ACEI or AIIRA. The groups were compared regarding demographic, nutritional, biochemical and inflammatory parameters. We also compared the mean darbepoietin dose. In GI the mean dose of darbepoietin was higher than in GII (0.543 vs. 0.325 microg/kg/week, P = 0.032). We did not find any difference regarding other parameters analysed. We conclude that ACEI and AIIRA can increase the needs of darbepoietin in predialysis elderly patients. However, when formally indicated to treat hypertension in a specific patient, they should not be switched to another antihypertensive agent. Instead, in such cases, higher doses of ESA should be used, if necessary.

Microalbuminuria

Microalbuminuria, originally described more than 3 decades ago as a predictor of nephropathy in patients who had type 1 diabetes mellitus and associated with higher cardiovascular risk, is now linked with increased risk for cardiovascular events rather than progression to end-stage kidney disease. This article reviews the role of microalbuminuria in the context of atherosclerotic vascular disease. It presents the methods for microalbuminuria assessment in clinical practice, its relations with other cardiovascular risk factors, and the pathophysiologic associations between microalbuminuria and vascular damage. In addition, this article discusses the prognostic significance of microalbuminuria for cardiovascular disease as well as existing therapeutic interventions for reducing urine albumin excretion in patients who are at high cardiovascular risk.

Mesangial hypercellularity predicts antiproteinuric response to dual blockade of RAS in primary glomerulonephritis

The greater antiproteinuric efficacy of converting enzyme inhibitor and angiotensin II receptor blocker combination (CEI+ARB), versus monotherapy with either drug, is not a consistent finding. We evaluated the clinicopathologic predictors of response to CEI+ARB in 43 patients with primary glomerulonephritis (GN), never treated with immunosuppressive drugs, and with persistent proteinuria after CEI alone. Main histological lesions were analyzed by obtaining on 557 glomeruli and 165 arteries formal score of mesangial cellularity, glomerulosclerosis, tubulointerstitial damage, mononuclear cell infiltration, arteriosclerosis, and arteriolar hyalinosis. Duration of CEI and CEI+ARB therapy was similar (4.7+/-2.4 and 5.0+/-1.5 months). Proteinuria (g/day) decreased from 3.5+/-2.9 to 2.4+/-2.3 after CEI, and to 1.5+/-1.3 after CEI+ARB (P<0.0001). Reduction of proteinuria after CEI+ARB was greater in proliferative versus non-proliferative GN (-63.3+/-23.4 versus 42.4+/-23.7%, respectively; P=0.006). When patients were categorized in responders and non-responders to CEI+ARB, no difference between the two groups was detected in any demographic or clinical variable, whereas histology showed in responders a greater prevalence of proliferative GN (71.4 versus 31.8%, P=0.009) and higher score of mesangial cellularity (1.76+/-0.53 versus 1.20+/-0.22, P<0.0001). At multiple regression analysis (r(2)=0.476, P=0.001), response to CEI+ARB resulted independently related only to mesangial cellularity (P<0.0001). In conclusion, the best independent predictor of antiproteinuric efficacy of CEI+ARB in patients with primary GN is the degree of mesangial cellularity. This finding supports the experimental evidence that high angiotensin II contributes to proliferation of mesangial cells.

Progression of renal disease: renoprotective specificity of renin-angiotensin system blockade

Recent guidelines for management of patients with chronic kidney disease recommend both lower optimal BP targets and agents that block the renin-angiotensin system (RAS) for specific additional BP-independent renoprotection. Although there are other compelling rationales to use RAS blockade in patients with chronic kidney disease, including its antihypertensive effectiveness and ability to counteract the adverse effects of diuretics, a critical review of the available scientific evidence suggests that the specificity of renoprotection that is provided by RAS blockade has been greatly overemphasized. Little evidence of truly BP-independent renoprotection is observed in experimental animal models when ambient BP is assessed adequately by chronic continuous BP radiotelemetry. Although the clinical trial evidence is somewhat stronger, nevertheless, even when interpreted favorably, the absolute magnitude of the BP-independent component of the renoprotection that is observed with RAS blockade is much smaller than what is due to its antihypertensive effects.

Prise en charge de l’hypertension artérielle d’origine rénale

Assessment of every hypertensive patient must include the search for kidney disease, i.e. elevated serum creatinine and proteinuria. Antihypertensive therapy may attenuate both the risk of progression toward renal failure and the cardiovascular risk associated with chronic kidney disease, albeit the cause or the consequence of hypertension. Any alteration in renal function will promote salt-sensitivity of blood pressure and increase the deleterious effects of salt intake on target organ damage. The goal of antihypertensive therapy in patients with chronic kidney disease is first to reduce systolic blood pressure below 130 mmHg. The second goal is to lower urinary protein excretion to less than 0.5 g per day. The presence of proteinuria calls for blockers of the renin-angiotensin system among antihypertensive drugs. Global risk management (i.e. fighting tobacco, obesity, dyslipemia) will reduce the renal as well as the cardiovascular risk.