Enhanced renoprotective effects of ultrahigh doses of irbesartan in patients with type 2 diabetes and microalbuminuria

Angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers for preventing the progression of diabetic kidney disease

BACKGROUND

Guidelines suggest that adults with diabetes and kidney disease receive treatment with angiotensin-converting-enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). This is an update of a Cochrane review published in 2006.

OBJECTIVES

We compared the efficacy and safety of ACEi and ARB therapy (either as monotherapy or in combination) on cardiovascular and kidney outcomes in adults with diabetes and kidney disease.

SEARCH METHODS

We searched the Cochrane Kidney and Transplants Register of Studies to 17 March 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included studies evaluating ACEi or ARB alone or in combination, compared to each other, placebo or no treatment in people with diabetes and kidney disease.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

One hundred and nine studies (28,341 randomised participants) were eligible for inclusion. Overall, the risk of bias was high. Compared to placebo or no treatment, ACEi may make little or no difference to all-cause death (24 studies, 7413 participants: RR 0.91, 95% CI 0.73 to 1.15; I2 = 23%; low certainty) and with similar withdrawals from treatment (7 studies, 5306 participants: RR 1.03, 95% CI 0.90 to 1.19; I2 = 0%; low certainty). ACEi may prevent kidney failure (8 studies, 6643 participants: RR 0.61, 95% CI 0.39 to 0.94; I2 = 0%; low certainty). Compared to placebo or no treatment, ARB may make little or no difference to all-cause death (11 studies, 4260 participants: RR 0.99, 95% CI 0.85 to 1.16; I2 = 0%; low certainty). ARB have uncertain effects on withdrawal from treatment (3 studies, 721 participants: RR 0.85, 95% CI 0.58 to 1.26; I2 = 2%; low certainty) and cardiovascular death (6 studies, 878 participants: RR 3.36, 95% CI 0.93 to 12.07; low certainty). ARB may prevent kidney failure (3 studies, 3227 participants: RR 0.82, 95% CI 0.72 to 0.94; I2 = 0%; low certainty), doubling of serum creatinine (SCr) (4 studies, 3280 participants: RR 0.84, 95% CI 0.72 to 0.97; I2 = 32%; low certainty), and the progression from microalbuminuria to macroalbuminuria (5 studies, 815 participants: RR 0.44, 95% CI 0.23 to 0.85; I2 = 74%; low certainty). Compared to ACEi, ARB had uncertain effects on all-cause death (15 studies, 1739 participants: RR 1.13, 95% CI 0.68 to 1.88; I2 = 0%; low certainty), withdrawal from treatment (6 studies, 612 participants: RR 0.91, 95% CI 0.65 to 1.28; I2 = 0%; low certainty), cardiovascular death (13 studies, 1606 participants: RR 1.15, 95% CI 0.45 to 2.98; I2 = 0%; low certainty), kidney failure (3 studies, 837 participants: RR 0.56, 95% CI 0.29 to 1.07; I2 = 0%; low certainty), and doubling of SCr (2 studies, 767 participants: RR 0.88, 95% CI 0.52 to 1.48; I2 = 0%; low certainty). Compared to ACEi plus ARB, ACEi alone has uncertain effects on all-cause death (6 studies, 1166 participants: RR 1.08, 95% CI 0.49 to 2.40; I2 = 20%; low certainty), withdrawal from treatment (2 studies, 172 participants: RR 0.78, 95% CI 0.33 to 1.86; I2 = 0%; low certainty), cardiovascular death (4 studies, 994 participants: RR 3.02, 95% CI 0.61 to 14.85; low certainty), kidney failure (3 studies, 880 participants: RR 1.36, 95% CI 0.79 to 2.32; I2 = 0%; low certainty), and doubling of SCr (2 studies, 813 participants: RR 1.14, 95% CI 0.70 to 1.85; I2 = 0%; low certainty). Compared to ACEi plus ARB, ARB alone has uncertain effects on all-cause death (7 studies, 2607 participants: RR 1.02, 95% CI 0.76 to 1.37; I2 = 0%; low certainty), withdrawn from treatment (3 studies, 1615 participants: RR 0.81, 95% CI 0.53 to 1.24; I2 = 0%; low certainty), cardiovascular death (4 studies, 992 participants: RR 3.03, 95% CI 0.62 to 14.93; low certainty), kidney failure (4 studies, 2321 participants: RR 1.15, 95% CI 0.67 to 1.95; I2 = 29%; low certainty), and doubling of SCr (3 studies, 2252 participants: RR 1.18, 95% CI 0.85 to 1.64; I2 = 0%; low certainty). Comparative effects of different ACEi or ARB and low-dose versus high-dose ARB were rarely evaluated. No study compared different doses of ACEi. Adverse events of ACEi and ARB were rarely reported.

AUTHORS' CONCLUSIONS

ACEi or ARB may make little or no difference to all-cause and cardiovascular death compared to placebo or no treatment in people with diabetes and kidney disease but may prevent kidney failure. ARB may prevent the doubling of SCr and the progression from microalbuminuria to macroalbuminuria compared with a placebo or no treatment. Despite the international guidelines suggesting not combining ACEi and ARB treatment, the effects of ACEi or ARB monotherapy compared to dual therapy have not been adequately assessed. The limited data availability and the low quality of the included studies prevented the assessment of the benefits and harms of ACEi or ARB in people with diabetes and kidney disease. Low and very low certainty evidence indicates that it is possible that further studies might provide different results.

Outcomes in patients with cardiometabolic disease who develop hyperkalemia while treated with a renin-angiotensin-aldosterone system inhibitor

BACKGROUND

Many patients with indications for renin-angiotensin-aldosterone system inhibitor (RAASi) therapy are not receiving these medications. Concern about hyperkalemia is thought to contribute to this lack of evidence-based therapy.

METHODS

A retrospective cohort study included adult patients in primary care practices affiliated with an integrated health care delivery system treated with RAASi between 2000 and 2019 for any of the following indications: (a) coronary artery disease (CAD); (b) heart failure (HF) with a left ventricle ejection fraction ≤ 40%; (c) diabetes mellitus (DM) with proteinuria; or (d) chronic kidney disease (CKD) with proteinuria. Relationship between hyperkalemia (K > 5.0 mEg/L) over the first 12 months of follow-up and a composite end point of cardiovascular events, renal dysfunction, and all-cause mortality was evaluated.

RESULTS

Among 82,732 study patients, 7,727 (9.34%) developed hyperkalemia. Patients with hyperkalemia were older (69.0 vs 64.6) and more likely to have CAD (57.8 vs 53.7%), CKD (57.3 vs 51.1%), HF (19.3 vs 9.7%), and DM (45.3 vs 33.3%) (P < .001 for all). Five-year cumulative risk of the primary outcome was higher in patients who did (63.9%; 95% CI: 62.8%-65.1%) versus did not (37.2%; 95% CI: 36.8%-37.6%) develop hyperkalemia. Five-year cumulative risk of ED visit or hospitalization for hyperkalemia was 15.6% (14.7%-16.6%) for patients with versus 2.7% (95% CI: 2.6-2.9) for patients without hyperkalemia, rising to 25.9% (95% CI: 22.4-29.9) for patients with severe (K > 6.0 mEq/dL) hyperkalemia. Patients who experienced hyperkalemia were more likely (34.4%) than patients who did not (29.2%) to deintensify RAASi therapy (P < .001). Five-year cumulative risk of the primary outcome was higher in patients who lowered RAASi dose (50.4%; 95% CI: 48.5%-52.4%) or stopped RAASi therapy completely (49.3%; 95% CI: 48.5%-50.1%), compared to patients who continued RAASi therapy (36.1%; 95% CI: 25.7-36.5). Similar findings were observed in multivariable analyses and for individual components of the primary outcome.

CONCLUSIONS

Hyperkalemia is a common complication of RAASi therapy and is associated with an increased risk of multiple adverse outcomes. Patients who have their RAASi medications deintensified after a hyperkalemic event have higher incidence of cardiovascular events, renal dysfunction and death.

Renin-Angiotensin-Aldosterone System (RAS) Inhibitors May Suppress the Prevalence of Peripheral Arterial Disease (PAD) in Elderly, Chronic Hemodialysis Patients

According to the hypertension guidelines, calcium antagonists are recommended as antihypertensive drugs for Stage 5 of chronic kidney disease (CKDG5) and late elderly patients, whereas renin-angiotensin-aldosterone system (RAS) inhibitors (RASi) are not recommended. We screened elderly CKDG5D patients at a single outpatient maintenance hemodialysis center for the progression of peripheral arterial disease (PAD) using the ankle-brachial index (ABI) and skin perfusion pressure (SPP) tests, as well as logistic regression analysis, to determine the association between PAD and the treatment with RASi and the association between the treatment with RASi and the need for hospitalization within one year of observation. With the presence of PAD as the explanatory variable and the presence of RASi as the objective variable, the odds ratio was 1.23 (95% confidence interval [CI] 0.37 to 3.82) in univariate analysis. After adjusting for confounding factors (age, gender, and hypertension), the odds ratio in multivariate analysis was 0.83 (95% CI 0.46 to 6.08). The presence or absence of PAD was significantly associated with an odds ratio of 3.24 (p = .04, 95% CI 1.0 to 10.25) and 4.63 (p = .026, 95% CI 1.20 to 17.84) in univariate and multivariate analyses, respectively, when the outcome was hospitalization at one year, regardless of the presence or absence of RASi. However, in univariate analysis, the odds ratio was 1.23 (95% CI 0.37 to 3.82) with RASi status as the explanatory variable and one-year hospitalization as the objective variable. After adjusting for confounders, the odds ratio in multivariate analysis was 0.83 (95% CI 0.46 to 6.08). Although further large-scale, multicenter studies are needed to establish the evidence, our results suggest that RASi treatment may have a suppressive effect on the prevalence of PAD and the need for hospitalization in elderly CKDG5 dialysis (CKDG5D) patients.

Efficacy and Safety of Candesartan 16 mg versus 64 mg Candesartan in Renal Disease Patients with Proteinuria: A Systematic Review and Meta-analysis

BACKGROUND: Chronic kidney disease (CKD) is a global health burden in the world. One of the complications of CKD is proteinuria. Candesartan is a drug that is often used in CKD patients to improve proteinuria. There are several studies that suggest that using a higher dose of candesartan can further improve its effectiveness in reducing proteinuria in CKD patient AIM: This paper is aimed to review the effectiveness and safety at a supramaximal dose of 64 mg to a dose of 16 mg of candesartan. METHODS: We performed a literature search using PubMed, SCOPUS, EuropePMC, ProQuest, and Cochrane Central Databases using these keywords: “candesartan” and “16 mg” and “64 mg” or “proteinuria renal disease” or “albuminuria” and “blood pressure” that were published within the year of 1980–2021. Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol were used to conduct this meta-analysis. We included randomized controlled trials, prospective cohort, retrospective or clinical observational evaluating the effect of candesartan in 16 mg or 64 mg in proteinuria renal disease patients regardless of clinical status. Non-randomized, controlled trials reporting efficacy were included if these trials were in the scope of our topic. Duplicate studies were excluded. Dichotomous variables were analyzed with the Mantel-Haenszel statistical method using risk ratio as the summary statistic and reported with 95% confidence intervals (CIs). RESULTS: Forty-six studies were initially generated using our search keyword. After applying inclusion and exclusion criteria, we included two studies in our analysis. Our pooled analysis found that candesartan 16mg dosage administration, compared to 64mg, was not associated with proteinuria reduction (std mean diff: −10.92 [95% CI: −40.09–18.26], p = 0.46). CONCLUSION: Candesartan supramaximal dosage 64 mg did not differ significantly in proteinuria reduction and blood pressure reduction against candesartan 16 mg. More studies are needed to determine this efficacy and safety.

Renal outcomes of treatment with telmisartan in patients with stage 3-4 chronic kidney disease: A prospective, randomized, controlled trial (JINNAGA)

Objectives:

Although angiotensin II receptor blockers are effective for patients with chronic kidney disease, dose-dependent renoprotective effects of angiotensin II receptor blockers in patients with moderate to severe chronic kidney disease with non-nephrotic proteinuria are not known. Our aim was to elucidate the dose-dependent renoprotective effects of angiotensin II receptor blockers on such patients.

Methods:

A multicenter, prospective, randomized trial was conducted from 2009 to 2014. Patients with non-nephrotic stage 3–4 chronic kidney disease were randomized for treatment with either 40 or 80 mg telmisartan and were observed for up to 104 weeks. Overall, 32 and 29 patients were allocated to the 40 and 80 mg telmisartan groups, respectively. The composite primary outcome was renal death, doubling of serum creatinine level, transition to stage 5 chronic kidney disease, and death from any cause. Secondary outcomes included the level of urinary proteins and changes in the estimated glomerular filtration rate.

Results:

There was no difference in the primary outcome (p = 0.78) and eGFR (p = 0.53) between the two groups; however, after 24 weeks, urinary protein level was significantly lower in the 80 mg group than in the 40 mg group (p < 0.05). No severe adverse events occurred in either group, and the occurrence of adverse events did not significantly differ between them (p = 0.56).

Conclusion:

Our findings do not demonstrate a direct dose-dependent renoprotective effect of telmisartan. The higher telmisartan dose resulted in a decrease in the amount of urinary protein. Even though high-dose angiotensin II receptor blockers may be preferable for patients with stage 3–4 chronic kidney disease, the clinical importance of the study results may be limited. The study was registered in the UMIN-CTR (https://www.umin.ac.jp/ctr) with the registration number UMIN000040875.

Exposure-response relationships of dapagliflozin on cardiorenal risk markers and adverse events: A pooled analysis of 13 phase II/III trials

AIMS

Dapagliflozin is a sodium-glucose co-transporter 2 inhibitor that has been developed as oral glucose lowering drug. The original dosefinding studies focused on optimal glycaemic effects. However, dapagliflozin also affects various cardiorenal risk markers and provides cardiorenal protection. To evaluate whether the currently registered doses of 5 and 10 mg are optimal for cardiorenal efficacy and safety, we characterized the relationship between dapagliflozin exposure and nonglycaemic cardiorenal risk markers as well as adverse events.

METHODS

Data were obtained from a pooled database of 13 24-week randomized controlled clinical trials of the clinical development programme of dapagliflozin. The exposure-response relationship was quantified using population pharmacodynamic and repeated time-to-event models.

RESULTS

A dose of 10 mg dapagliflozin resulted in an average individual exposure of 638 ng h/mL (95% prediction interval [PI]: 354-1061 ng h/mL), which translated to 71.2% (95% PI: 57.9-80.5%), 61.1% (95% PI: 58.0-64.8%), 91.3% (95% PI: 85.4-94.6%) and 25.7% (95% PI: 23.5-28.3%) of its estimated maximum effect for fasting plasma glucose, haematocrit, serum creatinine and urinary albumin-creatinine ratio, respectively.

CONCLUSION

We demonstrate that doses higher than 10 mg could provide additional beneficial effects in haematocrit, systolic blood pressure, urinary albumin-creatinine ratio and uric acid, without obvious increases in the rate of adverse events. These results raise the question whether future outcome studies assessing the benefits of higher than currently registered dapagliflozin doses are merited.

Effect of angiotensin receptor blockers on blood pressure and renal function in patients with concomitant hypertension and chronic kidney disease: a systematic review and meta-analysis

Objective: Angiotensin receptor blockers (ARB) are among the recommended first-line treatment options in patients with hypertension and chronic kidney disease (CKD). This meta-analysis evaluated the effect of ARB on blood pressure (BP) and renal function in patients with concomitant hypertension and CKD with or without diabetes.Methods: Literature search was performed in PubMed/MEDLINE, EMBASE and BIOSIS to identify parallel-group, randomized controlled trials (≥8 weeks) reporting the effects of ARB on office systolic/diastolic BP (SBP/DBP), estimated glomerular filtration rate (eGFR), serum creatinine (SCr), creatinine clearance (CrCl) or proteinuria in adults with hypertension and CKD. Mean difference (MD, generic inverse variance) with 95% confidence intervals (CIs) was used to report an outcome.Results: Among the 24 studies identified, 19 evaluated ARB as monotherapy, 4 evaluated ARB as combination therapy and one evaluated ARB both as monotherapy and combination therapy. Median (range) duration of the studies was 12 (1.84-54.0) months. ARB monotherapy significantly (p < 0.01) reduced BP (treatment ≥1 year: SBP [MD: -14.84 mmHg; 95% CI: -17.82 to -11.85]/DBP [-10.27 mmHg; -12.26 to -8.27]) and proteinuria (≥1 year [-0.90 g/L; -1.22 to -0.59]). Results were consistent for combination therapy. In these studies, non-significant changes were observed for eGFR, CrCl and SCr. The impact of SBP changes on eGFR was not significant; however, studies were of a relatively short duration.Conclusion: ARB had a favorable impact on BP and renal parameters such as proteinuria with monotherapy as well as with combination therapy, highlighting their potential benefits in patients with hypertension and CKD. During the short follow-up of these studies, no significant change in eGFR was observed.

Personalized medicine in diabetic kidney disease: a novel approach to improve trial design and patient outcomes

PURPOSE OF REVIEW

In the last decade many attempts have been made to reduce the high residual risk of end-stage kidney disease and cardiovascular disease in patients with diabetic kidney disease by targeting a variety of risk markers. Subsequent analyses revealed that the variation in individual drug response to the tested interventions partly explains why these trials did not result in additional kidney or cardiovascular protection. This review summarizes recent insights regarding individual variation in drug response. Additionally, we explore novel approaches to incorporate this drug response variability in the design of new clinical trials.

RECENT FINDINGS

Recent studies suggest that a plausible explanation for individual therapy resistance emanates from intrinsic individual characteristics such as genetic make-up or volume status and is likely only partially explained by drug characteristics such as the dose or type of intervention. Biomarker-based enrichment strategies to identify high-risk individuals and/or those who are more likely to respond to interventions offer opportunities to tailor therapies to individual patients.

SUMMARY

Individual drug response variability is a recognized phenomenon in clinical practice. It is time to implement novel approaches that take into account this response variability in the design of new trials in diabetic kidney disease in order to define optimal therapies for individual patients.

Pooled Analysis of Multiple Crossover Trials To Optimize Individual Therapy Response to Renin-Angiotensin-Aldosterone System Intervention

BACKGROUND AND OBJECTIVES

In the treatment of CKD, individual patients show a wide variation in their response to many drugs, including renin-angiotensin-aldosterone system inhibitors (RAASi). To investigate whether therapy resistance to RAASi can be overcome by uptitrating the dose of drug, changing the mode of intervention (with drugs from similar or different classes), or lowering dietary sodium intake, we meta-analyzed individual responses to different modes of interventions.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Randomized crossover trials were analyzed to assess correlation of individual responses to RAASi and nonsteroidal anti-inflammatory drugs (NSAIDs; n=395 patients). Included studies compared the antialbuminuric effect of uptitrating the dose of RAASi (n=10 studies) and NSAIDs (n=1), changing within the same class of RAASi (e.g., angiotensin-converting enzyme inhibition to angiotensin receptor blockers; n=5) or NSAIDs (n=1), changing from RAASi to NSAIDs (n=2), and changing from high to low sodium intake (n=5). A two-stage meta-analysis was conducted: Deming regression was conducted in each study to assess correlations in response, and individual study results were then meta-analyzed.

RESULTS

The albuminuria response to one dose of RAASi or NSAIDs positively correlated with the response to a higher dose of the same drug (r=0.72; 95% confidence interval [95% CI], 0.66 to 0.78), changes within the same class of RAASi or NSAIDs (r=0.54; 95% CI, 0.35 to 0.68), changes between RAASi and NSAIDs (r=0.44; 95% CI, 0.16 to 0.66), and changes from high to moderately low salt intake (r=0.36; 95% CI, 0.22 to 0.48). Results were similar when the individual systolic BP and potassium responses were analyzed, and were consistent in patients with and without diabetes.

CONCLUSIONS

Individuals who show a poor response to one dose or type of RAASi also show a poor response to higher doses, other types of RAASi or NSAIDs, or a reduction in dietary salt intake. Whether other drugs or drug combinations targeting pathways beyond the renin-angiotensin-aldosterone system and prostaglandins would improve the individual poor response requires further study.

Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

Objective:

To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS) among patients with type 2 diabetic kidney disease.

Data Sources:

We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included “diabetic nephropathy,” “chronic kidney disease,” “chronic renal insufficiency,” “diabetes mellitus,” “dual therapy,” “combined therapy,” “dual blockade,” “renin-angiotensin system,” “angiotensin-converting enzyme inhibitor,” “angiotensin-receptor blocker,” “aldosterone blockade,” “selective aldosterone blockade,” “renin inhibitor,” “direct renin inhibitor,” “mineralocorticoid receptor blocker,” etc.

Study Selection:

The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus.

Results:

Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons.

Conclusions:

Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an evidence-based practice.

Prevention of microalbuminuria using early intervention with renin-angiotensin system inhibitors in patients with type 2 diabetes: A systematic review

Hypothesis/objectives:

Early prevention of diabetic nephropathy by way of blocking the renin-angiotensin system (RAS) in patients with normoalbuminuria seems rational, but trials have so far shown conflicting results. The present meta-analysis was undertaken to investigate if such treatment can prevent development of microalbuminuria.

Materials and methods:

We searched MEDLINE, EMBASE and the Cochrane Library (2 June 2014) for randomised controlled trials, with a population of patients with type 2 diabetes and normoalbuminuria, comparing angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) to placebo. Studies had to have at least 50 participants in each arm and one year of follow-up. Random and fixed effect models were performed as well as trial sequential analysis.

Results:

Six trials were included in the analysis (n=16,921). Overall risk of bias was variable. In a fixed model analysis ACE or ARB treatment was superior to placebo in relation to prevention of development of microalbuminuria, risk ratio 0.84 (95% confidence interval (CI) 0.79–0.88) p<0.001, I²=23%, similar to random model results. Treatment also showed a trend towards a reduction in all-cause mortality(p=0.07).

Conclusions:

We conclude that in patients with type 2 diabetes and normoalbuminuria, early intervention with ACEis or ARBs reduces the risk for development of microalbuminuria.

Serum metabolites predict response to angiotensin II receptor blockers in patients with diabetes mellitus

Background

Individual patients show a large variability in albuminuria response to angiotensin receptor blockers (ARB). Identifying novel biomarkers that predict ARB response may help tailor therapy. We aimed to discover and validate a serum metabolite classifier that predicts albuminuria response to ARBs in patients with diabetes mellitus and micro- or macroalbuminuria.

Methods

Liquid chromatography-tandem mass spectrometry metabolomics was performed on serum samples. Data from patients with type 2 diabetes and microalbuminuria (n = 49) treated with irbesartan 300 mg/day were used for discovery. LASSO and ridge regression were performed to develop the classifier. Improvement in albuminuria response prediction was assessed by calculating differences in R² between a reference model of clinical parameters and a model with clinical parameters and the classifier. The classifier was externally validated in patients with type 1 diabetes and macroalbuminuria (n = 50) treated with losartan 100 mg/day. Molecular process analysis was performed to link metabolites to molecular mechanisms contributing to ARB response.

Results

In discovery, median change in urinary albumin excretion (UAE) was −42 % [Q1–Q3: −69 to −8]. The classifier, consisting of 21 metabolites, was significantly associated with UAE response to irbesartan (p < 0.001) and improved prediction of UAE response on top of the clinical reference model (R² increase from 0.10 to 0.70; p < 0.001). In external validation, median change in UAE was −43 % [Q1–Q35: −63 to −23]. The classifier improved prediction of UAE response to losartan (R² increase from 0.20 to 0.59; p < 0.001). Specifically ADMA impacting eNOS activity appears to be a relevant factor in ARB response.

Conclusions

A serum metabolite classifier was discovered and externally validated to significantly improve prediction of albuminuria response to ARBs in diabetes mellitus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0960-3) contains supplementary material, which is available to authorized users.

Individual long-term albuminuria exposure during angiotensin receptor blocker therapy is the optimal predictor for renal outcome

BACKGROUND

Albuminuria reduction due to angiotensin receptor blockers (ARBs) predicts subsequent renoprotection. Relating the initial albuminuria reduction to subsequent renoprotection assumes that the initial ARB-induced albuminuria reduction remains stable during follow-up. The aim of this study was to assess individual albuminuria fluctuations after the initial ARB response and to determine whether taking individual albuminuria fluctuations into account improves renal outcome prediction.

METHODS

Patients with diabetes and nephropathy treated with losartan or irbesartan in the RENAAL and IDNT trials were included. Patients with >30% reduction in albuminuria 3 months after ARB initiation were stratified by the subsequent change in albuminuria until Month 12 in enhanced responders (>50% albuminuria reduction), sustained responders (between 20 and 50% reduction), and response escapers (<20% reduction). Predictive performance of the individual albuminuria exposure until Month 3 was compared with the exposure over the first 12 months using receiver operating characteristics (ROC) curves.

RESULTS

Following ARB initiation, 388 (36.3%) patients showed an >30% reduction in albuminuria. Among these patients, the albuminuria level further decreased in 174 (44.8%), remained stable in 123 (31.7%), and increased in 91 (23.5%) patients. Similar albuminuria fluctuations were observed in patients with <30% albuminuria reduction. Renal risk prediction improved when using the albuminuria exposure during the first 12 months versus the initial Month 3 change [ROC difference: 0.78 (95% CI 0.75-0.82) versus 0.68 (0.64-0.72); P < 0.0001].

CONCLUSIONS

Following the initial response to ARBs, a large within-patient albuminuria variability is observed. Hence, incorporating multiple albuminuria measurements over time in risk algorithms may be more appropriate to monitor treatment effects and quantify renal risk.

Renin-Angiotensin-Aldosterone System Blockade in Diabetic Nephropathy. Present Evidences

Diabetic Kidney Disease (DKD) is the leading cause of chronic kidney disease in developed countries and its prevalence has increased dramatically in the past few decades. These patients are at an increased risk for premature death, cardiovascular disease, and other severe illnesses that result in frequent hospitalizations and increased health-care utilization. Although much progress has been made in slowing the progression of diabetic nephropathy, renal dysfunction and the development of end-stage renal disease remain major concerns in diabetes. Dysregulation of the renin-angiotensin-aldosterone system (RAAS) results in progressive renal damage. RAAS blockade is the cornerstone of treatment of DKD, with proven efficacy in many arenas. The theoretically-attractive option of combining these medications that target different points in the pathway, potentially offering a more complete RAAS blockade, has also been tested in clinical trials, but long-term outcomes were disappointing. This review examines the “state of play” for RAAS blockade in DKD, dual blockade of various combinations, and a perspective on its benefits and potential risks.

The Envy of Scholars: Applying the Lessons of the Framingham Heart Study to the Prevention of Chronic Kidney Disease

During the past 50 years, a dramatic reduction in the mortality rate associated with cardiovascular disease has occurred in the US and other countries. Statistical modeling has revealed that approximately half of this reduction is the result of risk factor mitigation. The successful identification of such risk factors was pioneered and has continued with the Framingham Heart Study, which began in 1949 as a project of the US National Heart Institute (now part of the National Heart, Lung, and Blood Institute). Decreases in total cholesterol, blood pressure, smoking, and physical inactivity account for 24%, 20%, 12%, and 5% reductions in the mortality rate, respectively. Nephrology was designated as a recognized medical professional specialty a few years later. Hemodialysis was first performed in 1943. The US Medicare End-Stage Renal Disease (ESRD) Program was established in 1972. The number of patients in the program increased from 5,000 in the first year to more than 500,000 in recent years. Only recently have efforts for risk factor identification, early diagnosis, and prevention of chronic kidney disease (CKD) been undertaken. By applying the approach of the Framingham Heart Study to address CKD risk factors, we hope to mirror the success of cardiology; we aim to prevent progression to ESRD and to avoid the cardiovascular complications associated with CKD. In this paper, we present conceptual examples of risk factor modification for CKD, in the setting of this historical framework.

The renal protective effect of angiotensin receptor blockers depends on intra-individual response variation in multiple risk markers

AIMS

Angiotensin receptor blockers (ARBs) are renoprotective and targeted to blood pressure. However, ARBs have multiple other (off-target) effects which may affect renal outcome. It is unknown whether on-target and off-target effects are congruent within individuals. If not, this variation in short term effects may have important implications for the prediction of individual long term renal outcomes. Our aim was to assess intra-individual variability in multiple parameters in response to ARBs in type 2 diabetes.

METHODS

Changes in systolic blood pressure (SBP), albuminuria, potassium, haemoglobin, cholesterol and uric acid after 6 months of losartan treatment were assessed in the RENAAL database. Improvement in predictive performance of renal outcomes (ESRD or doubling serum creatinine) for each individual using ARB-induced changes in all risk markers was assessed by the relative integrative discrimination index (RIDI).

RESULTS

SBP response showed high variability (mean -5.7 mmHg, 5(th) to 95(th) percentile -36.5 to +24.0 mmHg) between individuals. Changes in off-target parameters also showed high variability between individuals. No congruency was observed between responses to losartan in multiple parameters within individuals. Using individual responses in all risk markers significantly improved renal risk prediction (RIDI 30.4%, P < 0.01) compared with using only SBP changes. Results were successfully replicated in two independent trials with irbesartan, IDNT and IRMA-2.

CONCLUSIONS

In this post hoc analysis we showed that ARBs have multiple off-target effects which vary between and within individuals. Combining all ARB-induced responses beyond SBP provides a more accurate prediction of who will benefit from ARB therapy. Prospective trials are required to validate these findings.

Anti-albuminuric effect of the aldosterone blocker eplerenone in non-diabetic hypertensive patients with albuminuria: a double-blind, randomised, placebo-controlled trial

BACKGROUND

Renin-angiotensin system inhibitors have renoprotective effects in patients with chronic kidney disease, but most patients treated with these drugs have residual urinary albumin excretion. Some small clinical studies show that mineralocorticoid receptor blockade reduces albuminuria. Our study aimed to examine the beneficial effects of addition of a selective aldosterone antagonist, eplerenone, to renin-angiotensin system inhibitors in hypertensive patients with non-diabetic chronic kidney disease.

METHODS

In this double-blind, randomised, placebo-controlled trial, we enrolled hypertensive patients, aged 20–79 years, with albuminuria (urinary albumin-to-creatinine ratio [UACR] in the first morning void urine of 30–599 mg/g), an estimated glomerular filtration rate of 50 mL/min per 1·73 m2 or more, and who had received an angiotensin-converting enzyme inhibitor, an angiotensin receptor blocker, or both, for at least 8 weeks. Participants were from 59 clinics and hospitals in Japan. Eligible patients were randomly assigned (1:1), stratified by baseline characteristics, to either low-dose eplerenone (50 mg/day) or placebo, with continuation of standard antihypertensive treatment to attain therapeutic goals (<130/80 mm Hg) for 52 weeks. We assessed efficacy in all patients who received allocated treatment, provided a baseline and post-treatment urine sample, and remained in follow-up. We assessed safety in all patients who received allocated treatment. The primary efficacy measure was percent change in UACR in the first morning void urine at week 52 from baseline. The trial is registered at the clinical trials registry of University Hospital Medical Information Network (UMIN), trial identification number UMIN000001803.

FINDINGS

Between April 1, 2009, and March 31, 2012, we randomly allocated 170 patients to the eplerenone group and 166 patients to the placebo group. In the primary efficacy analysis, mean percent change in UACR from baseline was −17·3% (95% CI −33·65 to −0·94) for 158 patients in the eplerenone group compared with 10·3% (−6·75 to 22·3) for 146 patients in the placebo group (absolute difference −27·6% [–51·15 to −3·96]; p=0·0222). In the safety analyses, 53 (31%) of 169 patients in the eplerenone group had adverse events (five serious), as did 49 (30%) of 163 in the placebo group (seven serious). Although mean serum potassium concentration was higher in the eplerenone group than the placebo group, severe hyperkalaemia (>5·5 mmol/L) was not recorded in either group.

INTERPRETATION

Addition of low-dose eplerenone to renin-angiotensin system inhibitors might have renoprotective effects through reduction of albuminuria in hypertensive patients with non-diabetic chronic kidney disease, without serious safety concerns.

FUNDING

Pfizer.

Comprehensive approach to diabetic nephropathy

Diabetic nephropathy (DN) is a leading cause of mortality and morbidity in patients with diabetes. This complication reflects a complex pathophysiology, whereby various genetic and environmental factors determine susceptibility and progression to end-stage renal disease. DN should be considered in patients with type 1 diabetes for at least 10 years who have microalbuminuria and diabetic retinopathy, as well as in patients with type 1 or type 2 diabetes with macroalbuminuria in whom other causes for proteinuria are absent. DN may also present as a falling estimated glomerular filtration rate with albuminuria as a minor presenting feature, especially in patients taking renin-angiotensin-aldosterone system inhibitors (RAASi). The pathological characteristic features of disease are three major lesions: diffuse mesangial expansion, diffuse thickened glomerular basement membrane, and hyalinosis of arterioles. Functionally, however, the pathophysiology is reflected in dysfunction of the mesangium, the glomerular capillary wall, the tubulointerstitium, and the vasculature. For all diabetic patients, a comprehensive approach to management including glycemic and hypertensive control with RAASi combined with lipid control, dietary salt restriction, lowering of protein intake, increased physical activity, weight reduction, and smoking cessation can reduce the rate of progression of nephropathy and minimize the risk for cardiovascular events. This review focuses on the latest published data dealing with the mechanisms, diagnosis, and current treatment of DN.

Dose-dependent arterial destiffening and inward remodeling after olmesartan in hypertensives with metabolic syndrome

Whether angiotensin receptor blockers can dose-dependently remodel the arterial wall during long-term treatment has been largely debated. In this phase III, multicenter, randomized, double-blind, parallel-group study, 133 subjects with hypertension and metabolic syndrome were assigned to olmesartan, either 20 mg (n=44), 40 mg (n=42), or 80 mg (n=47) once a day, according to a force titration design during a 1-year period. Office blood pressure, 24-hour blood pressure, aortic stiffness (carotid-femoral pulse wave velocity), and carotid parameters were measured at baseline, 24 weeks, and 52 weeks. Pulse wave velocity significantly decreased (P<0.001) with time in each group, with no significant time-dose interaction, despite a tendency (P=0.0685) for a smaller effect of 20 mg, compared with 40 and 80 mg at week 52. When the 40 and 80 mg doses were combined (40/80 mg versus 20 mg), a significant blood pressure-independent reduction in pulse wave velocity (-0.61 m/s) was observed at week 52 (P=0.0066), whereas the nonadjusted reduction was -1.31 m/s (P<0.0001). By contrast, after 20 mg, the blood pressure-independent reduction in pulse wave velocity was not significant. Patients receiving the highest dose of olmesartan (40 and 80 mg) had an inward carotid remodeling and were shifted toward a lower elastic modulus at a given circumferential wall stress, indicating an improvement in the intrinsic elastic properties of the carotid artery wall material. These data suggest that 40 and 80 mg olmesartan were able to significantly remodel and destiffen the arterial wall material during long-term treatment, partly independently of blood pressure, compared with 20 mg.

Direct renin inhibition in chronic kidney disease

For approximately 6 years, the only commercially available direct renin inhibitor, aliskiren, which inhibits the renin-angiotensin-aldosterone system at the initial rate limiting step, has been marketed for the treatment of hypertension. Concurrently, much attention has been given to the possibility that renin inhibition could hold potential for improved treatment in patients with chronic kidney disease, with diabetic nephropathy as an obvious group of patients to investigate, as the activity of the renin-angiotensin-aldosterone system is enhanced in these patients and as there is an unmet need for improved treatment and prognosis in these patients. Several short term studies have been performed in diabetic nephropathy, showing a consistent effect on the surrogate endpoint lowering of albuminuria, both as monotherapy and in combination with other blockers of the renin-angiotensin-aldosterone system. In addition, combination treatment also seemed safe and effective in patients with impaired kidney function. These initial findings formed the basis for the design of a large morbidity and mortality trial investigating aliskiren as add-on to standard treatment. The study has just concluded, but was terminated early as a beneficial effect was unlikely and there was an increased frequency of side effects. Also in non-diabetic kidney disease a few intervention studies have been carried out, but there is no ongoing hard outcome study. In this review we provide the current evidence for renin inhibition in chronic kidney disease by reporting the studies published so far as well as a perspective on the future possibilities.

Aliskiren and the Kidney: Beyond Hypertension

Aliskiren is a novel drug with the ability to lower plasma renin activity, reducing proteinuria in hypertension and in diabetic nephropathy. In primary and secondary glomerular diseases, important causes of endstage kidney disease, proteinuria is a hallmark. Moreover, urinary protein is a marker of renal disease progression. The renin angiotensin-aldosterone system is generally activated in these patients. A complete blockade with the use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers with or without aldosterone receptor blockers is not easy to achieve, and side effects are not uncommon. Plasma renin activity is even increased in patients with this approach. Aliskiren should be considered as a new therapeutic option to be assessed in glomerular diseases, as plasma renin activity can be reduced and a better control of the renin-angiotensin system could be achieved with the consequent reduction in the amount of urinary protein excretion.

Angiotensin II receptor blockers improve peripheral endothelial function: a meta-analysis of randomized controlled trials

OBJECTIVE(S)

Several studies have assessed the effect of angiotensin II receptor blockers (ARBs) on peripheral endothelial dysfunction as measured by flow-mediated vasodilatation (FMD), a widely-used indicator for endothelial function. We conducted a meta-analysis to investigate the effect in comparison to placebo or no treatment and other antihypertensives.

METHODS

MEDLINE, Cochrane library and EMBASE were searched to September 2013 for randomized controlled trials (RCTs) that assessed the effect of ARBs versus placebo or no treatment and other antihypertensives (angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), β-blockers, diuretics) by forearm FMD. Furthermore, we also use meta-regression to analyze the relationship between the endothelial function and the duration of ARBs treatments.

RESULTS

In 11 trials including 590 patients, ARBs (n = 315) significantly improved FMD (1.36%, 95% confidence internal [CI]:1.28 to 1.44) versus placebo or no treatment (n = 275). In 16 trials that included 1028 patients, ARBs (n = 486) had a significant effect (0.59%, 95% CI: 0.25 to 0.94) on FMD when compared with other antihypertensives (n = 542). In 8 trials, ARBs (n = 174) had no significant effect (-0.14%, 95% CI: -0.32 to 0.03) compared with ACEI (n = 173). Compared with others, the benefits of ARBs, respectively, were 1.67% (95% CI: 0.65 to 0.93) in 7 trials with CCBs, 0.79% (95% CI: 0.42 to 1.01) with β-blockers in 3 trials and 0.9% (95% CI: 0.77 to 1.03) with diuretics in 3 trials. Importantly, we found ARBs were less effective in a long time span (95% CI: -1.990 to -0.622) than the first 6 months (95% CI: -0.484 to 0.360).

CONCLUSIONS

This study shows that ARBs improve peripheral endothelial function and are superior to CCBs, β-blockers and diuretics. However, the effect couldn't be maintained for a long time. In addition, there was no significant difference between ARBs and ACEI.

Sequential RAAS blockade: is it worth the risk?

Soon after the emergence of the renin-angiotensin-aldosterone system (RAAS) blocking treatment as the cornerstone of renoprotective treatment in the prevention and treatment of diabetic and nondiabetic CKD, it was investigated if a higher degree of achievable RAAS blockade by combining more than one compound is feasible and advantageous. Regardless of the benefits from using monotherapy for diabetic kidney disease, there is still much improvement to wish for in terms of kidney prognosis in these populations. A great deal of research has gone into evaluating combinations of the RAAS blocking treatments in different populations and with different drugs and doses. Studies have mostly been short-term and use surrogate endpoints such as albuminuria. Side effects have been well known and expected in terms of increasing potassium levels and hypotension, but to an acceptable extent. With recent disappointing results from major hard endpoint trials using dual RAAS blockade the concept is now under scrutiny. In this review we will discuss the pros and cons of dual RAAS blockade, with facts and findings from smaller studies, endpoint trials, and meta-analyses.

The effect of RAAS blockade on the progression of diabetic nephropathy

The renin-angiotensin-aldosterone system (RAAS) has a key role in the regulation of blood pressure, sodium and water balance, and cardiovascular and renal homeostasis. In diabetic nephropathy, excessive activation of the RAAS results in progressive renal damage. RAAS blockade using angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers is the cornerstone of treatment of diabetic renal disease. Alternative RAAS-blockade strategies include renin inhibition and aldosterone blockade. Data from small initial studies of these agents are promising. However, single-agent interventions do not fully block the RAAS and patients treated with these therapies remain at high residual renal risk. Approaches to optimize drug responses include dietary changes and increasing dosages. The theoretically attractive option of combining different RAAS interventions has also been tested in clinical trials but long-term outcomes were disappointing. However, dual RAAS blockade might represent a good therapeutic option for specific patients. A better knowledge of the pathophysiology of the RAAS is crucial to fully understand the mechanisms of action of RAAS blockers and to exploit their renoprotective effects. Moreover, lifestyle interventions or diagnostic tools might be used to optimize RAAS blockade and identify those patients who are most likely to benefit from the therapy.

Antihypertensive treatment and renal protection: the role of drugs inhibiting the renin-angiotensin-aldosterone system

The prevalence of chronic kidney disease, currently estimated to vary between 8 and 12 % in the general population, is steadily rising due to aging and to the ongoing epidemic of hypertension and type 2 diabetes. Even in its early stages, chronic kidney disease entails a greater risk for cardiovascular mortality, and its prevention and treatment is rapidly becoming a key medical issue for many health care systems worldwide. Adequate blood pressure control and reduction of urine protein excretion, preferably obtained by the use of renin-angiotensin-aldosterone system inhibitors, have traditionally been considered the mainstay of therapeutic strategies in patients with renal disease. Given the pivotal role of renin-angiotensin-aldosterone system activity in the pathogenesis and progression of renal and cardiovascular damage, a more profound inhibition of the system, either by the use of multiple agents or by a single agent at high dosage has recently been advocated, especially in the presence of proteinuria. Recent trials, however have failed to confirm the usefulness of this therapeutic approach, at least in unselected patients. This article will critically review the current literature and will discuss the clinical implications of targeting the renin-angiotensin-aldosterone system in order to provide the greatest renal protection.

Aggressive blood pressure reduction and renin-angiotensin system blockade in chronic kidney disease: time for re-evaluation?

Over the past decades, aggressive control of blood pressure (BP) and blockade of the renin-angiotensin-aldosterone system (RAAS) were considered the cornerstones of treatment against progression of chronic kidney disease (CKD), following important background and clinical evidence on the associations of hypertension and RAAS activation with renal injury. To this end, previous recommendations included a BP target of <130/80 mm Hg for all individuals with CKD (and possibly <125/75 mm Hg for those with proteinuria >1 g/day), as well as use of angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers as first-line therapy for hypertension in all CKD patients. However, long-term extensions of relevant clinical trials support a low-BP goal only for patients with proteinuria, whereas recent cardiovascular trials questioned the benefits of low systolic BP for diabetic patients, leading to more individualized recommendations. Furthermore, our previous knowledge of the specific renoprotective properties of RAAS blockers in patients with proteinuric CKD is now extended with data on the use of these agents in patients with less advanced nephropathy and/or absence of proteinuria, deriving mostly from subanalyses of cardiovascular trials. This review discusses previous and recent clinical evidence on the issues of BP reduction and RAAS blockade by type and stage of renal damage, aiming to aid clinicians in their treatment decisions for patients with CKD.

Antiproteinuric effect of angiotensin receptor blockers in normotensive patients with proteinuria: a meta-analysis of randomized controlled trials

INTRODUCTION

The objective of this article is to evaluate the antiproteinuric effect of angiotensin receptor blockers (ARBs) in normotensive patients with proteinuria.

MATERIALS AND METHODS

We reviewed randomized controlled trials assessing ARBs treatment in patients with normotension and proteinuria. Data concerning the study design, patient characteristics, and outcomes were extracted. Ratio of means was calculated by using the generalized inverse variance method.

RESULTS

Eight trials involving 866 patients were included in this study. Compared with a control group, ARBs group was associated with a significant reduction in urinary protein excretion (ratio of means 0.53, 95% CI 0.44-0.64). Subgroup analysis shows that ARBs therapy resulted in a significant decrease in urinary protein excretion in diabetic patients with microalbuminuria or nondiabetic nephropathy with overt proteinuria (ratio of means 0.57, 95% CI 0.47-0.69 and 0.46, 95% CI 0.26-0.83, respectively), in a Western population or an Asian population (ratio of means 0.61, 95% CI 0.54-0.69 and 0.49, 95% CI 0.37-0.64, respectively), and in patients followed up for one to three months or three to 12 months (ratio of means 0.62, 95% CI 0.54-0.70 and 0.49, 95% CI 0.38-0.63, respectively).

CONCLUSIONS

The data suggest that ARBs may have beneficial effects in preventing the progression of proteinuria in normotensive patients with renal disease.

Clinical Implications of the Change in Glomerular Filtration Rate with Adrenergic Blockers in Patients with Morning Hypertension: The Japan Morning Surge-1 Study

Background. The aim of this study was to clarify the relationship between the change in estimated glomerular filtration rate (eGFR) and urinary albumin by antihypertensive treatment.Methods. We randomized 611 treated patients with morning hypertension into either an added treatment group, for whom doxazosin was added to the current medication, or a control group, who continued their current medications. We compared the change in eGFR and urinary albumin creatinine ratio (UACR) between the groups.Results. The extent of the reduction in eGFR was significantly greater in the added treatment group than in the control group (−3.83  versus −1.08 mL/min/1.73 m2,P=0.001). In multivariable analyses, the change in eGFR was positively associated with the change in UACR in the added treatment group (β=0.20,P=0.001), but not in the control group (β=−0.002,P=0.97). When the changes in eGFR were divided by each CKD stage, eGFR was significantly more decreased in stage 1 than in the other stages in the added treatment group (P<0.001), but no differences were seen in the control group (P=0.44).Conclusion. The reduction of eGFR could be seen only in the early stage of CKD, and this treatment appeared to have no negative effect on renal function.

Combined renin angiotensin blockade in childhood steroid-resistant nephrotic syndrome

BACKGROUND

Reduced proteinuria results in delayed deterioration of renal function and remission of proteinuria predicts a good long-term prognosis in steroid-resistant nephrotic syndrome (SRNS). The aim of this study was to analyze the effects of the combined angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker in reducing proteinuria in SRNS.

METHODS

A prospective study of eight patients with SRNS was conducted at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University from September 2003 to December 2007. Enalapril was given at 0.1 mg/kg/day and was increased by 0.1 mg/kg/day every 4 weeks up to 0.6 mg/kg/day (maximum 40 mg/day) and 1 mg/kg/day of losartan was added for 4 weeks and stepped up to 2 mg/kg/day (maximum 100 mg/day) for another 4 weeks.

RESULTS

There were five boys (62.5%) and three girls (37.5%). The mean age at diagnosis was 8.3 ± 4.1 years (range 2.05-13 years) and age at enrollment was 11.7 ± 3.8 years (range 6-16 years). Renal histology revealed seven focal segmental glomerulosclerosis and one immunoglobulin M nephropathy. The results showed significant reduction on mean spot urine protein : creatinine ratio from 9.6 ± 2.3 to 3.6 ± 1.6 (P < 0.05) and 24-h urine protein from 182.8 ± 59.6 to 28.7 ± 8.2 mg/m(2) /h (P < 0.05). Urine protein reduction ratio at the end of the study was 50% (P= 0.08). Serum cholesterol, albumin, potassium, blood pressure and renal function had no significant change. No clinical and laboratory side-effects were reported.

CONCLUSION

Combined high-dose angiotensin II receptor blocker to high-dose angiotensin-converting enzyme inhibitor therapy is safe and effective in reducing proteinuria in childhood SRNS. However a large-scale study should be conducted to validate this result.

Renin-angiotensin system blockade and reduction of cardiovascular risk: future perspectives

Treatment with renin-angiotensin system blockers (angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) has shown clear benefits in distinct stages of cardiovascular disease. These treatments lower blood pressure and prevent the appearance of markers of subclinical disease (such as microalbuminuria), reduce cardiovascular and renal events in patients with subclinical lesions, and prolong survival in patients with clinical disease or organ dysfunction. Despite this unquestionable benefit, the residual risk in patients receiving these treatments often continues to be high and, consequently, strategies to reduce such risk are required. The present article reviews options that may help to reduce cardiovascular disease in such patients. They include efforts of primary prevention in healthy individuals, stricter therapeutic goals, comprehensive risk control, a more complete blocking of the renin-angiotensin system and the use of combinations of drugs with synergistic protective mechanisms.

Inhibition of the renin-angiotensin-aldosterone system: is there room for dual blockade in the cardiorenal continuum?

Antagonism of renin-angiotensin-aldosterone system is exerted through angiotensin-converting enzyme inhibitors, angiotensin receptor antagonists, renin inhibitors and mineralocorticoid receptor antagonists. These drugs have been successfully tested in numerous trials and in different clinical settings. The original indications of renin-angiotensin-aldosterone system blockers have progressively expanded from the advanced stages to the earlier stages of cardiorenal continuum. To optimize the degree of blockade of renin-angiotensin-aldosterone system, dose uptitrations of angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists or the use of a dual blockade, initially identified with the combination of angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists, have been proposed. The data from the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) study do not support this specific dual blockade approach. However, the dual blockade of angiotensin-converting enzyme inhibitors/angiotensin receptor antagonists with direct renin inhibitors is currently under investigation while that based on an aldosterone blocker with any of the previous three drugs requires more evidence beyond heart failure. In this review, we revisited potential advantages of dual blockade of renin-angiotensin-aldosterone system in arterial hypertension and diabetes.

Add-on aliskiren elicits stronger renoprotection than high-dose valsartan in type 2 diabetic KKAy mice that do not respond to low-dose valsartan

We hypothesized that aliskiren provides renoprotection in diabetic animals that did not receive sufficient renoprotection by AT1-receptor antagonist treatment. Type 2 diabetic KKAy mice were treated with group 1: vehicle or group 2: valsartan (15 mg/kg per day) from 12 to 16 weeks of age. The mice were subsequently divided into 4 groups and treated with the following combinations of drugs for another 6 weeks: 1: group 1 kept receiving vehicle, 2: group 2 continuously received 15 mg/kg per day of valsartan (Val-Val15), 3: group 2 received 50 mg/kg per day of valsartan (Val-Val50), 4: group 2 continuously received 15 mg/kg per day of valsartan with 25 mg/kg per day of aliskiren (Val-Val+Ali). Aliskiren exerted significant anti-albuminuric effects, whereas valsartan failed to ameliorate the albuminuria in the first four weeks. Surprisingly, the increasing dosage of valsartan in the Val-Val50 group showed non-significant tendencies to attenuate the albuminuria compared with vehicle infusion. Val-Val+Ali significantly suppressed the development of albuminuria and podocyte injury. Val-Val50 and Val-Val+Ali showed similar suppression of angiotensin II contents in the kidney of KKAy mice. In conclusion, the anti-albuminuric effect that was observed in the type 2 diabetic mice showing no anti-albuminuric effect by valsartan can be attributed to the add-on aliskiren.

Cardiorenal disease development under chronic renin–angiotensin–aldosterone system suppression

Drugs suppressing the renin-angiotensin-aldosterone system (RAAS) are now widely used to treat patients all along the cardiorenal continuum. It supposes that many patients, in particular those with arterial hypertension are treated with converting-enzyme inhibitors and angiotensin receptor blockers for years during which the development and prograssion of cardiorenal disease can be observed. The meaning of this progression in the presence of RAAS suppression requires to be clarified and to be treated in order to diminish the velocity of progression of cardiorenal disease.

Retarding the progression of chronic kidney disease with renin angiotensin system blockade

We assessed the effect of renin angiotensin system blockade (RASB) in chronic kidney disease (CKD) of diverse etiology. Two hundred and sixty-five consecutive CKD patients attending our renal clinic, with estimated glomerular filtration rate (eGFR) of 20-70 ml/min/1.73m(2) at baseline and a minimal follow-up of 1 year, were studied retrospectively. We devised a scoring system to quantify RASB, wherein the maximum dose of an agent recommended for control of hypertension was scored as 1. The renal endpoints studied were the rate of change in eGFR (ΔeGFR) and decline of eGFR>50%. The mean age was 48 ± 11.2 years and 69% were male. The mean duration of follow-up was 4 ± 2.7 years. The rate of ΔeGFR was -1.5 ± 5.0 ml/min/1.73 m(2) per year in patients who received RASB (N=168) and -6.0 ± 5.4 in those who did not (N=97) (P<0.001). The incidence of decline of eGFR >50% was 11.3% with RASB and 24.7% without (P=0.003). In a subgroup of patients who received RASB, the incidence of decline of eGFR >50% was 17.8% in the low-dose RASB group (N=84, RASB score 0.63 ± 0.38) and 4.8% in the high-dose group (N=84, RASB score 2.5 ± 0.7) (P=0.001). RASB was associated with significantly better renoprotection in CKD of diverse etiology, even in nonproteinuric diseases. This effect appeared to be dose-dependent, with higher supramaximal doses exhibiting better renoprotection than the lower conventional doses. Our results make a strong case for use of aggressive RASB in all CKD patients to postpone end-stage renal disease.

The effect of RAAS blockade on markers of renal tubular damage in diabetic nephropathy: u-NGAL, u-KIM1 and u-LFABP

AIM

Blockade of the renin-angiotensin-aldosterone system (RAAS) affects both the glomerulus and tubules. We aimed to investigate the effect of irbesartan on the tubular markers: urinary (u) neutrophil gelatinase associated protein (NGAL), Kidney injury molecule 1 (KIM1) and liver-fatty acid-binding protein (LFABP).

METHODS

A substudy of a double-masked, randomized, cross-over study including 52 patients with type 2 diabetes, hypertension and microalbuminuria. After 2 months washout of all antihypertensive medication except bendroflumethiazid, patients were treated in random order with irbesartan 300, 600 and 900 mg for 2 months.

END POINTS

Urinary tubular markers at baseline and after each treatment period (ELISA), 24-h blood pressure, glomerular filtration rate (GFR, (51)CrEDTA) and 24-h urine albumin excretion (UAER).

RESULTS

Fifty-two patients completed the study (41 male). Age (mean (SD)): 58(10) years and diabetes duration 13(8) years. Baseline GFR was 101(24) and UAER (geometric mean [95%CI]) 133 (103-172) mg/24 h. With increasing doses of irbesartan (300, 600, 900 mg) u-KIM1 was reduced with 15%, 10% and 15% (p = 0.07 between 300 mg vs. baseline and no difference between doses). Patients with high u-KIM1 at baseline (above median) had a 32% reduction in u-KIM1 during treatment (p = 0.01). No significant decline in U-NGAL compared to baseline. U-LFABP increased during treatment (p < 0.01).

CONCLUSIONS

Irbesartan treatment reduced levels of the tubular marker u-KIM1 in patients with type 2 diabetes and microalbuminuria. u-NGAL changed insignificantly and u-LFABP increased. More studies with longer follow up are needed to determine the role of tubular markers in monitoring treatment effect and prediction of prognosis in diabetic nephropathy.

[Slowing chronic kidney disease progression: hopes and disappointments. Vascular repair of chronic kidney]

In chronic kidney disease patients, inexorable renal function decline is reduced by renin-angiotensin system (RAS) blockers. ACE inhibitors and angiotensin receptor blockers decrease blood pressure and proteinuria. Guidelines recommend a reduction of blood pressure to less than 130/80 mmHg and urinary protein excretion below 0.5 g/d. The combined use of a diuretic increases anti-proteinuric effect and blood pressure control of RAS blockers. Drugs as mineralo-corticocoids receptor antagonist and endothelin receptor antagonists reduce further albuminuria in combination with RAS blocker, but side effects need to be precised. Both metabolic acidosis and hyperuricemia represent new therapeutic goals to slow renal function decline in CKD patients. Renal fibrosis treatment and regenerative medicine are stemming and will be important issues for kidney and other organs in the future.

Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure: randomised controlled trial

OBJECTIVE

To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE) inhibition at maximum dose.

DESIGN

Multicentre crossover randomised controlled trial.

SETTING

Outpatient clinics in the Netherlands.

PARTICIPANTS

52 patients with non-diabetic nephropathy.

INTERVENTIONS

All patients were treated during four 6 week periods, in random order, with angiotensin receptor blockade (valsartan 320 mg/day) or placebo, each combined with, consecutively, a low sodium diet (target 50 mmol Na(+)/day) and a regular sodium diet (target 200 mmol Na(+)/day), with a background of ACE inhibition (lisinopril 40 mg/day) during the entire study. The drug interventions were double blind; the dietary interventions were open label.

MAIN OUTCOME MEASURES

The primary outcome measure was proteinuria; the secondary outcome measure was blood pressure.

RESULTS

Mean urinary sodium excretion, a measure of dietary sodium intake, was 106 (SE 5) mmol Na(+)/day during a low sodium diet and 184 (6) mmol Na(+)/day during a regular sodium diet (P<0.001). Geometric mean residual proteinuria was 1.68 (95% confidence interval 1.31 to 2.14) g/day during ACE inhibition plus a regular sodium diet. Addition of angiotensin receptor blockade to ACE inhibition reduced proteinuria to 1.44 (1.07 to 1.93) g/day (P=0.003), addition of a low sodium diet reduced it to 0.85 (0.66 to 1.10) g/day (P<0.001), and addition of angiotensin receptor blockade plus a low sodium diet reduced it to 0.67 (0.50 to 0.91) g/day (P<0.001). The reduction of proteinuria by the addition of a low sodium diet to ACE inhibition (51%, 95% confidence interval 43% to 58%) was significantly larger (P<0.001) than the reduction of proteinuria by the addition of angiotensin receptor blockade to ACE inhibition (21%, (8% to 32%) and was comparable (P=0.009, not significant after Bonferroni correction) to the reduction of proteinuria by the addition of both angiotensin receptor blockade and a low sodium diet to ACE inhibition (62%, 53% to 70%). Mean systolic blood pressure was 134 (3) mm Hg during ACE inhibition plus a regular sodium diet. Mean systolic blood pressure was not significantly altered by the addition of angiotensin receptor blockade (131 (3) mm Hg; P=0.12) but was reduced by the addition of a low sodium diet (123 (2) mm Hg; P<0.001) and angiotensin receptor blockade plus a low sodium diet (121 (3) mm Hg; P<0.001) to ACE inhibition. The reduction of systolic blood pressure by the addition of a low sodium diet (7% (SE 1%)) was significantly larger (P=0.003) than the reduction of systolic blood pressure by the addition of angiotensin receptor blockade (2% (1)) and was similar (P=0.14) to the reduction of systolic blood pressure by the addition of both angiotensin receptor blockade and low sodium diet (9% (1)), to ACE inhibition.

CONCLUSIONS

Dietary sodium restriction to a level recommended in guidelines was more effective than dual blockade for reduction of proteinuria and blood pressure in non-diabetic nephropathy. The findings support the combined endeavours of patients and health professionals to reduce sodium intake. Trial registration Netherlands Trial Register NTR675.

Renin-angiotensin-aldosterone system blockade and urinary albumin excretion in community-based patients with Type 2 diabetes: the Fremantle Diabetes Study

AIMS

To determine whether the reduction in urinary albumin excretion through renin-angiotensin-aldosterone system blockade found in intervention trials extends to community-based patients with Type 2 diabetes.

METHODS

We analysed data from 302 participants in the longitudinal observational Fremantle Diabetes Study who commenced angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy during follow-up and who had an annual assessment on either side of this therapeutic change.

RESULTS

At baseline, the patients had a mean age of 63.8 years, a median diabetes duration of 4 years, a median HbA(1c) of 7.6% (60 mmol/mol) and a geometric mean (sd range) urinary albumin:creatinine ratio of 3.3 mg/mmol (0.8-13.1 mg/mmol). The percentages with normo-, micro- and macroalbuminuria were 49.0, 38.4 and 12.6%, respectively. During 6.1 ± 1.7 years of follow-up, initiation of renin-angiotensin-aldosterone system blockade was associated with a larger geometric mean (sd range) absolute albumin:creatinine ratio reduction in the patients with macroalbuminuria compared with those who had either normo- or microalbuminuria [-40.9 (-825.7 to 159.9) mg/mmol) vs. 1.7 (-1.6 to 20.0) mg/mmol and -0.5 (-23.0 to 39.5) mg/mmol, respectively; P < 0.001]. These changes remained significant after adjustment for changes in blood pressure and other potentially confounding variables, including drug dose and angiotensin-converting enzyme genotype. The post-treatment median albumin:creatinine ratios were 35.4 and 27.4% lower than before treatment in those with micro- or macroalbuminuria, respectively.

CONCLUSIONS

Usual-care initiation of renin-angiotensin-aldosterone system blockade confers a quantitatively similar renal benefit to that in intervention trials in Type 2 diabetes.

Therapeutic approaches in lowering albuminuria: travels along the renin-angiotensin-aldosterone-system pathway

Achieving optimal blood pressure and albuminuria control is a major therapeutic treatment goal in patients with renal insufficiency. Angiotensin-converting enzyme-inhibitors (ACEIs) and angiotensin-receptor blockers (ARB) are the mainstay of therapy in these patients. However, despite these therapies many patients remain at high risk of renal or cardiovascular disease that shows a relationship with albuminuria. Various approaches have been tested to maximize the efficacy of ACEI and ARB. Increasing the dose of an ACEI or ARB beyond the maximal registered antihypertensive dose causes a distinct decrease in albuminuria without additional effects on blood pressure. The combination of an ACEI and ARB is another possibility to further reduce albuminuria. However, the alleged beneficial effects on hard renal and cardiovascular outcome are not unambiguously demonstrated. Adding a direct renin inhibitor to an ACEI or ARB has been shown to lower albuminuria in patients with and without diabetes. Long-term trials are currently under way to determine the effects of direct renin inhibition on clinical outcomes. Volume excess has been shown to blunt the blood pressure and albuminuria response to ACEI or ARB therapy. Intervening in volume status by means of restricting dietary sodium intake or diuretic therapy has convincingly been shown to lower blood pressure and albuminuria. Whether this strategy translates into a reduction in the risk of renal or cardiovascular events has not (yet) been investigated in prospective randomized trials. Various options are at hand which have been shown to maximize the blood pressure and albuminuria response to ACEI and ARB treatment. However, long-term studies supporting the benefits of these strategies on hard renal and cardiovascular outcomes are warranted.

Effective antihypertensive strategies for high-risk patients with diabetic nephropathy

AIM

Clinical guidelines recommend blood pressure (BP) lowering and renin-angiotensin-aldosterone system inhibition to slow kidney disease progression in patients with diabetic nephropathy. This study's purpose was to determine whether an antihypertensive regimen including a maximally dosed angiotensin-converting enzyme inhibitor could safely achieve target BP in indigent, predominantly minority patients with this disease.

METHODS

We studied 81 hypertensive adults (52% Hispanic and 31% African American) with nephropathy attributed to type 1 or 2 diabetes during the run-in period of a randomized controlled trial. The subjects received lisinopril titrated to 80 mg daily and additional antihypertensives to target a systolic BP (SBP) lower than 130 mm Hg. Blood pressure and serum potassium level were measured weekly, and a 4-gram sodium diet was prescribed. The primary outcome variable was SBP change from screening to randomization. Success in achieving SBP goal, change in urine albumin-creatinine ratio, hyperkalemia (serum potassium ≥5.5 mmol/L) and hypotension (SBP < 100 mm Hg) were also analyzed.

RESULTS

The median SBP decreased from 144 to 133 mm Hg (median change, -9.6%.) Fifty-eight (71%) achieved goal SBP during run-in. The median UACR decreased from 206.8 to 112.7 mg/mmol (median change, -42.7%). The UACR reduction correlated with SBP reduction. Seventeen subjects experienced hyperkalemia responsive to dietary/medical management. Two subjects experienced hypotension responsive to medication adjustments.

CONCLUSION

A regimen using a maximally dosed angiotensin-converting enzyme inhibitor is safe and effective for achieving BP goal in high-risk, predominantly minority patients with diabetic nephropathy. Implementing this regimen necessitates close monitoring of serum potassium level.