Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. The Angiotensin-Converting-Enzyme Inhibition in Progressive Renal Insufficiency Study Group

Chronic kidney disease after pediatric hematopoietic cell transplant

There are 3 clearly distinct clinical entities that occur after HCT: TMA, idiopathic CKD, and nephrotic syndrome. The potentially independent role of GVHD and chronic inflammation in the development and progression of idiopathic CKD warrants further investigation. CKD after HCT is a relatively common occurrence. As the indications for and number of transplants performed world wide increases, so will the burden of kidney disease. Identifying those patients at risk for the development of CKD will be important for potential intervention and prevention of CKD and progression to end-stage renal disease in this patient population. There are those patients who will develop CKD that is not related to TBI or the conditioning regimen but rather to complications and/or therapy that occur after HCT, specifically aGVHD and cGVHD and prolonged calcinuerin inhibitor use. The burden of management will fall not only to the nephrologists but the oncologist as well to ensure close monitoring of renal function, blood pressure, and urinalyses posttransplant. It may be that our energies have been misdirected in trying to reduce exposure to TBI, and rather we should try to decrease the inflammatory and cytokine effects of GVHD and reduce exposure to calcineurin inhibitors to prevent CKD in this population of patients.

ACEI/ARB therapy for IgA nephropathy: a meta analysis of randomised controlled trials

BACKGROUND

Published reports examining the efficacy of RAS blockers: angiotensin converting-enzyme inhibitor (ACEI) and angiotensin II receptor blocker (ARB) agents for preserving renal function in IgA nephropathy (IgAN) have yielded conflicting results. To evaluate systematically the effects of ACEI/ARB agents on IgAN, we conducted a meta analysis of published randomised controlled trials (RCTs).

METHODS

MEDLINE, EMBASE, the Cochrane Library and article reference lists were searched for RCTs that compared ACEI/ARB with placebo and any other antihypertensive agents or non-immunosuppressive agents for treating IgAN. The quality of the studies was evaluated with the method of intention to treat analysis and allocation concealment, as well as with the Jadad method. Meta analyses were performed on the outcomes of proteinuria and renal function in patients with IgAN.

RESULTS

Eleven RCTs involving 585 patients were included in the review. Seven trials used placebo/no treatment as controls. Four trials used other antihypertensive agents as controls. Overall, ACEI/ARB agents had statistically significant effects on protecting renal function(p < 0.00001) and reduction of proteinuria (p < 0.00001) when compared with control group. Tests for heterogeneity showed no difference in effect among the studies. Systolic and diastolic blood pressure, glomerular filtration rate (GFR), age, did not influence treatment response. ACEI/ARB agents were well tolerated.

CONCLUSIONS

The current cumulative evidence suggests that ACEI/ARB agents had statistically significant effects on protecting renal function and reduction of proteinuria in patients with IgAN when compared with control groups. ACEI/ ARB agents are a promising medication and should be investigated further.

Physicians make different decisions from nephrologists at serum creatinine 2.0 mg/dl

BACKGROUND

It is very important, but not clear, how physicians differ from nephrologists in treatment of renal insufficiency.

AIM

To demonstrate differences in decision-making in treatment of renal insufficiency between physicians and nephrologists.

DESIGN OF STUDY

Postal questionnaire.

SETTING

All physicians were graduates from one medical school and certified by the Japanese Society of Internal Medicine. Nephrologists were certified by the Society and the Japanese Society of Nephrology.

METHOD

Questionnaires were sent to 1,395 physicians and 385 nephrologists, including audit of serum creatinine concentration that would indicate referral to nephrologist, audit of continuation of angiotensin converting enzyme inhibitor (ACEI) for a case of renal insufficiency and mild hyperkalemia due to ACEI. Outputs were proportion that selected "serum creatinine 177 micromol/l (2.0 mg/dl) and over" as a referral point to the nephrologist, and proportion that chose "suspend ACEI" for a case of renal insufficiency and mild hyperkalemia due to ACEI.

RESULTS

Six hundred and fourteen physicians replied (44%), and 111 certified in internal medicine were extracted from them. One hundred and eighty-six certified nephrologists replied (47%), and 114 certified in internal medicine were extracted. The proportion that chose "177 micromol/l" as a referral point to the nephrologist was 20% for physicians and 61% for nephrologists (P < 0.0001). An additional 17% of nephrologists recommended creatinine concentration below 177 micromol/l, whereas no such opinion was found among physicians. The proportion that chose "suspend ACEI" was 45% for physicians and 16% for nephrologists (P < 0.0001).

CONCLUSION

There is significant difference between decisions made by physicians and nephrologists regarding treatment for patients with serum creatinine concentration of 177 micromol/l.

Efficacy and safety of lisinopril for mild childhood IgA nephropathy: a pilot study

Even in children with mild immunoglobulin (Ig)A nephropathy (IgA-N) showing minimal/focal mesangial proliferation, persistent proteinuria seems to be a risk factor for progression of the disease, indicating the need for an effective and safe treatment even in such cases. Studies carried out to date have indicated that angiotensin-converting enzyme inhibitors (ACEIs) reduce urinary protein excretion and preserve renal function in adult IgA-N. However, no prospective study of ACEI only for childhood IgA-N has yet been carried out. In this prospective single-arm pilot trial, we administered lisinopril (0.4 mg/kg per day) as therapeutic treatment to 40 children with mild IgA-N with proteinuria [morning urinary protein/creatinine ratio (uP/Cr) >or= 0.2 g/g]. Thirty-three patients reached the primary endpoint (uP/Cr < 0.2) during the 2-year treatment period. The cumulative disappearance rate of proteinuria determined by the Kaplan-Meier method was 80.9%. Mean uP excretion was reduced from 0.40 to 0.18 g/m(2)/day (p < 0.0001). Of the 40 patients treated, five (12.5%) showed dizziness, and four of these five needed the lisinopril dose reduced. However, lisinopril therapy was continued in all patients during the 2-year treatment period. No other side effect, such as cough, was observed. We conclude that the efficacy and safety of lisinopril is seemingly acceptable for the treatment of children with mild IgA-N.

Cardiovascular abnormalities in autosomal-dominant polycystic kidney disease

Cardiovascular problems are a major cause of morbidity and mortality in patients with autosomal-dominant polycystic kidney disease (ADPKD). Hypertension is a common early symptom of ADPKD, and occurs in approximately 60% of patients before renal function has become impaired. Hypertension is associated with an increased rate of progression to end-stage renal disease and is the most important potentially treatable variable in ADPKD. Left ventricular hypertrophy, which is a powerful, independent risk factor for cardiovascular morbidity and mortality, also occurs frequently in patients with ADPKD. Both hypertension and left ventricular hypertrophy have important roles in cardiovascular complications in these individuals. Moreover, biventricular diastolic dysfunction, endothelial dysfunction, increased carotid intima-media thickness, and impaired coronary flow velocity reserve are present even in young patients with ADPKD who have normal blood pressure and well-preserved renal function. These findings suggest that cardiovascular involvement starts very early in the course of ADPKD. Intracranial and extracranial aneurysms and cardiac valvular defects are other potential cardiovascular problems in patients with ADPKD. Early diagnosis and treatment of hypertension, with drugs that block the renin-angiotensin-aldosterone system, has the potential to decrease the cardiovascular complications and slow the progression of renal disease in ADPKD.

Macrovascular Complications of Diabetes Mellitus

Adults with diabetes mellitus frequently develop macrovascular complications. Vascular disease is a frequent cause of morbidity and mortality among patients with diabetes. Diabetes and vascular diseases remain among the most common causes of death in the United States. A number of clinical trials and practice guidelines have been published addressing the management of macrovascular complications. The cornerstone of preventing or delaying the progression of macrovascular complications of diabetes is aggressive management of hypertension and cholesterol. Angiotensin-converting enzyme inhibitors have proven effective in managing hypertension and avoiding other complications of diabetes. The body of evidence for angiotensin receptor blockers is growing in this area as well. Statins have been repeatedly proven to be the first-line agents in the management of dyslipidemia. Lifestyle modification strategies and antiplatelet therapy also remain essential. This review will focus on the role of newer diagnostic techniques, clinical trial evidence, and appropriate pharmacotherapy for macrovascular complications of diabetes.

Pro-active provision of drug information as a technique to address overdosing in intensive-care patients with renal insufficiency

PURPOSE

To correct overdosing of drugs requiring adjustment based on renal function in intensive-care patients.

METHODS

In a prospective intervention study, we estimated individual glomerular filtration rate and assessed whether medication required dose adjustment based on renal function. Senior clinicians received a structured report containing recommendations as to whether and how to adjust dosage in the individual patient (intervention). Prevalence of overdosed drugs (primary outcome), extent of overdoses, and reasons for nonacceptance of recommendations (secondary outcomes) were assessed.

RESULTS

Of 138 screened intensive-care patients, 68 (49%) had renal impairment, and 110 (14%) of the 805 prescribed drugs required consideration of renal function. A potential overdose was found in 53/110 drugs (48%) and this rate decreased to 26/110 (24%, P < 0.001) after the intervention. The average extent of overdose was reduced from 54% before to 31% after the intervention (P < 0.001). The main reasons expressed by the physicians for nonacceptance of recommendations were a large therapeutic index or minor overdoses of the involved drugs.

CONCLUSIONS

In intensive-care patients, overdosing of drugs requiring adjustment based on renal function is still very common. Drug information counselling significantly decreased the prevalence and extent of overdose.

Resistive index predicts renal prognosis in chronic kidney disease

BACKGROUND

While the clinical validity of Doppler ultrasonography in renal parenchymal disease is still controversial, we have previously reported that the resistive index (RI) and the atrophic index (AI) could estimate tubulointerstitial injury. We aimed to determine whether these indices could estimate renal prognosis in chronic kidney disease (CKD).

METHODS

We performed a 2-year follow-up study with an observational cohort of 311 CKD patients. The patients were examined by Doppler ultrasonography to calculate RI and AI to be calculated. Glomerular filtration rate (GFR) was estimated with the abbreviated MDRD study equation every 6 months.

RESULTS

When we divided the patients into three groups by the RI value of 0.65 and 0.70, there were significant differences in the decrease in GFR among the three groups at 24 months. Kaplan-Meier analysis also showed a significant difference among the three groups in the survival rate of worsening renal function, which was defined as a decrease in GFR of at least 20 mL/min 1.73 m(2) or the need for long-term dialysis therapy until the end of the 2-year follow-up. Cox proportional-hazard analysis identified overt proteinuria (> or =1.0 g/g creatinine), high RI (>0.70) and high systolic blood pressure (> or =140 mmHg) as independent predictors of worsening renal function. In contrast, AI was of no significance in evaluating renal prognosis in CKD.

CONCLUSIONS

This study suggested that RI, and proteinuria and hypertension were independent risk factors for the progression of CKD.

Slit diaphragm dysfunction in proteinuric states: identification of novel therapeutic targets for nephrotic syndrome

Several recent studies have demonstrated that the slit diaphragm of the glomerular epithelial cell (podocyte) is the structure likely to be the principal barrier in the glomerular capillary wall. Nephrin identified as a gene product mutated in congenital nephrotic syndrome located at the outer leaflet of plasma membranes of the slit diaphragm. The anti-nephrin antibody is capable of inducing massive proteinuria, which indicates that nephrin is a key functional molecule in the slit diaphragm. Expression of nephrin was reduced in glomeruli of minimal change nephrotic syndrome. Some recent studies demonstrated that podocin, CD2-associated protein and NEPH1 are also functional molecules in the slit diaphragm, and their expressions are altered in membranous nephropathy and also in focal glomerulosclerosis. These observations suggested that the alteration of the molecular arrangement in the slit diaphragm is involved in the development of proteinuria in several kinds of glomerular diseases. Recent studies of our group have demonstrated that type 1 receptor-mediated angiotensin II action reduced the expression of the slit diaphragm-associated molecules and that type 1 receptor blockade ameliorated proteinuria by preventing the function of angiotensin II on the slit diaphragm. By the subtraction hybridization techniques using glomerular cDNA of normal and proteinuric rats, we detected that synaptic vesicle protein 2B and ephrin B1 are involved in the maintenance of the barrier function of the slit diaphragm.

Quality of life in autosomal dominant polycystic kidney disease patients not yet on dialysis

BACKGROUND AND OBJECTIVES

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited progressive disorder associated with significant pain and discomfort affecting quality of life. This study determined the impact of pain medication use and other clinical, biochemical and genetic characteristics on the physical and mental well being of predialysis ADPKD patients using the Short Form 36 (SF-36) questionnaire.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The authors prospectively evaluated ADPKD patients in the Cohort Study, funded by the Polycystic Kidney Disease Foundation. Data on clinical, biochemical, and radiologic variables were collected in patients who were given the Short Form-36 questionnaire. Variables independently associated with the Physical Component Summary (PCS) and the Mental Component Summary (MCS) scores were identified.

RESULTS

One hundred fifty-two patients had a mean PCS and MCS of 46.9 +/- 11.3 and 51.0 +/- 9.0, similar to the general population and better than the ESRD population. Eleven (7%) reported pain medication intake within 1 mo of evaluation and demonstrated lower PCS than those not taking pain medications. Patients with GFR >or= 80 ml/min/1.73 m(2) had greater PCS than those with GFR < 80 ml/min/1.73 m(2). Age, BMI, pulse pressure, pain medication use, and education level independently associate with PCS and account for 32% of the variability of the measurement. Pulse pressure correlated with MCS.

CONCLUSIONS

Predialysis ADPKD patients assess their quality of life similar to the general population. Age, BMI, pulse pressure, pain medication intake, and education level link to their physical well-being.

Therapies for feline chronic kidney disease. What is the evidence?

Practical relevance Successful treatment and prevention of kidney disease in pet animals requires a multidimensional approach to identify and eliminate causes or exacerbating factors, provide professional examination and care on a regular basis, and plan and implement a comprehensive treatment program when necessary.

Evidence base Over the years, many therapeutic and preventive interventions have been developed or advocated for chronic kidney disease (CKD), but evidence of efficacy or effectiveness is often lacking or highly variable. Accordingly, the main objective of this systematic review was to identify and critically appraise the evidence supporting various approaches to managing feline CKD; namely, fluid therapy, calcitrioi therapy, antihypertensive therapy, ACE inhibitor therapy, erythropoietic hormone replacement therapy, potassium supplementation, antioxidant supplementation, alkalinization therapy, dietary phosphorus restriction and intestinal phosphate binders, therapeutic renal foods, assisted feeding, dialysis and renal transplantation.

Proteinuria in cats. Prognostic marker or mediator?

Practical relevance Numerous tests are available to the practitioner for quantifying proteinuria. It is important to understand the advantages and limitations of these tests and how the information gained can contribute to optimal patient management.

Patient group Cats with chronic kidney disease or systemic hypertension, as well as geriatric cats without overt evidence of disease (including renal dysfunction), are at particular risk of proteinuria. Evidence base Several longitudinal studies of cats seen in first opinion clinics have shown an association between proteinuria and decreased survival time. However, it is unknown whether the deaths that occur in proteinuric cats are due to progression of renal disease because it is often difficult to ascribe a cause of death to a single underlying aetiology in clinical patients. It is also unknown whether proteinuria is contributing to disease progression in these cats or whether proteinuric renal disease is intrinsically more rapidly progressive.

Clinical significance More aggressive investigation and management of patients with proteinuria may be appropriate since they are more likely to have progressive disease and/or increased mortality.

Effect of pentoxifylline on GFR decline in CKD: a pilot, double-blind, randomized, placebo-controlled trial

BACKGROUND

Pentoxifylline is a nonspecific phosphodiesterase inhibitor with anti-inflammatory properties. It reduces proteinuria in patients with glomerular disease, although its impact on glomerular filtration rate (GFR) is unknown. We hypothesized that pentoxifylline would slow the estimated GFR decrease in patients with chronic kidney disease at high risk of progression.

STUDY DESIGN

Pilot randomized double-blind placebo-controlled trial.

SETTING & PARTICIPANTS

40 outpatients with decreased GFR, hypertension, and proteinuria greater than 1 g/24 h currently treated with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or the combination and followed up in a nephrology clinic at a tertiary medical care facility.

INTERVENTION

Pentoxifylline, 400 mg twice daily, or matching placebo.

OUTCOMES

Difference in rates of estimated GFR change during the 1-year study period between the 2 groups.

MEASUREMENTS

Estimated GFR (4-variable Modification of Diet in Renal Disease Study equation) and proteinuria by 24-hour urine collection were assessed at baseline and 6 and 12 months after enrollment.

RESULTS

Baseline characteristics were similar between the 2 groups. At 1 year, the mean estimated GFR decrease was significantly less in the pentoxifylline group than the placebo group (-1.2 +/- 7.0 versus -7.2 +/- 8.2 mL/min/1.73 m2/y; mean difference, -6.0 mL/min/1.73 m2/y; 95% confidence interval, -11.4 to -0.6; P = 0.03). For pentoxifylline-treated participants, the mean estimated GFR decrease during treatment was slower compared with the year before study enrollment (-9.6 +/- 11.9 mL/min/1.73 m2/y; mean difference, -8.4 mL/min/1.73 m2/y; 95% confidence interval, -14.8 to -2.1; P = 0.01). Proteinuria was not different between the pentoxifylline and placebo groups at baseline, 6 months, or 1 year.

LIMITATIONS

Small sample size and incomplete follow-up.

CONCLUSIONS

Pentoxifylline may slow the estimated GFR decrease in high-risk patients. This may be independent of its antiproteinuric properties and warrants further investigation.

Cardiovascular disease in chronic kidney disease

The presence of kidney disease, manifested by low glomerular filtration rates (GFR) and/or large amounts of protein in the urine, is independently associated with increased rates of cardiovascular disease (CVD). The severity of kidney disease is associated with graded increases in risk for CVD and death. Chronic kidney disease (CKD) should be recognized and treatment initiated early to maximize the chances for slowing nephropathy progression and reducing proteinuria. We recommend screening for CKD in all patients with CVD, including computing an estimated GFR and evaluating for proteinuria using a spot urine albumin:creatinine ratio. Aggressive management of traditional cardiovascular risk factors should be employed in this high-risk population, specifically rigorous hypertension control (including the use of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blocking agents (ARB)), management of hyperglycemia, hyperlipidemia and smoking cessation. Further studies are needed to identify the unique renal failure-related (non-traditional) risk factors that contribute to accelerated atherosclerosis in this population and performance of randomized trials to assess the effects of cardiovascular interventions in individuals with CKD.

[Chronic renal insufficiency and cardiovascular disease]

Renal insufficiency is frequently seen in patients with cardiovascular disease. In contrast, coronary artery disease is the leading cause of death in patients with renal impairment. The recognition of renal insufficiency is essential in these patients and preventive measures must be put in place to prevent the progression or onset of cardiovascular disease. In this article, we explain the methods to assess kidney function, the epidemiology of coronary heart disease in patients with renal impairment, risk factors conventional and non-conventional found in these patients and the main recommendations for their therapeutic care.

Phosphorylation of Nephrin Triggers Ca2+ Signaling by Recruitment and Activation of Phospholipase C-{gamma}1

A specialized intercellular junction between podocytes, known as the slit diaphragm (SD), forms the essential structural frame-work for glomerular filtration in the kidney. In addition, mounting evidence demonstrates that the SD also plays a crucial role as a signaling platform in physiological and pathological states. Nephrin, the major component of the SD, is tyrosine-phosphorylated by a Src family tyrosine kinase, Fyn, in developing or injured podocytes, recruiting Nck to Nephrin via its Src homology 2 domain to regulate dynamic actin remodeling. Dysregulated Ca(2+) homeostasis has also been implicated in podocyte damage, but the mechanism of how podocytes respond to injury is largely unknown. Here we have identified phospholipase C-gamma1 (PLC-gamma1) as a novel phospho-Nephrin-binding protein. When HEK293T cells expressing a chimeric protein consisting of CD8 and Nephrin cytoplasmic domain (CD) were treated with anti-CD8 and anti-mouse antibodies, clustering of Nephrin and phosphorylation of Nephrin-CD were induced. Upon this clustering, PLC-gamma1 was bound to phosphorylated Nephrin Tyr-1204, which induced translocation of PLC-gamma1 from cytoplasm to the CD8/Nephrin cluster on the plasma membrane. The recruitment of PLC-gamma1 to Nephrin activated PLC-gamma1, as detected by phosphorylation of PLC-gamma1 Tyr-783 and increase in inositol 1,4,5-trisphosphate level. We also found that Nephrin Tyr-1204 phosphorylation triggers the Ca(2+) response in a PLC-gamma1-dependent fashion. Furthermore, PLC-gamma1 is significantly phosphorylated in injured podocytes in vivo. Given the profound effect of PLC-gamma in diverse cellular functions, regulation of the Ca(2+) signaling by Nephrin may be important in modulating the glomerular filtration barrier function.

Renoprotective effect of calcium channel blockers

The advancing chronic renal failure is at most the consequence of secondary haemodynamic and metabolic factors as intraglomerular hypertension and glomerular hypertrophy. Although tight blood pressure control is the major preventive mechanism for progressive renal failure, ACE inhibitors and angiotensin receptor blockers have some other renoprotective mechanisms beyond the blood pressure control. That is why these two groups of antihypertensive drugs traditionally have advantages in treating renal patients especially those with proteinuria over 400-1000 mg/day. Even if earlier experimental studies have shown renoprotective effect of calcium channel blockers, later clinical studies did not prove that calcium channel blockers have any advantages in renal protection over ACE inhibitors given as monotherapy or in combination with ACE inhibitors. It was explained by action of calcium channel blockers on afferent but not on efferent glomerular arterioles; a well known mechanism that leads to intraglomerular hypertension. New generations of dihydropiridine calcium channel blockers can dilate even efferent arterioles not causing unfavorable haemodynamic disturbances. This finding was confirmed in clinical studies which showed that renoprotection established by calcium channel blockers was not inferior to that of ACE inhibitors and that calcium channel blockers and ACE inhibitors have additive effect on renoprotection. Newer generation of dihydropiridine calcium channel blockers seem to offer more therapeutic possibilities in renoprotection by their dual action on afferent and efferent glomerular arterioles and, possibly by other effects beyond the blood pressure control.

Design of combination angiotensin receptor blocker and angiotensin-converting enzyme inhibitor for treatment of diabetic nephropathy (VA NEPHRON-D)

Both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) can slow the progression of diabetic nephropathy. Even with ACEI or ARB treatment, the proportion of patients who progress to end-stage renal disease (ESRD) remains high. Interventions that achieve more complete blockade of the renin-angiotensin system, such as combination ACEI and ARB, might be beneficial. This approach may decrease progression of nondiabetic kidney disease. In diabetic nephropathy, combination therapy decreases proteinuria, but its effect in slowing progression is unknown. In addition, the potential for hyperkalemia may limit the utility of combined therapy in this population. VA NEPHRON-D is a randomized, double-blind, multicenter clinical trial to assess the effect of combination losartan and lisinopril, compared with losartan alone, on the progression of kidney disease in 1850 patients with diabetes and overt proteinuria. The primary endpoints are time to (1) reduction in estimated GFR (eGFR) of > 50% (if baseline < 60 ml/min/1.73 m(2)); (2) reduction in eGFR of 30 ml/min/1.73 m(2) (if baseline > or = 60 ml/min/1.73 m(2)); (3) progression to ESRD (need for dialysis, renal transplant, or eGFR < 15 ml/min/1.73 m(2)); or (4) death. The secondary endpoint is time to change in eGFR or ESRD. Tertiary endpoints are cardiovascular events, slope of change in eGFR, and change in albuminuria at 1 yr. Specific safety endpoints are serious hyperkalemia (potassium > 6 mEq/L, requiring admission, emergency room visit, or dialysis), all-cause mortality, and other serious adverse events. This paper discusses the design and key methodological issues that arose during the planning of the study.

Chronic kidney disease at high altitude

With a prevalence of 10 to 11% in the general population, it is likely that many patients with chronic kidney disease will visit or reside in mountainous areas. Little is known, however, about whether short- or long-duration, high-altitude exposure poses a risk in this patient population. Given that many areas of the kidney are marginally oxygenated even at sea level and that kidney disease may result in further renal hypoxia and hypoxia-associated renal injury, there is concern that high altitude may accelerate the progression of chronic kidney disease. In this review, we address how chronic kidney disease and its management is affected at high altitude. We postulate that arterial hypoxemia at high altitude poses a risk of faster disease progression in those with preexisting kidney disease. In addition, we consider the risks of developing acute altitude illness in patients with chronic kidney disease and the appropriate use of medications for the prevention and treatment of these problems.

Agents in development for the treatment of diabetic nephropathy

BACKGROUND

Nephropathy is a major cause of morbidity and mortality in diabetic patients. Current treatments include optimization of glycemic and blood pressure control, but more innovative strategies are needed for the prevention and treatment of diabetic nephropathy.

OBJECTIVES

To review emerging therapies for diabetic nephropathy.

METHODS

This paper discusses the molecular mechanisms of diabetic nephropathy and the potential therapeutic interventions.

RESULTS/CONCLUSION

New therapies, including those targeting the accumulation of advanced glycation end products (AGEs) and reactive oxygen species (ROS) generation, are likely to feature in future treatment regimens. Other approaches that at this stage do not appear to be progressing include the glycosaminoglycan sulodexide and the protein kinase C-beta (PKC-beta) inhibitor, ruboxistaurin.

Associations between proteinuria, systemic hypertension and glomerular filtration rate in dogs with renal and non-renal diseases

Proteinuria and systemic hypertension are well recognised risk factors in chronic renal failure (CRF). They are consequences of renal disease but also lead to a further loss of functional kidney tissue. The objectives of this study were to investigate the associations between proteinuria, systemic hypertension and glomerular filtration rate (GFR) in dogs with naturally occurring renal and non-renal diseases, and to determine whether proteinuria and hypertension were associated with shorter survival times in dogs with CRF. Measurements of exogenous creatinine plasma clearance (ECPC), urine protein:creatinine ratio (UPC), and Doppler sonographic measurements of systolic blood pressure (SBP) were made in 60 dogs with various diseases. There was a weak but significant inverse correlation between UPC and ECPC, a significant inverse correlation between SBP and ECPC and a weak but significant positive correlation between UPC and SBP. Some of the dogs with CRF were proteinuric and almost all were hypertensive. Neoplasia was commonly associated with proteinuria in the dogs with a normal ECPC. CRF was the most common cause leading to hypertension. In the dogs with CRF, hypertension and marked proteinuria were associated with significantly shorter survival times.

Reduction of proteinuria with angiotensin receptor blockers

Renal pathophysiology is elicited by activation of angiotensin II type 1 (AT(1)) receptors at all stages of renovascular disease. Angiotensin receptor blockers (ARBs) that specifically block the AT(1) receptor offer the potential to prevent or delay progression to end-stage renal disease independently of reductions in blood pressure. Proteinuria--an early and sensitive marker for progressive renal dysfunction--is reduced by ARB use in patients with type 2 diabetic nephropathy and microalbuminuria or macroalbuminuria. Retrospective analysis of data available from early trials has confirmed this finding and has shown that albuminuria reduction is associated with lessening of cardiovascular risk. The ARB telmisartan is equivalent to enalapril in preventing glomerular filtration rate decline, and equivalent to valsartan in reducing proteinuria. Telmisartan is more effective than conventional therapy in lowering the risk of transition to overt nephropathy in hypertensive and normotensive patients. An additive effect has been seen in smaller studies when telmisartan has been added to lisinopril therapy, and high-dose telmisartan reduces albuminuria better than low-dose telmisartan. Similar data were obtained with other ARBs such as candesartan, losartan, valsartan, or irbesartan. These data support the proposition that blockade of the renin-angiotensin system beyond that required for maximum blood pressure reduction provides optimum renal protection.

Combination therapy of prednisone and ACE inhibitor versus ACE-inhibitor therapy alone in patients with IgA nephropathy: a randomized controlled trial

BACKGROUND

Recent studies have shown that both steroids and angiotensin-converting enzyme (ACE) inhibitors improve kidney survival and decrease proteinuria in patients with immunoglobulin A nephropathy. In this study, we aim to investigate whether the addition of steroids to ACE-inhibitor therapy produces a more potent antiproteinuric effect and better protection of kidney function than an ACE inhibitor alone.

STUDY DESIGN

Randomized controlled trial.

SETTING & PARTICIPANTS

Patients with biopsy-proven immunoglobulin A nephropathy with proteinuria of 1 to 5 g/d of protein.

INTERVENTION

63 patients were randomly assigned to either cilazapril alone (ACE-inhibitor group; n = 30) or steroid plus cilazapril (combination group; n = 33).

OUTCOMES & MEASUREMENTS

The primary end point was kidney survival, defined as a 50% increase in baseline serum creatinine level.

RESULTS

After follow-up for up to 48 months, 7 patients in the ACE-inhibitor group (24.1%) reached the primary end point compared with 1 patient (3%) in the combination group. Kaplan-Meier kidney survival was significantly better in the combination group than the ACE-inhibitor group after 24 and 36 months (96.6% versus 75.7%, 96.6% versus 66.2%; P = 0.001). Urine protein excretion significantly decreased in patients in the combination group compared with the ACE-inhibitor group (time-average proteinuria, 1.04 +/- 0.54 versus 1.57 +/- 0.86 g/d of protein; P = 0.01). Multivariate analysis showed that combination treatment (hazard ratio, 0.1; 95% confidence interval, 0.014 to 0.946) and time-average proteinuria (hazard ratio, 14.3; 95% confidence interval, 2.86 to 71.92) were independent predictors of kidney survival.

LIMITATIONS

Small sample size, a single center, and slight imbalances at baseline.

CONCLUSIONS

Our results suggest that the addition of steroid to ACE-inhibitor therapy provided additional benefit compared with an ACE inhibitor alone. However, this was a pilot study with a small number of participants achieving the end points, and thus further validation is necessary.

Present and future drug treatments for chronic kidney diseases: evolving targets in renoprotection

At present, there are no specific cures for most of the acquired chronic kidney diseases, and renal transplantation is limited by organ shortage, therefore present efforts are concentrated on the prevention of progression of renal diseases. There is robust experimental and clinical evidence that progression of chronic nephropathies is multifactorial; however, intraglomerular haemodynamic changes and proteinuria play a key role in this process. With a focus on renoprotection, we first examine more established therapies--such as those that modulate the renin-angiotensin-aldosterone system--that can be used for the treatment of proteinuric renal diseases. We then discuss examples of novel drugs and biologics that might be used to target the inflammatory and profibrotic process, and glomerular injury, highlighting results from recent clinical trials.

Epidemiology of chronic kidney disease in heart failure

Heart failure is common and is associated with a poor prognosis. Chronic kidney disease is common in heart failure and shares many risk factors with heart failure, such as age, hypertension, diabetes, and coronary artery disease. Over half of all patients who have heart failure may have moderate-to-severe chronic kidney disease. The presence of chronic kidney disease is associated with increased morbidity and mortality, yet it is also associated with underuse of evidence-based heart failure therapy that may reduce morbidity and mortality. Understanding the epidemiology and outcomes of chronic kidney disease in heart failure is essential to ensure proper management of these patients.

A Novel Sartan Derivative With Very Low Angiotensin II Type 1 Receptor Affinity Protects the Kidney in Type 2 Diabetic Rats

Background— Antihypertensive angiotensin II receptor blockers (ARBs) protect the kidney, at least in part, independently of blood pressure lowering. Still, the extent to which blood pressure lowering is related to renoprotection remains unclear.

Methods and Results— 139 newly synthesized ARB-derivatives were assayed for inhibition of advanced glycation (AGEs). The 9 most powerful compounds were then tested for transition metal chelation, angiotensin II type 1 receptor (AT1R) affinity, and pharmacokinetic parameters. R-147176 was eventually selected as it strongly inhibits advanced glycation but is 6700 times less effective than olmesartan in AT1R binding. It is orally bioavailable and toxicologically safe. Despite a minimal blood pressure lowering effect, it provides significant renoprotection in 3 experimental rat models with renal injury, ie, obese, hypertensive, type 2 diabetic rats (SHR/NDmcr-cp), normotensive type 2 diabetic rats (Zucker diabetic fatty), and remnant kidney rats.

Conclusion— R-147176 retains renal protective properties despite a minimal blood pressure–lowering effect. Clearly, the renal benefits of ARBs do not necessarily depend on blood pressure lowering and AT1R affinity, but rather on the inhibition of AGEs and oxidative stress inherent to their chemical structure. R-147176 opens new avenues in the treatment of cardiovascular and kidney diseases.

Evidence-based guide to slowing the progression of early renal insufficiency

Early renal insufficiency (ERI), defined as a calculated or measured glomerular filtration rate (GFR) between 30 and 60 mL/min per 1.73 m2, is present in more than 10% of the adult Australian population. This pernicious condition is frequently unrecognised, progressive and accompanied by multiple associated comorbidities, including hypertension, renal osteodystrophy, anaemia, sleep apnoea, cardiovascular disease, hyperparathyroidism and malnutrition. Several treatments have been suggested to retard GFR decline in ERI, including blood pressure reduction, angiotensin-converting enzyme inhibition, angiotensin receptor antagonism, calcium channel blockade, cholesterol reduction, smoking cessation, erythropoietin therapy, dietary protein restriction, intensive glycaemic control and early intensive multidisciplinary patient education within a renal unit. In addition, specific interventions have been reported to be renoprotective in atherosclerotic renal artery stenosis, diabetic nephropathy, lupus nephritis and certain forms of primary glomerulonephritis. The present paper reviews the available published randomised controlled clinical trials and meta-analyses supporting (or refuting) a role for each of these therapeutic manoeuvres.

Clinical factors affecting serum potassium concentration in cardio-renal decompensation syndrome

BACKGROUND

Renin-angiotensin-aldosterone system (RAAS) inhibitors are currently indispensable for the treatment of heart failure. It is well known that hyperkalemia is likely to occur in renal failure; however, it has not yet been clarified how the serum potassium concentration changes as heart failure progresses. Currently, the cardio-renal decompensation syndrome holds that the serum potassium concentration is altered similarly by both heart failure and renal failure; however, there are no definitive reports on this. In order to use RAAS inhibitors more safely and effectively in heart failure, it is necessary to understand the factors affecting serum potassium concentration in the clinical setting.

METHODS AND RESULTS

We examined the clinical factors affecting serum potassium concentration in 1035 consecutive patients with cardiovascular disease who were hospitalized in our institution. Multiple regression analysis showed that the independent factors associated with an elevated serum potassium concentration were renal insufficiency evaluated by estimated glomerular filtration rate (eGFR) (P<0.0001), diabetes mellitus evaluated by HbA(1c) (P=0.0005) and the use of RAAS inhibitors (P=0.0010). The independent factors associated with a decreased serum potassium concentration were mean blood pressure (P<0.0001), heart failure evaluated by log BNP (P=0.0164) and the use of diuretics (P=0.0232).

CONCLUSIONS

The serum potassium concentration decreases with the severity of heart failure if renal function is preserved. From the perspective of potassium homeostasis, we could use the RAAS inhibitors more aggressively in patients with heart failure who do not have renal failure.

Management of heart failure with renal artery ischemia

With improved treatment, patients are surviving longer with impaired ventricular function. Hypertension results in ventricular remodeling in many patients. More than 5 million people have heart failure and are likely to have one or more co-existent diseases associated with aging, one of which is chronic kidney disease (CKD). Renal artery stenosis is fraught with varying opinions. Nephrologists, cardiologists, and interventional radiologists all manage these diseases with different strategies. This article outlines renovascular disease as it relates to CKD, the pathophysiology of development of renovascular disease and effects leading to congestive heart failure, treatment modalities, and outcomes of treatment regimens.

Slowing chronic kidney disease progression: results of prospective clinical trials in adults

Chronic kidney disease is generally thought to be a progressive disorder regardless of etiology. Over the past 15 years, investigations into the mechanisms of disease progression and treatment designed to slow or halt disease progression have been conducted, largely in the adult kidney disease population. Intervention trials have demonstrated that lowering blood pressure in hypertensive patients and administration of drugs that block the renin-angiotensin aldosterone system are effective at slowing kidney disease progression, including diabetes, hypertension, and various glomerular diseases. In addition, novel strategies including anemia therapy with erythropoietin-stimulating agents have been conducted to determine whether treatment of this common complication of kidney disease can stabilize kidney function. Whereas substantial success has been achieved in more common forms of adult kidney disease such as diabetes and hypertension, slowing progression of some immune-mediated glomerular disease such as lupus nephritis and immunoglobulin A (IgA) nephropathy remain a great challenge. Moreover, there is no proven strategy, including multifactorial interventions, that clearly halts progressive chronic kidney disease that has been studied prospectively in a large-scale, long-term trial. The purpose of this review is to discuss these trials, as they form the underpinnings for current clinical practice guidelines in adults with chronic kidney disease.

Inhibition of the renin-angiotensin system and chronic kidney disease

Chronic kidney disease (CKD), a major worldwide public-health problem which affects about 10% of the population, has an increased annual incidence rate of about 5-8%. This increased incidence is mainly due to type 2 diabetes and hypertension and the increasing incidence of elderly patients with CKD. Although the progression to end-stage renal failure (ESRF) is mainly based upon the underlying disease, comorbid conditions such as an initial low renal function, severe proteinuria, and high levels of blood pressure also play important roles in the development of ESRF. Since experimental and clinical evidence suggest that angiotensin II plays a central role in the progression of CKD, pharmacological inhibition of the renin-angiotensin-aldosteron system (RAAS) with angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists has been suggested as first-line treatment for hypertension and prevention of ESRF in these patients. Aliskiren, a novel renin inhibitor is also a promising medical intervention. However, independently of the category of the drugs used, low target blood pressure levels seem to be equally or more important for the delay or prevention of CKD. In this review the results of studies with pharmacological inhibition of the RAAS in patients with diabetic and nondiabetic nephropathy is discussed.

Effects of renin-angiotensin system blockers on renal outcomes and all-cause mortality in patients with diabetic nephropathy: an updated meta-analysis

BACKGROUND

In contrast to previous studies, recent data questioned the ability of renin-angiotensin-aldosterone system (RAAS) blockers to delay progression of diabetic nephropathy. This study evaluated the effect of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) in patients with diabetic nephropathy.

METHODS

A systematic literature search of MEDLINE/PubMed and EMBASE databases was performed to identify randomized trials published up to June 2007 comparing the effects of ACEIs or ARBs with placebo and/or a regimen not including a RAAS blocker on the incidence of end-stage renal disease (ESRD), doubling of serum creatinine (DSC), or death from any cause in patients with diabetic nephropathy. Treatment effects were summarized as relative risks (RRs) using the Mantel-Haenszel fixed-effects model.

RESULTS

Of the 1,028 originally identified studies, 24 fulfilled the inclusion criteria (20 using ACEIs and 4 using ARBs). Use of ACEIs was associated with a trend toward reduction of ESRD incidence (RR 0.70; 95% confidence interval (CI) 0.46-1.05) and use of ARBs with significant reduction of ESRD risk (RR 0.78; 95% CI 0.67-0.91). Both drug classes were associated with reduction in the risk of DSC (RR 0.71; 95% CI 0.56-0.91 for ACEIs and RR 0.79; 95% CI 0.68-0.91 for ARBs) but none affected all-cause mortality (RR 0.96; 95% CI 0.85-1.09 for ACEIs and RR 0.99; 95% CI 0.85-1.16 for ARBs).

CONCLUSION

Treatment of patients with diabetic nephropathy with a RAAS blocker reduces the risks of ESRD and DSC, but does not affect all-cause mortality. These findings are added to the evidence of a renoprotective role of RAAS blockers in such patients.

Recognition and management of chronic kidney disease in an elderly ambulatory population

BACKGROUND

Chronic kidney disease (CKD) is a growing problem among the elderly. Early detection is considered essential to ensure proper treatment and to avoid drug toxicity, but detection is challenging because elderly patients with CKD often have normal serum creatinine levels. We hypothesized that most cases of CKD in the elderly would go undetected, resulting in inappropriate prescribing.

OBJECTIVE

To determine whether recognition of CKD is associated with more appropriate treatment

DESIGN

Retrospective chart review

PARTICIPANTS

All patients aged >/=65 years with a measured serum creatinine in the past 3 years at 2 inner city academic health centers.

MEASUREMENTS

Estimated glomerular filtration rate (eGFR) calculated using the Modified Diet in Renal Disease equation, and for patients with eGFR < 60, documentation of CKD by the provider, diagnostic testing, nephrology referral and prescription of appropriate or contraindicated medications.

RESULTS

Of 814 patients with sufficient information to estimate eGFR, 192 (33%) had moderate (eGFR < 60 mL/min) and 5% had severe (eGFR < 30 mL/min) CKD. Providers identified 38% of moderate and 87% of severe CKD. Compared to patients without recognized CKD, recognized patients were more likely to receive an ACE/ARB (80% vs 61%, p = .001), a nephrology referral (58% vs 2%, p < .0001), or urine testing (75% vs 47%, p < .0001), and less likely to receive contraindicated medications (26% vs 40%, p = .013).

CONCLUSIONS

Physicians frequently fail to diagnose CKD in the elderly, leading to inappropriate treatment. Efforts should focus on helping physicians better identify patients with low GFR.

Approaches to testing new treatments in autosomal dominant polycystic kidney disease: insights from the CRISP and HALT-PKD studies

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited systemic disease characterized by a prolonged subclinical course of gradual renal cyst expansion, resulting in massively enlarged kidneys and renal failure by the fifth to sixth decade. Renal cyst expansion results in intrarenal ischemia and activation of the renin-angiotensin-aldosterone system (RAAS) and relates to the development and maintenance of hypertension in ADPKD. Hypertension relates to disease progression in ADPKD with regard to renal volume, proteinuria, cardiovascular complications, and progression to end-stage renal disease. Novel magnetic resonance imaging methods developed in the Consortium for Radiologic Imaging for the Study of Polycystic Kidney Disease (CRISP) provide accurate estimates of change in renal volume over a short period of time in ADPKD patients with intact renal function. In CRISP an increase in renal volume of 63.4 ml/yr was found. PKD1 status, male gender, hypertension, reduced renal blood flow, and proteinuria are associated with increased renal volume and change in renal volume over time. HALT-Polycystic Kidney Disease (HALT-PKD) is designed to test whether blockade of RAAS and/or rigorous blood pressure control play a role in slowing renal progression during early (using magnetic resonance imaging methods developed in CRISP) and during late (using measures, including composite of time to doubling of serum creatinine, onset of end-stage renal disease, or death) phases in ADPKD. Findings from CRISP and the rationale for interventions in ADPKD are described, and the design of the HALT-PKD clinical trial is outlined.

Exaggerated renal pathology of partial ablation-induced chronic renal failure in eNOS deficient mice

We investigated the role of endothelial nitric oxide synthase (eNOS) in the remnant kidney model of chronic renal failure, by using eNOS-deficient (eNOS-/-) and wild-type mice. There were significant increments of blood urea nitrogen level, plasma creatinine concentration and proteinuria in both wild-type and eNOS-/- mice at 8 weeks after 5/6 nephrectomy, but observed changes were more prominent in eNOS-/- mice. Only 7 out of 30 eNOS-/- mice were alive during 8-week experimental period, whereas survival rate in the wild-type mice was 69%. The glomerular size distribution indicated that the glomeruli of 5/6 nephrectomized eNOS-/- mice tended to be larger compared with cases of wild-type mice. It seems likely that eNOS-derived NO is protective against renal injuries in this disease model.

A genome-wide search replicates evidence of a quantitative trait locus for circulating angiotensin I-converting enzyme (ACE) unlinked to the ACE gene

Background

Angiotensin I-converting enzyme (ACE) plays an important role in cardiovascular homeostasis. There is evidence from different ethnic groups that circulating ACE levels are influenced by a quantitative trait locus (QTL) at the ACE gene on chromosome 17. The finding of significant residual familial correlations in different ethnic groups, after accounting for this QTL, and the finding of support for linkage to a locus on chromosome 4 in Mexican-American families strongly suggest that there may well be QTLs for ACE unlinked to the ACE gene.

Methods

A genome-wide panel of microsatellite markers, and a panel of biallelic polymorphisms in the ACE gene were typed in Nigerian families. Single locus models with fixed parameters were used to test for linkage to circulating ACE with and without adjustment for the effects of the ACE gene polymorphisms.

Results

Strong evidence was found for D17S2193 (Z_max = 3.5); other nearby markers on chromosome 17 also showed modest support. After adjustment for the effects of the ACE gene locus, evidence of "suggestive linkage" to circulating ACE was found for D4S1629 (Z_max = 2.2); this marker is very close to a locus previously shown to be linked to circulating ACE levels in Mexican-American families.

Conclusion

In this report we have provided further support for the notion that there are QTLs for ACE unlinked to the ACE gene; our findings for chromosome 4, which appear to replicate the findings of a previous independent study, should be considered strong grounds for a more detailed examination of this region in the search for genes/variants which influence ACE levels.

The poor yields, thus far, in defining the genetic determinants of hypertension risk suggest a need to look beyond simple relationships between genotypes and the ultimate phenotype. In addition to incorporating information on important environmental exposures, a better understanding of the factors which influence the building blocks of the blood pressure homeostatic network is also required. Detailed studies of the genetic determinants of ACE, an important component of the renin-angiotensin system, have the potential to contribute to this strategic objective.

A cost-effectiveness analysis of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in diabetic nephropathy

The aim of this study was to estimate the cost-effectiveness of renin-angiotensin-aldosterone system blockers in patients with diabetic nephropathy. A cost-effectiveness analysis was performed based on a meta-analysis of studies investigating the effect of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) as part of a treatment regimen on the incidence of end-stage renal disease (ESRD) in patients with diabetic nephropathy. The primary outcome was the cost to prevent 1 patient from developing ESRD. Cost analysis was performed from a third-party payer perspective in 2006 US dollars. As part of a treatment regimen, ARBs significantly reduced the incidence of ESRD and doubling of serum creatinine concentration (P<.05) but not total mortality. The cost to prevent 1 patient from developing ESRD was $31,729 (95% confidence interval, $19,443-$85,442; P<.01), $189,190 (P=.13) and $51,585 (P=.068) for patients receiving ARBs, ACE inhibitors, or either of them, respectively. This study demonstrates that blocking the RAAS, which delays the progression to ESRD, appears to be cost-effective. The current analysis favors ARBs in terms of cost-effectiveness.

Economic burden of chronic kidney disease

OBJECTIVES

To define the cost of care and evaluate interventions associated with improving outcomes and delaying the progression of chronic kidney disease (CKD).

METHODS

Using the PubMed database, a systematic review of the literature was conducted describing (i) the cost of care associated with treating earlier stages of CKD, and (ii) the role of early referral, erythropoiesis-stimulating proteins and anti-hypertensive agents in improving clinical outcomes and reducing the cost of CKD.

RESULTS

The higher costs associated with treatment of the CKD population are largely due to higher rates and duration of comorbidity-driven hospitalizations. Studies suggest that early referral to a nephrologist, use of erythropoiesis-stimulating proteins and anti-hypertensive agents may be associated with better outcomes and lower costs. In some instances, however, higher target haemoglobin levels could have harmful effects in CKD patients.

CONCLUSION

The substantial costs incurred during earlier stages of CKD increase markedly during the transition to renal replacement and remain elevated thereafter. An increase in awareness among health care providers may result in more timely interventions. More proactive management, in turn, can lead to improved clinical and economic outcomes through the slowing of disease progression and prevention of comorbidities.

Hypertension and kidney disease: a deadly connection

Kidney disease may be the cause or a consequence of hypertension. Hypertension affects 25% of the adult population in the United States. Similarly, chronic kidney disease (CKD) and end-stage renal disease (ESRD) have been steadily increasing in incidence because of the increasing age of the US population and rise in the incidence of risk factors, including hypertension. Substantial evidence supports the notion that elevated blood pressure is the most significant risk factor for developing CKD. Microalbuminuria has been shown to be the early marker of hypertensive renal disease. Furthermore, therapy to reduce microalbuminuria was associated with delayed progression of renal disease. Black Americans are at higher risk for developing hypertensive nephrosclerosis than whites. Hypertension is a major risk factor for cardiovascular events in patients with CKD and ESRD and those who have undergone renal transplantation. Studies have documented that elevated serum creatinine and CKD are risk factors for a cardiovascular event. Tight blood pressure control has been shown to reduce microalbuminuria and proteinuria and to delay progression of renal disease. Tailoring antihypertensive medication to the clinical setting to achieve a blood pressure goal is critical in reducing complications from this deadly connection.

New therapeutic strategies with combined renin-angiotensin system inhibitors for pediatric nephropathy

Renin-angiotensin system (RAS) inhibitors may delay progression of several chronic kidney diseases in adults. Two classes of RAS inhibitors--angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)--have been shown to have renoprotective abilities. Despite their different mechanisms of action, these two drug classes appear to have comparable antiproteinuric and renoprotective properties. Preliminary investigations suggest that combination therapy with an ACE inhibitor and ARB offers additional benefit. Only a few studies with these drugs for treatment of pediatric nephrology have been conducted; however, their results are encouraging. Additional clinical trials are needed to confirm these results.

Therapeutic strategies to slow chronic kidney disease progression

Childhood chronic kidney disease commonly progresses toward end-stage renal failure, largely independent of the underlying disorder, once a critical impairment of renal function has occurred. Hypertension and proteinuria are the most important independent risk factors for renal disease progression. Therefore, current therapeutic strategies to prevent progression aim at controlling blood pressure and reducing urinary protein excretion. Renin-angiotensin-system (RAS) antagonists preserve kidney function not only by lowering blood pressure but also by their antiproteinuric, antifibrotic, and anti-inflammatory properties. Intensified blood pressure control, probably aiming for a target blood pressure below the 75th percentile, may exert additional renoprotective effects. Other factors contributing in a multifactorial manner to renal disease progression include dyslipidemia, anemia, and disorders of mineral metabolism. Measures to preserve renal function should therefore also comprise the maintenance of hemoglobin, serum lipid, and calcium-phosphorus ion product levels in the normal range.

Renin angiotensin system blockade and cardiovascular outcomes in patients with chronic kidney disease and proteinuria: a meta-analysis

OBJECTIVE

The role of renin angiotensin system (RAS) blockade in controlling hypertension and the positive impact on cardiovascular (CV) outcomes is well known. However, the role of RAS blockade in improving CV outcomes in patients with chronic kidney disease (CKD) is still unclear.

METHODS

Randomized controlled trials that analyzed CV outcomes in patients with CKD/proteinuria treated with RAS blockade (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers) were included in our study. The relative risk across all study groups was computed using Mantel-Hanszel random effects model. Results were calculated with 95% CI and was considered statistically significant if 2-sided alpha error was <.05. Renin angiotensin system blockade-based therapy was compared with placebo and control (beta-blocker, calcium-channel blockers and other antihypertensive-based therapy) therapy in the study.

RESULTS

Twenty-five trials (N = 45758) were used for analysis. Renin angiotensin system blockade decreased the risk for heart failure in patients with diabetic nephropathy when compared with placebo 0.78 (95% CI 0.66-0.92, P = .003) and control therapy (0.63, 95% CI 0.47-0.86, P = .003). The risk for CV outcomes was decreased with RAS blockade (0.56, 95% CI 0.47-0.67, P < .001) in nondiabetic nephropathy patients with CKD when compared with control therapy. There was also a significant reduction of CV outcomes (0.84, 95% CI 0.78-0.91, P < .0001), myocardial infarction (0.78, 95% CI 0.65-0.97, P = .03), and heart failure (0.74, 95% CI 0.58-0.95, P = .02) when we pooled all the patients with CKD and compared RAS blockade to placebo.

CONCLUSIONS

A pooled analysis of all causes of CKD revealed a reduction in the risk for myocardial infarction, heart failure, and total CV outcomes when RAS blockade was compared with placebo. RAS blockade decreases the risk for CV outcomes and heart failure when compared with control therapy in patients with proteinuria. There were also benefits with RAS blockade in reducing the risk of CV outcomes and heart failure in patients with diabetic nephropathy when compared with placebo.