Rosuvastatin and cardiovascular events in patients undergoing hemodialysis

Reviewing the medical literature: five notable articles in general internal medicine from 2010 and 2011

Although the ongoing information explosion within medicine is indisputably beneficial, it is difficult to stay abreast of the large volume of new information being published in the peer-reviewed and grey literature. Practical strategies to organize the swelling tide of medical literature are essential for providers to recognize and incorporate new information into their practice. One strategy for managing new information is the traditional annual review, in which selected, appraised articles are presented for general consumption. Here, we present five notable articles for general internal medicine published from 1 Sept. 2010 to 31 Aug. 2011, with focused summaries of their key findings and supporting clinical vignettes to highlight their significance.

New insights into uremia-induced alterations in metabolic pathways

PURPOSE OF REVIEW

This article summarizes recent studies on uremia-induced alterations in metabolism, with particular emphasis on the application of emerging metabolomics technologies.

RECENT FINDINGS

The plasma metabolome is estimated to include more than 4000 distinct metabolites. Because these metabolites can vary dramatically in size and polarity and are distributed across several orders of magnitude in relative abundance, no single analytical method is capable of comprehensive metabolomic profiling. Instead, a variety of analytical techniques, including targeted and nontargeted liquid chromatography-mass spectrometry, have been employed for metabolomic analysis of human plasma. Recent efforts to apply this technology to study uremia have reinforced the common view that end-stage renal disease is a state of generalized small molecule excess. However, the identification of precursor depletion and downstream metabolite excess - for example, with tryptophan and downstream kynurenine metabolites, with low molecular weight triglycerides and dicarboxylic acids, and with phosphatidylcholines, choline, and trimethylamine-N-oxide - suggest that uremia may directly modulate these metabolic pathways. Metabolomic studies have also begun to expand some of these findings to individuals with chronic kidney disease and in model systems.

SUMMARY

Uremia is associated with diverse, but incompletely understood metabolic disturbances. Metabolomic approaches permit higher resolution phenotyping of these disturbances, but significant efforts will be required to understand the functional significance of select findings.

Rosuvastatin: a review of the pharmacology and clinical effectiveness in cardiovascular disease

Rosuvastatin is a new generation HMG-CoA reductase inhibitor which exhibits some unique pharmacologic and pharmacokinetic properties. It has low extrahepatic tissue penetration, low potential for CYP3A4 interactions and substantial LDL-C lowering capacity and therefore has distinct advantages. We conducted a Medline literature search to identify rosuvastatin papers published in English. In this review, we outline the pharmacology of rosuvastatin, highlighting its efficacy and safety. We also review the major clinical trials with reference to primary and secondary prevention, familial hypercholesterolaemia and comparison with other statins. Finally we address its place in clinical practice.

Adverse events associated with individual statin treatments for cardiovascular disease: an indirect comparison meta-analysis

BACKGROUND

Statins are the most widely prescribed drug available. Due to this reason, it is important to understand the risks involved with the drug class and individual statins.

AIM

We conducted a meta-analysis and employed indirect comparisons to identify differing risk effects across statins.

DESIGN

We included any randomized clinical trial (RCT) of atorvastatin, fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin and simvastatin used for cardiovascular disease event prevention. The main outcome was adverse events [all-cause mortality, cancers, rhabdomylosis, diabetes, aspartate and alanine aminotransferase (AST/ALT), and creatinine kinase (CK) increases beyond the upper limit of normal]. In order to evaluate the relative effects of each drug on adverse events, we calculated adjusted indirect comparisons of the adverse-event outcomes.

RESULTS

Seventy-two trials involving 159,458 patients met our inclusion criteria. Overall, statin treatments significantly increased the rate of diabetes when compared to controls (OR: 1.09; 95% CI: 1.02-1.16) and elevated AST (OR: 1.31; 95% CI: 1.04-1.66) and ALT (OR: 1.28; 95% CI: 1.11-1.48) levels when compared to controls. Using indirect comparisons, we also found that atorvastatin significantly elevated AST levels compared to pravastatin (OR: 2.21; 95% CI: 1.13-4.29) and simvastatin significantly increased CK levels when compared to rosuvastatin (OR: 4.39; 95% CI: 1.01-19.07). Higher dose studies had increased risk of AST elevations.

DISCUSSION

Although statins are generally well tolerated, there are risks associated with almost all drugs. With few exceptions, statins appear to exert a similar risk across individual drugs.

The Role of Statin Therapy for Primary Prevention: What is the Evidence?

Almost one third of annual worldwide mortality is attributed to cardiovascular disease (CVD), making it the leading cause of global death. Dyslipidemia is a well-established risk factor for CVD and plays a pivotal role in the pathogenesis of atherosclerosis. Statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and lower low-density lipoprotein cholesterol, have emerged as the most effective therapy to date against atherothrombotic CVD. Although their role in secondary prevention of CVD is undisputed, it remains a topic for debate as to how widely they should be used for primary prevention. The Framingham Risk Score and the National Cholesterol Education Program Adult Treatment Panel III guidelines are the cornerstones for the current guidelines for primary prevention statin therapy. Although these guidelines serve as help to evaluate cardiovascular risk and effectively identify many patients who will benefit from statin therapy, there is a growing population of "intermediate-risk" patients who may be undertreated. Additional noninvasive tests may complement the traditional risk scores, potentially expanding the indications for statins.

Regression of left ventricular mass following conversion from conventional hemodialysis to thrice weekly in-centre nocturnal hemodialysis

Background

Increased left ventricular mass (LVM) is associated with adverse outcomes in patients receiving chronic hemodialysis. Among patients receiving conventional hemodialysis (CHD, 3×/week, 4 hrs/session), we evaluated whether dialysis intensification with in-centre nocturnal hemodialysis (INHD, 3×/week, 7-8 hrs/session in the dialysis unit) was associated with regression of LVM.

Methods

We conducted a retrospective cohort study of CHD recipients who converted to INHD and received INHD for at least 6 months. LVM on the first echocardiogram performed at least 6 months post-conversion was compared to LVM pre-conversion. In a secondary analysis, we examined echocardiograms performed at least 12 months after starting INHD. The effect of conversion to INHD on LVM over time was also evaluated using a longitudinal analysis that incorporated all LVM data on patients with 2 or more echocardiograms.

Results

Thirty-seven patients were eligible for the primary analysis. Mean age at conversion was 49 ± 12 yrs and 30% were women. Mean pre-conversion LVM was 219 ± 66 g and following conversion, LVM declined by 32 ± 58 g (p = 0.002). Among patients whose follow-up echocardiogram occurred at least 12 months following conversion, LVM declined by 40 ± 56 g (p = 0.0004). The rate of change of LVM decreased significantly from 0.4 g/yr before conversion, to -11.7 g/yr following conversion to INHD (p < 0.0001).

Conclusion

Conversion to INHD is associated with a significant regression in LVM, which may portend a more favourable cardiovascular outcome. Our preliminary findings support the need for randomized controlled trials to definitively evaluate the cardiovascular effects of INHD.

Chronic kidney disease

Chronic kidney disease is a general term for heterogeneous disorders affecting kidney structure and function. The 2002 guidelines for definition and classification of this disease represented an important shift towards its recognition as a worldwide public health problem that should be managed in its early stages by general internists. Disease and management are classified according to stages of disease severity, which are assessed from glomerular filtration rate (GFR) and albuminuria, and clinical diagnosis (cause and pathology). Chronic kidney disease can be detected with routine laboratory tests, and some treatments can prevent development and slow disease progression, reduce complications of decreased GFR and risk of cardiovascular disease, and improve survival and quality of life. In this Seminar we discuss disease burden, recommendations for assessment and management, and future challenges. We emphasise clinical practice guidelines, clinical trials, and areas of uncertainty.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Evidence-based prediction of statin use with lipid-panel data from the National Health and Nutrition Examination Survey

OBJECTIVES

This study compared actual use of individual statin drugs to expected use based on their efficacy and safety profiles.

METHODS

Five panels covering the years 1999 to 2008 from the National Health and Nutrition Examination Survey provided interview, demographic, and laboratory data for 8769 (365,503,838 weighted) people aged 20 years or older who were not taking a statin medication. An individual's risk for coronary heart disease and low-density lipoprotein (LDL) cholesterol goal were determined, following the Adult Treatment Panel III Cholesterol Guidelines. The percentage LDL cholesterol lowering required to reach his/her LDL cholesterol level goal was calculated. Depending on the amount of LDL cholesterol lowering needed and on if the individual had a liver condition (i.e., enhanced risk of rhabdomyolysis) statins were hypothetically prescribed. Predicted use was compared to actual use by U.S. Medicaid beneficiaries in the third quarter of 2009, obtained from the Medicaid State Drug Utilization Data maintained by the Centers for Medicare and Medicaid Services.

RESULTS

Results showed that 72.34% of the population was in the lowest coronary heart disease risk group and that 86.30% required no statin therapy. Among the people who did require LDL cholesterol lowering, a significant majority (37.3 million or 10.22% of the population) needed 30% lowering or less. Only 314,784 (0.09%) required LDL cholesterol lowering of greater than 60%. Utilization shares based on safety and efficacy were estimated at 19.26% (rosuvastatin), 18.67% (atorvastatin), 16.48% (simvastatin), 16.30% (lovastatin), 14.93% (pravastatin), and 14.36% (fluvastatin).

CONCLUSIONS

Actual statin use differed substantially from predicted use. It may be appropriate to develop and maintain policies that encourage use of less costly products that have essentially equivalent safety profiles and efficacy.

Observational studies versus randomized controlled trials: avenues to causal inference in nephrology

A common frustration for practicing Nephrologists is the adage that the lack of randomized controlled trials (RCTs) does not allow us to establish causality, but merely associations. The field of nephrology, like many other disciplines, has been suffering from a lack of RCTs. The view that without RCTs, there is no reliable evidence has hampered our ability to ascertain the best course of action for our patients. However, many clinically important questions in medicine and public health, such as the association of smoking and lung cancer, are not amenable to RCTs owing to ethical or other considerations. Whereas RCTs unquestionably hold many advantages over observational studies, it should be recognized that they also have many flaws that render them fallible under certain circumstances. We provide a description of the various pros and cons of RCTs and of observational studies using examples from the nephrology literature, and argue that it is simplistic to rank them solely based on preconceived notions about the superiority of one over the other. We also discuss methods whereby observational studies can become acceptable tools for causal inferences. Such approaches are especially important in a field like nephrology where there are myriads of potential interventions based on complex pathophysiologic states, but where properly designed and conducted RCTs for all of these will probably never materialize.

Randomized controlled trials in nephrology: state of the evidence and critiquing the evidence

The randomized controlled trial (RCT) remains the "gold standard" for the evaluation of therapies. Despite some progress during the past decade, the number and quality of published RCTs addressing the core issues for patients with CKD and with renal diseases, in general, lag behind other areas in internal medicine. The paucity of robust evidence results in fewer patients receiving evidence-based therapies in nephrology and fewer rigorous systematic reviews to inform nephrology practice and health care policy. Because trials of lower methodologic rigor continue to be published, the evidence-based practitioner must evaluate new evidence from the medical literature carefully before incorporating that evidence into their clinical practice. The types of errors that may limit the validity or applicability of evidence from RCTs is outlined. A detailed discussion of the most important design elements for the conduct of a high-quality RCT is described in the text. These considerations are placed into the context of critical appraisal tools. These tools allow the clinician to efficiently assess the quality of published RCTs and to determine how the new RCT evidence should change current best practice.

Utilization and costs of cardiovascular disease medications in dialysis patients in Medicare Part D

BACKGROUND

Cardiovascular disease (CVD) is a major source of mortality and morbidity in dialysis patients. Population-level descriptions of CVD medication use are lacking in this population.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adult dialysis patients in the United States, alive on December 31, 2006, with Medicare Parts A and B and enrollment in Medicare Part D continuously in 2007.

PREDICTOR

CVDs and demographic characteristics.

OUTCOME

≥1 prescription fill during follow-up (2007).

MEASUREMENTS

Average out-of-pocket costs per user per month and average total drug costs per member per month were calculated.

RESULTS

Of 225,635 dialysis patients who met inclusion criteria during the entry period, 70% (n = 158,702) had continuous Part D coverage during follow-up. Of these, 76% received the low-income subsidy. β-Blockers were the most commonly used CVD medication (64%), followed by renin-angiotensin system inhibitors (52%), calcium channel blockers (51%), lipid-lowering agents (44%), and α-agonists (23%). Use varied by demographics, geographic region, and low-income subsidy status. For CVD medications, mean out-of-pocket costs per user per month were $3.44 and $49.59 and mean total costs per member per month were $124.02 and $110.32 for patients with and without the low-income subsidy, respectively.

LIMITATIONS

Information was available for only filled prescriptions under the Part D benefit; information for clinical contraindications was lacking, information for over-the-counter medications was unavailable, and medication adherence and persistence were not examined.

CONCLUSIONS

Most Medicare dialysis patients in 2007 were enrolled in Part D, and most enrollees received the low-income subsidy. β-Blockers were the most used CVD medication. Total costs of CVD medications were modestly higher for low-income subsidy patients, but out-of-pocket costs were much higher for patients not receiving the subsidy. Further study is warranted to delineate sources of variation in the use and costs of CVD medications across subgroups.

Association between depression and vascular disease in systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease with increased prevalence of cardiovascular disease (CVD) and depression. Although depression may contribute to CVD risk in population-based studies, its influence on cardiovascular morbidity in SLE has not been evaluated. We evaluated the association between depression and vascular disease in SLE.

METHODS

A cross-sectional study was conducted from 2002-2005 in 161 women with SLE and without CVD. The primary outcome measure was a composite vascular disease marker consisting of the presence of coronary artery calcium and/or carotid artery plaque.

RESULTS

In total, 101 women met criteria for vascular disease. In unadjusted analyses, several traditional cardiovascular risk factors, inflammatory markers, adiposity, SLE disease-related factors, and depression were associated with vascular disease. In the final multivariable model, the psychological variable depression was associated with nearly 4-fold higher odds for vascular disease (OR 3.85, 95% CI 1.37, 10.87) when adjusted for other risk factors of age, lower education level, hypertensive status, waist-hip ratio, and C-reactive protein.

CONCLUSION

In SLE, depression is independently associated with vascular disease, along with physical factors.

Chronic kidney disease, dyslipidemia, and atherosclerosis

Patients with chronic kidney disease (CKD) are at an increased risk not only for end-stage kidney disease (ESKD) but also for cardiovascular disease (CVD). In this review article, we summarize the current evidence of CKD as a high-risk condition for CVD based on reports from Japan and other countries to draw attention to the close clinical association between CKD and CVD. Several epidemiologic studies have shown that the presence of CKD and reduced renal function are independent predictors of CVD also in Japan. According to a post-hoc analysis of CASE-J, the power of CKD as a predictor of CVD is as strong as diabetes mellitus and a previous history of ischemic heart disease. CKD worsens classical risk factors including hypertension and dyslipidemia, and dyslipidemia is associated with increased thickness and stiffness of large arteries independent of major confounders. A post-hoc analysis of MEGA indicates that lipid-lowering therapy with statins reduces the risk of CVD, and that it appears to be more efficacious in patients with than without CKD. These reports from Japan and other countries suggest that CKD should be regarded as a high-risk condition comparable to diabetes mellitus, and that strict control of dyslipidemia would be beneficial in preventing CVD, at least early stages of CKD.

Diagnosis, prevention, and management of statin adverse effects and intolerance: proceedings of a Canadian Working Group Consensus Conference

While the proportion of patients with significant statin-associated adverse effects or intolerance is very low, the increasing use and broadening indications have led to a significant absolute number of such patients commonly referred to tertiary care facilities and specialists. This report provides a comprehensive overview of the evidence pertaining to a broad variety of statin-associated adverse effects followed by a consensus approach for the prevention, assessment, diagnosis, and management. The overview is intended both to provide clarification of the untoward effects of statins and to impart confidence in managing the most common issues in a fashion that avoids excessive ancillary testing and/or subspecialty referral except when truly necessary. The ultimate goal is to ensure that patients who warrant cardiovascular risk reduction can be treated optimally, safely, and confidently with statin medications or alternatives when warranted.

Statins and prevention of infections: systematic review and meta-analysis of data from large randomised placebo controlled trials

OBJECTIVE

To evaluate whether the potential of statins to lower the risk of infections as published in observational studies is causal.

DESIGN

Systematic review and meta-analysis of randomised placebo controlled trials.

DATA SOURCES

Medline, Embase, and the Cochrane Library.

STUDY SELECTION

Randomised placebo controlled trials of statins (up to 10 March 2011) enrolling a minimum of 100 participants, with follow-up for at least one year.

DATA EXTRACTION

Infection or infection related death.

RESULTS

The first study selection yielded 632 trials. After screening of the corresponding abstracts and full text papers, 11 trials totalling 30 947 participants were included. 4655 of the participants (2368 assigned to statins and 2287 assigned to placebo) reported an infection during treatment. Meta-analysis showed no effect of statins on the risk of infections (relative risk 1.00, 95% confidence interval 0.96 to 1.05) or on infection related deaths (0.97, 0.83 to 1.13).

CONCLUSION

These findings do not support the hypothesis that statins reduce the risk of infections. Absence of any evidence for a beneficial effect in large placebo controlled trials reduces the likelihood of a causal effect as reported in observational studies.

Lipid lowering in patients with chronic kidney disease: a SHARP turn in the wrong direction?

The question whether lipid-lowering treatment is associated with a decrease in cardiovascular morbidity and mortality in patients with chronic kidney disease has been disputed for a while, with recent trials in patients on haemodialysis failing to show benefit. Recently, the long-awaited results of the SHARP (Study of Heart And Renal Protection) trial were published. This randomized trial compared the effects of either simvastatin 20 mg plus ezetimibe 10 mg daily or placebo on the occurrence of a first major vascular event in 9720 patients with chronic kidney disease. There was a 17% relative risk reduction but no benefit on survival. We address our concerns regarding the conclusions drawn from this trial. The trial has a major design flaw by comparing the effects of two different lipid-lowering drugs with placebo. Although the SHARP trial showed that lipid lowering may be beneficial for patients with chronic kidney disease, the clinically as well as economically important question remains unanswered as to whether it was statin therapy and/or ezetimibe that mediated this effect. A great opportunity to investigate superiority, equipoise, or potential inferiority of ezetimibe compared to statins was missed.

Management of chronic kidney disease in the elderly

Both chronic kidney disease (CKD) and end-stage renal disease are strongly age related. Although the morbidity and mortality of CKD have significantly improved in recent years because of a greater understanding of its pathophysiology and evidence-based approach to management, the application of this evidence to the elderly CKD patients is often fraught with difficulty. This is because, besides age, the clinical and biological variables that are widely prevalent in the elderly, such as multiple co-morbidities, functional impairments and polypharmacy, and quality of life and functional outcome measures, which are pertinent to this age group, have generally not been incorporated into the available evidence. This paper reviews the current evidence with a view to providing a framework for diagnosing and managing CKD in the elderly. Special references are made to age-related physiological changes in the renal system, assessment of renal function, and management of metabolic complications and end-stage renal disease.

Endogenous erythropoietin and the association with inflammation and mortality in diabetic chronic kidney disease

BACKGROUND AND OBJECTIVES

Anemia and inflammation are prevalent in diabetic patients with chronic kidney disease (CKD). The role of endogenous erythropoietin (EPO) in the pathophysiology of anemia in chronic diseases and its relationship to clinical outcomes remain uncertain. In this cohort study, we aimed to identify factors associated with endogenous EPO levels and investigate their relation to all-cause mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 2004 and 2005, 215 patients with type 2 diabetes were enrolled. Exclusion criteria included stage renal disease ESRD and any form of anemia therapy. The association of EPO levels with clinical and laboratory variables was investigated by linear regression modeling. Predictors of all-cause mortality were evaluated by Cox proportional hazards analyses.

RESULTS

Patients (median age, 67 years; 52% men; median duration of diabetes, 10 years; median estimated GFR, 49 ml/min per 1.73 m²) were followed for up to 7.0 years. Forty-one patients died. Elevated EPO levels were independently associated with elevated C-reactive protein, low ferritin, and hypertension, in a multivariate model that also included age, cardiovascular disease, kidney function, albumin, cholesterol, and hemoglobin. Higher EPO levels were independently predictive for mortality, as were age, low levels of albumin, and cardiovascular disease.

CONCLUSIONS

In diabetic patients with CKD, elevated endogenous EPO levels were predictive for mortality and were related mainly to markers of inflammation, independent of kidney function, and despite low hemoglobin levels. Understanding the phenomenon of EPO resistance and iron dysregulation caused by inflammation is crucial for effective and safe treatment of anemia in patients with CKD.

Vascular incompetence in dialysis patients--protein-bound uremic toxins and endothelial dysfunction

Patients with chronic kidney disease (CKD) have a much higher risk of cardiovascular diseases than the general population. Endothelial dysfunction, which participates in accelerated atherosclerosis, is a hallmark of CKD. Patients with CKD display impaired endothelium-dependent vasodilatation, elevated soluble biomarkers of endothelial dysfunction, and increased oxidative stress. They also present an imbalance between circulating endothelial populations reflecting endothelial injury (endothelial microparticles and circulating endothelial cells) and repair (endothelial progenitor cells). Endothelial damage induced by a uremic environment suggests an involvement of uremia-specific factors. Several uremic toxins, mostly protein-bound, have been shown to have specific endothelial toxicity: ADMA, homocysteine, AGEs, and more recently, p-cresyl sulfate and indoxyl sulfate. These toxins, all poorly removed by hemodialysis therapies, share mechanisms of endothelial toxicity: they promote pro-oxidant and pro-inflammatory response and inhibit endothelial repair. This article (i) reviews the evidence for endothelial dysfunction in CKD, (ii) specifies the involvement of protein-bound uremic toxins in this dysfunction, and (iii) discusses therapeutic strategies for lowering uremic toxin concentrations or for countering the effects of uremic toxins on the endothelium.

Clinical usefulness of novel prognostic biomarkers in patients on hemodialysis

Prognosis, risk stratification and monitoring the effects of treatment are fundamental elements in the decision-making process when implementing prevention strategies for chronic kidney disease. The use of biomarkers is increasingly proposed as a method to refine risk stratification and guide therapy. In this Review, we present basic concepts regarding the validation of biomarkers and highlight difficulties inherent to the identification of useful new biomarkers in patients on hemodialysis. We focus on prognostic biomarkers that have been consistently linked to survival in this group of patients. To date, no biomarker has had sufficient full-scale testing to qualify as a useful addition to standard prognostic factors or to guide the prescription of specific treatments in this population. Furthermore, little information exists on the relative strength of various biomarkers for their prediction of mortality. A multimarker approach might refine prognosis in patients on hemodialysis, but this concept needs to be properly evaluated in large longitudinal studies and clinical trials. The potential of proteomics for the identification and study of new biomarkers in the pathophysiology of cardiovascular disease in patients with end-stage renal disease is also discussed.

Lack of modulatory effect of simvastatin on indoxyl sulfate-induced activation of cultured endothelial cells

AIMS

Endothelial dysfunction is a common manifestation of chronic kidney disease (CKD). The protein-bound uremic toxins have emerged as important factors associated with cardiovascular disease and the outcome of CKD. The effect of indoxyl sulfate (IS) on endothelial cells remains unclear.

MAIN METHODS

Human umbilical endothelial cells (HUVEC) were incubated using IS at two concentrations: 100 μM and 1000 μM over two periods of time: 16 and 48 h. HUVEC were also pre-treated with simvastatin to examine its effect. RT-PCR was used to assess changes in the gene expression of intracellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), Monocyte chemotactic protein-1 (MCP-1), E-selectin, and angiotensin receptor type 1 (AT1R). Protein abundance of the investigated molecules was assessed by immunoblotting.

KEY FINDINGS

Treatment with 100 μM IS for 16 h induced a 2-fold increase in the expression of ICAM-1, VCAM-1, and MCP-1. At a concentration of 1000 μM, there was a 2-3-fold increase. An extended treatment period at low concentrations was associated with a 2-3 fold increase and the increase of ICAM-1 and VCAM-1 was more prominent under high concentration. Results of immunoblotting confirmed an increase in the abundance of ICAM-1, VCAM-1 and MCP-1. No significant change was noted in E-selectin and AT1R according to concentration or treatment duration. Pre-treatment with simvastatin did not alter IS-induced changes.

SIGNIFICANCE

IS increased the expression of adhesion molecules of endothelial cells exhibiting a concentration and duration dependent pattern. Simvastatin did not demonstrate any effect on IS-associated endothelial activation.

Using a genetic, observational study as a strategy to estimate the potential cost-effectiveness of pharmacological CCR5 blockade in dialysis patients

BACKGROUND AND OBJECTIVE

Randomized clinical trials are expensive and time consuming. Therefore, strategies are needed to prioritise tracks for drug development. Genetic association studies may provide such a strategy by considering the differences between genotypes as a proxy for a natural, lifelong, randomized at conception, clinical trial. Previously an association with better survival was found in dialysis patients with systemic inflammation carrying a deletion variant of the CC-chemokine receptor 5 (CCR5). We hypothesized that in an analogous manner, pharmacological CCR5 blockade could protect against inflammation-driven mortality and estimated if such a treatment would be cost-effective.

METHODS

A genetic screen and treat strategy was modelled using a decision-analytic Markov model, in which patients were screened for the CCR5 deletion 32 polymorphism and those with the wild type and systemic inflammation were treated with pharmacological CCR5 blockers. Kidney transplantation and mortality rates were calculated using patient level data. Extensive sensitivity analyses were performed.

RESULTS

The cost-effectiveness of the genetic screen and treat strategy was &OV0556;18 557 per life year gained and &OV0556;21 896 per quality-adjusted life years gained. Concordance between the genetic association and pharmacological effectiveness was a main driver of cost-effectiveness. Sensitivity analyses showed that even a modest effectiveness of pharmacological CCR5 blockade would result in a treatment strategy that is good value for money.

CONCLUSION

Pharmacological blockade of the CCR5 receptor in inflamed dialysis patients can be incorporated in a potentially cost-effective screen and treat programme. These findings provide formal rationale for clinical studies. This study illustrates the potential of genetic association studies for drug development, as a source of Mendelian randomized evidence from an observational setting.

[The role of statins in atherosclerotic peripheral arterial disease]

The use of statins for secondary prevention in patients with peripheral (extracoronary) arterial disease is not widespread. Their possible use has only relatively recently been studied and data in the literature are sometimes controversial or are not disclosed. The aim of this paper is to review the recent literature and to discuss possible reasons for using statins in patients with extracoronary atherosclerotic arterial involvement, focusing on the areas in which they have been investigated. The main conclusions are that statins should be prescribed with the objective of reducing coronary and cerebrovascular morbidity and mortality in patients with carotid disease, abdominal aortic aneurysm and lower limb occlusive disease. There is sufficient evidence to suggest a reduction in the perioperative risk of vascular surgery when statins are used, and in patients with carotid stenosis they also appear to reduce perioperative risk in endarterectomy. Nevertheless, there are insufficient data to recommend the use of statins to control post-endarterectomy restenosis. In patients with intermittent claudication, statins improve walking distance and may be used for this purpose. Finally, there is insufficient evidence to recommend statins to prevent restenosis in lower limb revascularization procedures, to control progression of abdominal aortic aneurysms, or to reduce the severity of renal artery stenosis or renal dysfunction.

Statins and intracerebral hemorrhage: collaborative systematic review and meta-analysis

BACKGROUND

A recent large, randomized trial suggested that statins may increase the risk of intracerebral hemorrhage. Accordingly, we systematically reviewed the association of statins with intracerebral hemorrhage in randomized and observational data.

METHODS AND RESULTS

We screened 17 electronic bibliographic databases to identify eligible studies and consulted with experts in the field. We used DerSimonian-Laird random-effects models to compute summary risk ratios with 95% confidence intervals. Randomized trials, cohort studies, and case-control studies were analyzed separately. Only adjusted risk estimates were used for pooling observational data. We included published and unpublished data from 23 randomized trials and 19 observational studies. The complete data set comprised 248 391 patients and 14 784 intracerebral hemorrhages. Statins were not associated with an increased risk of intracerebral hemorrhage in randomized trials (risk ratio, 1.10; 95% confidence interval, 0.86-1.41), cohort studies (risk ratio, 0.94; 95% confidence interval, 0.81-1.10), or case-control studies (risk ratio, 0.60; 95% confidence interval, 0.41-0.88). Substantial statistical heterogeneity was evident for the case-control studies (I(2)=66%, P=0.01), but not for the cohort studies (I(2)=0%, P=0.48) or randomized trials (I(2)=30%, P=0.09). Sensitivity analyses by study design features, patient characteristics, or magnitude of cholesterol lowering did not materially alter the results.

CONCLUSIONS

We found no evidence that statins were associated with intracerebral hemorrhage; if such a risk is present, its absolute magnitude is likely to be small and outweighed by the other cardiovascular benefits of these drugs.

Predialysis nephrology care of older patients approaching end-stage renal disease

BACKGROUND

Little is known about trends in the timing of first nephrology consultation and associated outcomes among older patients initiating dialysis.

METHODS

Data from patients aged 67 years or older who initiated dialysis in the United States between January 1, 1996, and December 31, 2006, were stratified by timing of the earliest identifiable nephrology visit. Trends of earlier nephrology consultation were formally examined in light of concurrently changing case mix and juxtaposed with trends in 1-year mortality rates after initiation of dialysis.

RESULTS

Among 323,977 older patients initiating dialysis, the proportion of patients receiving nephrology care less than 3 months before initiation of dialysis decreased from 49.6% (in 1996) to 34.7% (in 2006). Patients initiated dialysis with increasingly preserved kidney function, from a mean estimated glomerular filtration rate of 8 mL/min/1.73 m(2) in 1996 to 12 mL/min/1.73 m(2) in 2006. Patients were less anemic in later years, which was partly attributable to increased use of erythropoiesis-stimulating agents, and fewer used peritoneal dialysis as the initial modality. During the same period, crude 1-year mortality rates remained unchanged (annual change in mortality rate, +0.2%; 95% confidence interval, 0% to +0.4%). Adjustment for changes in demographic and comorbidity patterns yielded estimated annual reductions in 1-year mortality rates of 0.9% (95% confidence interval, 0.7% to 1.1%), which were explained only partly by concurrent trends toward earlier nephrology consultation (annual mortality reduction after accounting for timing of nephrology care was attenuated to 0.4% [0.2% to 0.6%]).

CONCLUSIONS

Despite significant trends toward earlier use of nephrology consultation among older patients approaching maintenance dialysis, we observed no material improvement in 1-year survival rates after dialysis initiation during the same time period.

β-blocker prevents sudden cardiac death in patients with hemodialysis

BACKGROUND

Beta blockers were shown to prevent SCD in cardiomyopathy or coronary artery disease patients. Dialysis patients show elevated mortality rates, predominantly due to cardiovascular disease. SCD is now one of the leading causes of death in this population. However, the prevention of SCD remains to be elucidated.

METHODS

We conducted a retrospective study of 316 patients from a database of all patients undergoing maintenance hemodialysis and followed up for 4.9 years. All patients were followed-up until death. Cox regression analysis was used to adjust the hazard ratio for beta blocker use with time until death.

RESULTS

SCD occurred during the study period in 3 (3.8%) patients in the beta blocker group and in 27 (11.4%) patients in the non-beta blocker group (P=0.047). Death from all causes occurred in 15 (18.8%) patients in the beta blocker group and in 97 (41.3%) patients in the non-beta blocker group (P<0.001). Kaplan-Meier curve showed that the rates of both SCD and all-cause death were lower in the beta blocker group (log-rank test, P=0.028 and P<0.001, respectively). In the Cox regression model, beta blocker use was significantly associated with lower adjusted risk of SCD (multivariate adjusted hazard ratio, 0.201; 95% confidence interval, 0.058-0.693; P=0.011).

CONCLUSION

In hemodialysis patients, beta blocker use was associated with lower risks of SCD and death from all causes. Thus, beta blocker use in this high-risk population may substantially improve outcome.

Cardiac and vascular structure and function parameters do not improve with alternate nightly home hemodialysis: an interventional cohort study

BACKGROUND

Nightly extended hours hemodialysis may improve left ventricular hypertrophy and function and endothelial function but presents problems of sustainability and increased cost. The effect of alternate nightly home hemodialysis (NHD) on cardiovascular structure and function is not known.

METHODS

Sixty-three patients on standard hemodialysis (SHD: 3.5-6 hours/session, 3-5 sessions weekly) converted to NHD (6-10 hours/session overnight for 3-5 sessions weekly). 2Dimensional transthoracic echocardiography and ultrasound measures of brachial artery reactivity (BAR), carotid intima-media thickness (CIMT), total arterial compliance (TAC) and augmentation index (AIX) were performed post dialysis at baseline and 18-24 months following conversion to NHD. In 37 patients, indices of oxidative stress: plasma malonyldialdehyde (MDA) and anti-oxidant enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD) activity and total antioxidant status (TAS) were measured at baseline, 3 and 6 months.

RESULTS

Left ventricular mass index (LVMI) remained stable. Despite significant derangement at baseline, there were no changes in diastolic function measures, CIMT, BAR and TAC. AIX increased. Conversion to NHD improved bone mineral metabolism parameters and blood pressure control. Interdialytic weight gains increased. No definite improvements in measures of oxidative stress were demonstrated.

CONCLUSIONS

Despite improvement in uremic toxin levels and some cardiovascular risk factors, conversion to an alternate nightly NHD regimen did not improve cardiovascular structure and function. Continuing suboptimal control of uremic toxins and interdialytic weight gains may be a possible explanation. This study adds to the increasing uncertainty about the nature of improvement in cardiovascular parameters with conversion to intensive hemodialysis regimens. Future randomized controlled trials will be important to determine whether increases in dialysis session duration, frequency or both are most beneficial for improving cardiovascular disease whilst minimizing costs and the impact of dialysis on quality of life.

Diabetic dyslipidaemia in Asian populations in the Western Pacific Region: what we know and don't know

Approximately 77 million persons with diabetes reside in the Western Pacific Region. This number is estimated to rise to 113 million in 2030 with increasing burden of cardio-renal disease, affecting an increasingly young population. Randomized clinical trials have confirmed the benefits of using statins to reduce low-density lipoprotein cholesterol in preventing cardiovascular disease (CVD) in Caucasians, although similar data are lacking in Asia. Experts from the Western Pacific Region met and reviewed evidence regarding risk association of diabetic dyslipidaemia with cardio-renal disease, effects of lipid lowering, recommended guidelines and clinical practices in Asian populations. There is strong evidence supporting the role of diabetic dyslipidaemia in cardio-renal disease and the benefits of lipid lowering in these populations. The high rate of diabetic kidney disease, its close links with CVD, and the benefits of lipid lowering on renal function are particularly relevant to this population. While most national guidelines use criteria similar to the West in management of diabetic dyslipidaemia, there are consistently low rates of use of lipid-lowering drugs and attaining treatment goals in the region. The group recommends conducting randomized studies, strengthening of the health care system to promote early detection, and intervention of diabetic dyslipidaemia to prevent end organ damage.