Lipid abnormalities and cardiovascular risk in renal disease

Association between the triglyceride to high-density lipoprotein cholesterol ratio and mortality in Chinese maintenance haemodialysis patients: a retrospective cohort study

OBJECTIVE

To investigate the relationship between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and all-cause and cardiovascular (CV) mortality in Chinese haemodialysis (HD) patients.

DESIGN

Retrospective cohort study.

SETTING

Patients from June 2015 to September 2016 and followed through September 2021 were categorised into quartiles according to the follow-up averaged TG/HDL-C ratio. The association between TG/HDL-C and mortality was examined by univariate and multivariate time-varying Cox regression analyses. The C-index was used to assess the predictive accuracy of the Cox regression models.

PARTICIPANTS

A total of 534 maintenance HD patients were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcomes were all-cause death and CV mortality.

RESULTS

During the median follow-up of 61 months, 207 patients died, with 94 (45.4%) classified as CV death. After adjusting for confounders, multivariate time-varying Cox regression analysis showed that the quartile 4 group (TG/HDL-C ≥2.64) was associated with decreased all-cause mortality (adjusted HR 0.51, 95% CI 0.33-0.77, p=0.001) and CV mortality (adjusted HR 0.31; 95% CI 0.16 to 0.62; p=0.001) in maintenance HD patients. Model 1 of all-cause mortality achieved a C-index of 0.72 (95% CI 0.68 to 0.75), and model 2 achieved a C-index of 0.77 (95% CI 0.73 to 0.82). The C-index for model 1 in CV mortality was 0.74 (95% CI 0.70 to 0.77), and the C-index for model 2 was 0.80 (95% CI 0.75 to 0.84).

CONCLUSIONS

High TG/HDL-C was associated with decreased all-cause and CV mortality in HD patients.

Pathophysiological concepts and screening of cardiovascular disease in dialysis patients

Dialysis patients experience 10-20 times higher cardiovascular mortality than the general population. The high burden of both conventional and nontraditional risk factors attributable to loss of renal function can explain higher rates of cardiovascular disease (CVD) morbidity and death among dialysis patients. As renal function declines, uremic toxins accumulate in the blood and disrupt cell function, causing cardiovascular damage. Hemodialysis patients have many cardiovascular complications, including sudden cardiac death. Peritoneal dialysis puts dialysis patients with end-stage renal disease at increased risk of CVD complications and emergency hospitalization. The current standard of care in this population is based on observational data, which has a high potential for bias due to the paucity of dedicated randomized clinical trials. Furthermore, guidelines lack specific guidelines for these patients, often inferring them from non-dialysis patient trials. A crucial step in the prevention and treatment of CVD would be to gain better knowledge of the influence of these predisposing risk factors. This review highlights the current evidence regarding the influence of advanced chronic disease on the cardiovascular system in patients undergoing renal dialysis.

The association between obesity indicators and metabolic risk factors in type-2 diabetic patients

Rationale and objectives

Obesity, accumulation of adipose tissue, is a global disease that can lead to cardiovascular and metabolic complications. The aim of this study was to investigate the relationship between obesity indicators and metabolic risk factors in type 2 diabetes mellitus (T2DM) patients.

Materials and methods

A total of 337 T2DM subjects were included in our study. The metabolic risk factors including diabetes duration, fast plasma glucose (FPG), height, weight, systolic blood pressure (SBP), diastolic blood pressure (DBP), estimated average glucose (eAG), glycated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), triglyceride (TG), blood urea nitrogen (BUN), serum creatinine (Scr), free fatty acid (FFA), uric acid (UA), cystatin c (cysc), albumin (Alb), urinary albumin creatinine ratio (UACR) were recorded. The obesity indicators included body surface area (BSA), body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), para-perirenal fat thickness (PRFT), total abdominal fat (TAF), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT). The association between obesity indicators and metabolic risk factors was investigated by univariate and multivariate analysis.

Results

HDL-c was independently associated with WHR and PRFT (β = -0.126 vs. -0.214, both p < 0.05). TG and Scr were both independently associated with PRFT (β = 0.173 vs. 0.218, both p < 0.01, respectively). UA was independently associated with BSA (β = 0.172, p < 0.01) and PRFT (β = 0.151, p < 0.01). cysc, Alb and UACR were independently associated with WC (β = 0.274 vs. 0.204 vs. 0.182, all p < 0.01).

Conclusion

In T2DM patients, obesity indicators were significantly associated with metabolic risk factors.

Non-High-Density Lipoprotein Cholesterol and Cardiovascular Outcomes in Chronic Kidney Disease: Results from KNOW-CKD Study

As non-high-density lipoprotein cholesterol (non-HDL-C) levels account for all atherogenic lipoproteins, serum non-HDL-C level has been suggested to be a marker for cardiovascular (CV) risk stratification. Therefore, to unveil the association of serum non-HDL-C levels with CV outcomes in patients with non-dialysis chronic kidney disease (ND-CKD), the patients at stages 1 to 5 (n = 2152) from the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD) were prospectively analyzed. The subjects were divided into quintiles by serum non-HDL-C level. The primary outcome was a composite of all-cause death or non-fatal CV events. The median duration of follow-up was 6.940 years. The analysis using the Cox proportional hazard model unveiled that the composite CV event was significantly increased in the 5th quintile (adjusted hazard ratio 2.162, 95% confidence interval 1.174 to 3.981), compared to that of the 3rd quintile. A fully adjusted cubic spline model depicted a non-linear, J-shaped association between non-HDL-C and the risk of a composite CV event. The association remained robust in a series of sensitivity analyses, including the analysis of a cause-specific hazard model. Subgroup analyses reveled that the association is not significantly altered by clinical conditions, including age, gender, body mass index, estimated glomerular filtration rate, and albuminuria. In conclusion, high serum non-HDL-C level increased the risk of adverse CV outcomes among the patients with ND-CKD. Further studies are warranted to define the optimal target range of non-HDL-C levels in this population.

Atherosclerotic-nephropathy: an updated narrative review

The increased prevalence of chronic kidney disease (CKD) in elderly patients recognizes, as main cause, the long-term exposure to atherosclerosis and hypertension. Chronic ischemic damage due to critical renal arterial stenosis induces oxidative stress and intra-renal inflammation, resulting in fibrosis and microvascular remodelling, that is the histological picture of atherosclerotic renal vascular disease (ARVD). The concomitant presence of a long history of hypertension may generate intimal thickening and luminal narrowing of renal arteries and arterioles, glomerulosclerosis, interstitial fibrosis and tubular atrophy, more typically expression of hypertensive nephropathy. These complex mechanisms contribute to the development of CKD and the progression to End Stage Kidney Disease. In elderly CKD patients, the distinction among these nephropathies may be problematic; therefore, ischemic and hypertensive nephropathies can be joined in a unique clinical syndrome defined as atherosclerotic nephropathy. The availability of novel diagnostic procedures, such as intra-vascular ultrasound and BOLD-MRI, in addition to traditional imaging, have opened new scenarios, because these tools allow to identify ischemic lesions responsive to renal revascularization. Indeed, although trials have deflated the role of renal revascularization on the renal outcomes, it should be still used to avoid dialysis initiation and/or to reduce blood pressure in selected elderly patients at high risk. Nonetheless, lifestyle modifications (smoking cessation, increased physical activity), statins and antiplatelet use, as well as cautious use of renin-angiotensin system inhibitors, remain the main therapeutic approach aimed at slowing the renal damage progression. Mesenchymal stem cells and Micro-RNA are promising target of anti-fibrotic therapy, which might provide potential benefit in ARVD patients, though safety and efficacy profile in humans is unknown too.

Perirenal fat thickness is associated with metabolic risk factors in patients with chronic kidney disease

Background

Adipose tissue accumulation in specific body compartments has been associated with diabetes, hypertension and dyslipidemia. Perirenal fat (PRF) may lead to have direct lipotoxic effects on renal function and intrarenal hydrostatic pressure. This study was undertaken to explore the association of PRF with cardiovascular risk factors and different stages of chronic kidney disease (CKD).

Methods

We studied 103 patients with CKD of different stages (1 to 5). PRF was measured by B-mode renal ultrasonography in the distal third between the cortex and the hepatic border and/or spleen.

Results

The PRF thickness was greater in CKD patients with impaired fasting glucose than in those with normal glucose levels (1.10 ± 0.40 cm vs. 0.85 ± 0.39 cm, P < 0.01). Patients in CKD stages 4 and 5 (glomerular filtration rate [GFR] < 30 mL/min/1.73 m²) had the highest PRF thickness. Serum triglyceride levels correlated positively with the PRF thickness; the PRF thickness was greater in patients with triglyceride levels ≥ 150 mg/dL (1.09 ± 0.40 cm vs. 0.86 ± 0.36 cm, P < 0.01). In patients with a GFR < 60 mL/min/1.73 m², uric acid levels correlated positively with the PRF thickness (P < 0.05).

Conclusion

In CKD patients, the PRF thickness correlated significantly with metabolic risk factors that could affect kidney function.

Atherosclerosis in Chronic Kidney Disease: More, Less, or Just Different?

Patients with chronic kidney disease (CKD) are at an increased risk of premature mortality, mainly from cardiovascular causes. The association between CKD on hemodialysis and accelerated atherosclerosis was described >40 years ago. However, more recently, it has been suggested that the increase in atherosclerosis risk is actually observed in early CKD stages, remaining stable thereafter. In this regard, interventions targeting the pathogenesis of atherosclerosis, such as statins, successful in the general population, have failed to benefit patients with very advanced CKD. This raises the issue of the relative contribution of atherosclerosis versus other forms of cardiovascular injury such as arteriosclerosis or myocardial injury to the increased cardiovascular risk in CKD. In this review, the pathophysiogical contributors to atherosclerosis in CKD that are shared with the general population, or specific to CKD, are discussed. The NEFRONA study (Observatorio Nacional de Atherosclerosis en NEFrologia) prospectively assessed the prevalence and progression of subclinical atherosclerosis (plaque in vascular ultrasound), confirming an increased prevalence of atherosclerosis in patients with moderate CKD. However, the adjusted odds ratio for subclinical atherosclerosis increased with CKD stage, suggesting a contribution of CKD itself to subclinical atherosclerosis. Progression of atherosclerosis was closely related to CKD progression as well as to the baseline presence of atheroma plaque, and to higher phosphate, uric acid, and ferritin and lower 25(OH) vitamin D levels. These insights may help design future clinical trials of stratified personalized medicine targeting atherosclerosis in patients with CKD. Future primary prevention trials should enroll patients with evidence of subclinical atherosclerosis and should provide a comprehensive control of all known risk factors in addition to testing any additional intervention or placebo.

Clinical implications of fetuin-A

Fetuin-A, also termed alpha2-Heremans-Schmid glycoprotein, is a 46kDa hepatocyte derived protein (hepatokine) and serves multifaceted functions.

Clinical Studies of Interventions to Mitigate Cardiovascular Risk in Peritoneal Dialysis Patients

Cardiovascular disease (CVD) is highly prevalent in the peritoneal dialysis (PD) population, affecting up to 60% of cohorts. CVD is the primary cause of death in up to 40% of PD patients in Australia, New Zealand, and the United States. Cardiovascular mortality rates are reported to be approximately 14 per 100 patient-years, which are 10- to 20-fold greater than those of age- and sex-matched controls. The excess risk of CVD is related to a combination of traditional risk factors (such as hypertension, dyslipidemia, obesity, smoking, sedentary lifestyle, and insulin resistance), nontraditional (kidney disease-related) risk factors (such as anemia, chronic volume overload, inflammation, malnutrition, hyperuricemia, and mineral and bone disorder), and PD-specific risk factors (such as dialysis solutions, glycation end products, hypokalemia, residual kidney function, and ultrafiltration failure). Interventions targeting these factors may mitigate cardiovascular risk, although high-level clinical evidence is lacking. This review summarizes the evidence relating to cardiovascular interventions targeting modifiable CVD risk factors in PD patients, as well as highlighting the key recommendations of the International Society for Peritoneal Dialysis Cardiovascular and Metabolic Guidelines.

Dyslipidemia and risk of renal replacement therapy or death in incident pre-dialysis patients

Globally the number of patients on renal replacement therapy (RRT) is rising. Dyslipidemia is a potential modifiable cardiovascular risk factor, but its effect on risk of RRT or death in pre-dialysis patients is unclear. The aim of this study was to assess the association between dyslipidemia and risk of RRT or death among patients with CKD stage 4–5 receiving specialized pre-dialysis care, an often under represented group in clinical trials. Of the 502 incident pre-dialysis patients (>18 y) in the Dutch PREPARE-2 study, lipid levels were available in 284 patients and imputed for the other patients. During follow up 376 (75%) patients started RRT and 47 (9%) patients died. Dyslipidemia was defined as total cholesterol ≥5.00 mmol/L, LDL cholesterol ≥2.50 mmol/L, HDL cholesterol <1.00 mmol/L, HDL/LDL ratio <0.4, or triglycerides (TG) ≥2.25 mmol/L, and was present in 181 patients and absent in 93 patients. After multivariable adjustment Cox regression analyses showed a HR (95% CI) for the combined endpoint for dyslipidemia of 1.12 (0.85–1.47), and for high LDL of 1.20 (0.89–1.61). All other HRs were smaller. In conclusion, we did not find an association between dyslipidemia or the separate lipid levels and RRT or death in CKD patients on specialized pre-dialysis care.

Pathophysiologic and treatment strategies for cardiovascular disease in end-stage renal disease and kidney transplantations

The inextricable link between the heart and the kidneys predestines that significant cardiovascular disease ensues in the face of end-stage renal disease (ESRD). As a point of fact, the leading cause of mortality of patients on dialysis is still from cardiovascular etiologies, albeit differing in particular types of disease from the general population. For example, sudden cardiac death outnumbers coronary artery disease in patients with ESRD, which is the reverse for the general population. In this review, we will focus on the pathophysiology and treatment options of important traditional and nontraditional risk factors for cardiovascular disease in ESRD patients such as hypertension, anemia, vascular calcification, hyperparathyroidism, uremia, and oxidative stress. The evidence of erythropoietin-stimulating agents, phosphate binders, calcimimetics, and dialysis modalities will be presented. We will then discuss how these risk factors may be changed and perhaps exacerbated after renal transplantation. This is largely due to the immunosuppressive agents that are both crucial yet potentially detrimental in the posttransplant state. Calcineurin inhibitors, corticosteroids, and mammalian target of rapamycin inhibitors, the mainstay of transplant immunosuppression, are all known to increase the risks of developing new onset diabetes as well as the metabolic syndrome. Thus, we need to carefully negotiate between patients' cardiovascular profile and their risks of rejection. Finally, we end by considering strategies by which we may minimize cardiovascular disease in the transplant population, as this modality still confers the highest chance of survival in patients with ESRD.

Estimated glomerular filtration rate progression in UK primary care patients with type 2 diabetes and diabetic kidney disease: a retrospective cohort study

AIMS

To examine the rates of diabetic kidney disease (DKD) progression and associated factors, we undertook a study of estimated glomerular filtration rate (eGFR) in a historical cohort of UK primary care patients with type 2 diabetes mellitus (T2DM) and associated DKD from the Clinical Practice Research Datalink.

METHODS

Our eligible population were patients with definitive T2DM from a recorded diagnostic code with either a diagnosis of chronic kidney disease (CKD) or renal function test values and renal abnormalities consistent with a CKD diagnosis, identified between 1 October 2006 and 31 December 2011. Only patients with albuminuria results reported in mg/l were used for the longitudinal statistical analyses of the eGFR rate of change using multilevel models.

RESULTS

We identified 111,030 patients with T2DM. Among them 58.6% (95% confidence interval (CI): 58.3-58.9) had CKD and 37.2% (95% CI: 36.9-37.5%) had presumed DKD at baseline. Only 19.4% of patients had urinary albumin test results expressed as mg/l in the year prior to index date. Almost two-thirds (63.8%) of patients with T2DM and presumed DKD received prescriptions for angiotensin-converting enzyme (ACE) inhibitors or angiotensin type 1 receptor blockers (ARB) or both. Time-dependent variables that predict subsequent eGFR decline include increased albuminuria, time from index date and older age.

CONCLUSION

Only a minority of diabetic patients with DKD had quantitative albuminuria assessments. The relatively low proportion of DKD patients with ACEi or ARB prescriptions suggests a gap between healthcare practice and available scientific evidence during the study period. Increased albuminuria and older age were the most consistent predictors of subsequent eGFR decline.

Glucose Serum Concentrations and Cardiovascular Disease in Patients on the End Stage of Renal Disease without Diabetes Mellitus

Background/Aim: It is still controversial whether tighter glycemic control is associated with better clinical outcomes in patients with kidney failure. We examined the association between glucose serum concentrations and cardiovascular disease in patients on the end stage of renal disease without diabetes mellitus. Methods: We studied 76 patients on on-line hemodiafiltration. Cardiovascular disease was defined by the existence of coronary disease (CD). Arterial stiffness was measured as carotid-femoral pulse wave velocity (c-fPWV) and carotid augmentation index (AIx). The concentrations of beta2-microglobulin (β2M) and insulin were measured by radioimmunoassays and insulin resistance by HOMA-IR. We built a logistic-regression analysis to examine the role of glucose on cardiovascular disease after adjustment for the traditional and specific risk factors for dialysis patients. Results: Serum glucose was positively correlated with beta2M, insulin and HOMA-IR (r = 0.361, p = 0.002, r = 0.581, p = 0.001 and r = 0.753, p = 0.001 respectively). Logistic-regression analysis did not show significant impact of glucose concentrations on cardiovascular disease after adjustment for traditional and specific risk factors. Conclusions: The association between elevated glucose serum concentrations and represented by coronary syndrome cardiovascular disease in patients on the end stage of renal disease without diabetes mellitus was not found significant.

Toward individualized cholesterol-lowering treatment in end-stage renal disease

There is broad evidence that lowering low-density lipoprotein (LDL) cholesterol will reduce cardiovascular risk. However, in patients on maintenance hemodialysis treatment, lowering LDL cholesterol is not as effective in preventing cardiovascular complications as in the general population. Cholesterol is either endogenously synthesized or absorbed from the intestine. It has been suggested that the benefit of using statins to prevent atherosclerotic complications is less pronounced in people with high absorption of cholesterol. Recent data indicate that patients on hemodialysis have high absorption of cholesterol. Therefore, these patients may benefit from dietary counseling to reduce cholesterol intake, from functional foods containing plant sterols and stanols, and from drugs that interfere with intestinal absorption of sterols (i.e., ezetimibe, bile acid resins, and sevelamer). This review discusses cholesterol homeostasis and the perspective of personalized treatment of hypercholesterolemia in hemodialysis.

Dual PPAR α / γ Agonism Normalizes Lipoprotein Profile of Renal Dyslipidemia

Chronic kidney disease (CKD) is characterised by specific lipoprotein abnormalities and insulin resistance. Dual activation of the peroxisome proliferators-activated receptors (PPAR) α and γ can significantly improve insulin sensitivity. The aim of the study was to investigate the effects of a dual PPAR α / γ agonist on lipoprotein abnormalities in patients with CKD. One mg of the dual PPAR α / γ agonist tesaglitazar was given once daily during six weeks to CKD patients, and to healthy subjects. Plasma lipids, apolipoproteins (apo) and discrete lipoprotein subclasses were measured at baseline and end of treatment. In the CKD patients apoA-I increased significantly by 9%, and apoB decreased by 18%. There was an increase of apoC-III in HDL by 30%, and a parallel decrease of apoC-III in VLDL + LDL by 13%. Both the apoB-containing cholesterol-rich and the triglyceride-rich subclasses decreased significantly. With the exception of ApoC-III,all plasma lipids apolipoproteins and lipoprotein subclasses were reduced by treatment down to similar levels as the baseline levels of a healthy group of reference subjects. This study suggests that by improving insulin sensitivity a dual PPAR α / γ agonist has the potential to normalise most of the lipoprotein abnormalities in patients with CKD.

White adipose tissue overproduces the lipid-mobilizing factor zinc α2-glycoprotein in chronic kidney disease

Chronic kidney disease (CKD) is frequently associated with protein-energy wasting, a recognized strong predictive factor of mortality. Zinc α2-glycoprotein (ZAG) is a new adipokine involved in body weight control through its lipid-mobilizing activity. Here we tested whether the uremic environment in CKD could alter ZAG production by white adipose tissue and contribute to CKD-associated metabolic disturbances. Compared with normal plasma, uremic plasma induced a significant increase in ZAG synthesis (124%), was associated with a significant increase in basal lipolysis (31%), and significantly blunted lipogenesis (-53%) in 3T3-L1 adipocytes in vitro. In 5/6 nephrectomized rats and mice in vivo, there was a significant decrease in white adipose tissue accretion (-44% and -43%, respectively) and a significantly higher white adipose tissue content of ZAG protein than in sham-operated, pair-fed control animals (498% and 106%, respectively). Subcutaneous white adipose tissue biopsies from patients with end-stage renal disease exhibited a higher content of ZAG (573%) than age-matched controls. Thus, the ZAG content is increased in white adipose tissue from patients or animal models with CKD. Overproduction of ZAG in CKD could be a major contributor to metabolic disturbances associated with CKD.

Treatment of dyslipidemia in chronic kidney disease: Effectiveness and safety of statins

Several cardiovascular (CV) risk factors may explain the high rate of CV death among patients with chronic kidney disease (CKD). Among them both traditional and uremia-related risk factors are implicated and, moreover, the presence of kidney disease represents “per se” a multiplier of CV risk. Plasma lipid and lipoprotein profiles are changed in quantitative, but above all in qualitative, structural, and functional ways, and lipoprotein metabolism is influenced by the progressive loss of renal function. Statin therapy significantly reduces cholesterol synthesis and both CV morbidity and mortality either directly, by reducing the lipid profile, or via pleiotropic effects; it is supposed to be able to reduce both the progression of CKD and also proteinuria. These observations derive from a post-hoc analysis of large trials conducted in the general population, but not in CKD patients. However, the recently published SHARP trial, including over 9200 patients, either on dialysis or pre-dialysis, showed that simvastatin plus ezetimibe, compared with placebo, was associated with a significant low-density lipoprotein cholesterol reduction and a 17% reduction in major atherosclerotic events. However, no benefit was observed in overall survival nor in preserving renal function in patients treated. These recent data reinforce the conviction among nephrologists to consider their patients at high CV risk and that lipid lowering drugs such as statins may represent an important tool in reducing atheromatous coronary disease which, however, represents only a third of CV deaths in patients with CKD. Therefore, statins have no protective effect among the remaining two-thirds of patients who suffer from sudden cardiac death due to arrhythmia or heart failure, prevalent among CKD patients. The safety of statins is demonstrated in CKD by several trials and recently confirmed by the largest SHARP trial, in terms of no increase in cancer incidence, muscle pain, creatine kinase levels, severe rhabdomyolysis, hepatitis, gallstones and pancreatitis; thus confirming the handiness of statins in CKD patients. Here we will review the latest data available concerning the effectiveness and safety of statin therapy in CKD patients.

Serum triglycerides and risk for death in Stage 3 and Stage 4 chronic kidney disease

BACKGROUND

An elevated triglyceride level is associated with cardiovascular and all-cause mortality in the general population. The associations between serum triglyceride and all-cause mortality among patients with chronic kidney disease (CKD) are unclear.

METHODS

Patients with Stage 3 and Stage 4 CKD (estimated glomerular filtration rate 15-59 mL/min/1.73 m(2)) who had serum triglycerides measured prior to being classified as CKD were included. We examined the associations of serum triglyceride levels with all-cause mortality among 25 641 Stage 3 and Stage 4 CKD patients using Cox proportional hazard models and Kaplan-Meier survival curves.

RESULTS

In the Cox model, after adjusting for relevant covariates including other lipid parameters, serum triglyceride level 150-199 mg/dL was not associated with death [hazard ratio (HR) 1.00, 95% confidence interval (95% CI) 0.92-1.10] relative to serum triglyceride <150 mg/dL while serum triglyceride ≥ 200 mg/dL was associated with a 11% increased hazard for death (95% CI 1.01-1.22). Age modified the association between serum triglyceride levels ≥ 200 mg/dL and mortality with patients <65 years having a 38% higher hazard for death (95% CI 1.15-1.65) and ≥ 65 years with no increased risk for death (HR 0.97, 95% CI 0.88-1.08, P for interaction <0.001). When serum triglycerides were examined as a continuous log-transformed variable, similar associations with mortality were noted.

CONCLUSIONS

Serum triglyceride ≥ 200 mg/dL was independently associated with all-cause mortality in Stage 3 and Stage 4 CKD patients aged <65 years but not among patients of age ≥ 65 years. Future studies should confirm these findings and examine the mechanisms that may explain these associations.

Neither oxidized nor anti-oxidized low-density lipoprotein level is associated with atherosclerosis or mortality in hemodialysis patients

It is anticipated that oxidized low-density lipoprotein (oxLDL) and anti-oxLDL are associated with atherosclerosis and mortality. However, data on this issue are controversial and limited. We aimed to investigate the effect of these two markers on the extent and progression of atherosclerosis and mortality in a group of hemodialysis patients. In this prospective observational study with a follow-up of 36 months, 124 hemodialysis patients were studied. Ninety-five patients underwent carotid intima media thickness (CA-IMT) measurement by B-Mode ultrasonography both at baseline and at the end of the study. oxLDL and anti-oxLDL were measured by enzyme-linked immunosorbent assay. The extent and progression of CA-IMT, along with overall and cardiovascular mortality, were assessed. The mean age at baseline was 54.0 ± 14.8 years, 57.3% male and 20% diabetic. The mean oxLDL and anti-oxLDL levels were 8.11 ± 3.16 mU/L and 1.30 ± 0.31, respectively. Baseline mean CA-IMT was 0.82 ± 0.20 mm. Fifteen patients died during a follow-up period of 28.5 ± 6.6 months, 11 from cardiovascular causes. Only oxLDL, not anti-oxLDL, was correlated with the extent of atherosclerosis at baseline. However, both had no role in the progression of atherosclerosis. Also, in unadjusted and adjusted models, both parameters were not associated with overall or cardiovascular mortality. Neither oxLDL nor anti-oxLDL level is associated with the progression of atherosclerosis or mortality in hemodialysis patients.

Rosuvastatin in diabetic hemodialysis patients

A randomized, placebo-controlled trial in diabetic patients receiving hemodialysis showed no effect of atorvastatin on a composite cardiovascular endpoint, but analysis of the component cardiac endpoints suggested that atorvastatin may significantly reduce risk. Because the AURORA (A Study to Evaluate the Use of Rosuvastatin in Subjects on Regular Hemodialysis: An Assessment of Survival and Cardiovascular Events) trial included patients with and without diabetes, we conducted a post hoc analysis to determine whether rosuvastatin might reduce the risk of cardiac events in diabetic patients receiving hemodialysis. Among the 731 participants with diabetes, traditional risk factors such as LDL-C, smoking, and BP did not associate with cardiac events (cardiac death and nonfatal myocardial infarction). At baseline, only age and high-sensitivity C-reactive protein were independent risk factors for cardiac events. Assignment to rosuvastatin associated with a nonsignificant 16.2% reduction in risk for the AURORA trial's composite primary endpoint of cardiac death, nonfatal MI, or fatal or nonfatal stroke (HR 0.84; 95% CI 0.65 to 1.07). There was no difference in overall stroke, but the rosuvastatin group had more hemorrhagic strokes than the placebo group (12 versus two strokes, respectively; HR, 5.21; 95% CI 1.17 to 23.27). Rosuvastatin treatment significantly reduced the rates of cardiac events by 32% among patients with diabetes (HR 0.68; 95% CI 0.51 to 0.90). In conclusion, among hemodialysis patients with diabetes mellitus, rosuvastatin might reduce the risk of fatal and nonfatal cardiac events.

Fighting protein-energy wasting in chronic kidney disease: a challenge of complexity

Chronic uremia is often characterized by wasting of muscle and fat mass, which has been defined as protein-energy wasting (PEW), and is responsible for substantial worsening of patient outcome in terms of morbidity and mortality, mostly from cardiovascular events. Despite major advances in patient treatment, nutritional outcome in patients with end-stage renal disease has not improved substantially in recent years. Extensive research in this field has provided plausible explanations for this limitation by indicating that the pathogenesis of PEW in kidney disease is complex and multifactorial. Complexity involves underlying metabolic alterations, including inflammation, oxidative stress, and insulin resistance. In addition, patient heterogeneity is increasing with large numbers of obese individuals as a result of the ongoing obesity epidemics. Several tissues are involved in cross-talk and contribute to metabolic derangements, including adipose tissue, the gut, and the central nervous system, with novel mediators including the gastric hormone ghrelin. Acknowledging its complex pathogenesis may favor the development of novel and more effective therapeutic tools for PEW. These should ideally be effective in treating the underlying common mechanisms of wasting, which appear to include oxidative stress, inflammation, and insulin resistance.

Role of statins in preventing adverse cardiovascular outcomes in patients with chronic kidney disease

PURPOSE OF REVIEW

Cardiovascular disease accounts for the majority of deaths in chronic kidney disease (CKD). Dyslipidemia is a well established cardiovascular risk factor. We summarize key aspects of available evidence relating to beneficial effects of statins in nondialysis-dependent CKD, dialysis-dependent CKD and renal transplant recipients.

RECENT FINDINGS

Previous trials and their meta-analyses suggested that statins reduce lipid levels, the risk of cardiovascular disease and all-cause mortality in nondialysis-dependent CKD. The Study of Heart and Renal Protection (SHARP) study that enrolled both dialysis-dependent and nondialysis-dependent CKD patients showed a 17% decrease in major atherosclerotic events with statins or ezetimibe. Similar cardiovascular benefits are observed in renal transplant recipients. However, such positive effects were not found in two recent clinical trials that enrolled hemodialysis patients alone. This lack of benefit might be attributed to differences in the cause of cardiovascular death seen in dialysis patients and smaller sample size. The overall benefits-harms tradeoff may benefit from meta-analysis and individual patient data meta-analysis in hemodialysis patients including the SHARP data.

SUMMARY

Nondialysis-dependent CKD patients and renal transplant recipients benefit from statins. Statins have also been found to be beneficial in one of the three large trials in hemodialysis patients, a matter which may be further explored.

Dyslipidemia in chronic kidney disease: are statins still indicated in reduction cardiovascular risk in patients on dialysis treatment?

BACKGROUND

Chronic kidney disease (CKD) is an increasingly health disease all around the world with a high burden of mortality and cardiovascular (CV) morbidity rate. Even when renal replacement therapy is reached, more than half patients die, mainly for CV causes due either to uremia-related cardiovascular risk factors (such as anemia, hyperhomocysteinemia, mineral bone disease-CKD with hyperparathyroidism, oxidative stress, hypoalbuminemia, chronic inflammation, prothrombotic factors) or to traditional ones (age, male gender, diabetes, obesity, hypertension, smoking, insulin levels, family history, dyslipidemia). Among the latter causes dyslipidemia represents one of the major, potentially correctable risk factor.

METHODS AND RESULTS

Statins have demonstrated to effectively and safely reduce cholesterol levels in CKD patients. Here we will examine the effects of statins on CV risk factors in CKD patients and particularly in patients on dialysis treatment, in the light of the unfavorable results of the large trials 4D and AURORA, recently published, underlining the role of malnutrition/inflammation as confounding factor. Probably it will be that only with a real prevention, starting statins even in the early stages of CKD, as indicated by post hoc analysis of large trials, that we will reach results in reducing the mortality rate in CKD patients. In the meanwhile, all the other remediable CV risk factors have to be at the same time corrected.

Evaluation of metabolic risk marker in obesity-related glomerulopathy

OBJECTIVE

Insulin resistance is a common metabolic abnormality, which increases the risk of renal events in obesity. The present study is aimed to examine the relation between metabolic factors and obesity-related glomerulopathy (ORG), and then compare the risk markers of insulin resistance for clinical prediction.

METHODS

A total of 112 cases with proven renal ORG and 135 age- and gender-matched lean controls were included. The degree of proteinuria, endogenous creatinine clearance rate, body mass index, amylin, fasting glucose, insulin, lipid and lipoprotein concentrations were measured during the steady state.

RESULTS

The patients with ORG were clinically characterized by increased body mass index and proteinuria, with higher levels of amylin, homeostasis model assessment of insulin resistance (HOMA-IR), insulin, glucose, and lipid proteins when compared with the lean controls. Multiple logistic regression analysis revealed that amylin and HOMA-IR were significantly associated with the prevalence of ORG. In patients with ORG, proteinuria level correlated with amylin, total cholesterol, fasting insulin, and HOMA-IR. Moreover, proteinuria correlated positively with HOMA-IR and amylin in a multiple regression analysis. In addition, the endogenous creatinine clearance rate did not correlate with any metabolic marker.

CONCLUSION

This study suggested that screening for HOMA-IR might have predictive value for renal damage in obese patients. In addition to insulin resistance, amylin also showed positive effects on evaluation of such renal impairment.

Recapture of hepatic apolipoprotein B mRNA editing may be a promising strategy to relieve nephrotic dyslipidemia

A high total plasma cholesterol concentration is the most common abnormality found in patients with kidney disease, which may be associated with the increased hepatic synthesis of apoB containing lipoproteins. ApoB mRNA editing plays an important physiological role in mammalian lipid metabolism by modifying the distribution of apoB-100 and apoB-48. However, it is regretful that apoB mRNA editing cannot be found in human liver because of the absence of apobec-1 expression. In this context, we hypothesize that the recapture of hepatic apoB mRNA editing may be a promising strategy to relieve nephrotic dyslipidemia. The data presented below focus on those which support this hypothesis with regards to evidence in vitro and in vivo. (1) Human wild-type apoB mRNA can be edited only when both apobec-1 and ACF proteins are presented simultaneously in vitro. (2) Adenoviral vectors can produce short-term expression of exogenous apobec-1 in the livers and lower plasma apoB-100 and LDL levels transiently. (3) Apobec-1 transgenic animals exhibit massive hepatic editing of apoB mRNA and fundamental decreased plasma levels of apoB-100 and LDL, but are exposed to high risk of liver dysplasia and hepatocellular carcinomas. In summary, taking into account the therapeutic security, we put forward that apobec-1 recombinant adenoviral vectors can be used for the recapture of hepatic apoB mRNA editing with a transient low-level manner and may achieve satisfactory lipid-lowing effect in nephropathic animals.

Differences in associated factors between aortic and mitral valve calcification in hemodialysis

Increased prevalence of aortic and mitral valve calcification has been reported in patients on hemodialysis, but it remains unknown whether aortic and mitral valve calcification arise from similar pathogenesis. We detected heart valve calcification using two-dimensional echocardiography, and we related valve calcification to various clinical parameters in patients treated with hemodialysis three times a week for more than 1 year. In 112 patients (77 men and 35 women, age 67+/-10 years, duration on hemodialysis 95+/-67 months), aortic and mitral valve calcification were observed in 84 (75.0%) and 58 (51.7%) patients, respectively. Aortic valve calcification was associated with increased age, higher serum calcium, lower serum albumin, lower total cholesterol and higher high-sensitivity C-reactive protein. Multivariate analysis showed that increased age and higher serum calcium were independently associated with aortic valve calcification. Conversely, mitral valve calcification was associated with increased age, higher high-sensitivity C-reactive protein and higher serum beta(2)-microglobulin, but not with higher serum calcium. In multivariate analysis, increased age and higher serum beta(2)-microglobulin were independently associated with mitral valve calcification. Serum beta(2)-microglobulin was associated with longer duration on hemodialysis, malnutrition inflammation (lower serum albumin and higher high-sensitivity C-reactive protein) and dyslipidemia. Considering the results in previous studies showing that the distribution of beta(2)-microglobulin amyloid deposition was consistent with that of tissue calcification in patients on hemodialysis, beta(2)-microglobulin may have pathogenic roles in valve calcification.

Reducing lipids for CV protection in CKD patients-current evidence

Lipid parameters are altered in the earliest stages of primary kidney disease, some even when measured glomerular filtration rate (GFR) is still normal. The main problem is that routinely measured lipid parameters are deceivingly normal except low high-density lipoprotein (HDL) and moderately elevated triglycerides (TGs) (>150 mg per 100 ml). Behind this unimpressive spectrum, serious anomalies are hidden: increased very low-density lipoprotein (VLDL) and chylomicron remnants, accumulation of delipidated small dense low-density lipoprotein (LDL), post translational modification of lipoproteins, abnormal concentrations of Lp(a) and nonprotective HDL. A routine parameter with some predictive value is the concentration of non-HDL cholesterol. Several of these abnormal lipoprotein particles stimulate cellular free oxygen radical formation which in turn induce inflammation and impact on endothelial function.A bone of contention is the indication for treatment with statins in endstage renal disease. Poor survival is paradoxically predicted by low cholesterol. This appears to be the result of confounding by microinflammation. One controlled interventional study in hemodialysed type 2 diabetics, the 4-D study, failed to show a significant benefit on the primary cardiovascular endpoint. We discuss potential explanations for this 'negative' outcome and the implications for statin treatment.

Proteinuria lowering needs a multifactorial and individualized approach to halt progression of renal disease

This Practice Point commentary discusses the implementation of an intensive, multifactorial intervention in patients who had proteinuria >3 g/day despite treatment with angiotensin-converting-enzyme inhibitors. In their 'Remission Clinic' in Bergamo, Italy, Ruggenenti et al. implemented an individual titration regimen using ramipril 5-10 mg/day, losartan 50-100 mg/day, verapamil 80-120 mg/day and atorvastatin 10-20 mg/day in successive steps, aiming for a low blood pressure target of <120/80 mmHg and a proteinuria target of <0.3 g/day. They found that patients treated in the Remission Clinic had a much slower decline in estimated glomerular filtration rate than a matched historical reference group treated with 1.25-5.00 mg ramipril (diastolic blood pressure goal <90 mmHg). Only 3.6% of Remission Clinic patients reached end-stage renal disease, compared with 30.4% of the historical controls. No information was provided on the individual responses to the different titration steps; therefore, the contributions of the specific components of the regimen towards the therapeutic benefit cannot be established. The data do, however, encourage an individualized and more active approach to preventing end-stage renal disease in individuals with proteinuric chronic kidney disease.