Rationale and design of a trial improving outcome of type 2 diabetics on hemodialysis. Die Deutsche Diabetes Dialyse Studie Investigators

Interleukin-16 is increased in dialysis patients but is not a cardiovascular risk factor

Oxalate, a uremic toxin that accumulates in dialysis patients, is associated with cardiovascular disease. As oxalate crystals can activate immune cells, we tested the hypothesis that plasma oxalate would be associated with cytokine concentrations and cardiovascular outcomes in dialysis patients. In a cohort of 104 US patients with kidney failure requiring dialysis (cohort 1), we measured 21 inflammatory markers. As IL-16 was the only cytokine to correlate with oxalate, we focused further investigations on IL-16. We searched for associations between concentrations of IL-16 and mortality and cardiovascular events in the 4D cohort (1255 patients, cohort 2) and assessed further associations of IL-16 with other uremic toxins in this cohort. IL-16 levels were positively correlated with pOx concentrations (ρ = 0.39 in cohort 1, r = 0.35 in cohort 2) and were elevated in dialysis patients when compared to healthy individuals. No significant association could be found between IL-16 levels and cardiovascular events or mortality in the 4D cohort. We conclude that the cytokine IL-16 correlates with plasma oxalate concentrations and is substantially increased in patients with kidney failure on dialysis. However, no association could be detected between IL-16 concentrations and cardiovascular disease in the 4D cohort.

Recurrent cardiovascular events in patients with type 2 diabetes and haemodialysis: analysis from the 4D Study

Background

In the 'Die Deutsche Diabetes Dialyse Studie' (4D Study), treatment of patients with type 2 diabetes mellitus (T2DM) on haemodialysis (HD) with atorvastatin compared with placebo had no significant effect on the first composite primary major adverse cardiovascular event (MACE) endpoint of death from cardiac causes, fatal stroke, non-fatal myocardial infarction or non-fatal stroke. In this study we analysed first and recurrent events in 1255 patients from the 4D Study.

Methods

We conducted an event history analysis to investigate the effects of previous clinical events on the risk of different endpoints in the total patient group and after stratification by randomization group.

Results

During a median follow-up of 4 years, a total of 548 MACEs occurred, with 469 first and 79 recurrent events. The most frequent event was sudden cardiac death, followed by death due to infection/sepsis. Of the 548 total MACEs, 260 occurred in the atorvastatin group and 288 in the placebo group [hazard ratio 0.91 (95% confidence interval 0.76-1.07), P = .266]. Interestingly, analyses of the baseline hazard functions for first and recurrent events as a function of time after randomization demonstrated that the risks of the composite primary endpoint continually increased in the placebo group with increasing time in the study, whereas the risk in the atorvastatin group remained constant after ≈1.5 years.

Conclusion

This recurrent and total event analysis from the 4D Study underscores the high risk of sudden cardiac death and death due to infection/sepsis in patients with T2DM receiving HD and raises the hypothesis that atorvastatin may stabilize cardiovascular risk only after 1-2 years in this high-risk population.

Triglyceride-Rich Lipoproteins, Apolipoproteins, and Atherosclerotic Cardiovascular Events Among Patients with Diabetes Mellitus and End-Stage Renal Disease on Hemodialysis

Hypertriglyceridemia may be implicated in the high atherosclerotic cardiovascular disease (ASCVD) risk experienced by patients with end-stage renal disease (ESRD). In this post-hoc analysis of the "Die Deutsche Diabetes Dialyse Studie (4D)" clinical trial, we examined incident ASCVD events, defined as myocardial infarction, ischemic stroke, or a coronary revascularization procedure, among 1255 participants with type 2 diabetes and ESRD treated with hemodialysis. Cox-regression methods were used to evaluate the association of triglycerides, very-low density lipoprotein cholesterol (VLDL-C), and apolipoproteins B (Apo B) and C-III (Apo C-III) with ASCVD. During a median follow-up time of 2.3 years, 340 (27%) participants experienced an ASCVD event. Higher concentrations of triglycerides were not associated with ASCVD risk: Hazard ratio (HR) 0.95; 95% CI (0.83, 1.10) per doubling concentration. Similarly, VLDL-C HR 1.01; 95% CI (0.90, 1.13); Apo B HR 1.04; 95% CI (0.93, 1.16); and Apo C-III HR 0.97; 95% CI (0.86, 1.09) (per one standard deviation higher concentrations), were not associated with ASCVD events. These associations did not differ by allocation to treatment to atorvastatin or by concentrations of markers of inflammation or malnutrition. In conclusion, we found no evidence that triglycerides, triglyceride-rich lipoproteins, or apolipoproteins B or C-III were associated with risk of ASCVD events among patients with type 2 diabetes and ESRD on hemodialysis. These results suggest that lowering triglycerides may not decrease atherosclerotic cardiovascular risk in this population.

Sample size determination for jointly testing a cause-specific hazard and the all-cause hazard in the presence of competing risks

This article considers sample size determination for jointly testing a cause-specific hazard and the all-cause hazard for competing risks data. The cause-specific hazard and the all-cause hazard jointly characterize important study end points such as the disease-specific survival and overall survival, which are commonly used as coprimary end points in clinical trials. Specifically, we derive sample size calculation methods for 2-group comparisons based on an asymptotic chi-square joint test and a maximum joint test of the aforementioned quantities, taking into account censoring due to lost to follow-up as well as staggered entry and administrative censoring. We illustrate the application of the proposed methods using the Die Deutsche Diabetes Dialyse Studies clinical trial. An R package "powerCompRisk" has been developed and made available at the CRAN R library.

[Chronic kidney disease in the elderly patient]

Chronic kidney disease (CKD) is widely prevalent worldwide, with a special impact on elderly population. Around half of people aged over 75 meet diagnostic criteria for CKD according to the recent 'Kidney disease improving global outcomes' (KDIGO) 2012 clinical practice guideline on the evaluation and management of CKD. However, geriatric patients have characteristics that may not be addressed by general guidelines. Therefore, it is important to know the natural history of the disease, symptoms, and 'red-flags' that could help in the management of these patients. In this review, a complete approach is presented on the pathophysiology, diagnosis, and treatment of CKD in the geriatric population.

High Glycated Albumin and Mortality in Persons with Diabetes Mellitus on Hemodialysis

BACKGROUND

Monitoring of glycemic control with hemoglobin A_1c (A1c) in hemodialysis patients may be compromised by anemia and erythropoietin therapy. Glycated albumin (GA) is an alternative measure of glycemic control but is not commonly used because of insufficient evidence of association to clinical outcomes. We tested whether GA measurements were associated with mortality in hemodialysis patients with diabetes mellitus.

METHODS

The German Diabetes and Dialysis Study (4D) investigated effects of atorvastatin on survival in 1255 patients with diabetes mellitus receiving hemodialysis. We measured GA during months 0, 6, and 12. Cox proportional hazards analysis was used to measure associations between GA and A1c and all-cause mortality.

RESULTS

Patients with high baseline GA (fourth quartile) had a 42% higher 4-year mortality compared to those in the first quartile (HR 1.42; 95% CI, 1.09-1.85, P = 0.009). Repeated measurements of GA during year one also demonstrated that individuals in the top quartile for GA (analyzed as a time-varying covariate) had a 39% higher 4-year mortality (HR 1.39; 95% CI, 1.05-1.85, P = 0.022). The associations between high A1c and mortality using similar analyses were less consistent; mortality in individuals with baseline A1c values in the 3rd quartile was increased compared to 1st quartile (HR 1.36; 95% CI, 1.04-1.77, P = 0.023), but risk was not significantly increased in the 2nd or 4th quartiles, and there was a less consistent association between time-varying A1c values and mortality.

CONCLUSIONS

High GA measurements are consistently associated with increased mortality in patients with diabetes mellitus on hemodialysis.

Clinical trial simulation methods for estimating the impact of DPP-4 inhibitors on cardiovascular disease

Introduction

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic agents for the treatment of type 2 diabetes mellitus, which lower blood glucose without causing severe hypoglycemia. However, the first cardiovascular (CV) safety trials have only recently reported their results, and our understanding of these therapies remains incomplete. Using clinical trial simulations, we estimated the effectiveness of DPP-4 inhibitors in preventing major adverse cardiovascular events (MACE) in a population like that enrolled in the SAVOR-TIMI (the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus – Thrombolysis in Myocardial Infarction) 53 trial.

Methods

We used the Archimedes Model to simulate a clinical trial of individuals (N=11,000) with diagnosed type 2 diabetes and elevated CV risk, based on established disease or multiple risk factors. The DPP-4 class was modeled with a meta-analysis of HbA_1c and weight change, pooling results from published trials of alogliptin, linagliptin, saxagliptin, sitagliptin, and vildagliptin. The study treatments were added-on to standard care, and outcomes were tracked for 20 years.

Results

The DPP-4 class was associated with an HbA_1c drop of 0.66% (0.71%, 0.62%) and a weight drop of 0.14 (−0.07, 0.36) kg. These biomarker improvements produced a relative risk (RR) for MACE at 5 years of 0.977 (0.968, 0.986). The number needed to treat to prevent one occurrence of MACE at 5 years was 327 (233, 550) in the elevated CV risk population.

Conclusion

Consistent with recent trial publications, our analysis indicates that DPP-4 inhibitors do not increase the risk of MACE relative to the standard of care. This study provides insights about the long-term benefits of DPP-4 inhibitors and supports the interpretation of the published CV safety trial results.

Quantification of HDL proteins, cardiac events, and mortality in patients with type 2 diabetes on hemodialysis

BACKGROUND AND OBJECTIVES

Impairment of HDL function has been associated with cardiovascular events in patients with kidney failure. The protein composition of HDLs is altered in these patients, presumably compromising the cardioprotective effects of HDLs. This post hoc study assessed the relation of distinct HDL-bound proteins with cardiovascular outcomes in a dialysis population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The concentrations of HDL-associated serum amyloid A (SAA) and surfactant protein B (SP-B) were measured in 1152 patients with type 2 diabetes mellitus on hemodialysis participating in The German Diabetes Dialysis Study who were randomly assigned to double-blind treatment of 20 mg atorvastatin daily or matching placebo. The association of SAA(HDL) and SP-B(HDL) with cardiovascular outcomes was assessed in multivariate regression models adjusted for known clinical risk factors.

RESULTS

High concentrations of SAA(HDL) were significantly and positively associated with the risk of cardiac events (hazard ratio per 1 SD higher, 1.09; 95% confidence interval, 1.01 to 1.19). High concentrations of SP-B(HDL) were significantly associated with all-cause mortality (hazard ratio per 1 SD higher, 1.10; 95% confidence interval, 1.02 to 1.19). Adjustment for HDL cholesterol did not affect these associations.

CONCLUSIONS

In patients with diabetes on hemodialysis, SAA(HDL) and SP-B(HDL) were related to cardiac events and all-cause mortality, respectively, and they were independent of HDL cholesterol. These findings indicate that a remodeling of the HDL proteome was associated with a higher risk for cardiovascular events and mortality in patients with ESRD.

HMG CoA reductase inhibitors (statins) for dialysis patients

BACKGROUND

People with advanced kidney disease treated with dialysis experience mortality rates from cardiovascular disease that are substantially higher than for the general population. Studies that have assessed the benefits of statins (HMG CoA reductase inhibitors) report conflicting conclusions for people on dialysis and existing meta-analyses have not had sufficient power to determine whether the effects of statins vary with severity of kidney disease. Recently, additional data for the effects of statins in dialysis patients have become available. This is an update of a review first published in 2004 and last updated in 2009.

OBJECTIVES

To assess the benefits and harms of statin use in adults who require dialysis (haemodialysis or peritoneal dialysis).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 February 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care or other statins on mortality, cardiovascular events and treatment-related toxicity in adults treated with dialysis were sought for inclusion.

DATA COLLECTION AND ANALYSIS

Two or more authors independently extracted data and assessed study risk of bias. Treatment effects were summarised using a random-effects model and subgroup analyses were conducted to explore sources of heterogeneity. Treatment effects were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI).

MAIN RESULTS

The risk of bias was high in many of the included studies. Random sequence generation and allocation concealment was reported in three (12%) and four studies (16%), respectively. Participants and personnel were blinded in 13 studies (52%), and outcome assessors were blinded in five studies (20%). Complete outcome reporting occurred in nine studies (36%). Adverse events were only reported in nine studies (36%); 11 studies (44%) reported industry funding.We included 25 studies (8289 participants) in this latest update; 23 studies (24 comparisons, 8166 participants) compared statins with placebo or no treatment, and two studies (123 participants) compared statins directly with one or more other statins. Statins had little or no effect on major cardiovascular events (4 studies, 7084 participants: RR 0.95, 95% CI 0.88 to 1.03), all-cause mortality (13 studies, 4705 participants: RR 0.96, 95% CI 0.90 to 1.02), cardiovascular mortality (13 studies, 4627 participants: RR 0.94, 95% CI 0.84 to 1.06) and myocardial infarction (3 studies, 4047 participants: RR 0.87, 95% CI 0.71 to 1.07); and uncertain effects on stroke (2 studies, 4018 participants: RR 1.29, 95% CI 0.96 to 1.72).Risks of adverse events from statin therapy were uncertain; these included effects on elevated creatine kinase (5 studies, 3067 participants: RR 1.25, 95% CI 0.55 to 2.83) or liver function enzymes (4 studies, 3044 participants; RR 1.09, 95% CI 0.41 to 1.25), withdrawal due to adverse events (9 studies, 1832 participants: RR 1.04, 95% CI 0.87 to 1.25) or cancer (2 studies, 4012 participants: RR 0.90, 95% CI 0.72 to 1.11). Statins reduced total serum cholesterol (14 studies, 1803 participants; MD -44.86 mg/dL, 95% CI -55.19 to -34.53) and low-density lipoprotein cholesterol (12 studies, 1747 participants: MD -39.99 mg/dL, 95% CI -52.46 to -27.52) levels. Data comparing statin therapy directly with another statin were sparse.

AUTHORS' CONCLUSIONS

Statins have little or no beneficial effects on mortality or cardiovascular events and uncertain adverse effects in adults treated with dialysis despite clinically relevant reductions in serum cholesterol levels.

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.

Uric acid levels and all-cause and cardiovascular mortality in the hemodialysis population

BACKGROUND AND OBJECTIVES

Hyperuricemia is associated with hypertension, coronary artery disease, and chronic kidney disease. However, there are no specific data on the relationship of uric acid to cardiovascular disease in the chronic hemodialysis setting.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from 5827 patients on chronic hemodialysis from six countries affiliated with the Dialysis Outcomes and Practice Patterns Study (DOPPS) were analyzed. All laboratory data were based upon the initial cross-section of patients in DOPPS I and II. Cox regression was used to calculate the hazard ratio (HR) of all-cause and cardiovascular (CV) mortality with adjustments for case-mix including 14 classes of comorbidity.

RESULTS

There were no clinically significant differences in baseline characteristics between those who had measured uric acid (n = 4637) and those who did not (n = 1190). Uric acid level was associated with lower all-cause mortality (HR: 0.95, 95% confidence interval [CI]: 0.90 to 1.00 per 1 mg/dl higher uric acid level) and CV mortality (HR: 0.92, 95% CI: 0.86 to 0.99). When analyzed as a dichotomous variable, the adjusted HR at uric acid ≤8.2 mg/dl compared with >8.2 mg/dl was 1.24 (95% CI: 1.03 to 1.49) for all-cause mortality and 1.54 (95% CI: 1.15 to 2.07) for CV mortality.

CONCLUSIONS

Higher uric acid levels were associated with lower risk of all-cause and CV mortality in the hemodialysis population. These results are in contrast to the association of hyperuricemia with higher cardiovascular risk in the general population and should be the subject of further research.

Atorvastatin and low-density lipoprotein cholesterol in type 2 diabetes mellitus patients on hemodialysis

BACKGROUND AND OBJECTIVES

Patients undergoing maintenance hemodialysis are at high cardiovascular risk. Lowering LDL-cholesterol with statins reduces the incidence rate of cardiovascular events in patients with chronic kidney disease. In contrast, two randomized, prospective, placebo-controlled trials have been completed in hemodialysis patients that showed no significant effects of statins on cardiovascular outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A post hoc analysis was conducted of the 4D (Die Deutsche Diabetes Dialyze) study to investigate whether LDL-cholesterol at baseline is predictive of cardiovascular events and whether the effect of atorvastatin on clinical outcomes depends on LDL-cholesterol at baseline.

RESULTS

High concentrations of LDL-cholesterol by tendency increased the risks of cardiac endpoints and all-cause mortality. Concordantly, atorvastatin significantly reduced the rates of adverse outcomes in the highest quartile of LDL-cholesterol (≥145 mg/dl, 3.76 mmol/L). The hazard ratios and 95% confidence intervals were 0.69 (0.48 to 1.00) for the composite primary endpoint, 0.58 (0.34 to 0.99) for cardiac death, 0.48 (0.25 to 0.94) for sudden cardiac death, 0.62 (0.33 to 1.17) for nonfatal myocardial infarction, 0.68 (0.47 to 0.98) for all cardiac events combined, and 0.72 (0.52 to 0.99) for death from all causes, respectively. No such decrease was seen in any of the other quartiles of LDL-cholesterol at baseline.

CONCLUSIONS

In patients with type 2 diabetes mellitus undergoing hemodialysis, atorvastatin significantly reduces the risk of fatal and nonfatal cardiac events and death from any cause if pretreatment LDL-cholesterol is >145 mg/dl (3.76 mmol/L).

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.

Modeling the 4D Study: statins and cardiovascular outcomes in long-term hemodialysis patients with diabetes

BACKGROUND AND OBJECTIVES

Randomized, controlled trials (RCTs) are the gold standard for defining causal inferences but are sometimes not feasible because of cost, ethical, or time considerations. We explored the accuracy and potential use of a "simulated trial" through the modeling of a previously published RCT, Die Deutsche Diabetes Dialyse Studie (4D Study), a landmark study that investigated the cardiovascular benefit of atorvastatin use in 1255 patients with ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a large historical database of interventions and outcomes in dialysis patients, we conducted an observational model of the 4D Study in dialysis patients who had type 2 diabetes and were prescribed a statin (5144 patients) and matched to a non-statin user (5144 control subjects) before multivariate modeling. Inclusion, exclusion, and outcome parameters of the study, as prespecified by the 4D Study, were strictly modeled in this analysis.

RESULTS

In covariate- and propensity-adjusted Cox regression, statin use (versus nonuse) was associated with a decrease in the composite primary outcome of cardiac death, nonfatal myocardial infarction, and stroke. Statin use was also associated with a decrease in cardiovascular mortality and all cardiac events combined. The hazard ratios in this observational model were numerically comparable to the hazard ratios reported in the 4D Study; however, because of the larger number of patients "enrolled," results in this simulated study achieved statistical significance.

CONCLUSIONS

Statin use was associated with some cardiovascular benefit in a simulated trial of patients with ESRD; however, the size of benefit was considerably smaller than that seen in the general population. Such simulated trials may represent an exploratory, cost-effective option when RCTs are not immediately feasible.

Antibodies to platelet factor 4-heparin complex and outcome in hemodialysis patients with diabetes

BACKGROUND AND OBJECTIVES

Hemodialysis patients with type 2 diabetes exhibit an excessive cardiovascular risk and regularly receive heparin. We tested whether antibodies to the platelet factor 4-heparin complex (PF4-H-AB) contribute to outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 1255 hemodialysis patients with type 2 diabetes, the German Diabetes Dialysis Study evaluated the effect of atorvastatin (20 mg/d) versus placebo. In a post hoc analysis, the association among PF4-H-ABs, biochemistry, and prespecified, centrally adjudicated end points (combined cardiovascular end point [CVE], all-cause mortality, sudden death, myocardial infarction, stroke) was investigated.

RESULTS

During 4 years, 460 patients reached the CVE; 605 died, 159 of sudden death. Myocardial infarction and stroke occurred in 199 and 97 patients, respectively. Positive PF4-H-AB status was found in 231 (18.7%) of 1236 tested patients and was associated with lower albumin, higher C-reactive protein, and arrhythmia. In a multivariate model adjusted for demographics, comorbidities, and biochemistry, PF4-H-ABs were associated with sudden death. No significant association between PF4-H-ABs and all-cause mortality, myocardial infarction, stroke, or the CVE was observed. Detecting an interaction between acetylsalicylic acid and PF4-H-ABs regarding sudden death and mortality, we found that the association between PF4-H-ABs and outcomes was restricted to patients with acetylsalicylic acid use, most likely because of indication bias.

CONCLUSIONS

In hemodialysis patients who have type 2 diabetes and are treated with acetylsalicylic acid, PF4-H-ABs are associated with sudden and all-cause death. Further studies are needed to elucidate this association.

HMG CoA reductase inhibitors (statins) for dialysis patients

BACKGROUND

Cardiovascular disease accounts for more than half the number of deaths among dialysis patients. The role of HMG CoA reductase inhibitors (statins) in the treatment of dyslipidaemia in dialysis patients is unclear and their safety has not been established.

OBJECTIVES

To assess the benefits and harms of statins in peritoneal dialysis (PD) and haemodialysis patients (HD).

SEARCH STRATEGY

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled trials (CENTRAL, in The Cochrane Library), the Cochrane Renal Group's specialised register and handsearched reference lists of textbooks, articles and scientific proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing statins with placebo, no treatment or other hypolipidaemic agents in dialysis patients.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model after testing for heterogeneity. The results were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Fourteen studies (2086 patients) compared statins versus placebo or other lipid lowering agents. Compared to placebo, statins did not decrease all-cause mortality (10 studies, 1884 patients; RR 0.95, 95% CI 0.86 to 1.06) or cardiovascular mortality (9 studies, 1839 patients: RR 0.96, 95% CI 0.65 to 1.40). There was a lower incidence of nonfatal cardiovascular events with statins compared to placebo in haemodialysis patients (1 study, 1255 patients; RR 0.86, 95% CI 0.74 to 0.99). Compared with placebo, statin use was associated with a significantly lower end of treatment average total cholesterol (14 studies, 1823 patients; MD -42.61 mg/dL, 95% CI -53.38 to -31.84), LDL cholesterol (13 studies, 1801 patients; MD -43.06 mg/dL, 95% CI -53.78 to -32.35) and triglycerides (14 studies, 1823 patients: MD -24.01 mg/dL, 95% CI -47.29 to -0.72). There was similar occurrence of rhabdomyolysis and elevated liver function tests with statins in comparison to placebo.

AUTHORS' CONCLUSIONS

Statins decreased cholesterol levels in dialysis patients similar to that of the general population. With the exception of one study, studies were of short duration and therefore the efficacy of statins in decreasing the mortality rate is still unclear. Statins appear to be safe in this high-risk population. Ongoing studies should provide more insight about the efficacy of statins in reducing mortality rates in dialysis patients.

Apolipoprotein E genotype predicts cardiovascular endpoints in dialysis patients with type 2 diabetes mellitus

OBJECTIVE

Cardiovascular disease (CVD) is the leading cause of death in patients with type 2 diabetes (T2DM) and end-stage renal disease (ESRD). Lipid metabolism is influenced by environmental and genetic factors. Among the latter, the apolipoprotein E (apoE) genotype is known to be associated with CVD risk and thus may affect cardiovascular outcome.

METHODS AND RESULTS

Based on the German Diabetes and Dialysis Study evaluating 1255 T2DM patients on haemodialysis (HD) (median follow-up 4 years), the impact of the apoE genotype (available for 1177 patients) on pre-specified, centrally adjudicated endpoints was investigated: all-cause mortality (n=558), combined cardiovascular events (CVE: cardiac death, MI, stroke; n=442), and cardiac death (n=218). Patients with at least one epsilon4 allele (epsilon4+) showed a 30% increased risk for CVE (HR 1.299, 95%CI 1.045-1.615, p=0.018) and a 36% increased risk for cardiac death (HR 1.362, 95%CI 1.002-1.852, p=0.048) compared to patients with no epsilon4 allele. Consistently, addition of epsilon4+ to a multivariate ROC model for risk prediction of CVE including atorvastatin treatment, history of cardiovascular disease, dialysis and lipoprotein parameters, hsCRP, and NT-pro-BNP increased the area under the curve from 0.666 (95%CI 0.634-0.698) to 0.671 (95%CI 0.639-0.702), p=0.013.

CONCLUSIONS

The presence of the epsilon4 allele increases the risk for CVE and cardiac death in patients with T2DM and ESRD. Whether treatment strategies guided by apoE genotype will improve outcome needs to be evaluated in the future.

HMG CoA reductase inhibitors (statins) for dialysis patients

BACKGROUND

Cardiovascular disease accounts for more than half the number of deaths among dialysis patients. The role of HMG CoA reductase inhibitors (statins) in the treatment of dyslipidaemia in dialysis patients is unclear and their safety has not been established.

OBJECTIVES

To assess the benefits and harms of statins in peritoneal dialysis (PD) and haemodialysis patients (HD).

SEARCH STRATEGY

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled trials (CENTRAL, in The Cochrane Library), the Cochrane Renal Group's specialised register and handsearched reference lists of textbooks, articles and scientific proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing statins with placebo, no treatment or other hypolipidaemic agents in dialysis patients.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model after testing for heterogeneity. The results were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Fourteen studies (2086 patients) compared statins versus placebo or other lipid lowering agents. Compared to placebo, statins did not decrease all-cause mortality (10 studies, 1884 patients; RR 0.95, 95% CI 0.86 to 1.06) or cardiovascular mortality (9 studies, 1839 patients: RR 0.96, 95% CI 0.65 to 1.40). There was a lower incidence of nonfatal cardiovascular events with statins compared to placebo in haemodialysis patients (1 study, 1255 patients; RR 0.86, 95% CI 0.74 to 0.99). Compared with placebo, statin use was associated with a significantly lower end of treatment average total cholesterol (14 studies, 1823 patients; MD -42.61 mg/dL, 95% CI -53.38 to -31.84), LDL cholesterol (13 studies, 1801 patients; MD -43.06 mg/dL, 95% CI -53.78 to -32.35) and triglycerides (14 studies, 1823 patients: MD -24.01 mg/dL, 95% CI -47.29 to -0.72). There was similar occurrence of rhabdomyolysis and elevated liver function tests with statins in comparison to placebo.

AUTHORS' CONCLUSIONS

Statins decreased cholesterol levels in dialysis patients similar to that of the general population. With the exception of one study, studies were of short duration and therefore the efficacy of statins in decreasing the mortality rate is still unclear. Statins appear to be safe in this high-risk population. Ongoing studies should provide more insight about the efficacy of statins in reducing mortality rates in dialysis patients.

Ongoing clinical trials of the pleiotropic effects of statins

BACKGROUND

The multiple effects (ie, pleiotropic effects of statins) have received increasing recognition and may have clinical applicability across a broad range of cardiovascular and noncardiovascular conditions.

OBJECTIVE

To determine the relevance and significance of ongoing clinical trials of the pleiotropic effects of statins, focusing on nonlipid effects.

METHOD

Ongoing trials were identified through personal communication, reports presented at scientific meetings (2000-2004), and queries made to AstraZeneca, Bristol-Myers Squibb Co, Merck & Co, Novartis, and Pfizer, manufacturers of the currently marketed statins. Published trials and other source material were identified through electronic searches on MEDLINE (1990-2003), abstract books, and references identified from bibliographies of pertinent articles. Eligible studies were the clinical trials of statins currently under way in which primary or secondary outcomes included the statins' nonlipid (ie, pleiotropic) effect(s). Data were extracted and trial quality was assessed by the authors.

RESULTS

Of the 22 ongoing trials of the nonlipid effects of statins identified, 10 assessed inflammatory markers and plaque stabilization, 4 assessed oxidized low density lipoprotein/vascular oxidant stress, 3 assessed end-stage renal disease, 3 assessed fibrinogen/viscosity, 2 assessed endothelial function, 2 assessed acute coronary syndrome, 2 assessed aortic stenosis progression, and 1 each assessed hypertension, osteoporosis, ischemic burden, Alzheimer's disease, multiple sclerosis, and stroke (outcomes often overlapped).

CONCLUSION

Given the excellent safety and tolerability of statins as a class, full exploration of their pleiotropic effects has the potential to provide additional benefits to many patients.

Hidden population substructures in an apparently homogeneous population bias association studies

Linkage- and association-based approaches have been applied to attempt to unravel the genetic predisposition for complex diseases. However, studies often report contradictory results even when similar population backgrounds are investigated. Unrecognized population substructures could possibly explain these inconsistencies. In an apparently homogeneous German sample of 612 patients with type 2 diabetic and end-stage diabetic nephropathy and 214 healthy controls, we tested for hidden population substructures and their possible effects on association. Using a genetic vector space analysis of genotypes of 20 microsatellite markers, we identified four distinct subsets of cases and controls. The significance of these substructures was demonstrated by subsequent association analyses, using three genetic markers (UCSNP-43,-19,-63; intron 3 of the calpain-10 gene). In the undivided sample, we found no association between individual SNPs or any haplogenotypes (ie the genotype combination of two multilocus haplotypes) and type 2 diabetes. In contrast, when analyzing the four groups separately, we found that there was evidence for association of the common C allele of UCSNP-63 with the trait in the largest group (n=547 cases/101 controls; P=0.002). In this subset haplotype 112 was more frequent in controls than in cases (P=0.006; haplogenotype 112/121: odds ratio (OR)=0.27, 95% confidence intervals (CI)=0.13-0.57), indicating a protective effect against the development of type 2 diabetes. Our study demonstrates that unconsidered population substructures (ethnicity-dependent factors) can severely bias association studies.

Heart disease in diabetic patients

Cardiac artery disease and heart failure are major causes for morbidity and mortality in diabetes in general and in those with chronic kidney disease (CKD) in particular. Hypertension and dyslipidemia are more common in diabetes and the prevalence of coronary artery disease in diabetics is two-fold to four-fold higher than in nondiabetics. In those with CKD the incidence of cardiovascular complications is nearly two-fold higher than those without CKD. Recent studies suggest that the pathophysiology of cardiac disease is complex process involving both microvascular and macrovascular disease. In addition, myocardial lipotoxicity may be a novel contributing factor particularly in type 2 diabetics. Compelling evidence from cardiovascular outcomes trials indicates that treatment with drugs that block the renin-angiotensin system are cardioprotective in diabetics with microalbuminuria and early stages of kidney disease. Multiple risk factor intervention aimed at optimal blood pressure control (BP <130/<80 mmHG), lowering LDL cholesterol below 100 mg/dl, lowering triglyceride level to 150 mg/dl, A1C <6.5%, treatment with an ACE inhibitor or an angiotensin II receptor blocker, administration of once daily low-dose aspirin and smoking cessation together reduce cardiovascular morbidity and mortality in type 2 diabetics. Novel studies including diabetics with nephropathy aimed at improving outcomes in diabetics by treatment of anemia and optimal control of dyslipidemia are now underway. These and other clinical trials should provide important new insights into improving the quality of life in diabetics and ultimately preventing cardiac disease.

Kidney disease and cardiovascular disease: implications of dyslipidemia

Cardiovascular complications are common inpatients with kidney disease. Regulating the lipid levels in these patients is important so that the risks of kidney and cardiovascular complications can be minimized. Lipid regulation decreases the incidence of coronary vascular events and other vascular complications in patients with kidney disease; however, whether lipid regulation slows progression of kidney disease is not yet known. Additional studies of the implications of dyslipidemia in patients with kidney disease are needed.

Predictors of Cardiovascular Death in ESRD

End stage renal disease (ESRD) is a situation with a cardiovascular risk profile of almost unique severity. While traditional risk factors dominate the scene in the general population, non traditional risk factors like inflammation (high C Reactive Protein, CRP), high brain natriuretic peptide, as an expression of left ventricular hypertrophy and left ventricular dysfunction, and accumulation of the endogenous inhibitor of the NO synthase, asymmetric dimethyl arginine are all markers of high CV risk of ESRD patients. To obtain a quantitative insight on the predictive power of traditional and emerging risk factors in ESRD, we performed a detailed multivariate survival analysis in the cardiovascular risk extended evaluation (CREED) cohort database. As expected, traditional risk factors (ie, age, sex, smoking, diabetes, and risk factors peculiar to the uremic state such as low serum albumin level) and treatment modality contributed to explain the all-cause mortality (37%) and cardiovascular variation mortality (24%) variation as well. When cardiovascular comorbidities were considered in this analysis, the explained variation in mortality increased to 45.4% and 36.4%, respectively. Furthermore, a combined score based on 2 biomarkers (brain natriuretic peptide and C-reactive protein levels) increased the explanatory power of these models by about 10%. In conclusion, traditional risk factors explain about half of all-cause and cardiovascular mortality variation in the ESRD population. The combined use of 2 biomarkers reflecting inflammation and left ventricular mass and function increases by about one fifth the explained mortality variation in this population. Biomarkers give information beyond that provided by traditional risk factors and therefore represent an useful adjunct for the definition of the risk profile of ESRD patients.

Pleiotropic effects of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors on renal function

Pleiotropic, or non-lipid-dependent, effects mediated by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have important clinical implications for the cardiovascular (CV) system. Atherosclerosis is an inflammatory process accompanied by increases in levels of plasma inflammatory markers and accumulation of immune cells within atherosclerotic plaques. Statins not only decrease serum lipid levels, but also inhibit signaling molecules at several points in inflammatory pathways. The anti-inflammatory effects and improved endothelial function associated with statin therapy are thought to be partly responsible for the reduction in CV morbidity and mortality. In analogy, patients with chronic kidney disease administered statins for CV risk reduction show evidence of improved renal function. However, whether statins confer similar protective benefits on the kidney has not been established. Several lines of evidence suggest that similar etiologic and pathological processes may be involved in CV and chronic kidney diseases. If inflammation and functional changes in the renovascular endothelium contribute to the progression of kidney disease, statins are likely to be effective in the treatment of renal disease. In this review, we critically consider emerging data indicating that statins may modulate renal function by altering the inflammatory response of the kidney and renal vasculature to dyslipidemia. Whether the amelioration of renal function by statins is separable from the lipid-lowering effects of these drugs still remains to be delineated. Other questions that remain to be addressed and issues that should be investigated also are presented.

Atorvastatin in patients with type 2 diabetes mellitus undergoing hemodialysis

BACKGROUND

Statins reduce the incidence of cardiovascular events in persons with type 2 diabetes mellitus. However, the benefit of statins in such patients receiving hemodialysis, who are at high risk for cardiovascular disease and death, has not been examined.

METHODS

We conducted a multicenter, randomized, double-blind, prospective study of 1255 subjects with type 2 diabetes mellitus receiving maintenance hemodialysis who were randomly assigned to receive 20 mg of atorvastatin per day or matching placebo. The primary end point was a composite of death from cardiac causes, nonfatal myocardial infarction, and stroke. Secondary end points included death from all causes and all cardiac and cerebrovascular events combined.

RESULTS

After four weeks of treatment, the median level of low-density lipoprotein cholesterol was reduced by 42 percent among patients receiving atorvastatin, and among those receiving placebo it was reduced by 1.3 percent. During a median follow-up period of four years, 469 patients (37 percent) reached the primary end point, of whom 226 were assigned to atorvastatin and 243 to placebo (relative risk, 0.92; 95 percent confidence interval, 0.77 to 1.10; P=0.37). Atorvastatin had no significant effect on the individual components of the primary end point, except that the relative risk of fatal stroke among those receiving the drug was 2.03 (95 percent confidence interval, 1.05 to 3.93; P=0.04). Atorvastatin reduced the rate of all cardiac events combined (relative risk, 0.82; 95 percent confidence interval, 0.68 to 0.99; P=0.03, nominally significant) but not all cerebrovascular events combined (relative risk, 1.12; 95 percent confidence interval, 0.81 to 1.55; P=0.49) or total mortality (relative risk, 0.93; 95 percent confidence interval, 0.79 to 1.08; P=0.33).

CONCLUSIONS

Atorvastatin had no statistically significant effect on the composite primary end point of cardiovascular death, nonfatal myocardial infarction, and stroke in patients with diabetes receiving hemodialysis.

Sample sizes for clinical trials with time-to-event endpoints and competing risks

We consider clinical trials where the time to occurrence of events in the presence of competing risks is the primary endpoint for treatment evaluation. The number of events with regard to the defined primary endpoint required to ensure the specified power can be calculated according to Schoenfeld's formula like in classical survival studies. However, determination of the number of patients that have to be recruited to observe the calculated number of events requires specification of the length of the accrual period, the trial duration and assumptions about the event-specific hazard functions. Information from previous studies about expected failure rates for the reference treatment is useful and can be translated into assumptions about the appropriate model parameters. A formula for sample size computation is presented for two competing outcome states. Nomograms help to communicate different alternatives of duration and size of the trial to interdisciplinary committees whose members plan and monitor the clinical trial. The 4D trial (Die Deutsche Diabetes Dialyse Studie) designed to compare lipid lowering treatment with HMG-CoA reductase inhibitor atorvastatin with placebo in type 2 diabetic patients on hemodialysis with respect to time to the composite event "cardiovascular death or non-fatal myocardial infarction" is used as an example to outline the statistical methods.

Traditional and nontraditional cardiovascular risk factors in chronic kidney disease

Chronic kidney disease (CKD) is public health problem, with as many as 20 million individuals affected in the United States. Patients with CKD should be considered in the highest-risk group for development of cardiovascular disease (CVD), and aggressive treatment of traditional and nontraditional risk factors should be instituted. Additional randomized controlled trials are urgently needed to evaluate potential treatments in this population. This article focuses attention on the major modifiable cardiovascular risk factors in CKD.

Epidemiology and prevention of cardiovascular complication in chronic kidney disease patients

The risk for cardiovascular disease is significantly higher among patients with chronic kidney disease (CKD) than among the general population, considering that cardiovascular disease is the prominent cause of both morbidity and mortality in dialysis patients. This is explained mainly by the considerable prevalence of cardiovascular risk factors among CKD patients since the earliest stages of renal impairment, which include not only the so-called traditional risk factors, but also a number of additional risk factors that are specific to CKD and to the dialytic treatment itself. Considering the multiplicity of cardiovascular risk factors operating in CKD patients, as well as the crucial impact of their cardiovascular condition on long-term outcome, it is mandatory that all the available interventions aimed at the correction of all the modifiable risk factors for cardiovascular disease are performed as early as possible in the progression of the disease. In particular, the results of several controlled clinical trials have shown that a timely correction of anemia and of calcium-phosphate disorders leads to a significant improvement in the cardiovascular conditions of CKD patients. Evidence also is growing regarding the benefits of intervention of newly recognized risk factors for cardiovascular disease such as inflammation and oxidant stress.

Roles of metabolic and endocrinological alterations in atherosclerosis and cardiovascular disease in renal failure: another form of metabolic syndrome

Patients with end-stage renal disease have markedly increased risk for death from cardiovascular disease. Renal failure is associated with multiple metabolic and endocrinologic abnormalities, and these alterations are involved in advanced atherosclerosis and high cardiovascular risk. Increased insulin resistance index by homeostasis model assessment (HOMA-IR), a simple index of insulin resistance, was an independent predictor of cardiovascular mortality in nondiabetic patients on maintenance hemodialysis. Renal failure impairs lipoprotein metabolism leading to the atherogenic lipoprotein profile characterized by increased triglyceride-rich remnant lipoproteins such as intermediate-density lipoprotein, an independent factor of increased aortic stiffness. Non-high-density lipoprotein cholesterol, the sum of cholesterol of intermediate-density lipoprotein and other apoB-containing lipoproteins, is an independent factor associated with increased arterial thickness and a predictor of cardiovascular death in hemodialysis patients. The risk for cardiovascular death in hemodialysis patients is associated closely with hypertension and malnutrition, but not with obesity. The constellation of insulin resistance, dyslipidemia, hypertension, and malnutrition in renal failure suggests the presence of another type of metabolic syndrome promoting cardiovascular disease. In addition, vitamin D deficiency and abnormalities in calcium, phosphate, and parathyroid hormone levels increase the death risk from cardiovascular disease in renal failure. It is expected that treatment of these metabolic and endocrinologic alterations would improve the survival of patients with renal failure.

Chronic kidney disease as a metabolic syndrome with malnutrition--need for strict control of risk factors

Patients with chronic kidney disease (CKD) have an increased risk for death from cardiovascular disease (CVD). They have multiple metabolic abnormalities that may accelerate atherosclerosis, such as hypertension, insulin resistance, and dyslipidemia, along with other CKD-related risk factors. In addition, a considerable proportion of patients with advanced stages of CKD are malnourished, presenting "metabolic syndrome with malnutrition". The presence of malnutrition/inflammation dramatically changes the apparent relationship between CVD death risk and some risk factors. For example, in stage 5 CKD patients on hemodialysis, a higher body mass index and a higher plasma cholesterol are predictors of better survival. To understand the paradoxic epidemiology, we should recognize risk factors for occurrence of CVD events and risk factors of fatality after an event. In this article, we review the unique situation of CKD, emphasizing the need of more strict control of both types of risk factors to improve survival of CKD patients.

Cardiorenal Disease: A Clinical Intersection

This review focuses on the association between renal insufficiency and cardiovascular disease and discusses therapeutic options. Although the association of chronic renal insufficiency and cardiovascular risk was first shown in patients with end-stage renal disease, even minor renal dysfunction has now been established as an independent risk for atherosclerotic cardiovascular disease. Treatment with angiotensin-converting enzyme inhibitors and statins can reduce cardiovascular morbidity and mortality in patients with renal insufficiency. Coronary revascularization improves the prognosis in patients with renal dysfunction, but there is still an underutilization of coronary revascularization procedures in patients with renal insufficiency. There is enough data that shows high mortality after percutaneous transluminal coronary angioplasty in patients with reduced renal function and that slight renal dysfunction exposes the patient with a cardiac event to an excessive cardiac mortality. Further investigation should focus on the cause of and possible preventive interventions, for the staggering cardiovascular risk in the ever-increasing number of people with renal dysfunction.

HMG-coenzyme a reductase inhibitor use is associated with mortality reduction in hemodialysis patients

BACKGROUND

Cardiovascular disease is the most common cause of mortality in patients with end-stage renal disease. Cardiovascular benefits of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been clearly established in the general population, but not in dialysis patients. This study examined statin prescription patterns and assessed the relationship between statin prescription and clinical outcomes in hemodialysis (HD) patients.

METHODS

Data were analyzed from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of HD patients randomly selected from representative dialysis facilities in France, Germany, Italy, Spain, the United Kingdom, Japan, and the United States. Predictors of statin prescription were investigated by means of logistic regression. Cox regression models tested the association between statin prescription and risk for mortality and cardiac events, with adjustments for common demographic factors and comorbid conditions.

RESULTS

Statins were prescribed for 11.8% of HD patients overall. Most facilities (81.2%) prescribed statins to less than 20% of their patients. Patients prescribed statins had a 31% lower relative risk for death compared with those not prescribed statins (P < 0.0001). Statins were associated with a 23% lower cardiac mortality risk (P = 0.03) and a 44% lower noncardiac mortality risk (P < 0.0001). At a facility level, prescribing statins was associated with lower overall mortality rate, with a 5% lower risk for every 10% increase in number of patients prescribed statins within the facility (P = 0.02).

CONCLUSION

Statin prescription is associated with reduced mortality in HD patients, providing additional support for the value of statin therapy in this patient group.

Statin therapy in kidney disease populations: potential benefits beyond lipid lowering and the need for clinical trials

PURPOSE OF REVIEW

This review outlines the limited information currently available on the effects of statins among patients with chronic kidney disease, and summarizes the ongoing randomized trials designed to address this question.

RECENT FINDINGS

The effects of fluvastatin on major coronary events among renal transplant patients, and the effects of pravastatin and simvastatin in small subgroups of coronary patients with minor degrees of renal impairment, appear broadly compatible with those observed in trials conducted in non-renal populations. In addition, recent evidence from trials among patients with vascular disease or diabetes suggests that statin therapy may delay progressive loss of renal function. However, there remains substantial uncertainty regarding the effects of statin therapy among patients with established chronic kidney disease (pre-dialysis or dialysis patients). In particular, there does not appear to be a strongly positive relationship between blood cholesterol and cardiovascular events in such patients. This may be because uraemic cardiomyopathy and arteriosclerosis, which cause the majority of these events in chronic kidney disease patients, do not depend strongly on blood cholesterol.

SUMMARY

Statins appear effective for the prevention of vascular events in people with established vascular disease and mild renal impairment, and may delay renal disease progression in such individuals. However, the effects of statins in patients with established chronic kidney disease are unknown, and we await the results of ongoing large-scale randomized trials of statin therapy among such patients.

Evidence for increased cardiovascular disease risk in patients with chronic kidney disease

PURPOSE OF REVIEW

Chronic kidney disease is becoming recognized as an important risk factor for cardiovascular disease. Recent publications on cardiovascular disease risk in chronic kidney disease, cardiovascular disease risk factors in chronic kidney disease and clinical trials for cardiovascular disease risk reduction in chronic kidney disease are summarized.

RECENT FINDINGS

An American Heart Association statement published in 2003 recommended that patients with chronic kidney disease be considered as members of the 'highest risk group' for subsequent cardiovascular disease events. In the past year, several large prospective studies have reported that cardiovascular disease risk is independently associated with chronic kidney disease markers, e.g. elevated serum creatinine, low estimated glomerular filtration rate and microalbuminuria. The populations studied have included community samples of middle-aged and older adults, subjects with myocardial infarction, those undergoing coronary angiography, and transplant patients. There is a very strong crude association between a low glomerular filtration rate and cardiovascular disease and mortality. Much of the association is explained by traditional cardiovascular disease risk factors, but an independent risk remains. Studies have documented a disturbing underutilization of preventive treatments for cardiovascular disease among patients with chronic kidney disease. Studies of non-traditional cardiovascular disease risk factors are reviewed. The utility of targeting these for cardiovascular disease risk reduction needs to be proved. A summary of large ongoing clinical trials intended to reduce cardiovascular disease risk in chronic kidney disease is presented.

SUMMARY

Increasing data support the importance of chronic kidney disease as a predictor of cardiovascular disease risk. However, treatments designed to lower cardiovascular disease risk are used less often in patients with chronic kidney disease than in patients without chronic kidney disease. There is a need for increased application and testing of cardiovascular disease prevention treatments in chronic kidney disease.

Managing dyslipidemia in chronic kidney disease

OBJECTIVE

Patients with chronic kidney disease (CKD) are at higher risk for cardiovascular disease (CVD) than patients in the general population. One potentially modifiable risk factor for CVD in patients with CKD is dyslipidemia. In the current manuscript we review observational and trial data assessing dyslipidemia and its treatment in this patient population.

RESULTS

Observational studies have noted a "reverse epidemiology" in patients with CKD such that low total cholesterol levels are associated with a higher mortality rate. The complex lipid profile of patients with CKD also raises questions as to whether lipid-lowering therapy will be beneficial in this patient population. Although there are only a few trials assessing the relationship between lipid-lowering therapy and CVD outcomes in CKD patients, many lipid-lowering medications are both safe and effective. In addition, there is suggestive evidence that statin therapy, in particular, also may reduce inflammation and slow the decline in glomerular filtration rate (GFR) in patients during the earlier stages of CKD.

CONCLUSION

Because of the high rate of CVD in patients with CKD and the overall safety of most medical therapies for dyslipidemia in CKD, current guidelines from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative recommend aggressive therapy of dyslipidemia. These guidelines do, however, acknowledge the paucity of trial data in this patient population. There are 3 ongoing randomized controlled trials that are assessing the effect of statin therapy on CVD outcomes. These studies will hopefully provide definitive answers as to the appropriate treatment of dyslipidemia in CKD.

Intérêt des statines en néphrologie

STATINS IN THE CASE OF CHRONIC RENAL DISEASE: Data of several large clinical trials in the general population demonstrated that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) are effective in cardiovascular disease prevention with a relatively safe profile. Patients with chronic kidney disease (CKD) are at high risk for developing premature cardiovascular disease, so the benefits of statin therapy might be expected to be substantial in this population. Adjusted dose of statins to calcinurine inhibitors and renal function seem to exhibit a favorable risk/benefit ratio in CKD patients.

STUDY RESULTS

Statin use is CKD patients has been associated with a certain efficacy of cardiovascular disease prevention in several uncontrolled trials, and one randomized trial in renal transplant recipients. Several other large-scale randomized trials in CKD patients [4D (atorvastatin), AURORA (rosuvastatin) and SHARP (simvastatin/ezetimib) are currently underway. The results of these trials will permit evidence-based medicinal arguments justifying life-long clinical use of statins for cardiovascular prevention in CKD patients with progressive renal dysfunction, but data are inconclusive.

OTHER POSSIBLE EFFECTS

Clinically relevant plethoric effects associated with statin therapy in CKD patients might be restricted to the decrease of inflammation and oxidative stress.

New and emerging data from clinical trials of statins

Recent clinical trials of statins have clearly demonstrated the benefit of statin therapy in preventing both coronary and cerebral vascular events. These benefits have been demonstrated to be present without reference to older age, sex, or comorbid conditions, including hypertension and diabetes. Future trials will test the value of more aggressive low-density lipoprotein cholesterol lowering, the value of immediate statin intervention during acute coronary syndromes, the role of cholesterol lowering with or without angioplasty, and the role of cholesterol lowering in stroke prevention.

Clinical practice guidelines for managing dyslipidemias in kidney transplant patients: a report from the Managing Dyslipidemias in Chronic Kidney Disease Work Group of the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

The incidence of cardiovascular disease (CVD) is very high in patients with chronic kidney (CKD) disease and in kidney transplant recipients. Indeed, available evidence for these patients suggests that the 10-year cumulative risk of coronary heart disease is at least 20%, or roughly equivalent to the risk seen in patients with previous CVD. Recently, the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) published guidelines for the diagnosis and treatment of dyslipidemias in patients with CKD, including transplant patients. It was the conclusion of this Work Group that the National Cholesterol Education Program Guidelines are generally applicable to patients with CKD, but that there are significant differences in the approach and treatment of dyslipidemias in patients with CKD compared with the general population. In the present document we present the guidelines generated by this workgroup as they apply to kidney transplant recipients. Evidence from the general population indicates that treatment of dyslipidemias reduces CVD, and evidence in kidney transplant patients suggests that judicious treatment can be safe and effective in improving dyslipidemias. Dyslipidemias are very common in CKD and in transplant patients. However, until recently there have been no adequately powered, randomized, controlled trials examining the effects of dyslipidemia treatment on CVD in patients with CKD. Since completion of the K/DOQI guidelines on dyslipidemia in CKD, the results of the Assessment of Lescol in Renal Transplantation (ALERT) Study have been presented and published. Based on information from randomized trials conducted in the general population and the single study conducted in kidney transplant patients, these guidelines, which are a modified version of the K/DOQI dyslipidemia guidelines, were developed to aid clinicians in the management of dyslipidemias in kidney transplant patients. These guidelines are divided into four sections. The first section (Introduction) provides the rationale for the guidelines, and describes the target population, scope, intended users, and methods. The second section presents guidelines on the assessment of dyslipidemias (guidelines 1-3), while the third section offers guidelines for the treatment of dyslipidemias (guidelines 4-5). The key guideline statements are supported mainly by data from studies in the general population, but there is an urgent need for additional studies in CKD and in transplant patients. Therefore, the last section outlines recommendations for research.

Potential nontraditional applications of statins

OBJECTIVE

To review the current evidence for use of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) in nontraditional lipid-related applications, including acute coronary syndromes, peripheral arterial disease, stroke, and renal disease, and to describe ongoing trials evaluating the role of statins in these conditions.

DATA SOURCES

Clinical literature was identified by a MEDLINE search (1990-November 2002) using >/=1 of the following search terms: acute coronary syndrome(s), angina pectoris, atherosclerosis, atorvastatin, clinical trials, diabetes mellitus, end-stage renal disease, fluvastatin, lovastatin, myocardial infarction, peripheral arterial disease, pravastatin, simvastatin, statins, and stroke. Treatment guidelines issued by professional and governmental organizations, such as the American Diabetes Association, American Heart Association, National Cholesterol Education Program, National Kidney Foundation, and National Stroke Foundation, were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Articles identified from the data sources were included if they pertained to the conditions described in the objectives and provided unique information concerning use of statins.

DATA SYNTHESIS

Substantial evidence exists for the use of statins in acute coronary syndromes. Meta-analyses of data from major clinical trials indicate that statins prevent first and recurrent stroke, and large-scale trials are underway to evaluate the efficacy of statins in this setting. Accumulating evidence suggests that statins may be beneficial in reducing the morbidity and mortality associated with peripheral arterial disease and end-stage renal disease, and results from ongoing trials may confirm these benefits. Statins may also have a future role in amelioration of other conditions associated with atherosclerosis, such as diabetes mellitus.

CONCLUSIONS

A large body of evidence supports the evaluation of statins in clinical settings beyond primary and secondary prevention of morbidity and mortality associated with coronary atherosclerosis.

Are HMG-CoA reductase inhibitors underutilized in dialysis patients?

Patients with end-stage renal disease (ESRD) treated with dialysis have a dramatically elevated rate of cardiovascular disease (CVD) compared to the general population. Lipid-lowering therapy with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors ("statins") has been shown to markedly reduce cardiovascular risk in patients without renal failure, but their effect has not been fully studied in the dialysis population. In this article we will first discuss the known benefits of statin therapy in the general population and summarize the current guidelines for such therapy. We will then examine the evidence linking dyslipidemia and cardiac disease in the dialysis population and discuss possible pathophysiologic mechanisms by which statins could prevent cardiac disease in these patients. We will also review prior clinical studies of the effects of statins in patients on dialysis, with particular attention to the safety and efficacy of these drugs in this population. Finally, we will review how statins are currently being used in the care of dialysis patients and suggest whether an expanded utilization of these drugs could help reduce the enormously high rates of cardiac disease in this patient population.

Pharmacokinetics of atorvastatin and its metabolites after single and multiple dosing in hypercholesterolaemic haemodialysis patients

BACKGROUND

Patients with chronic renal failure commonly suffer from a secondary form of complex dyslipidaemia, and may benefit from lipid-lowering treatment. Atorvastatin has been shown to reduce efficiently the levels of atherogenic lipoproteins also in patients with renal failure, but pharmacokinetic data in haemodialysis patients are lacking.

METHODS

In this study, hypercholesterolaemic haemodialysis patients received 40 mg (n=12) or 80 mg (n=11) atorvastatin once daily, first as a single dose and then continuously for 2 weeks. Plasma levels of atorvastatin and its active and inactive metabolites were measured by LC/MS/MS, and pharmacokinetic parameters (C(max), t(max), AUC, t(1/2)) compared between single and multiple dosing, and between the different doses.

RESULTS

The pharmacokinetic parameters of the parent drug atorvastatin acid were not significantly different after single and 2-week multiple dosing; they showed dose-proportionality between the 40 and 80 mg dose, and were comparable to findings in healthy volunteers. Dose-proportionality and absence of accumulation was also observed for the major active metabolite ortho-hydroxy-atorvastatin and the inactive metabolites atorvastatin lactone and ortho-hydroxy-atorvastatin lactone, but the levels of the active metabolite were relatively lower, and the inactive metabolites higher, compared with healthy volunteers. The para-hydroxy-metabolites constituted only a minor pathway in atorvastatin's metabolic elimination. Haemodialysis did not cause enhanced clearance of atorvastatin or its metabolites, the drug was well tolerated and there were no serious adverse events.

CONCLUSION

While subtle differences may exist in the metabolic processing of atorvastatin in haemodialysis patients, active drug did not accumulate nor did it show enhanced elimination, and levels were comparable to those measured in healthy volunteers. Therefore there is no need to adapt atorvastatin dosage in this particular patient population.

Why do we need a statin trial in hemodialysis patients?

BACKGROUND

The risk of cardiovascular complications is markedly increased in patients on dialysis treatment. This includes cardiac disease, stroke, and peripheral vascular disease. The mortality in dialysis patients is markedly higher compared to a nonuremic population. There are several cardiovascular (CV) risk factors that are unique to this population, one of which is dyslipidemia. Uremic patients do not usually develop hypercholesterolemia, but rather are characterized by high levels of very low density lipoprotein (VLDL) triglycerides, low high density lipoprotein (HDL) cholesterol, and elevated levels of modified low density lipoprotein (LDL) particles, which are particularly harmful to the vascular wall. HMG-CoA reductase inhibitors (statins) have been proven to be very efficient in reducing CV events in a nonrenal population. There are several landmark trials that have demonstrated that statins reduce the mortality in cardiovascular disease (CVD) in populations with normal, or close to normal, renal function. There are some observational registry data indicating that this may also be true in hemodialysis (HD) patients, but no prospective controlled trial has been performed to date.

METHODS

We present the rationale for, and a brief outline of, a randomized placebo-controlled trial using a novel drug, rosuvastatin, in HD patients, to target cardiovascular events (the AURORA study). This study will include close to 3000 male and female HD patients, aged 50-80 years. The study is event driven and it has been estimated that it will run for a follow-up time close to four years.

CONCLUSION

There is a sound rationale for making a randomized placebo-controlled statin trial in HD patients, with the objective to demonstrate an effect on CV mortality and morbidity.

Why is coronary heart disease of uraemic patients so frequent and so devastating?

On September 6, 2001, Professor Fernando Valderrabano (Hospital Gregorio Marañon, Madrid) died at the age of 59 years. He was a leading figure in Spanish nephrology, a full professor of Medicine/Nephrology at the University Complutense of Madrid, and an outstanding scientist who published more than 300 articles in medical journals. He was a very intelligent and cultured person, and a man of great style who enjoyed a wide range of hobbies and interests in addition to his medical work. All his colleagues and friends mourn his passing.

Clinical epidemiology of cardiac disease in dialysis patients: left ventricular hypertrophy, ischemic heart disease, and cardiac failure

Patients with end-stage renal disease (ESRD) are at extreme cardiovascular risk. At least half of all patients starting dialysis therapy have overt cardiovascular disease (CVD). In addition, recent studies suggest annual incidence rates for new-onset cardiac failure, peripheral vascular disease, ischemic heart disease (IHD), and stroke of approximately 7%, 7%, 5%, and 1%, respectively. High-level exposure to traditional risk factors, such as smoking and dyslipidemia, hemodynamic overload factors, such as anemia and hypertension, and a myriad of metabolic factors related to uremia are all likely to play a role. There has been explosive growth in observational studies and a heartening, if less dramatic, increase in risk factor intervention trials, suggesting that risk factor modification can lead to meaningful benefit.

Uremia-related metabolic cardiac risk factors in chronic kidney disease

Growing evidence has been gathered over the last 15 years regarding the role of nontraditional or uremia-related risk factors in the pathogenesis of atherosclerosis in subjects with renal failure. Among those factors, dyslipidemia, inflammation, hyperhomocysteinemia, and oxidant stress have been extensively studied. However, the clinical significance of many of these factors remains controversial in light of reported studies. In this article, the existing evidence regarding the role of uremia-related risk factors in the pathogenesis of atherosclerosis is reviewed, with special emphasis on prevalence, cardiac risk, and management in patients with chronic kidney disease (CKD). Consensus treatment recommendations are provided for risk factors for which there is evidence to support preventive or therapeutic interventions.