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Vera Krane

Publications and source records attributed to Vera Krane.

14 recordsLinked to original sources
PubMed2007

Lipid metabolism in chronic kidney disease: the role of statins in cardiovascular risk.

In the general population, the relation between lipids and cardiovascular disease is clearcut, whereas it is highly controversial in chronic kidney disease (CKD) patients. This is primarily due to diverging results of retrospective observational trials. This study design often encounters confounding, especially in renal disease patients. Even if analyses are corrected for multiple influences, there might be unknown confounders changing the results. Prospective randomized trials assure that groups are comparable except for the intervention used. Confounding is eliminated by randomization. Nevertheless, the lipid discussion was restarted when two randomized, placebo-controlled, interventional trials on lipid-lowering therapy in renal patients have been published (Assessment of Lescol in Renal Transplantation and 4D Study [Atorvastatin in patients with type 2 diabetes on hemodialysis]). Surprisingly, both showed no significant reduction of the primary endpoint by statin therapy. In addition to other factors, this might be due to an altered pathogenesis of atherosclerosis in renal patients where multiple nontraditional cardiovascular risk factors are to be mentioned and different characteristics of cardiovascular disease with a high proportion of sudden cardiac death are present. This review will focus on dyslipidemia in renal failure and its treatment. The data published so far is summarized and grouped according to the different stages of CKD.

Cardiovascular Diseases↗
PubMed2006

Lessons learnt from the 4D trial.

Renal dysfunction alters the pathogenesis of cardiovascular disease (CVD) profoundly conferring a very high-risk to the patients. Currently strategies are developed to combat CVD and clinical studies test a number of hypothesis. In this setting the results of the 4D study, comparing atorvastatin with placebo on cardiovascular outcomes in 1255 type 2 diabetic patients on maintenance hemodialysis, came as a great and unsuspected surprise. After a median follow-up of 4 years atorvastatin (20 mg/d) decreased the relative risk by 8% (95% confidence interval, 0.77-1.10; P=0.37) despite a high number of cardiovascular events and an overall 24% cardiovascular mortality. This indicates, that the risk in type 2 diabetic patients on hemodialysis origins from factors other than an atherogenic lipoprotein phenotype alone. Due to non-significant effects of atorvastatin on the primary endpoint and the different quality of such endpoints in dialysis patients as well as an unexplained higher rate of fatal strokes in atorvastatin treated patients we do not recommend to initiate statin treatment in patients with type 2 diabetes mellitus undergoing hemodialysis therapy at the present time. Statin therapy should be implemented earlier during the course of progressive vascular damage.

Atorvastatin↗
PubMed2006

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.

Bias↗
PubMed2006

Dyslipidemia, inflammation and dialysis outcomes: what we know now.

PURPOSE OF REVIEW: The limited prognosis of patients with chronic kidney disease starts when renal function begins to decline. RECENT FINDINGS: Available interventions did not prove their efficacy. Treatment of dyslipidemia and inflammation by statins was shown to be effective in post-hoc subgroup analyses of large-scale randomized controlled trials in patients with chronic kidney disease stages 2 and 3. So far, randomized controlled trials in dialysis patients (HEMO, ADEMEX, 4D study) and after kidney transplantation (ALERT study) have produced so-called 'negative results'. It is most likely that these trials had limited power to prove the primary hypothesis. It is also probable that cardiac disease in renal patients changes its character from a vascular atherosclerotic to a more complex structural heart disease in combination with stiff arteries (arteriosclerosis). Clinically, this leads to a high proportion of sudden cardiac deaths: of 270 cardiac deaths in the 4D trial, 160 were of sudden cardiac origin. A complex pathogenetic process and a number of new emerging cardiovascular disease risk factors in the setting of high-grade inflammation/infection are proposed as being responsible. SUMMARY: This review focuses on outcome variables in diabetic hemodialysis patients with special focus on risk factors such as inflammation and dyslipidemia.

C-Reactive Protein↗
PubMed2005

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.

Aged↗
PubMed2005

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.

Clinical Trials Data Monitoring Committees↗
PubMed2004

Randomized controlled trial on the efficacy and safety of atorvastatin in patients with type 2 diabetes on hemodialysis (4D study): demographic and baseline characteristics.

Patients with type 2 diabetes on dialysis are at a substantially increased risk of cardiovascular and cerebrovascular diseases. Dyslipidemia characterized by moderately elevated low-density lipoprotein cholesterol and high triglycerides and low high-density lipoprotein cholesterol levels is common in this population. We hypothesized that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors would reduce vascular morbidity and mortality in this patient group. The 'Deutsche Diabetes Dialyse Studie' (4D study) is a prospective, randomized, double-blind study involving 178 dialysis centers throughout Germany. Between March 1998 and October 2002, 1,255 patients were randomized to either atorvastatin 20 mg or placebo; 677 men and 578 women, aged 30-83 years, have been enrolled. The study will be terminated as soon as the predefined number of 424 patients with primary combined end points (i.e., cardiovascular death, nonfatal myocardial infarction, or fatal/nonfatal stroke) will have occurred. The total cohort had the following characteristics at baseline: the mean age was 65.7 years, 54% were men, 89% had a history of hypertension, 21% had coronary artery disease, 17.8% had a history of stroke or a transient ischemic attack, and 45% suffered from peripheral arterial disease. The mean time interval between the diagnosis of diabetes and the onset of dialysis was 17.4 years. On average, the patients were on hemodialysis for 8.3 months. Mean lipid and lipoprotein levels were: total cholesterol 219 +/- 43 mg/dl, low-density lipoprotein cholesterol 126 +/- 30 mg/dl, high-density lipoprotein cholesterol 36 +/- 13 mg/dl, and triglycerides 264 +/- 167 mg/dl. The results of the study will provide important information on the efficacy and safety of atorvastatin to support its use in patients with an impaired renal function who are at a high risk of vascular morbidity and mortality.

Adult↗
PubMed2003

Fabry disease: diagnosis and treatment.

Fabry disease is an X-linked lysosomal storage disorder that results from a deficiency of the enzyme alpha-galactosidase A (alpha-Gal A). The lack of alpha-Gal A causes an intracellular accumulation of glycosphingolipids, mainly globotriaosyceramide (GL3). Affected organs include, among others, the vascular endothelium, heart, brain, and kidneys, leading to end-stage renal disease (ESRD). Since Fabry disease cannot be cured at present, clinical management is symptomatic. Enzyme replacement therapy (ERT) with recombinant alpha-Gal A has been introduced as a new therapeutic option for the treatment of Fabry patients. Short-term (one year) clinical studies have positively correlated ERT with improvement of clinical symptoms and microvascular endothelial cell clearance. Treatment outcome concerning severe organ manifestations such as proteinuria and renal function impairment, left ventricular hypertrophy, and heart failure in the long run has yet to be shown. In our studies we used sensitive and noninvasive techniques such as ultrasound-based strain rate imaging and magnetic resonance imaging (MRI), combined with MR-spectroscopy (MR-S), for the quantification of functional abnormalities at an early stage of the disease and during long-term follow-up. Future issues should determine the appropriate timing to start therapy and how children and heterozygous females should be managed. Given the diagnostic and therapeutic potential today, it is of importance to identify patients at an early stage and to start therapeutic intervention before progression of organ damage is inevitable.

Fabry Disease↗
PubMed2003

Non-high-density lipoprotein cholesterol: a target of lipid-lowering in dialysis patients.

BACKGROUND: The finding of an increased prevalence and levels of atherogenic lipoproteins in the context of normal plasma total and low-density lipoprotein (LDL) cholesterol (LDL-C) levels in hemodialysis (HD) patients highlights the need to look beyond the basic assessment of plasma concentrations of total cholesterol and LDL-C. Measurement of atherogenic lipoproteins (remnant lipoprotein particles [RLPs], particularly intermediate-density lipoprotein [IDL]), is not routinely performed at the present time. METHODS: The National Cholesterol Education Program guidelines indicate that the secondary goal in persons with triglyceride levels greater than 200 mg/dL is non-high-density lipoprotein cholesterol (HDL-C). Non-HDL-C comprises all RLPs, including IDL, as well as atherogenic small dense LDL. RESULTS: We propose, for practical reasons, that non-HDL-C be used as a primary target in HD patients when lipid-lowering therapy is indicated. However, it remains unclear whether and how effective statins are in lowering remnant particle levels in dialysis patients. Recent data show that both simvastatin and atorvastatin reduce non-HDL-C levels effectively. Atorvastatin preferentially reduces RLP levels in patients with combined hyperlipidemia. CONCLUSION: The safety profile of statins predisposes prescription of this class of drugs to correct dyslipidemia or modulate lipoprotein particle composition in uremic patients. Whether atorvastatin influences myocardial infarction or all-cause mortality by adequately correcting dyslipidemia should be seen fairly quickly in the 1,252 dialysis patients with diabetes randomly assigned in the ongoing Die Deutsche Diabetes Dialyse study.

Animals↗
PubMed2002

The metabolic burden of diabetes and dyslipidaemia in chronic kidney disease.

Hyperglycaemia induces mitochondrial superoxide production, increases oxidative stress, and leads to activation of the acute-phase response. Hyperglycaemia, impaired renal function, and uraemia cause inflammatory and oxidative processes. Advanced oxidation protein products and advanced glycation end products are formed, leading to subsequent cytokine release. This promotes alterations in lipoprotein metabolism, composition, and function. These changes result in a highly atherogenic environment, perpetuating the vicious cycle of accelerated atherogenesis. The terminal pathway is an elevation of C-reactive protein, a biomarker of both overall and cardiovascular outcome.

Diabetes Mellitus↗
PubMed2002

Uremia-specific alterations in lipid metabolism.

Uremic patients suffer from a secondary form of complex dyslipidemia consisting of quantitative and qualitative abnormalities in serum lipoproteins resulting in altered lipoprotein composition and metabolism. The most prominent are an increase in serum triglyceride levels (due to elevated very-low-density lipoprotein remnants and intermediate-density lipoprotein) and low high-density lipoprotein (HDL) cholesterol. Low-density lipoprotein (LDL) cholesterol is often normal, but the cholesterol may originate from the atherogenic small and dense LDL subclass. The apolipoprotein B-containing part of the lipoprotein may undergo modifications (peptide modification of the enzymatic and advanced glycation end-product, oxidation or glycosylation). Modifications contribute to impaired LDL receptor-mediated clearance from plasma and promote prolonged circulation. HDL particles are structurally altered during states of inflammation. The contribution of this complex and atherogenic form of dyslipidemia to cardiovascular disease in patients with renal disease is at present unclear. Most studies are negative in demonstrating the predictive power of serum lipids for the development of cardiovascular disease. This is most likely due to interference with deteriorating aspects of the activated acute-phase response. Since it is also still unclear whether we have therapeutics available with a sufficient impact on LDL size, remnant lipoprotein lowering and restoration of HDL function, we urgently need specific intervention trials.

Coronary Artery Disease↗