Cardiovascular risk factors in predialysis patients: baseline data from the Chronic Renal Impairment in Birmingham (CRIB) study

Predictive Model for High Coronary Artery Calcium Score in Young Patients with Non-Dialysis Chronic Kidney Disease

Cardiovascular disease is a major complication of chronic kidney disease. The coronary artery calcium (CAC) score is a surrogate marker for the risk of coronary artery disease. The purpose of this study is to predict outcomes for non-dialysis chronic kidney disease patients under the age of 60 with high CAC scores using machine learning techniques. We developed the predictive models with a chronic kidney disease representative cohort, the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD). We divided the cohort into a training dataset (70%) and a validation dataset (30%). The test dataset incorporated an external dataset of patients that were not included in the KNOW-CKD cohort. Support vector machine, random forest, XGboost, logistic regression, and multi-perceptron neural network models were used in the predictive models. We evaluated the model’s performance using the area under the receiver operating characteristic (AUROC) curve. Shapley additive explanation values were applied to select the important features. The random forest model showed the best predictive performance (AUROC 0.87) and there was a statistically significant difference between the traditional logistic regression model and the test dataset. This study will help identify patients at high risk of cardiovascular complications in young chronic kidney disease and establish individualized treatment strategies.

Metformin decreased myocardial fibrosis and apoptosis in hyperhomocysteinemia -induced cardiac hypertrophy

BACKGROUND

Hyperhomocysteinemia (HHcy) is one of the major risk factors of cardiovascular diseases. Metformin acts as a cardioprotective role in several cardiovascular diseases, including ischemia/reperfusion, atherosclerosis, and myocardial infarction. However, whether metformin protects against HHcy-induced cardiac hypertrophy is unclear.

METHODS AND RESULTS

HHcy model was established in C57BL/6 mice with high L-methionine (L-MET) diet for 12 weeks. AC16 cells were exposed to homocysteine (Hcy) and then intervened with different concentrations of metformin in in vitro studies. The results showed that HHcy was able to induce cardiac hypertrophy, and metformin could abrogate this effect. HHcy increased the fibrosis area and induced apoptosis in the myocardium, whereas metformin could reverse the detrimental effects above. TUNEL assay showed that metformin was able to decrease Hcy-induced apoptosis in AC16 cells. Moreover, western blotting assay revealed that metformin could decrease Hcy-induced expression of Bax and cleaved caspase3, and increase the expression of Bcl-2.

CONCLUSIONS

This study demonstrates that metformin is able to attenuate HHcy-induced cardiac hypertrophy by decreasing myocardial fibrosis and apoptosis.

Abdominal aortic calcification in predialysis patients: Contribution of traditional and uremia-related risk factors

Cardiovascular disease is the main cause of morbidity and mortality in end-stage renal disease (ESRD) patients. Recent population based epidemiological studies demonstrated a correlation between reduced renal function and risk for all causes and cardiovascular mortality, 50% of patients dying before the commencement of renal replacement therapy. Vascular calcifications (VC) and arterial stiffness are major contributors to cardiovascular disease and are independent predictors of cardiovascular mortality in ESRD patients. Scarce information is available on the risk factors and prognosis of predialysis patients with VC. The aim of this study was to evaluate the contribution of traditional and uremia related risk factors to abdominal aortic calcification in predialysis patients. A single center, retrospective study was performed on 305 adult patients monitored at the Bucharest University Emergency Hospital for at least 6 months. Our study reports an increased incidence of VC in predialysis chronic kidney disease (CKD) patients, higher in those with advanced age, history of cardiovascular disease, osteoporosis, and declining renal function.

Biological variation of cardiac troponins in chronic kidney disease

Background

Patients with chronic kidney disease often have increased plasma cardiac troponin concentration in the absence of myocardial infarction. Incidence of myocardial infarction is high in this population, and diagnosis, particularly of non ST-segment elevation myocardial infarction (NSTEMI), is challenging. Knowledge of biological variation aids understanding of serial cardiac troponin measurements and could improve interpretation in clinical practice. The National Academy of Clinical Biochemistry (NACB) recommended the use of a 20% reference change value in patients with kidney failure. The aim of this study was to calculate the biological variation of cardiac troponin I and cardiac troponin T in patients with moderate chronic kidney disease (glomerular filtration rate [GFR] 30–59 mL/min/1.73 m2).

Methods and results

Plasma samples were obtained from 20 patients (median GFR 43.0 mL/min/1.73 m2) once a week for four consecutive weeks. Cardiac troponin I (Abbott ARCHITECT® i2000SR, median 4.3 ng/L, upper 99th percentile of reference population 26.2 ng/L) and cardiac troponin T (Roche Cobas® e601, median 11.8 ng/L, upper 99th percentile of reference population 14 ng/L) were measured in duplicate using high-sensitivity assays. After outlier removal and log transformation, 18 patients’ data were subject to ANOVA, and within-subject (CVI), between-subject (CVG) and analytical (CVA) variation calculated. Variation for cardiac troponin I was 15.0%, 105.6%, 8.3%, respectively, and for cardiac troponin T 7.4%, 78.4%, 3.1%, respectively. Reference change values for increasing and decreasing troponin concentrations were +60%/–38% for cardiac troponin I and +25%/–20% for cardiac troponin T.

Conclusions

The observed reference change value for cardiac troponin T is broadly compatible with the NACB recommendation, but for cardiac troponin I, larger changes are required to define significant change. The incorporation of separate RCVs for cardiac troponin I and cardiac troponin T, and separate RCVs for rising and falling concentrations of cardiac troponin, should be considered when developing guidance for interpretation of sequential cardiac troponin measurements.

Treatment of Dyslipidemia in Chronic Kidney Disease

Dyslipidemia is a common feature of various renal diseases. This perturbed lipid metabolism results in accelerated atherosclerosis and increased cardiovascular morbidity and mortality. Treatment of dyslipidemia, in addition to normalization of blood pressure and reduction of proteinuria, could provide additional means to retard the progression of chronic renal insufficiency. Possible therapeutic approaches include mainly dietary and life-style modifications, selective use of some technical components of dialysis systems, and the judicious prescriptions of lipid-lowering drugs. Even with relatively normal lipid and lipoprotein profiles statin therapy seems to prevent atherogenesis acceleration. A wide range of therapeutic interventions, targeting the lipid abnormalities that may develop in chronic renal patients and end-stage renal disease (ESRD) are currently available, though still without convincing evidence based on long-term prospective studies which clearly demonstrate a significant reduction in cardiovascular morbidity and mortality of ESRD patients. However, extensive investigations, concerning the best long-term therapeutic strategy for this high-risk population of patients, are still missing.

Associations among time-average mineral values, mortality and cardiovascular events in hemodialysis patients

Mineral and bone disease (CKD-MBD), disorders of mineral metabolism, is associated with mortality and cardiovascular disease in dialysis patients. However, the associations among time average mineral values (P, Ca and PTH) and clinical outcomes are not well investigated.

OBJECTIVES

This study examines the associations among mineral values and clinical outcomes from a single medical center.

METHODS

Adult patients who initiate hemodialysis in Taoyuan General Hospital from 2008 to 2013 were enrolled. We examined these associations using baseline and time-average model. The clinical outcomes included mortality, major adverse cardiovascular events (MACE) and cardiovascular events. We also examined the association between achieve K/DOQI guidelines' targets and clinical outcomes.

RESULTS

From a total of 284 hemodialysis patients, none of the baseline mineral values is associated with mortality and cardiovascular event, except hyperphosphatemia. Compared to patients achieved K/DOQI guidelines' targets, time average hyperphosphatemia is associated with MACE and first cardiovascular event [the adjusted hazard ratios (AHRs) are 6.343 and 3.278); whereas time average hypercalcemia is associated with MACE marginally (the AHR is 5.964). None of above clinical outcomes is related to hyperparathyroidism. The AHRs for mortality in those who only met PTH targets and none of the mineral value targets are 1.73 and 1.74, whereas the AHRs for cardiovascular events in those who met only Ca, only PTH, and none of the targets are 1.73, 1.81 and 2.54 (all ps < 0.05).

CONCLUSION

Time-average phosphate is associated with cardiovascular events after initiation of dialysis. Among mineral values, serum phosphate is still the strongest predictor for mortality and cardiovascular events.

Analysis of factors predicting mortality of new patients commencing renal replacement therapy 10 years of follow-up

BACKGROUND

The natural history of patients commencing dialysis in East Yorkshire is not well characterised and there is little convincing evidence which has studied the impact of potential factors prior to commencement of renal replacement therapy (RRT) at predicting mortality during dialysis. The aim of this study was to examine the previously published 5-year data on end stage renal disease and co-morbid risk factors for mortality at 10 years.

METHODS

An observational cohort study of subjects commencing dialysis in 2001/02 in East Yorkshire with a mean follow up from dialysis initiation of 8.8 years. Predictors of mortality were determined by univariate, multivariate analysis and survival via Kaplan-Meier analysis. Assessment of the utility of the Tangri risk calculator was carried out in addition to slope change in eGFR prior to dialysis commencement.

RESULTS

Baseline characteristics and the preferred mode of dialysis remained concordant with the original trial. The mortality rate at the end of the study period was 60% (56/94) with 30% (29) of patients having been transplanted. Highlighted in the 5 year data a significant proportion of mortality was made up of vascular disease and sepsis (71%) but this proportion had decreased (57%) by 10 years. Cardiac disease was the commonest cause of death but notably in 18% of patients, death was related to dialysis or withdrawal of treatment. Vascular disease and diabetes remained independent risk factors and predicative of mortality. Calcium-phosphate product which was associated in the early years with mortality was not in later years. Use of the risk calculator was predictive of commencement of RRT but not mortality but slope change in eGFR was predictive of mortality.

CONCLUSIONS

Although diabetes and vascular disease remained predictive of mortality, interestingly calcium-phosphate levels are no longer significant and may be a more specific predictor of early cardiac mortality. Slope eGFR changes prior to RRT are a predictor of mortality. We speculate that aggressive management of cardiac risk factors in addition to early transplantation may be key to influencing the impact of survival in this cohort in addition to possible measures to delay renal progression.

Cohort profile: Canadian study of prediction of death, dialysis and interim cardiovascular events (CanPREDDICT)

Background

The Canadian Study of Prediction of Death, Dialysis and Interim Cardiovascular Events (CanPREDDICT) is a large, prospective, pan-Canadian, cohort study designed to improve our understanding of determinants of renal and cardiovascular (CV) disease progression in patients with chronic kidney disease (CKD). The primary objective is to clarify the associations between traditional and newer biomarkers in the prediction of specific renal and CV events, and of death in patients with CKD managed by nephrologists. This information could then be used to better understand biological variation in outcomes, to develop clinical prediction models and to inform enrolment into interventional studies which may lead to novel treatments.

Methods/Designs

Commenced in 2008, 2546 patients have been enrolled with eGFR between 15 and 45 ml/min 1.73m2 from a representative sample in 25 rural, urban, academic and non academic centres across Canada. Patients are to be followed for an initial 3 years at 6 monthly intervals, and subsequently annually. Traditional biomarkers include eGFR, urine albumin creatinine ratio (uACR), hemoglobin (Hgb), phosphate and albumin. Newer biomarkers of interest were selected on the basis of biological relevance to important processes, commercial availability and assay reproducibility. They include asymmetric dimethylarginine (ADMA), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), troponin I, cystatin C, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6) and transforming growth factor beta 1 (TGFβ1). Blood and urine samples are collected at baseline, and every 6 monthly, and stored at −80°C. Outcomes of interest include renal replacement therapy, CV events and death, the latter two of which are adjudicated by an independent panel.

Discussion

The baseline distribution of newer biomarkers does not appear to track to markers of kidney function and therefore may offer some discriminatory value in predicting future outcomes. The granularity of the data presented at baseline may foster additional questions.

The value of the cohort as a unique resource to understand outcomes of patients under the care of nephrologists in a single payer healthcare system cannot be overstated. Systematic collection of demographic, laboratory and event data should lead to new insights.

The mean age of the cohort was 68 years, 90% were Caucasian, 62% were male, and 48% had diabetes. Forty percent of the cohort had eGFR between 30–45 mL/min/1.73m², 22% had eGFR values below 20 mL/min/1.73m²; 61% had uACR < 30. Serum albumin, hemoglobin, calcium and 25-hydroxyvitamin D (25(OH)D) levels were progressively lower in the lower eGFR strata, while parathyroid hormone (PTH) levels increased. Cystatin C, ADMA, NT-proBNP, hsCRP, troponin I and IL-6 were significantly higher in the lower GFR strata, whereas 25(OH)D and TGFβ1 values were lower at lower GFR. These distributions of each of the newer biomarkers by eGFR and uACR categories were variable.

The natural history of, and risk factors for, progressive chronic kidney disease (CKD): the Renal Impairment in Secondary care (RIISC) study; rationale and protocol

BACKGROUND

Chronic kidney disease (CKD) affects up to 16% of the adult population and is associated with significant morbidity and mortality. People at highest risk from progressive CKD are defined by a sustained decline in estimated glomerular filtration rate (eGFR) and/or the presence of significant albuminuria/proteinuria and/or more advanced CKD. Accurate mapping of the bio-clinical determinants of this group will enable improved risk stratification and direct the development of better targeted management for people with CKD.

METHODS/DESIGN

The Renal Impairment In Secondary Care study is a prospective, observational cohort study, patients with CKD 4 and 5 or CKD 3 and either accelerated progression and/or proteinuria who are managed in secondary care are eligible to participate. Participants undergo a detailed bio-clinical assessment that includes measures of vascular health, periodontal health, quality of life and socio-economic status, clinical assessment and collection of samples for biomarker analysis. The assessments take place at baseline, and at six, 18, 36, 60 and 120 months; the outcomes of interest include cardiovascular events, progression to end stage kidney disease and death.

DISCUSSION

The determinants of progression of chronic kidney disease are not fully understood though there are a number of proposed risk factors for progression (both traditional and novel). This study will provide a detailed bio-clinical phenotype of patients with high-risk chronic kidney disease (high risk of both progression and cardiovascular events) and will repeatedly assess them over a prolonged follow up period. Recruitment commenced in Autumn 2010 and will provide many outputs that will add to the evidence base for progressive chronic kidney disease.

Risk factors of cardiovascular disease among children with chronic kidney disease in Gaza strip

Background:

Chronic kidney disease (CKD) is increasingly recognized as a global public health problem. Cardiovascular disease (CVD) is a major cause of mortality in patients with mild-to-moderate CKD and end-stage renal disease. There is accumulating evidence that the increase in CVD burden is present in CKD patients prior to dialysis, due both to conventional risk factors and kidney-specific disease. Detection and initiation of treatment for CVD risk factors at early stages of CKD should be effective in reducing CVD events before as well as after the onset of kidney failure.

Materials and Methods:

The study sample consisted of a total of 112 subjects aged ≤12 years: 60 CKD patients and 52 healthy control individuals. All subjects were investigated for a group of CVD risk factors such as: Hypertension, diabetes, dyslipidemia, physical inactivity, body mass index (BMI), family history of CVD, hypoalbuminemia, albuminuria, anemia, Ca x P product, and inflammation in terms of C-reactive protein (CRP).

Results:

Patients (40 males and 20 females) were categorized into four CKD stages (2, 3, 4, and 5) where, Stage 4 had the highest frequency, followed by Stages 3, 5 and 2. Evaluation of the patients indicated that they were shorter, had lower weight and had higher systolic and diastolic blood pressure as compared with control subjects. Frequency of physical inactivity among patients was two-fold higher than controls (50% vs. 25%). The patients showed significantly higher levels of cholesterol (163.6±39.8 vs. 141.8±24.2 mg/dL, P<0.0001), triglycerides (145.5±67.1 vs. 82.9±39.8 mg/dL, P<0.0001), low-density lipoprotein (92.6±31.9 vs. 72.5±19 mg/dL, P<</i>0.0001) and albumin/creatinine ratio (1792±3183 vs. 11.1±6.6 mg/g, P<0.0001). Moreover, the patients had lower levels of high-density lipoprotein (41.9±11.0 vs. 52.7±11.7 mg/dL, P<0.0001), hemoglobin (9.8±1.4 vs. 11.9±0.8 g/dL, P<0.0001) and albumin (4.6±0.6 vs. 4.8±0.2 g/dL, P=0.012). The CRP showed higher occurrence among patients (40% were positive for CRP). Calcium and phosphorus evaluation showed significantly lower calcium and higher phosphorus among patients. However, the difference in Ca X P product was not statistically significant.

Conclusions:

The study indicates that many of the CVD risk factors are associated with the different stages of CKD in children patients prior to dialysis, and that some of these factors are exacerbated as CKD progresses.

Development and reproducibility of a computed tomography-based measurement of renal sinus fat

Background

Renal sinus fat may mediate obesity-related vascular disease, although this fat depot has not been assessed in a community-based sample. We sought to develop a protocol to quantify renal sinus fat accumulation using multi-detector computed tomography (MDCT).

Methods

Protocol development was performed in participants in the Framingham Offspring cohort who underwent MDCT. Volumetric renal sinus fat was measured separately within the right and left kidneys, and renal sinus fat area within a single MDCT scan slice was measured in the right kidney. Due to the high correlation of volumetric and single-slice renal sinus fat in the right kidney (Pearson correlation [r] = 0.85, p < 0.0001), we optimized a single-slice protocol to capture renal sinus fat in the right kidney alone. Pearson correlation coefficients were used to compare to assess the correlation of volumetric and single-slice renal sinus fat in the right kidney with other measures of adiposity. Inter- and intra-reader reproducibility was assessed using intra-class correlation coefficients.

Results

Single-slice measurements were obtained in 92 participants (mean age 60 years, 49% women, median renal sinus fat 0.43 cm²). Intra- and inter-reader intra-class correlation coefficients were 0.93 and 0.86, respectively. Single-slice renal sinus fat was correlated with body mass index (r = 0.35, p = 0.0006), waist circumference (r = 0.31, p = 0.003), and abdominal visceral fat (r = 0.48, p < 0.0001). Similar correlations were observed for volumetric renal sinus fat in the right kidney.

Conclusions

Measuring renal sinus fat is feasible and reproducible using MDCT scans in a community-based sample.

Biomarkers in chronic kidney disease: a review

Chronic kidney disease (CKD) is a major public health problem. The classification of CKD by KDOQI and KDIGO and the routine eGFR reporting have resulted in increased identification of CKD. It is important to be able to identify those at high risk of CKD progression and its associated cardiovascular disease (CVD). Proteinuria is the most sensitive marker of CKD progression in clinical practice, especially when combined with eGFR, but these have limitations. Hence, early, more sensitive, biomarkers are required. Recently, promising biomarkers have been identified for CKD progression and its associated CVD morbidity and mortality. These may be more sensitive biomarkers of kidney function, the underlying pathophysiological processes, and/or cardiovascular risk. Although there are some common pathways to CKD progression, there are many primary causes, each with its own specific pathophysiological mechanism. Hence, a panel measuring multiple biomarkers including disease-specific biomarkers may be required. Large, longitudinal observational studies are needed to validate candidate biomarkers in a broad range of populations prior to implementation into routine CKD management. Recent renal biomarkers discovered include neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and liver-type fatty acid-binding protein. Although none are ready for use in clinical practice, it is timely to review the role of such biomarkers in predicting CKD progression and/or CVD risk in CKD.

Prevalence of Early Stages of Chronic Kidney Disease in Healthy Army Personnel

INTRODUCTION

Chronic kidney disease (CKD) is associated with significant morbidity and mortality. Screening and detection of early stages of CKD can help institute interventions that may delay the progression of the disease. One aim was to study the prevalence of early stages of CKD in the Army.

METHODS

A cross-sectional study of Army Personnel in an Army cantt in Central India was carried out. All participants filled a structured questionnaire and anthropometric data was collected. Investigative profile included routine urine exam, semi-quantitative microalbuminuria (MAU), serum creatinine, lipid profile and fasting blood glucose. Glomerular Filteration rate (eGFR) was calculated using the Modification of Diet in Renal Diseases (MDRD) study equation.

RESULT

A total of 1920 subjects were examined with 731 (38.07%) from Arms and 1189 (61.93%) from Services. 348 were excluded and of the remaining 1572 subjects, 141 (8.97 %) had MAU and 157 (9.99 %) had deranged Albumin Creatinine Ratio (ACR). Mean eGFR by MDRD equation was 102 ± 25.84 ml/min/1.73m (2) . Early CKD was seen in 150 (9.54 %) with 84 (5.34 %) in stage I CKD, 55 (3.5%) in stage II and 11 (0.7%) in stage III. Multiple logistic regression showed BMI > 23, the presence of DM and HTN were independent risk factors for CKD.

CONCLUSION

9.54% of healthy army personnel were found to have early stages of CKD. Institution of screening programs can result in early detection of CKD.

Frequency of cardiovascular risk factors and metabolic syndrome in patients with chronic kidney disease

OBJECTIVE

Metabolic syndrome is a clustering of cardio-metabolic risk factors. Cardiovascular disease is the main cause of morbidity and mortality in end-stage renal disease. The aim of this study was to elucidate the frequency of traditional and novel cardiovascular and metabolic syndrome risk factors in patients with chronic kidney disease. Identification of these risk factors will allow for precautions to be taken earlier to prevent cardiovascular diseases and metabolic syndrome in chronic kidney disease patients.

METHODS

A total of 214 patients (91 females, 123 males, mean age 56.1 ± 14.4 years) with chronic kidney disease who were followed in the Nephrology Department of Istanbul Goztepe Training and Research Hospital were included in the study. Anthropometric and biochemical measurements for cardiovascular risk factors and metabolic syndrome parameters were recorded. Glomerular filtration rates (GFR) were estimated using the Cockroft Gault formula. Metabolic syndrome was defined according to International Diabetes Federation criteria.

RESULTS

Thirty-seven percent of patients with chronic renal failure were found to have three or more major cardiovascular risk factors. Seventy percent of patients were found to have metabolic syndrome. The mean numbers of major cardiovascular risk factors and metabolic syndrome parameters in patients with different GFR stages were: 1.8 ± 1.0, 2.6 ± 1.2 (GFR <15 mL/min per 1.73 m(2), n = 102); 2.4 ± 1.0, 3.0 ± 1.0 (GFR 15-29 mL/min per 1.73 m(2), n = 51 ); 2.5 ± 1.1, 3.3 ± 1.0 (GFR 30-59 mL/min per 1.73 m(2), n = 39); 2.4 ± 1.1, 3.5 ± 0.7 (GFR 60-89 mL/min per 1.73 m(2), n = 22), respectively (P = .001).

CONCLUSION

Although the frequency of cardiovascular risk factors and metabolic syndrome were high in patients with chronic kidney disease, they were negatively correlated with the stage of renal failure.

Cardiovascular morbidity and mortality and renal artery stenosis

Renal artery stenosis (RAS) is a common manifestation of atherosclerosis and is associated with many other atherosclerotic conditions. Cardiovascular morbidity and mortality is increased among patients with RAS. This increase is likely due in part to the associated disease states; however, RAS itself may also contribute. Current strategies to limit cardiovascular morbidity and mortality in RAS include various pharmacologic interventions targeting both RAS atherosclerosis in general. Additionally, revascularization has been advocated; however, clear data are lacking. Ongoing clinical trials such as the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial will ultimately help to determine the best strategies to limit the morbidity and mortality associated with RAS.

Dyslipidemia and the treatment of lipid disorders in African Americans

BACKGROUND

Despite the high prevalence of cardiovascular disease documented among the African-American population, there has been little emphasis on the role of dyslipidemia as a prominent risk factor in this large subpopulation. Questions of medication efficacy also have been raised. Together, these factors may have affected awareness, diagnosis, and treatment rates.

METHODS AND RESULTS

Dyslipidemia was defined as the presence of either hypercholesterolemia or hypertriglyceridemia using National Cholesterol Education Program III criteria and the fasting lipid measurements, self-reported treatment history, and medication survey available from 5302 Jackson Heart Study participants. Dyslipidemia was more common in men (compared with women) aged less than 50 years and increased with age in both genders. Hypercholesterolemia prevalence rates approached 50% in women aged more than 65 years. The lifestyle-related attributes found to be related to prevalence were being overweight and less physically active, and all disease status variables exhibited significant (P<.05) associations. Awareness of hypercholesterolemia is approximately 55% or more in both men and women aged more than 35 years. Treatment rates lag far behind awareness, particularly in younger adult men, and less than 50% of women and men aged less than 65 years were treated for hypercholesterolemia.

CONCLUSION

Higher rates of identification and effective treatment of dyslipidemia are clearly needed in this, and probably other African-American communities. Despite the less than optimal treatment, the identification and importance of the known cardiovascular disease states and risk factors in these analyses suggest the adoption of National Cholesterol Education Program III "high-risk strategy" algorithms in treatment recommendations and decisions by providers is occurring.

Anaemia in diabetic renal failure: is there a role for early erythropoietin treatment in preventing cardiovascular mortality?

The mortality rate in diabetics with chronic kidney disease (CKD) is seven times higher than end-stage renal disease mainly because of cardiac causes. Anaemia may have a relevant role in the pathogenesis of cardiovascular (CV) disease in CKD. Anaemia occurs at an earlier stage of CKD in diabetic individuals than in those with other causes of CKD. Observational findings support the unfavourable influence of anaemia on mortality in CKD patients, and the combination of anaemia and CKD in diabetics identifies a group with a particularly high mortality risk. While the effect of erythropoietin on these patients' quality of life is known, its impact on mortality and CV risk is uncertain. The recent Anaemia Correction in Diabetes (ACORD) trial in diabetic CKD patients, which targeted haemoglobin levels of 13-15 mg/dl, disclosed no statistically significant favourable or adverse effects on mortality or morbidity over the 2-year follow-up, while other studies endeavouring to nearly normalize haemoglobin have reportedly proved risky. Even if anaemia is causally involved, the pathogenesis of CV disease in diabetics with CKD is so complex that addressing just one factor (anaemia) may not suffice to prevent CV risk, and normalizing haemoglobin levels may even be harmful.

Relations of measures of endothelial function and kidney disease: the Framingham Heart Study

BACKGROUND

Endothelial dysfunction is prevalent in individuals with end-stage renal disease. Whether endothelial dysfunction is present in patients with moderate chronic kidney disease (CKD) is uncertain.

STUDY DESIGN

Cross-sectional study.

SETTINGS & PARTICIPANTS

Brachial reactivity measurements were obtained during the seventh examination cycle in 2,818 (diameter measurements) and 2,256 (flow measurements) Framingham Heart Study Offspring cohort participants (53% women; mean age, 61 +/- 9 years).

PREDICTOR

Estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) derived from creatinine- and cystatin C-based estimating equations; microalbuminuria status.

OUTCOME

Brachial reactivity measurements (baseline brachial diameter, flow-mediated dilation, baseline and hyperemic mean flow).

MEASUREMENTS

Linear regression models were used to model brachial measures as a function of CKD and microalbuminuria status.

RESULTS

Overall, 7.3% (n = 206) of participants had CKD, and of 2,301 with urinary measurements, 10.0% (n = 230) had microalbuminuria. Brachial reactivity measures did not differ significantly by CKD status in either creatinine- or cystatin C-based equations in either age- and sex- or multivariable-adjusted models. In age- and sex-adjusted models, microalbuminuria was associated with decreased hyperemic mean flow (47.2 +/- 1.4 versus 51.4 +/- 0.5 mg/g; P = 0.005), but the association was not significant after multivariable adjustment (P = 0.09).

LIMITATIONS

Predominantly white ambulatory cohort; results may not be generalizable to other ethnic groups or individuals with severe CKD.

CONCLUSIONS

Endothelial dysfunction was not a major correlate of CKD in our sample.

Overweight, obesity, and the development of stage 3 CKD: the Framingham Heart Study

BACKGROUND

Prior research yielded conflicting results about the magnitude of the association between body mass index (BMI) and chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort study.

SETTINGS & PARTICIPANTS

Framingham Offspring participants (n = 2,676; 52% women; mean age, 43 years) free of stage 3 CKD at baseline who participated in examination cycles 2 (1978-1981) and 7 (1998-2001).

PREDICTOR

BMI.

OUTCOME

Stage 3 CKD (estimated glomerular filtration rate < 59 mL/min/1.73 m(2) for women and < 64 mL/min/1.73 m(2) for men).

MEASUREMENTS

Age-, sex-, and multivariable-adjusted (diabetes, systolic blood pressure, hypertension treatment, current smoking status, and high-density lipoprotein cholesterol level) logistic regression models were used to examine the relationship between BMI at baseline and incident stage 3 CKD and incident dipstick proteinuria (trace or greater).

RESULTS

At baseline, 36% of the sample was overweight and 12% was obese; 7.9% (n = 212) developed stage 3 CKD during 18.5 years of follow-up. Relative to participants with normal BMI, there was no association between overweight individuals and stage 3 CKD incidence in age- and sex-adjusted models (odds ratio [OR], 1.29; 95% confidence interval [CI], 0.93 to 1.81; P = 0.1) or multivariable models (OR, 1.06; 95% CI, 0.75 to 1.50; P = 0.8). Obese individuals had a 68% increased odds of developing stage 3 CKD (OR, 1.68; 95% CI, 1.10 to 2.57; P = 0.02), which became nonsignificant in multivariable models (OR, 1.09; 95% CI, 0.69 to 1.73; P = 0.7). Similar findings were observed when BMI was modeled as a continuous variable or quartiles. Incident proteinuria occurred in 14.4%; overweight and obese individuals were at increased odds of proteinuria in multivariable models (OR, 1.43; 95% CI, 1.09 to 1.88; OR, 1.56; 95% CI, 1.08 to 2.26, respectively).

LIMITATIONS

BMI is measure of generalized obesity and not abdominal obesity. Participants are predominantly white, and these findings may not apply to different ethnic groups.

CONCLUSIONS

Obesity is associated with increased risk of developing stage 3 CKD, which was no longer significant after adjustment for known cardiovascular disease risk factors. The relationship between obesity and stage 3 CKD may be mediated through cardiovascular disease risk factors.

Correlations between homocysteine levels and atherosclerosis in Japanese type 2 diabetic patients

Elevated total plasma homocysteine (tHcy) level and aortic stiffness are associated with high mortality in type 2 diabetic patients. We tested the hypothesis that tHcy correlates with aortic stiffness and insulin resistance in type 2 diabetic patients. The study consisted of 40 Japanese patients with type 2 diabetes mellitus and high tHcy levels (mean age +/- SD, 57 +/- 7 years) and a control group of 45 age-matched patients with normal tHcy levels (mean age +/- SD, 57 +/- 6 years). Brachial-ankle pulse wave velocity (BaPWV) was measured by an automatic oscillometric method. Brachial-ankle pulse wave velocity was used as an index of atherosclerosis. Body mass index values (P < .05), waist circumferences (P < .05), and the waist-to-hip ratios (P < .05) were larger in the high-tHcy group than in the normal-tHcy group. The BaPWV was higher in the high-tHcy group than in the normal-tHcy group (P < .0001). Fasting plasma glucose (P < .005) and insulin concentrations (P < .0001), and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-tHcy group than in the normal-tHcy group. Multiple regression analysis showed that tHcy levels were independently predicted by BaPWV and the HOMA index. In conclusion, our results indicate that the elevated level of tHcy in Japanese patients with type 2 diabetes mellitus is characterized by increased aortic stiffness and insulin resistance, and that the BaPWV and the HOMA index are independent predictors of tHcy.

Exercise in the end-stage renal disease population

Many of the known benefits of exercise in the general population are of particular relevance to the ESRD population. In addition, the poor physical functioning that is experienced by patients who are on dialysis is potentially addressable through exercise interventions. The study of exercise in the ESRD population dates back almost 30 yr, and numerous interventions, including aerobic training, resistance exercise training, and combined training programs, have reported beneficial effects. Recently, interventions during hemodialysis sessions have become more popular and have been shown to be safe. The risks of exercise in this population have not been rigorously studied, but there have been no reports of serious injury as a result of participation in an exercise training program. It is time that we incorporate exercise into the routine care of patients who are on dialysis, but identification of an optimal training regimen or regimens, according to patient characteristics or needs, is still needed to facilitate implementation of exercise programs.

Left Ventricular Geometry and Renal Function in Hypertensive Patients With Diastolic Heart Failure

BACKGROUND

The objective is to define the relationship between cardiac geometry and renal function in hypertensive subjects with and without diastolic heart failure (DHF).

METHODS

This is a prospective observational study in a tertiary-care teaching institute in a 15-month period of consecutive hospitalized hypertensive patients. Patients on dialysis therapy or with atrial fibrillation, systolic heart failure, gross proteinuria, and glomerular diseases were excluded. Two-dimensional echocardiography was performed and stable glomerular filtration rate (GFR) was calculated by using the Modification of Diet in Renal Disease formula. Patients were classified into stage 1 to 5 chronic kidney disease (CKD).

RESULTS

Five hundred forty hypertensive patients were separated into 2 groups: 286 patients with DHF and 254 patients without DHF. Mean age was 69.1 +/- 13.7 (SD) years in general. In patients with DHF, from stages 1 to 5 CKD, there was a significant graded increase in left ventricular mass index (from 117.3 to 162.4 g/m(2)) and relative wall thickness (from 0.42 to 0.52) and a significant graded decrease in aortic cusp separation (from 1.85 to 1.55 cm). Among echocardiographic variables, left ventricular mass index and relative wall thickness were associated inversely and aortic cusp separation was associated directly with GFR. In the absence of DHF, only left ventricular mass index was associated inversely with GFR, suggesting a prominent role of aortic cusp separation and relative wall thickness in the variability in GFR in patients with DHF through a hemodynamic disturbance.

CONCLUSION

Hemodynamic alterations have a prominent role in the variability of GFR in patients with CKD with DHF. Adverse cardiac geometry is linked to the severity of CKD in hypertensive patients, raising the possibility of preserving both cardiac and renal function by means of hypertension control.

Impaired renal function and duration of dialysis therapy are associated with oxidative stress and proatherogenic cytokine levels in patients with end-stage renal disease

OBJECTIVES

The present study was undertaken to clarify the role of the impaired renal function and the dialysis therapy on plasma levels of proatherogenic cytokines and Cu/Zn superoxide dismutase (Cu/Zn SOD)--as a marker of oxidative stress (SOX) in uraemia.

DESIGN AND METHODS

We have measured the levels of Cu/Zn SOD, monocyte chemoattractant protein-1 (MCP-1) macrophage inflammatory proteins (MIP-1alpha, MIP-1beta) and vascular endothelial growth factor (VEGF) in the plasma of predialysis (CRF) (n=42), on maintenance hemodialysis (HD) (n=25) or peritoneal dialysis (PD) (n=45) patients and in the healthy volunteers (n=20).

RESULTS

The increase in Cu/Zn SOD levels was in PD and HD patients compared to controls (215.56+/-125.18 and 356.28+/-122.57 versus 53.53+/-23.65 ng/ml, respectively). In plasma of the CRF, PD and HD subjects we have also observed the significant increase in the levels of MIP-1beta: [31.5 (2-149), 33.0 (1-203) and 76.0 (9-345), respectively]; MCP-1 (616.50+/-240.15, 943.64+/-348.99 and 968.50+/-355.85, respectively) and VEGF (387.93+/-184.63, 371.56+/-125.18 and 645.56+/-136.30, respectively) compared to healthy people. In the predialysis group, creatinine clearance correlated with Cu/Zn SOD and cytokine levels. Moreover, the cytokine levels were also associated with age. In dialysis patients, the correlations were between duration of dialysis treatment and both Cu/Zn SOD and cytokine levels. There was also a direct relationship between Cu/Zn SOD and both MIP-1beta and VEGF levels.

CONCLUSIONS

This study has shown that impaired renal function, age and duration of dialysis treatment are associated with increased oxidative stress and proatherogenic cytokine levels in uremic patients.

Homocysteine levels are associated with the results of 123I-metaiodobenzylguanidine myocardial scintigraphy in type 2 diabetic patients

PURPOSE

Elevated total plasma homocysteine (tHcy) levels and cardiovascular autonomic dysfunction are associated with a high mortality in type 2 diabetic patients. We tested the hypothesis that hyperhomocysteinemia is associated with insulin resistance and cardiovascular autonomic dysfunction in type 2 diabetic patients not receiving insulin treatment.

METHODS

The study group consisted of 17 type 2 diabetic patients with high tHcy levels (>15 mmol/l, age 58+/-5 years, high tHcy group). The control group consisted of 23 age-matched type 2 diabetic patients with normal tHcy levels (<or=15 mmol/l, age 58+/-9 years, normal tHcy group). Cardiovascular autonomic function was assessed by baroreflex sensitivity, heart rate variability, plasma norepinephrine concentrations, and cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphy.

RESULTS

Early and delayed (123)I-MIBG myocardial uptake values were lower (p<0.005 and p<0.01, respectively) and the percent washout rate of (123)I-MIBG was higher (p<0.001) in the high tHcy group than in the normal tHcy group. The fasting plasma insulin concentrations (p<0.0001) and the homeostasis model assessment (HOMA) index values (p<0.0001) were higher in the high tHcy group than in the normal tHcy group. Multiple regression analysis revealed that the level of tHcy was independently predicted by the HOMA index values and the myocardial uptake of (123)I-MIBG at the delayed phase.

CONCLUSION

Our results demonstrate that high levels of tHcy are associated with depressed cardiovascular autonomic function and insulin resistance in patients with type 2 diabetes mellitus.

Impact of comorbidities on mortality in managed care patients with CKD

BACKGROUND

Our previous work showed that patients with chronic kidney disease (CKD) were 10 times more likely to die than progress to end-stage renal disease. This study examines the impact of comorbidities on mortality risk in a cohort with CKD at 3 levels of progression and a sex- and age-matched comparison group.

METHODS

In a historical, prospective, cohort study, we selected electronic medical record data for health maintenance organization (HMO) members with an index and repeated glomerular filtration rate (GFR) in the range of 15 to 90 mL/min/1.73 m(2) (0.25 to 1.50 mL/s/1.73 m(2)) in 1996 who were followed up for at least 54 months or died during this period. These were matched for birth year and sex with HMO members not meeting GFR criteria, but with the same follow-up criteria. Major comorbid chronic conditions also were identified based on International Classification of Diseases, Ninth Revision, diagnostic codes in the electronic medical record. Conditional logistic regression was used to estimate the relative risk for mortality versus comparison subjects as a function of GFR, age, and other chronic conditions.

RESULTS

In the final sample of 19,945 pairs, we found that risk for mortality increases as GFR decreases, but also that both age and other chronic conditions are significant risk factors for mortality.

CONCLUSION

Baseline levels of estimated GFR and other major chronic disorders all contributed negatively to survival. The relative impact of these comorbidities was greatest among younger (<60 years) patients with CKD, and their relative effect diminished with age.

Effects of resistance exercise training and nandrolone decanoate on body composition and muscle function among patients who receive hemodialysis: A randomized, controlled trial

Patients who are on hemodialysis commonly experience muscle wasting and weakness, which have a negative effect on physical functioning and quality of life. The objective of this study was to determine whether anabolic steroid administration and resistance exercise training induce anabolic effects among patients who receive maintenance hemodialysis. A randomized 2 x 2 factorial trial of anabolic steroid administration and resistance exercise training was conducted in 79 patients who were receiving maintenance hemodialysis at University of California, San Francisco-affiliated dialysis units. Interventions included double-blinded weekly nandrolone decanoate (100 mg for women; 200 mg for men) or placebo injections and lower extremity resistance exercise training for 12 wk during hemodialysis sessions three times per week using ankle weights. Primary outcomes included change in lean body mass (LBM) measured by dual-energy x-ray absorptiometry, quadriceps muscle cross-sectional area measured by magnetic resonance imaging, and knee extensor muscle strength. Secondary outcomes included changes in physical performance, self-reported physical functioning, and physical activity. Sixty-eight patients completed the study. Patients who received nandrolone decanoate increased their LBM by 3.1 +/- 2.2 kg (P < 0.0001). Exercise did not result in a significant increase in LBM. Quadriceps muscle cross-sectional area increased in patients who were assigned to exercise (P = 0.01) and to nandrolone (P < 0.0001) in an additive manner. Patients who exercised increased their strength in a training-specific fashion, and exercise was associated with an improvement in self-reported physical functioning (P = 0.04 compared with nonexercising groups). Nandrolone decanoate and resistance exercise produced anabolic effects among patients who were on hemodialysis. Further studies are needed to determine whether these interventions improve survival.

Phenotypic and genotypic risk factors for cardiovascular events in an incident dialysis cohort

Cardiovascular disease (CVD) remains the major cause of death in patients with end-stage renal disease (ESRD). Traditional risk factors do not explain the high prevalence of CVD in this population, and other non-traditional cardiovascular (CV) risk markers have now been described. Therefore, the potential relationship between CVD and phenotypic and genotypic risk markers was investigated prospectively in incident dialysis patients cohort. The 279 patients (244 on hemodialysis, 35 on peritoneal dialysis) within the Diamant Alpin Dialysis Cohort Study were investigated. Phenotypic and genotypic parameters were determined at dialysis initiation, patients monitored over a 2-year period, and CV events (morbidity and mortality) recorded. Globally, 82 CV events occurred and 26 patients (9.3%) died from CVD, whereas 28 (10%) died from non-CV causes. Previous CV events were strongly predictive of CV events occurrence, whatever patients had had one (hazard ratio (HR) 2, 95% confidence intervals (CI) 1.1-3.5) or more (HR 3.9, 95% CI 2.1-7.1) CV accidents before starting dialysis. Both lipoprotein(a) (HR 1.67, 95% CI 1-2.5) and total plasma homocysteine at cutoff 30 micromol/l (HR 1.7, 95% CI 1.1-2.8) were independent predictors of CV events outcome. In the subgroup of patients with homocysteine < 30 micromol/l, methylenetetrahydrofolate reductase (MTHFR) TT was the sole biological parameter predictive of CV event outcome (HR 2.5, 95% CI 1.1-10, P = 0.03). ESRD patients who enter chronic dialysis with a previous CV event, high total homocysteinemia levels, or MTHFR 677TT genotype must be considered at high risk of incident CV events.

Risk scores for predicting outcomes in patients with type 2 diabetes and nephropathy: the RENAAL study

Diabetic nephropathy is the most important cause of ESRD. The aim of this study was to develop a risk score from risk predictors for ESRD, with and without death, in the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study and to compare ability of the ESRD risk score and its components to predict ESRD. The risk score was developed from coefficients of independent risk factors from multivariate analysis of baseline variables and equals (1.96 x log [urinary albumin:creatinine ratio]) - (0.78 serum albumin [g/dl]) + (1.28 x serum creatinine [mg/dl]) - (0.11 x hemoglobin [g/dl]). It was robust with respect to severity of nephropathy, gender, race, and treatment group. The risk score for ESRD or death was comparable. The four risk predictors for progression of kidney disease were independent of therapy. For combined treatment groups, the hazard ratio between the fourth and first quartiles of the ESRD risk score was 49.0, as compared with the corresponding hazard ratios for each component: 14.7 for urinary albumin:creatinine ratio, 9.2 for serum creatinine, 5.5 for hemoglobin, and 10.2 for serum albumin. The RENAAL risk scores for ESRD with or without death emphasize the importance of identification of level of albuminuria, serum albumin, serum creatinine, and hemoglobin to predict development of ESRD in patients with type 2 diabetes and nephropathy. Although albuminuria is a strong risk factor for ESRD, the contribution of serum albumin, serum creatinine, and hemoglobin level further enhances prediction of ESRD. Future trials with a similar patient population and outcomes measures should consider adjusting analyses for baseline risk factors.

Multifactorial approach and superior treatment efficacy in renal patients with the aid of nurse practitioners. Design of The MASTERPLAN Study [ISRCTN73187232]

BACKGROUND

Patients with chronic kidney disease (CKD) are at a greatly increased risk of developing cardiovascular disease. Recently developed guidelines address multiple risk factors and life-style interventions. However, in current practice few patients reach their targets.A multifactorial approach with the aid of nurse practitioners was effective in achieving treatment goals and reducing vascular events in patients with diabetes mellitus and in patients with heart failure. We propose that this also holds for the CKD population.

DESIGN

MASTERPLAN is a multicenter randomized controlled clinical trial designed to evaluate whether a multifactorial approach with the aid of nurse-practicioners reduces cardiovascular risk in patients with CKD. Approximately 800 patients with a creatinine clearance (estimated by Cockcroft-Gault) between 20 to 70 ml/min, will be included. To all patients the same set of guidelines will be applied and specific cardioprotective medication will be prescribed. In the intervention group the nurse practitioner will provide lifestyle advice and actively address treatment goals. Follow-up will be five years. Primary endpoint is the composite of myocardial infarction, stroke and cardiovascular mortality. Secondary endpoints are cardiovascular morbidity, overall mortality, decline of renal function, change in markers of vascular damage and change in quality of life. Enrollment has started in April 2004 and the study is on track with 700 patients included on October 15th, 2005. This article describes the design of the MASTERPLAN study.

Losartan: lessons learned from the RENAAL study

Renal and cardiovascular diseases associated with Type 2 diabetes are increasing at rapid rates, and are significant burdens to patients and healthcare systems. The RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) study was conducted from 1996 to 2001. This landmark clinical trial provided the opportunity to study renal and cardiovascular outcomes, as well as risk predictors, in a relatively large number of patients with Type 2 diabetes and nephropathy. The RENAAL study also provided information that will be valuable to those designing future clinical trials in this patient population. This review highlights key findings from the RENAAL study.

Left ventricular geometry in children with mild to moderate chronic renal insufficiency

Left ventricular hypertrophy (LVH) is the most important independent marker of cardiovascular risk in adults with chronic kidney disease. Cardiovascular morbidity seems increased even in children with chronic renal insufficiency (CRI), but the age and stage of CRI when cardiac alterations become manifest are unknown. For assessing the prevalence and factors associated with abnormal LV geometry in children with CRI, echocardiograms, ambulatory BP monitoring, and biochemical profiles were obtained in 156 children aged 3 to 18 yr with stages 2 through 4 chronic kidney disease (GFR 49 +/- 19 ml/min per 1.73 m2) and compared with echocardiograms obtained in 133 healthy children of comparable age and gender. LV mass was indexed to height2.7. Concentric LV remodeling was observed in 10.2%, concentric LVH in 12.1%, and eccentric LVH in 21% of patients. LVH was more common in boys (43.3 versus 19.4%; P < 0.005). Probability of LVH independently increased with male gender (odds ratio [OR] 2.62; P < 0.05) and standardized body mass index (OR 1.56; P = 0.01). Low hemoglobin, low GFR, young age, and high body mass index were independent correlates of LV mass index (0.005 < P < 0.05). LV concentricity (relative wall thickness) was positively associated with serum albumin (P < 0.05). Probability of abnormal LV geometry increased with C-reactive protein >10 mg/dl (OR 26; P < 0.001). In conclusion, substantial cardiac remodeling of both concentric and eccentric type is present at young age and early stages of CRI in children. Prevalence of LVH is related to male gender, anemia, and ponderosity but not to BP. Additional effects of volume status and inflammation on cardiac geometry are also evident.

Cardiovascular risk factor profiles and kidney function stage in the US general population: the NHANES III study

OBJECTIVE

To determine the prevalence of cardiovascular risk factors in the general population based on kidney function.

SUBJECTS AND METHODS

We retrospectively analyzed data from the Third National Health and Nutrition Examination Survey of noninstitutionalized US adults, which was conducted from 1988 to 1994. Data were gathered on 9 cardiovascular risk factors (smoking; obesity; hypertension; high total cholesterol, C-reactive protein, glycosylated hemoglobin, and homocysteine levels; low hemoglobin level; and high urinary albumin-to-creatinine ratio) and estimated glomerular filtration rate (GFR).

RESULTS

For the 15,837 subjects, the estimated GFR was at least 90 mL/min per 1.73 m2 (normal) in 65.4%, 60 to 89.9 mL/ min per 1.73 m2 (stage 2 kidney function) in 27.9%, 30 to 59.9 mL/min per 1.73 m2 (stage 3 kidney function) in 6.2%, and less than 30 mL/min per 1.73 m2 (stages 4 and 5 kidney function) In 0.5%. The number of cardiovascular risk factors Increased with stage of kidney dysfunction. Of subjects with a normal GFR, 30.4% had no risk factors, 34.9% had 1 risk factor, and 34.7% had 2 or more risk factors. Of subjects with stage 2 kidney function, 24.8% had no risk factors, 30.3% had 1 risk factor, and 44.9% had 2 or more risk factors. Of subjects with stage 3 kidney function, 1.4% had no risk factors, 14.9% had 1 risk factor, and 83.6% had 2 or more risk factors. All subjects with stages 4 and 5 kidney function had 2 or more risk factors. After covariate adjustment, odds ratios for having an estimated GFR lower than 60 mL/min per 1.73 m2 were 1, 3.7 (95% confidence interval, 1.2-11.3), and 10.4 (95% confidence interval, 3.9-27.8) times greater in subjects with 0, 1, and 2 or more cardiovascular risk factors, respectively (P<.001).

CONCLUSION

Persons with chronic kidney disease are much more likely to need multiple cardiovascular risk factor interventions than those without chronic kidney disease.

Neural and metabolic mechanisms of excessive muscle fatigue in maintenance hemodialysis patients

Dialysis patients have severe exercise limitations related to metabolic disturbances, but muscle fatigue has not been well studied in this population. We investigated the magnitude and mechanisms of fatigue of the ankle dorsiflexor muscles in patients on maintenance hemodialysis. Thirty-three dialysis patients and twelve healthy control subjects performed incremental isometric dorsiflexion exercise, beginning at 10% of their maximal voluntary contraction (MVC) and increasing by 10% every 2 min. Muscle fatigue (fall of MVC), completeness of voluntary activation, and metabolic responses to exercise were measured. Before exercise, dialysis subjects exhibited reduced strength and impaired peripheral activation (lower compound muscle activation potential amplitude) but no metabolic perturbation. During exercise, dialysis subjects demonstrated threefold greater fatigue than controls with evidence of central activation failure but no change in peripheral activation. All metabolic parameters were significantly more perturbed at end exercise in dialysis subjects than in controls, including lower phosphocreatine (PCr) and pH, and higher Pi, Pi/PCr, and H2PO4−. Oxidative potential was markedly lower in patients than in controls [62.5 (SD 27.2) vs. 134.6 (SD 31.7), P < 0.0001]. Muscle fatigue was negatively correlated with oxidative potential among dialysis subjects ( r = −0.52, P = 0.04) but not controls. Changes in central activation ratio were also correlated with muscle fatigue in the dialysis subjects ( r = 0.59, P = 0.001) but not the controls. This study provides new information regarding the excessive muscular fatigue of dialysis patients and demonstrates that the mechanisms of this fatigue include both intramuscular energy metabolism and central activation failure.

Complications of chronic kidney disease: anemia, mineral metabolism, and cardiovascular disease

This article focuses on the importance of three major complications of chronic kidney disease: (1) anemia, (2) calcium-phosphorus regulation and bone disease, and (3) cardiovascular risk profiling and treatment. The arguments for early and effective intervention have been amply made with respect to these three complications. Substantive trial data are sorely need to provide the definitive evidence that effective treatment of these complications results in better outcomes.

Effects of anemia and left ventricular hypertrophy on cardiovascular disease in patients with chronic kidney disease

Left ventricular hypertrophy (LVH) and anemia are highly prevalent in moderate chronic kidney disease (CKD). Because anemia may potentiate the adverse effects of LVH on cardiovascular outcomes, the effect of both anemia and LVH on outcomes in CKD was examined. Data from four community-based longitudinal studies were pooled: Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Framingham Heart Study, and Framingham Offspring Study. Serum creatinine levels were calibrated indirectly across studies, and GFR was estimated using the Modification of Diet in Renal Disease equation. CKD was defined as GFR between 15 and 60 ml/min per 1.73 m(2). LVH was based on electrocardiogram criteria. Anemia was defined as hematocrit <36% in women and 39% in men. The primary outcome was a composite of myocardial infarction, stroke, and death; a secondary cardiac outcome included only myocardial infarction and fatal coronary heart disease. Among 2423 patients with CKD, 96% had electrocardiogram and anemia data. Median follow-up was 102 mo. In adjusted analysis, LVH was associated with increased risk for composite and cardiac outcomes (hazard ratio [HR], 1.67 [95% confidence interval (CI), 1.34 to 2.07] and 1.62 [95% CI, 1.18 to 2.24], respectively), whereas anemia was associated with increased risk for the only composite outcome (HR, 1.51 [95% CI, 1.27 to 1.81]). The combination of anemia and LVH was associated with an increased risk for both study outcomes compared with individuals with neither risk factor (HR, 4.15 [95% CI, 2.62 to 6.56] and 3.92 [95% CI, 2.05 to 7.48]; P = 0.02 and 0.01 for interaction term, respectively). The combination of anemia and LVH in CKD identifies a high-risk population.

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.

Association of kidney function and hemoglobin with left ventricular morphology among African Americans: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Left ventricular (LV) hypertrophy (LVH) is present in more than 70% of patients with kidney failure. Hypertension and anemia, 2 strong risk factors for LVH, are common in patients with moderate kidney dysfunction. It is unknown whether kidney function and lower hemoglobin levels are associated with LV morphological characteristics among African Americans with moderate kidney dysfunction, independent of blood pressure.

METHODS

As part of the Atherosclerosis Risk in Communities Study, 1,968 African Americans aged 50 to 75 years underwent an echocardiogram after 6 to 9 years of follow-up. LV mass was indexed (LVMI) to body surface area. Glomerular filtration rate (GFR) was estimated from calibrated serum creatinine levels measured at baseline and after 3 years (<30 mL/min/1.73 m2 excluded). Hemoglobin was measured at baseline and after 3 years. Blood pressure was measured every 3 years.

RESULTS

A mean GFR of 30 to 59 mL/min/1.73 m2 was associated with a 15.3 g/m2 greater LVMI, 0.9 mm greater posterior wall thickness, and 1.0 mm greater interventricular septal thickness compared with a GFR of 90 mL/min/1.73 m2 or greater. These associations remained after adjustment for age, sex, hemoglobin level, blood pressure, and other covariates. Wall thickness and LVMI increased with lower GFR less than 75 mL/min/1.73 m2 (5.5 g/m2 greater LVMI [95% confidence interval (CI), 0.9 to 10.1] per 10 mL/min/1.73 m2 lower GFR). A lower hemoglobin level was associated with greater LV diameter (0.5 mm [95% CI, 0.2 to 0.7] per 1 g/dL [10 g/L]), but not wall thickness, after adjustment.

CONCLUSION

These results in a general population sample of middle-aged African Americans suggest that moderately decreased kidney function independently predicts greater LV wall thickness, and lower hemoglobin level independently predicts greater LV diameter. These findings may explain, in part, the high risk for cardiovascular disease observed among individuals with kidney disease.