Ethnicity and renal disease: lessons from the Multiple Risk Factor Intervention Trial and the Treatment of Mild Hypertension Study

Tissue Sodium in Patients With Early Stage Hypertension: A Randomized Controlled Trial

Background

Sodium (Na⁺) stored in skin and muscle tissue is associated with essential hypertension. Sodium magnetic resonance imaging is a validated method of quantifying tissue stores of Na⁺. In this study, we evaluated tissue Na⁺ in patients with elevated blood pressure or stage I hypertension in response to diuretic therapy or low Na⁺ diet.

Methods and Results

In a double‐blinded, placebo‐controlled trial, patients with systolic blood pressure 120 to 139 mm Hg were randomized to low sodium diet (<2 g of sodium), chlorthalidone, spironolactone, or placebo for 8 weeks. Muscle and skin Na⁺ using sodium magnetic resonance imaging and pulse wave velocity were assessed at the beginning and end of the study. Ninety‐eight patients were enrolled to undergo baseline measurements and 54 completed randomization. Median baseline muscle and skin Na⁺ in 98 patients were 16.4 mmol/L (14.9, 18.9) and 13.1 mmol/L (11.1, 16.1), respectively. After 8 weeks, muscle Na⁺ increased in the diet and chlorthalidone arms compared with placebo. Skin sodium was decreased only in the diet arm compared with placebo. These associations remained significant after adjustment for age, sex, body mass index, systolic blood pressure, and urinary sodium. No changes were observed in pulse wave velocity among the different groups when compared with placebo.

Conclusions

Diuretic therapy for 8 weeks did not decrease muscle or skin sodium or improve pulse wave velocity in patients with elevated blood pressure or stage I hypertension.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02236520.

The Effectiveness and Safety of Bushen Huoxue Decoction on Treating Coronary Heart Disease: A Meta-Analysis

Objective

The aim of this meta-analysis was to systematically evaluate the effectiveness and safety of the traditional Chinese medicine (TCM) formula Bushen Huoxue Decoction (BSHXD) in treating coronary heart disease (CHD).

Methods

Randomized controlled trials (RCTS) of BSHXD in treating CHD were searched until March 2020, through six electronic databases: PubMed, Cochrane Library, CNKI, WanFang, SinoMed, and VIP. This study used the Cochrane Risk Test bias tool in the Cochrane Handbook to assess the quality of the methodology. Review Manager (RevMan) 5.3 was used to analyze the results. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria were applied in the classification of evidence quality.

Results

Ten RCTs involving 901 patients were finally included in this meta-analysis. It revealed that the effectiveness of BSHXD in treating CHD was significantly better than that of the conventional western medicine (CWM) treatment (P < 0.00001). The effective rate of BSHXD treatment group on ECG was also significantly higher than that of CWM group (P < 0.00001). The low-density lipoprotein cholesterol was decreased in the treatment groups compared with those in the control groups (P < 0.00001). There was also a reduction in frequency and duration of angina pectoris (P < 0.00001). There were no significant differences in TC level (P=0.08), TG level (P=0.86), and HDL level (P=0.76) between the treatment and control groups. Five studies had informed adverse events, including nausea and diarrhea.

Conclusion

Our findings laid the foundation to the use of TCM Formula BSHXD in combination with conventional western medicine for treating CHD. However, due to the limitation of the quality of the included researches, in addition to potential reporting bias, the above conclusions still need verification by higher-quality and better-designed studies.

Atorvastatin Has a Dose-Dependent Beneficial Effect on Kidney Function and Associated Cardiovascular Outcomes: Post Hoc Analysis of 6 Double-Blind Randomized Controlled Trials

Background

Kidney function decreases during the lifetime, and this decline is a powerful predictor of both kidney and cardiovascular outcomes. Statins lower cardiovascular risk, which may relate to beneficial effects on kidney function. We studied whether atorvastatin influences kidney function decline and assessed the association between individual kidney function slopes and cardiovascular outcome.

Methods and Results

Data were collected from 6 large atorvastatin cardiovascular outcome trials conducted in patients not selected for having kidney disease. Slopes of serum creatinine reciprocals representing measures of kidney function change ([mg/dL]⁻¹/y), were analyzed in 30 621 patients. Based on treatment arms, patients were categorized into 3 groups: placebo (n=10 057), atorvastatin 10 mg daily (n=12 763), and 80 mg daily (n=7801). To assess slopes, mixed‐model analyses were performed for each treatment separately, including time in years and adjustment for study. These slopes displayed linear improvement over time in all 3 groups. Slope estimates for patients randomized to placebo or atorvastatin 10 mg and 80 mg were 0.009 (0.0008), 0.011 (0.0006), and 0.014 (0.0006) (mg/dL)⁻¹/y, respectively. A head‐to‐head comparison of atorvastatin 10 and 80 mg based on data from 1 study (TNT [Treating to New Targets]; n=10 001) showed a statistically significant difference in slope between the 2 doses (P=0.0009). From a Cox proportional hazards model using slope as a predictor, a significant (P<0.0001) negative association between kidney function and cardiovascular outcomes was found.

Conclusions

In patients at risk of or with cardiovascular disease, atorvastatin improved kidney function over time in a dose‐dependent manner. In the 3 treatment groups, kidney function improvement was strongly associated with lower cardiovascular risk.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00327418; NCT00147602; NCT00327691.

Association of Intensive Blood Pressure Control and Kidney Disease Progression in Nondiabetic Patients With Chronic Kidney Disease: A Systematic Review and Meta-analysis

Importance

The optimal blood pressure (BP) target remains debated in nondiabetic patients with chronic kidney disease (CKD).

Objective

To compare intensive BP control (<130/80 mm Hg) with standard BP control (<140/90 mm Hg) on major renal outcomes in patients with CKD without diabetes.

Data Sources

Searches of PubMed, MEDLINE, Embase, and Cochrane Library for publications up to March 24, 2016.

Study Selection

Randomized clinical trials that compared an intensive vs a standard BP target in nondiabetic adults with CKD, reporting changes in glomerular filtration rate (GFR), doubling of serum creatinine level, 50% reduction in GFR, end-stage renal disease (ESRD), or all-cause mortality.

Data Extraction and Synthesis

Random-effects meta-analyses for pooling effect measures. Meta-regression and subgroup analyses for exploring heterogeneity.

Main Outcomes and Measures

Differences in annual rate of change in GFR were expressed as mean differences with 95% CIs. Differences in doubling of serum creatinine or 50% reduction in GFR, ESRD, composite renal outcome, and all-cause mortality were expressed as risk ratios (RRs) with 95% CIs.

Results

We identified 9 trials with 8127 patients and a median follow-up of 3.3 years. Compared with standard BP control, intensive BP control did not show a significant difference on the annual rate of change in GFR (mean difference, 0.07; 95% CI, -0.16 to 0.29 mL/min/1.73 m2/y), doubling of serum creatinine level or 50% reduction in GFR (RR, 0.99; 95% CI, 0.76-1.29), ESRD (RR, 0.96; 95% CI, 0.78-1.18), composite renal outcome (RR, 0.99; 95% CI, 0.81-1.21), or all-cause mortality (RR, 0.95; 95% CI, 0.66-1.37). Nonblacks and patients with higher levels of proteinuria showed a trend of lower risk of kidney disease progression with intensive BP control.

Conclusions and Relevance

Targeting BP below the current standard did not provide additional benefit for renal outcomes compared with standard treatment during a follow-up of 3.3 years in patients with CKD without diabetes. However, nonblack patients or those with higher levels of proteinuria might benefit from the intensive BP-lowering treatments.

Assessment of Renal Function and Risk Factors for Chronic Kidney Disease in Patients With Peripheral Arterial Disease

Chronic kidney disease (CKD) and peripheral arterial disease (PAD) share common risk factors. We assessed renal function and the prevalence of CKD in patients with PAD and investigated the characteristics of the risk factors for CKD in this population. Renal function of 421 patients with PAD was evaluated. Among the participants, 194 (46.1%) patients had decreased estimated glomerular filtration rate (eGFR). The prevalence of CKD was much higher among patients with PAD. Hypertension (odds ratios [ORs] 2.156, 95% confidence interval [CI] 1.413-3.289, P < .001), serum uric acid (OR 3.794, 95% CI 2.220-6.450, P < .001), and dyslipidemia (OR 1.755, 95% CI 1.123-2.745, P = .014) were significantly associated with CKD and the independent risk factors for CKD in patients with PAD. CKD is common and has a high prevalence in a population with PAD. Patients with PAD may be considered as a high-risk population for CKD. Recognition and modification of risk factors for CKD might beneficially decrease CKD incidence and improve prognosis in patients with PAD.

Severity of coronary artery disease is an independent risk factor for decline in kidney function

BACKGROUND AND AIM

Chronic kidney disease (CKD) and cardiovascular disease are closely interrelated and the presence of one condition synergistically affects the prognosis of the other, in a negative manner. There are surprisingly very few data on the relationship between baseline coronary artery disease (CAD) severity and subsequent decline in kidney function. We aimed to evaluate for the first time whether baseline coronary artery lesion severity predicts the decline in kidney function.

MATERIALS AND METHODS

The study population was derived from a series of consecutive patients presenting with stable angina pectoris or angina equivalents, who underwent coronary angiography. SYNTAX score for each patient was calculated to define severity of CAD. Change in kidney function was defined by calculating the rates of change in eGFR.

RESULTS

Among the 823 patients included in our study, the mean age was 59.2±10.7years, 78.4% were males, and 32% had diabetes. The mean baseline eGFR was 87.3±24.9ml/min/1.73m(2) and the median Syntax score was 14 (IQR=10-20). The median length of follow-up was 2.75years (IQR=2.42-3.50). The mean yearly change for eGFR in the entire study population was 4.06 (95% CI: 3.59-4.51)ml/min/1.73m(2). A higher Syntax score was associated with a significantly faster decline in eGFR in all (unadjusted and adjusted) models. During the follow-up, 103 patients developed CKD. A higher Syntax score, analyzed both as continuous and categorical variable, was associated with incident CKD in all models.

CONCLUSION

We have demonstrated for the first time that severity of CAD is an independent risk factor for the decline in kidney function. Studies are needed to highlight the potential mechanisms regarding the association between severity of CAD and decline in kidney function.

Review: Renal dysfunction as a marker of increased vascular risk

Minimisation of risk factors for the development of vascular disease has made a major contribution to the decline in vascular morbidity and mortality reported over the last decade. Recent evidence has highlighted that elevation of serum creatinine is a strong marker of increased vascular risk, with a predictive value as high as the development of diabetes. As serum creatinine is easily measured — albeit often misinterpreted — this provides another easily applied clinical tool for the stratification of cardiovascular risk and the targeting of preventative medicine in primary and secondary care.

Renal function trajectory over time and adverse clinical outcomes

The growing burden of chronic kidney disease (CKD), with its associated morbidity and mortality, is recognized as a major public health problem globally and causing substantial load on health care systems. The current framework for the definition and staging of CKD, based on eGFR levels or presence of kidney damage, is useful for clinical classification of patients, but identifies a huge number of people as having CKD which is too many to target for intervention. The ability to identify a subset of patients, at high risk for adverse outcomes, would be useful to inform clinical management. The current staging system applies static definitions of kidney function that fail to capture the dynamic nature of the kidney disease over time. Now-a-days, it is possible to capture multiple measurements of different laboratory test results for an individual including eGFR values. A new possibility for identifying individuals at higher risk of adverse outcomes is being explored through assessment and consideration of the rate of change in kidney function over time, and this approach will be feasible in the current context of digitalization of health record keeping system. On the basis of the existing evidence, this paper summarizes important findings that support the concept of dynamic changes in kidney function over time, and discusses how the magnitude of these changes affect the future adverse outcomes of kidney disease, particularly the End Stage Renal Disease (ESRD), CVD and mortality.

An analysis of the blood pressure and safety outcomes to renal denervation in African Americans and Non-African Americans in the SYMPLICITY HTN-3 trial

SYMPLICITY HTN-3, the first trial of renal denervation (RDN) versus sham, enrolled 26% African Americans, a prospectively stratified cohort. Although the 6-month systolic blood pressure (SBP) reduction in African Americans (AAs) was similar in the RDN group (-15.5 ± 25.4 mm Hg, n = 85 vs. -17.8 ± 29.2, n = 49, P = .641), the sham SBP response was 9.2 mm Hg greater (P = .057) in AAs than non-AAs. In multivariate analyses, sham SBP response was predicted by an interaction between AA and a complex antihypertensive regimen (at least one antihypertensive medication prescribed ≥3 times daily), while in the RDN group, SBP response was predicted by an interaction between AA race and baseline BP ≥ 180 mm Hg. AA race did not independently predict SBP response in either sham or RDN. There appears to be effect modification by race with individual-level patient characteristics in both treatment arms that affect the observed pattern of SBP responses.

Epidemiology and Management Cost of Myocardial Infarction in North Punjab, Pakistan

Background:

Coronary heart disease (CHD) is an important cause of morbidity and mortality in Pakistan. The temporal trends in the risk factors for myocardial infarction (MI) and the impact of socioeconomic status on these risk factors remain ambiguous.

Objectives:

The objectives of the present analysis were to investigate the potential association between various risk factors and MI in North Punjab, Pakistan, and to assess the status of the control of the risk factors associated with MI in this population.

Patients and Methods:

The present study included 515 patients admitted to the coronary care units or equivalent cardiology wards of the participating hospitals between 2011 and 2012 in North Punjab, Pakistan. The analysis was focused on identifying the socioeconomic status, lifestyle, family history of MI, and risk factors (i.e. hypertension, diabetes, smoking, and hyperlipidemia). A structured questionnaire was designed to collect data. The lipid profile was recorded from the investigation chart of every patient. For statistical analysis, the Kruskal Wallis, Mann-Whitney U, Wilcoxon, and chi-square tests were used.

Results:

MI was common in the males at the age of 41 - 60 years as compared to the females (P = 0.015). Patients with a positive parental history of CHD experienced MI at a younger age (P = 0.0001) at a body mass index (BMI) ≤ 25 kg/m². Sedentary lifestyle (70%) and smoking (60%) had a male predominance. Hypertension accounted for nearly 37%, hyperlipidemia 26%, and diabetes 19.4% of the rural and urban subjects (P < 0.01). High-density lipoprotein cholesterol decreased (up to 34 mg/dl), while low-density lipoprotein cholesterol and hypertension increased with age. The mean monthly cost of medicines and physicians’ fees per patient was 2381.132 Pakistani Rupees (24.24 USD).

Conclusions:

Higher BMI, positive family history, smoking, hypertension, hyperlipidemia, and diabetes were the strong predictors of MI in North Punjab, Pakistan. Preventive efforts are needed to start early in life and continue throughout the life course.

Epidemiology of hypertension in CKD

Both hypertension (HTN) and CKD are serious interrelated global public health problems. Nearly 30% and 15% of US adults have HTN and CKD, respectively. Because HTN may cause or result from CKD, HTN prevalence is higher and control more difficult with worse kidney function. Etiology of CKD, presence and degree of albuminuria, and genetic factors all influence HTN severity and prevalence. In addition, socioeconomic and lifestyle factors influence HTN prevalence and control. There are racial and ethnic disparities in the prevalence, treatment, risks, and outcomes of HTN in patients with CKD. Control of blood pressure (BP) in Hispanic and African Americans with CKD is worse than it is whites. There are disparities in the patterns of treatment and rates of progression of CKD in patients with HTN. The presence and severity of CKD increase treatment resistance. HTN is also extremely prevalent in patients receiving hemodialysis, and optimal targets for BP control are being elucidated. Although the awareness, treatment, and control of HTN in CKD patients is improving, control of BP in patients at all stages of CKD remains suboptimal.

Relationship between CCR and NT-proBNP in Chinese HF patients, and their correlations with severity of HF

Aim. To evaluate the relationship between creatinine clearance rate (CCR) and the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in heart failure (HF) patients and their correlations with HF severity. Methods and Results. Two hundred and one Chinese patients were grouped according to the New York Heart Association (NYHA) classification as NYHA 1-2 and 3-4 groups and 135 cases out of heart failure patients as control group. The following variables were compared among these three groups: age, sex, body mass index (BMI), smoking status, hypertension, diabetes, NT-proBNP, creatinine (Cr), uric acid (UA), left ventricular end-diastolic diameter (LVEDD), and CCR. The biomarkers of NT-proBNP, Cr, UA, LVEDD, and CCR varied significantly in the three groups, and these variables were positively correlated with the NHYA classification. The levels of NT-proBNP and CCR were closely related to the occurrence of HF and were independent risk factors for HF. At the same time, there was a significant negative correlation between the levels of NT-proBNP and CCR. The area under the receiver operating characteristic curve suggested that the NT-proBNP and CCR have high accuracy for diagnosis of HF and have clinical diagnostic value. Conclusion. NT-proBNP and CCR may be important biomarkers in evaluating the severity of HF.

Should African Americans with hypertension be treated differently than non-African Americans?

African Americans have a higher burden of hypertension, more severe blood pressure (BP) elevations, more concurrent risk-enhancing co-morbidities (e.g., diabetes), sub-clinical vascular injury at lower non-hypertensive BP levels, lower BP control rates, and significantly greater risk for adverse pressure-related clinical complications (e.g., stroke, heart failure) than whites. Randomized prospective data from hypertension endpoint trials show a virtually identical percentage reduction in CVD risk for a given magnitude of BP lowering, irrespective of the presence or absence of pre-treatment CVD across a broad range of BP down to pre-treatment BP levels of 110/70 mm Hg. These data, mostly emanating from white populations, do not necessarily inform practitioners as to the level below which BP should be lowered in those with established, long-standing hypertension; however, these data do provide support for initiating hypertension treatment at lower than conventional BP thresholds. A Mendelian randomized study examining the impact of life-long lower SBP levels showed that lifelong exposure to 10 mm Hg lower SBP was associated with an 82 % lesser rate of SBP rise per decade and a 58 % lower CHD risk that was much greater than the 22 % reduction in CHD reported for the same magnitude of SBP reduction in clinical trials. Arguably, it is the hypertension treatment paradigm that merits reexamination. Earlier hypertension treatment in all populations prior to the onset of significant pressure-related target organ injury might conceivably prevent, or at least significantly attenuate, the well documented age-related rise in BP seen in most Western societies. In addition, this treatment paradigm might also reduce the significant residual CVD risk observed under the current recommended approach to hypertension treatment. This new approach to therapy would likely have substantial clinical and public health benefits in the high-risk, under-treated African American population that suffers outsized devastating consequences from inadequate control of BP.

Rise or fall of glomerular filtration rate: does it matter?

A new observational study in Canadian patients shows a U-shaped association between longitudinal change in estimated glomerular filtration rate over a 4-year period and all-cause mortality. This study confirms the findings of previous studies done in middle-aged Taiwanese patients, community-dwelling Medicare beneficiaries, and chronic kidney disease patients. Future studies are needed to confirm whether such simple objective risk assessment tools can identify subgroups of people at maximum risk for adverse events.

Should African Americans have a lower blood pressure goal than other ethnic groups to prevent organ damage?

African Americans manifest an inordinately high burden of hypertension, pressure-related target-organ injury (eg, left ventricular hypertrophy, stroke), and sub-optimal hypertension control rates to conventional levels (<140/90 mm Hg). A substantive proportion of the excessive premature mortality in African Americans relative to Whites is pressure-related. Randomized prospective pharmacologic hypertension end-point trials have shown invariable cardiovascular disease (CVD) risk reduction across a broad range of pre-treatment BP levels down to 110/70 mm Hg with the magnitude of CVD risk reduction across the 5 major antihypertensive drug classes being directly linked to degree of blood pressure (BP) lowering. Pooled endpoint data from pharmacologic hypertension trials in African Americans showed that CVD risk reduction was the same with major antihypertensive drug classes when similar levels of BP were achieved. A lower than conventional BP target for African Americans seems justified and prudent because attainment of lower BP should incrementally lower CVD risk in this high-risk population.

The prognostic value of estimated glomerular filtration rate, amino-terminal portion of the pro-hormone B-type natriuretic peptide and parameters of cardiopulmonary exercise testing in patients with chronic heart failure

The aim of this study was to evaluate the prognostic value of renal function in relation to amino-terminal portion of the pro-hormone B-type natriuretic peptide (NT-proBNP) and parameters of cardiopulmonary exercise testing in predicting mortality and morbidity in patients with moderate chronic heart failure (CHF). Sixty-one CHF patients were included in the study. Patients' characteristics were: age 64.3±11.6 years; New York Heart Association class I/II/III: 14/37/10; left ventricular ejection fraction: 0.30±0.13 (%); NT-proBNP: 252.2±348.0 (ng/L); estimated creatinine clearance (e-CC): 73.6±31.4 (mL/min); estimated glomerular filtration rate (e-GFR): 66.1±24.6 (mL/min/1.73 m²); the highest O2 uptake during exercise (VO_2-peak): 1.24±0.12 mL/kg/min; VO₂/workload: 8.52±1.81 (mL/min/W)]. During follow up (59.5±4.0 months) there were 15 cardiac deaths and 16 patients were hospitalized due to progression of heart failure. NT-proBNP and VO₂/workload were independently associated with cardiac death (P=0.007 and P=0.006, respectively). Hospitalization for progressive CHF was only associated with NT-proBNP (P=0.002). The combined cardiac events (cardiac death and hospitalization) were associated with NT-proBNP and VO₂/ workload (P=0.007 and P=0.005, respectively). The addition of estimates of renal function (neither serum creatinine nor e-GFR) did not improve the prognostic value for any of the models.In conclusion, in patients with moderate CHF, increased NT-proBNP and reduced VO₂/ work-load identify those with increased mortality and morbidity, irrespective of estimates of renal function.

Renal Function in Relation to Cardiac (123)I-MIBG Scintigraphy in Patients with Chronic Heart Failure

The aim of this study was to explore if estimates of renal function could explain variability of (123)I-metaiodobenzylguanidine ((123)I-MIBG) assessed myocardial sympathetic activity. Furthermore estimates of renal function were compared to (123)I-MIBG as predictors of cardiac death in chronic heart failure (CHF). Semi-quantitative parameters of (123)I-MIBG myocardial uptake and washout were calculated using early heart/mediastinum ratio (H/M), late H/M and washout. Renal function was calculated as estimated Creatinine Clearance (e-CC) and as estimated Glomerular Filtration Rate (e-GFR). Thirty-nine patients with CHF (24 males; age: 64.4 ± 10.5 years; NYHA II/III/IV: 17/20/2; LVEF: 24.0 ± 11.5%) were studied. Variability in any of the semi-quantitative (123)I-MIBG myocardial parameters could not be explained by e-CC or e-GFR. During follow-up (60 ± 37 months) there were 6 cardiac deaths. Cox proportional hazard regression analysis showed that late H/M was the only independent predictor for cardiac death (Chi-square 3.2, regression coefficient: -4.095; standard error: 2.063; hazard ratio: 0.17 [95% CI: 0.000-0.950]). Addition of estimates of renal function did not significantly change the Chi-square of the model. Semi-quantitative (123)I-MIBG myocardial parameters are independent of estimates of renal function. In addition, cardiac sympathetic innervation assessed by (123)I-MIBG scintigraphy seems to be superior to renal function in the prediction of cardiac death in CHF patients.

Prevalence and risk factors for chronic kidney disease in patients with coronary artery disease

OBJECTIVES

Chronic renal disease (CKD) is recognized as a worldwide public health problem. Traditional risk factors for CKD are also present in coronary artery disease (CAD). The purpose of this study is to examine the prevalence and characteristics of risk factors for CKD in the population with CAD.

METHODS

Renal function was evaluated in 527 patients with CAD in order to assess characteristics of the incidence, risk factors for CKD in the population with CAD. In the present study in order to concentrate on evaluation for eGFR of the patients with CAD proteinuria is not included in the definition of CKD.

RESULTS

Univariate analysis demonstrated that the major risk factors associated with CKD in the patients with CAD were age (P ≤ 0.001), smoking (P = 0.016), diabetes mellitus (P = 0.021), hypertension (P ≤ 0.001), and systolic blood pressure (P = 0.004). The percentages of patients with both hypertension and diabetes mellitus were significantly greater in the CKD3-4 group (P < 0.001). The results of multivariable analysis showed that hypertension (OR 1.925, 95% CI 1.196-3.098, P = 0.007), diabetes mellitus (OR 1.744, 95% CI 1.044-2.914, P = 0.034) and serum uric acid (OR 1.008, 95% CI 1.006-1.010, P ≤ 0.001) were independent risk factors for reduced eGFR.

CONCLUSIONS

CKD is common and has a high prevalence in the population with CAD. Several risk factors are known to simultaneously affect heart and kidney. The patients with CAD may be considered as a high-risk population for CKD.

Vascular time-activity variation in patients undergoing ¹²³I-MIBG myocardial scintigraphy: implications for quantification of cardiac and mediastinal uptake

Purpose

For the quantification of cardiac ¹²³I-metaiodobenzylguanidine (MIBG) uptake, the mediastinum is commonly used as a reference region reflecting nonspecific background activity. However, variations in the quantity of vascular structures in the mediastinum and the rate of renal clearance of ¹²³I-MIBG from the blood pool may contribute to increased interindividual variation in uptake. This study examined the relationship between changes in heart (H) and mediastinal (M) counts and the change in vascular ¹²³I-MIBG activity, including the effect of renal function.

Methods

Fifty-one subjects with ischemic heart disease underwent early (15 min) and late (4 h) anterior planar images of the chest following injection of ¹²³I-MIBG. Vascular ¹²³I-MIBG activity was determined from venous blood samples obtained at 2 min, 15 min, 35 min, and 4 h post-injection. From the vascular clearance curve of each subject, the mean blood counts/min per ml at the time of each acquisition and the slope of the clearance curve were determined. Renal function was expressed as the estimated creatinine clearance (e-CC) and the estimated glomerular filtration rate (e-GFR). Relations between H and M region of interest (ROI) counts/pixel, vascular activity, and renal function were then examined using linear regression.

Results

Changes in ROI activity ratios between early and late planar images could not be explained by blood activity, the slope of the vascular clearance curves, or estimates of renal function. At most 3% of the variation in image counts could be explained by changes in vascular activity (p = 0.104). The e-CC and e-GFR could at best explain approximately 1.5% of the variation in the slopes of the vascular clearance curve (p = 0.194).

Conclusion

The change in measured H and M counts between early and late planar ¹²³I-MIBG images is unrelated to intravascular levels of the radiopharmaceutical. This suggests that changes in M counts are primarily due to decrease in soft tissue activity and scatter from the adjacent lungs.

Hypertension in special populations: chronic kidney disease, organ transplant recipients, pregnancy, autonomic dysfunction, racial and ethnic populations

The benefits of appropriate blood pressure (BP) control include reductions in proteinuria and possibly a slowing of the progressive loss of kidney function. Overall, medication therapy to lower BP during pregnancy should be used mainly for maternal safety because of the lack of data to support an improvement in fetal outcome. The major goal of hypertension treatment in those with baroreceptor dysfunction is to avoid the precipitous, severe BP elevations that characteristically occur during emotional stimulation. The treatment of hypertension in African Americans optimally consists of comprehensive lifestyle modifications along with pharmacologic treatments, most often with combination, not single-drug, therapy.

Serial decline of kidney function as a novel biomarker for the progression of atherothrombotic disease

OBJECTIVE

Impaired kidney function is associated with cardiovascular disease. However, from the available data it cannot be discerned which of the two entities presents first and entails the other. If renal dysfunction is first, a dynamic decline in the estimated glomerular filtration rate (eGFR) should predict vascular events and prove a useful biomarker for atherothrombotic disease. We therefore tested the hypothesis that a decrease in kidney function predicts future vascular events in a high-risk population of angiographically characterized coronary patients.

METHODS

We calculated the eGFR by the Mayo clinic quadratic equation at baseline and after two years in a high-risk population of 400 consecutive men undergoing coronary angiography, of whom 355 had coronary artery disease (CAD). Vascular events were recorded over six years.

RESULTS

A serial decrease in kidney function from baseline to the follow-up visit two years later significantly predicted vascular events in the subsequent four years independently from the baseline eGFR with a standardized adjusted hazard ratio (HR) of 1.41 (1.13-1.76); p=0.003. This result proved robust after adjustment for age, BMI, hypertension, diabetes, LDL-C, HDL-C, smoking, and high-sensitivity C-reactive protein (HR=1.41 [1.12-1.78]; p=0.004). The predictive power of eGFR loss was confirmed even after further adjustment for the presence of CAD at baseline (HR=1.43 [1.12-1.81]; p=0.004). In this fully adjusted model a 10 ml/min/1.73 m2 decrease in eGFR independently conferred a 31% increase in cardiovascular event risk (p=0.004).

CONCLUSION

A decline of eGFR over two years strongly, significantly, and independently predicts vascular events over the subsequent four years. Declining eGFR is a readily obtainable and inexpensive candidate new biomarker for the progression of atherothrombotic disease.

Chronic kidney disease as a predictor of coronary lesion morphology

Coronary artery disease (CAD) is the main cause of death in patients with chronic kidney disease (CKD). We investigated whether CKD stage affected coronary lesion morphology in patients with established CAD. Coronary angiograms of 264 patients were evaluated. Chronic kidney disease was staged using the estimated glomerular filtration rate (eGFR) from the serum creatinine prior to coronary angiography. Patients were divided into 3 groups: dialysis or severe decrease in GFR <30 mL/min per 1.73 m(2) (group 1; n = 60), patients with moderate kidney failure (group 2; n = 116), and patients with normal renal function or mild decrease in GFR (group 3; n = 88). The likelihood of CAD and lesion complexity increased with decreasing eGFR (P = .001). Patients with CKD also had more significant CAD. The risk of significant coronary obstruction and lesion complexity increased progressively with decreasing eGFR. The eGFR may predict lesion complexity among patients with CKD undergoing coronary angiography.

Change in estimated GFR associates with coronary heart disease and mortality

Kidney function predicts cardiovascular and all-cause mortality, but little is known about the association of changes in estimated GFR (eGFR) with clinical outcomes. We investigated whether 3- and 9-yr changes in eGFR associated with risk for coronary heart disease (CHD) and all-cause mortality among 13,029 participants of the Atherosclerosis Risk in Communities (ARIC) Study. After adjustment for baseline covariates including eGFR in Cox proportional hazards models, the quartile of participants with the greatest annual decline (annual decline > or =5.65%) in eGFR were at significantly greater risk for CHD and all-cause mortality (hazard ratio 1.30 [95% confidence interval 1.11 to 1.52] and 1.22 [95% confidence interval 1.06 to 1.41], respectively) compared with the third quartile (annual decline between 0.33 and 0.47%). We observed similar results when we analyzed 9-yr changes in eGFR. Adjustment for covariates at the second eGFR used to estimate change reduced the association with CHD but not with mortality. Among participants with stage 3 chronic kidney disease, an increase in eGFR during the first 3 yr also associated with a higher risk for mortality, perhaps as a result of clinical instability. In conclusion, a steeper than average decline in eGFR associates with a higher risk for CHD and all-cause mortality. Increases in eGFR among participants with chronic kidney disease associate with similar increased risks.

Cardiovascular risk factors in patients with chronic kidney disease

Patients with chronic kidney disease have a higher burden of cardiovascular disease, which increases in a dose-dependent fashion with worsening kidney function. Traditional cardiovascular risk factors, including advanced age, diabetes mellitus, hypertension and dyslipidemia, have an important role in the progression of cardiovascular disease in patients who have a reduced glomerular filtration rate, especially in those with mild-to-moderate kidney disease. In patients with severe kidney disease, nontraditional or 'novel' risk factors, including inflammation, oxidative stress, vascular calcification, a prothrombotic milieu, and anemia, seem to confer additional risk. In this Review, we highlight factors that increase cardiovascular risk in patients with a reduced estimated glomerular filtration rate. In addition, we discuss therapeutic strategies for reducing cardiovascular risk in patients with kidney disease, whose unique atherosclerotic phenotype might require an approach that differs from traditional models developed in populations with normal kidney function. Therapeutic paradigms for patients with chronic kidney disease and cardiovascular risk factors must be evaluated in randomized trials, from which such patients have often been excluded.

Glomerular filtration rate and coronary artery disease burden in patients with acute coronary syndrome

BACKGROUND

Mild renal dysfunction may be associated with increased cardiovascular morbidity and mortality.

METHODS

The relation between estimated glomerular filtration rate (eGFR), as calculated from plasma creatinine at admission, and coronary artery disease burden (CADB), was studied in a cohort of 110 patients with acute coronary syndrome and coronary atherosclerosis.

RESULTS

A relatively weak but significant negative correlation was found between eGFR and CADB as measured by angiography (coefficient correlation of - 0.26, probability value of 0.006); a similar association was seen in multiple regression analysis, taking CADB as dependent variable, and eGFR, age, plasma calcium and plasma phosphorus as independent variables. After dividing the 110 patients into eGFR tertiles (with mean values of 102.9 +/- 22.8, n = 37, 75.7 + or - 5.6, n = 36, and 53.1 +/- 13.4, n = 37, all in mL/min per 1.73 m(2)), mean CADB values of the lower and higher eGFR tertiles were found to be significantly different (270.6 +/- 176.4 and 192.9 +/- 78.5, respectively). Similar mean values for CADB and for eGFR were noted when patients with elevated ST segment/new left bundle branch block and patients with nonelevated ST segment acute coronary syndrome were compared.

CONCLUSIONS

We conclude that renal function of patients with acute coronary syndromes and coronary atherosclerosis, as estimated at admission, is negatively correlated with coronary artery disease burden. It is unknown whether renal dysfunction acts as a cause for accelerated coronary artery disease or if it merely acts as a surrogate marker for the overall systemic vascular system status.

Association Between Carotid Artery Intima-Media Thickness and Early-Stage CKD in a Chinese Population

BACKGROUND

Increased carotid artery intima-media thickness (IMT) predicts future vascular events in the general population. However, the relationship between IMT and chronic kidney disease (CKD) seldom was tested in subjects with early-stage CKD.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

1,046 residents in 1 district of Beijing participated in the study.

OUTCOMES & MEASUREMENTS

Carotid artery IMT was measured by means of high-resolution B-mode ultrasonography. Estimated glomerular filtration rate (eGFR) was calculated using the modified Modification of Diet in Renal Disease Study equation based on data for Chinese patients with CKD. Albuminuria was evaluated by means of urinary albumin-creatinine ratio on a morning spot urine sample.

RESULTS

Compared with subjects with eGFR greater than 90 mL/min/1.73 m(2) (>1.50 mL/s/1.73 m(2)), subjects with eGFR of 60 to 89 mL/min/1.73 m(2) (1.00 to 1.49 mL/s/1.73 m(2)) and 30 to 59 mL/min/1.73 m(2) (0.50 to 0.99 mL/s/1.73 m(2)) had higher mean IMT (0.74 +/- 0.27 versus 0.82 +/- 0.30 versus 0.94 +/- 0.38 mm; P < 0.001). IMTs of subjects with albuminuria tended to be higher than the mean value (0.79 +/- 0.29 versus 0.93 +/- 0.38 mm; P < 0.001). eGFR and urinary albumin-creatinine ratio significantly correlated with IMT in univariable analysis, but not after adjusting for traditional cardiovascular disease risk factors.

LIMITATIONS

Selection bias and low prevalence of CKD might affect the strength of the study.

CONCLUSIONS

In this Chinese population older than 40 years, carotid artery IMT was significantly higher in subjects with early-stage CKD. The greater prevalence of cardiovascular disease risk factors in patients with CKD appeared to account for the higher carotid artery IMT.

Decline in kidney function before and after nephrology referral and the effect on survival in moderate to advanced chronic kidney disease

BACKGROUND

The burden of chronic kidney disease (CKD) is high, but its natural history and the benefit of routine nephrology care is unclear. This study investigated the decline in kidney function prior to and following nephrology referral and its association with mortality.

METHODS

This study provides a retrospective review of the individual rates of glomerular filtration rate (GFR) decline (millilitre per minute per 1.73 m(2)/year) for the 5 years before and after referral in 726 new referrals with stages 3-5 CKD to one renal unit between 1997 and 2003. Blood pressures are averages at referral, 1 and 3 years post referral. Logistic regression and Cox's models tested factors predicting post-referral GFR decline and the impact on mortality.

RESULTS

Mean (SD) age was 72 (14), and 389 (54%) patients had stages 4-5 CKD. GFR decline slowed significantly from -5.4 ml/min/1.73 m(2)/year (-13. to -2) before to -0.35 ml/min/1.73 m(2)/year (-3 to +3) after referral (P < 0.001). Blood pressure also reduced significantly (155/84 to 149/80, P < 0.05) with most changes occurring within 1 year of referral. Factors predicting a non-progressive post-referral decline included a lower systolic blood pressure at referral and 1 year after referral, a CKD diagnosis other than diabetic nephropathy, less baseline proteinuria and a non-progressive pre-referral GFR decline. A non-progressive post-referral GFR decline was independently associated with significantly better survival (hazard ratio 0.55, 95% CI 0.40-0.75, P <or = 0.001) after adjustment for known risk factors.

CONCLUSIONS

Following nephrology referral, GFR decline slowed significantly and was associated with better survival. Earlier detection of patients with progressive CKD and interventions to slow progression may have benefits on both kidney and patient survival.

Chronic renal failure: a cardiovascular risk factor

The risk of developing cardiovascular disease is greatly increased in patients undergoing renal replacement therapy and, notably, morbidity and mortality due to therapy is much higher in these patients than in the general population. Minimal alterations in renal function, as evidenced by reduced glomerular filtration rate and the presence of albuminuria, have been described as potent cardiovascular risk factors. The classic risk factors only partly explain this difference; hence, we must admit the existence of known and emerging factors associated with increased cardiovascular risk in patients with renal disease. This article provides a review of these factors. It describes the role of hyperphosphoremia and elevated calcium-phosphorous product in the formation of cardiovascular calcifications, the contribution of anemia to left ventricular hypertrophy, and the consequences of accelerated atherogenesis with oxidative stress and a microinflammatory state resulting from endothelial dysfunction. Hyperhomocysteinemia, increased sympathetic nervous system activity, lipoprotein alterations with elevated lipoprotein A, and increases in the concentrations of asymmetrical dimethyl-arginine are other examples of the changes described in this population. Patients with renal disease should be considered to be at high risk for developing cardiovascular disease and candidates for implementation of secondary prevention strategies. It is for this reason that early identification of renal failure, which remains hidden in many cases, is of prime importance.

Cardiovascular risk in patients with mild renal insufficiency: implications for the use of ACE inhibitors

We review the evidence linking mild renal insufficiency (MRI) with increased cardiovascular risk. MRI is associated with a number of cardiovascular risk factors, including nighttime hypertension, and increased levels of lipoprotein (a), homocysteine, asymmetric dimethyl-arginine, and inflammation and insulin resistance markers and mediators. Epidemiologic evidence associates coronary artery disease and nephrosclerosis, a frequent cause of early renal insufficiency in the elderly. In a middle-aged general population MRI was found in 8% of women and 9% of men, but was not associated with cardiovascular disease. Nonetheless, in a representative sample of middle-aged British men the risk of stroke was 60% higher for the sub-group with MRI: in people at high cardiovascular risk (mostly coronary disease), the HOPE study found a 2-fold (unadjusted) or 1.4-fold (adjusted) higher incidence of cardiovascular outcomes with MRI. The combined incidence of cardiovascular death, myocardial infarction and stroke increased with the level of serum creatinine. Several studies have examined the cardiovascular risk associated with MRI in hypertension. In HDFP, as in HOPE, cardiovascular mortality increased with serum creatinine (five-fold difference in cardiovascular mortality between the lowest and the highest creatinine strata). The risk associated with renal insufficiency was independent of other classic cardiovascular risk factors. Two trials of hypertensives with low risk (HOT and a small Italian trial) found that cardiovascular outcomes approximately doubled in subjects with MRI. Another study (MRFIT) found that it was not baseline creatinine, but its increase on follow-up that predicted future cardiovascular disease. These observational data suggest that regardless of etiology MRI is a strong predictor of cardiovascular disease and is found in 10% of populations at low cardiovascular risk and in up to 30% of those at high risk. No prospective therapeutic trials aimed at reducing the cardiovascular burden in people with MRI are available. Subgroup analyses of the HOPE study indicate that angiotensin-converting enzyme (ACE) inhibition with ramipril is beneficial and does not increase the risk of such side effects as acute renal failure or hyperkalemia. Thus the frequent practice of withholding ACE inhibitors from patients with mild renal insufficiency is unwarranted, especially since MRI identifies a group at high risk that appears to benefit most from treatment. Moreover, there is evidence that ACE inhibitors improve renal outcomes in renal insufficiency. Prospective studies should test the predictive power of early renal insufficiency for cardiovascular disease and prognosis with various therapeutic options.

New risk factors for atherosclerosis in hypertension: focus on the prothrombotic state and lipoprotein(a)

Although adequate control of blood pressure is of basic importance in cardiovascular prevention in hypertensive patients, correction of additional risk factors is an integral part of their management. In addition to classical risk factors, epidemiological research has identified a number of other conditions that might significantly contribute to cardiovascular risk in the general population and might achieve specific relevance in patients with high blood pressure. In fact, more than 20% of patients with premature cardiovascular events do not have any of the traditional risk factors and, although effective intervention on blood pressure and additional risk factors has significantly reduced cardiovascular morbidity and mortality, the contribution to stroke, coronary artery disease and renal failure is still unacceptably high. Evaluation of new risk factors may further expand our capacity to predict atherothrombotic events when these factors are included along with the traditional ones in the assessment of global cardiovascular risk in hypertensive patients. Because it could be anticipated that the role of these novel factors will become increasingly evident in the future, researchers with an interest in hypertension and physicians dealing with problems related to cardiovascular prevention should give them appropriate consideration. This review summarizes the basic biology and clinical evidence of two emerging risk factors that are reciprocally related and contribute to the development and progression of organ damage in hypertension: the prothrombotic state and lipoprotein(a).

Global differences in blood pressure control and clinical outcomes in the INternational VErapamil SR-Trandolapril STudy (INVEST)

BACKGROUND

The INternational VErapamil SR-Trandolapril Study (INVEST), a prospective, randomized, antihypertensive trial, found that two different medication regimens produced similar blood pressure (BP) control with equivalent cardiovascular (CV) outcomes (death from any cause, nonfatal myocardial infarction [MI], or nonfatal stroke).

HYPOTHESIS

The study was undertaken to investigate whether differences exist by global regions in demographics, treatment, and outcomes in the INVEST trial.

METHODS

Data were analyzed for 22,576 patients with stable coronary artery disease (CAD) enrolled in INVEST. We investigated differences in patient characteristics, treatment approaches, BP control, and clinical outcomes by creating three global regions based on geographical location: Northern Americas (NA), Caribbean (CA), and Eurasia (EA).

RESULTS

We observed significant regional differences in patient characteristics, treatment patterns, BP control, and CV outcomes. At baseline, patients from NA were older and had greater body mass index, higher rates of diabetes, peripheral vascular disease, and coronary revascularization, but lower rates of MI or left ventricular hypertrophy than patients in CA and EA. At 24 months, there were regional differences in both study and nonstudy antihypertensive drug use. Despite having higher mean baseline BP, patients from CA and EA achieved lower mean systolic BP throughout study follow-up. Furthermore, patients from both CA and EA had lower rates of all-cause mortality, fatal or nonfatal MI, fatal or nonfatal stroke, and newly diagnosed diabetes than patients from NA.

CONCLUSIONS

In INVEST, regional differences in medication utilization, BP control, and CV outcomes were identified. These disparities warrant further investigation to define appropriate care for patients with hypertension and stable CAD from an international public health perspective.

Renal dysfunction and ischemic heart disease mortality in a hypertensive population

OBJECTIVE

While recent studies indicate that renal dysfunction may be predictive of all-cause mortality and cardiovascular disease (CVD) outcomes in hypertensive individuals, there has been little attention to the specific association of ischemic heart disease (IHD) mortality and renal function. This study examines the relationship between IHD mortality and baseline glomerular filtration rate (GFR) (estimated by the Cockcroft and Gault formula) among treated hypertensive subjects.

DESIGN

A prospective cohort study of participants in a worksite-based antihypertensive treatment program in New York City (1981-1999).

PATIENTS

We studied 9929 subjects who had at least 6 months follow-up (mean 9.6 years) with a baseline serum creatinine.

MAIN OUTCOME MEASURES

IHD death outcomes (n=343) ascertained from the National Death Index.

RESULTS

Multivariate Cox proportional hazard models were constructed adjusting for known cardiovascular risk factors. Mean GFR of the cohort was 91.6 ml/min per 1.73 m. Those with lower GFR were more likely to be older, female, White, report a history of cardiovascular disease, have higher cholesterol and blood urea nitrogen values, and lower hemoglobin and body mass index than those with highest GFR. After adjustment for known cardiovascular risk factors, the risk of IHD death increased progressively as the GFR decreased. Hazard ratio for IHD mortality for each 10-unit reduction of estimated GFR below the normal threshold of >or=90 ml/min per 1.73 m was 1.33 (95% confidence interval 1.17, 1.50; P<0.001).

CONCLUSIONS

The results of this study suggest an independent inverse association between estimated GFR and IHD mortality among treated hypertensive individuals.

Predominant effect of kidney disease on mortality in Pima Indians with or without type 2 diabetes

BACKGROUND

We examined the effect of kidney disease (KD) on mortality in nondiabetic and diabetic Pima Indians aged > or = 45 years old.

METHODS

Deaths and person-years of follow-up were stratified in a time-dependent fashion into categories of (1) no proteinuria and normal serum creatinine (SCr); (2) proteinuria and normal SCr; (3) high SCr [SCr > or = 133 micromol/L (1.5 mg/dL) in men, > or = 124 micromol/L (1.4 mg/dL) in women] but not on renal replacement therapy (RRT); or (4) RRT.

RESULTS

Among 1993 subjects, 55.8% had type 2 diabetes at baseline. Overall death rates increased with declining kidney function in both the nondiabetic and diabetic subjects (P < 0.0001). Death rates were similar in nondiabetic and diabetic subjects with comparable levels of kidney function, although the number of deaths among nondiabetic subjects with advanced KD was small. Infections and malignancy were the leading causes of death in nondiabetic subjects with KD. Among diabetic subjects, overall mortality increased with diabetes duration (P = 0.0001) and was highest in those on RRT (P < 0.0001). High SCr was associated with higher death rates from cardiovascular disease (CVD), diabetic nephropathy (DN), infections, and malignancy.

CONCLUSION

Death rates increased comparably with worsening kidney function in both nondiabetic and diabetic subjects and were similar in nondiabetic and diabetic subjects without KD. KD was associated with excess mortality from DN, CVD, infections, and malignancy in diabetic subjects, and from infections in those without diabetes.

Impaired renal function and atherosclerosis in a Pakistani cohort

OBJECTIVE

To investigate the relationship of creatinine and calculated glomerular filtration rate (GFR) with coronary arterial disease (CAD) in Pakistani patients.

SUBJECTS

Four hundred individuals with chest pain; 200 with angiographic disease matched with 200 without occlusive disease.

DESIGN

A prospective case-control study.

SETTING

A tertiary referral cardiology unit in Pakistan.

RESULTS

Impaired renal function as estimated by calculated GFR was common in this population. Creatinine and glomerular filtration rate, as calculated by the Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae, were associated with CAD and atherosclerotic burden in Pakistani patients. Calculation of creatinine clearance, correcting for age, sex and body mass index, showed that clearance was 81 (17-257) mL/min/1.73 m2 in patients with CAD compared with 88 (23-167) mL/min/1.73 m2 in controls with a significant number of patients (18.5 vs. 6.5%; RR = 2.85; p < 0.001) showing significant renal impairment (< 60 mL/min/1.73 m2) by CG and more by the MDRD equation (26 vs. 9%; RR = 2.88; p < 0.001). The unadjusted odds ratios for CAD for a GFR < 60 mL/min/1.73 m2 were 3.66 (1.87-7.16) and 3.29 (1.81-6.01), respectively and, after adjustment for diabetes, smoking, insulin resistance, inflammation and apolipoprotein A1, 1.04 (1.02-1.09) and 1.04 (1.02-1.09), respectively.

CONCLUSIONS

Impaired renal function is common in Pakistani patients with coronary arterial disease and is strongly associated with a risk of atherosclerosis independent of insulin resistance.

Clinical epidemiology of cardiovascular disease in chronic kidney disease

Cardiovascular disease (CVD) is the most common cause of death in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). The clinical epidemiology of CVD in CKD is challenging due to a prior lack of standardized definitions of CKD, inconsistent measures of renal function, and possible alternative effects of 'traditional' CVD risk factors in patients with CKD. These challenges add to the complexity of the role of renal impairment as the cause or the consequence of cardiovascular disease. The goal of this review is to summarize the current evidence on: (1) the incidence and prevalence of CVD in chronic renal insufficiency and in ESRD, (2) risk factors for CVD in CKD, (3) the outcomes of patients with renal failure with CVD, and (4) CKD as a risk factor for CVD. The epidemiological associations implicating the huge burden of CVD throughout all stages of CKD highlight the need to better understand and implement adequate screening, and diagnostic and treatment strategies.

Chronic kidney disease as cause of cardiovascular morbidity and mortality

To make an evidence-based evaluation of the relationship between kidney failure and cardiovascular risk, we reviewed the literature obtained from a PubMed search using pre-defined keywords related to both conditions and covering 18 years (1986 until end 2003). Eighty-five publications, covering 552 258 subjects, are summarized. All but three studies support a link between kidney dysfunction and cardiovascular risk. More importantly, the association is observed very early during the evolution of renal failure: an accelerated cardiovascular risk appears at varying glomerular filtration rate (GFR) cut-off values, which were >/=60 ml/min in at least 20 studies. Many studies lacked a clear definition of cardiovascular disease and/or used a single determination of serum creatinine or GFR as an index of kidney function, which is not necessarily corresponding to well-defined chronic kidney disease. In six studies, however, chronic kidney dysfunction and cardiovascular disease were well defined and the results of these confirm the impact of kidney dysfunction. It is concluded that there is an undeniable link between kidney dysfunction and cardiovascular risk and that the presence of even subtle kidney dysfunction should be considered as one of the conditions necessitating intensive prevention of this cardiovascular risk.

Cardiovascular disease and chronic kidney disease: insights and an update

Despite the high prevalence and significant morbidity and mortality rates of chronic kidney disease (CKD) related to cardiovascular disease, it remains vastly understudied. Most of the current practice recommendations come from small under-powered prospective studies, retrospective reviews, and assuming patients with CKD will similarly benefit from medications and treatments as patients with normal renal function. In addition, because of the previous lack of a consistent definition of CKD and how to measure renal function, definitions of the degree of renal dysfunction have varied widely and compounded the confusion of these data. Remarkably, despite patients with CKD representing the group at highest risk from cardiovascular complications, even greater than patients with diabetes mellitus, there has been a systematic exclusion of patients with CKD from therapeutic trials. This review outlines our current understanding of CKD as a cardiovascular risk factor, treatment options, and the future directions that are needed to treat cardiovascular disease in patients with CKD.

Do associations with C-reactive protein and extent of coronary artery disease account for the increased cardiovascular risk of renal insufficiency?

OBJECTIVES

We sought to determine whether the association of higher C-reactive protein levels (CRP) and more extensive coronary artery disease (CAD) explains the high cardiovascular risk of renal insufficiency (RI).

BACKGROUND

Renal insufficiency and renal failure (RF) have been associated with increased cardiovascular risk in several studies, and it has been suggested that this association may be due to higher CRP levels and greater extent of CAD. To what extent CRP or severity of CAD explains this risk is uncertain.

METHODS

A total of 1,484 patients without myocardial infarction (MI) undergoing angiography were entered and followed for 3.0 +/- 1.6 years; RI and RF were defined as estimated glomerular filtration rates (GFR) of 30 to 60 and <30 ml/min; CRP was measured by immunoassay and > or = 1.0 mg/dl defined as elevated. A CAD score was determined by extent and severity of angiographic disease. Multivariate Cox regressions were performed using seven standard risk factors, homocysteine, GFR, CRP, and CAD score.

RESULTS

Mean age was 64 years, and 67% were men; CAD was absent in 24%, mild in 11%, and severe (> or =70% stenosis) in 60%; CRP and CAD scores increased with declining renal function (median CRP: 1.2, 1.4, 2.2 mg/dl, p < 0.001 and CAD score: 8.1, 8.7, 9.3, p = 0.008 for no-RI, RI, and RF). During follow-up, 208 patients (15%) died or had nonfatal MI. Unadjusted hazard ratio (HR) for death/MI was 2.3 for RI and 5.1 for RF (p < 0.0001). Adjustment for CRP (HR, 2.2, 4.5), CAD score (HR, 2.1, 5.1), and all other risk factors (HR, 1.7, 4.5) had minimal or modest impact on RI and RF risk; HR increased to 5.4 (p < 0.001) for presence of both elevated CRP and RI/RF.

CONCLUSIONS

Renal insufficiency, CRP, and angiographic CAD, although correlated, are largely independent predictors of cardiovascular risk, suggesting the importance of both inflammation and as yet undefined RI-related risk factors.

Cardiovascular risk in patients with mild renal insufficiency

We reviewed the evidence linking mild renal insufficiency (MRI) to an increased cardiovascular risk. A number of cardiovascular risk factors become prevalent with MRI, including night-time hypertension, increase in lipoprotein(a), in homocysteine, in asymmetric dimethyl-arginine (ADMA), markers and mediators of inflammation, and insulin resistance. Also, an epidemiologic association between coronary artery disease and nephrosclerosis, a frequent cause of mild renal insufficiency in the elderly, is documented. In the middle-aged, general population MRI, found in 8% of women and 9% of men, was not associated with cardiovascular disease. However, in a representative sample of middle-aged British men, the risk of stroke was 60% higher for the subgroup of people with MRI; in people at high cardiovascular risk (mostly coronary disease), the HOPE study found a 2-fold (unadjusted), or 1.4-fold (adjusted), higher incidence of cardiovascular outcomes with MRI. The incidence of primary outcome increased with the level of serum creatinine. Several studies determined the cardiovascular risk associated with MRI in hypertension. In HDFP, as in HOPE, cardiovascular mortality increased with higher serum creatinine (five-fold difference in cardiovascular mortality between the lowest and the highest creatinine strata). The risk associated with renal insufficiency was independent from other classic cardiovascular risk factors. In hypertensives with low risk, the HOT, and a small Italian trial found about a doubling in cardiovascular outcomes in MRI. However, in MRFIT, increase in follow-up creatinine predicted future cardiovascular disease, not baseline creatinine. These observational data suggest that MRI, independent of etiology, is a strong predictor of cardiovascular disease, present in 10% of a population at low risk, and up to 30% at high cardiovascular risk. No prospective therapeutic trials, aimed at reducing the cardiovascular burden in people with MRI, are available. Subgroup analyses of the HOPE study indicate that ACE inhibition with ramipril is beneficial without an increased risk for side effects like acute renal failure or hyperkalemia. Thus, the frequent practice of withholding ACE inhibitors from patients with mild renal insufficiency is unwarranted, especially since this identifies a group at high risk that appears to benefit most from treatment. In addition, there is evidence that ACE inhibitors improve renal outcomes in renal insufficiency. Prospective studies should test the predictive power of MRI for cardiovascular disease and therapeutic options.

Level of kidney function as a risk factor for cardiovascular outcomes in the elderly

BACKGROUND

There is a high prevalence of both reduced kidney function as well as cardiovascular disease (CVD) in the elderly. We evaluated whether the level of kidney function is an independent risk factor for CVD outcomes in the Cardiovascular Health Study (CHS), a cohort of subjects whose age at baseline was 65 years old or older.

METHODS

Cox proportional-hazards regression was used to evaluate the association of predicted glomerular filtration rate (GFR) with CVD after adjustment for the major CVD risk factors. We searched for nonlinear relationships between GFR and CVD, as well as interactions between level of kidney function and major CVD risk factors on CVD.

RESULTS

A total of 4893 subjects with predicted GFR of 15 to 130 mL/min/1.73 m2 were included in the analysis. Fifty-six percent were female and the mean age was 73.4 years. Of the subjects, 549 (11.2%) died and 1229 (25.1%) experienced CVD events in 5.05 years of follow-up. Each 10 mL/min/1.73 m2 lower GFR was associated with an adjusted hazard ratio for CVD, de novo CVD, recurrent CVD and all-cause mortality of 1.05 (1.02, 1.09), 1.07 (1.01, 1.12), 1.04 (0.99, 1.09), and 1.06 (1.00, 1.12), respectively. There was no significant interaction between level of GFR and other traditional CVD risk factors on CVD outcomes. A linear model best described the relationship between GFR and CVD.

CONCLUSION

The level of GFR is an independent risk factor for CVD, de novo CVD, and all-cause mortality in the elderly.

Level of kidney function as a risk factor for atherosclerotic cardiovascular outcomes in the community

OBJECTIVES

The goal of this study was to determine whether the level of kidney function is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD) outcomes in the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort study of subjects aged 45 to 64 years.

BACKGROUND

The level of kidney function is now recognized as a risk factor for ASCVD outcomes in patients at high risk for ASCVD, but it remains unknown whether the level of kidney function is a risk factor for ASCVD outcomes in the community.

METHODS

Cox proportional-hazards regression was used to evaluate the association of glomerular filtration rate (GFR) with ASCVD after adjustment for the major ASCVD risk factors in 15,350 subjects. We searched for nonlinear relationships between GFR and ASCVD.

RESULTS

During a mean follow-up time of 6.2 years, 965 (6.3%) of subjects had ASCVD events. Subjects with GFR of 15 to 59 ml/min/1.73 m(2) (n = 444, hazard ratio 1.38 [1.02, 1.87]) and 60 to 89 ml/min/1.73 m(2) (n = 7,665, hazard ratio 1.16 [1.00, 1.34]) had an increased adjusted risk of ASCVD compared with subjects with GFR of 90 to 150 ml/min/1.73 m(2). Each 10 ml/min/1.73 m(2) lower GFR was associated with an adjusted hazard ratio of 1.05 (1.02, 1.09), 1.07 (1.01, 1.12), and 1.06 (0.99, 1.13) for ASCVD, de novo ASCVD, and recurrent ASCVD, respectively. A nonlinear model did not fit the data better than a linear model.

CONCLUSIONS

The level of GFR is an independent risk factor for ASCVD and de novo ASCVD in the ARIC study.

Epidemiology of hypertension and cardiovascular disease in African Americans

Hypertension is a major cause of cardiovascular-renal morbidity and mortality and all-cause mortality. It is a highly significant problem for African Americans; about 30% of all deaths in this population are attributable to hypertension. Compared with whites, hypertension in African Americans is more prevalent, occurs earlier in life, is more severe, and is more often associated with target organ injury such as left ventricular hypertrophy and other cardiovascular complications. Only 25% of all African Americans with hypertension and fewer than 50% of those receiving drug treatment attain a blood pressure <140/90 mm Hg. These control rates are somewhat less than in white Americans. Enhanced awareness and understanding of the epidemiologic patterns of hypertension, other cardiovascular risk factors, risk-factor control rates, and factors influencing these control rates should lead to better approaches to risk-factor control. This most likely would result in a reduction of cardiovascular disease complications.

Mild renal insufficiency is associated with increased cardiovascular mortality: The Hoorn Study

BACKGROUND

Cardiovascular mortality is extremely high in end-stage renal disease. Cardiovascular mortality risk also is increased in selected (high-risk) individuals with mild to moderate impairment of renal function. It is not clear whether a similar association exists in the general population and, if so, through what mechanisms. We investigated the association of renal function with all-cause and cardiovascular mortality in a population-based cohort and explored potential mechanisms underlying any such relationship.

METHODS

An age-, sex-, and glucose-tolerance-stratified sample (N = 631) of a population-based cohort aged 50 to 75 years was followed prospectively. After up to 10.2 years of follow-up, 117 subjects had died (50 of cardiovascular causes). At baseline, renal function was estimated by the serum creatinine level, the Cockcroft-Gault formula and Levey's equation.

RESULTS

At baseline, the mean age was 64 +/- 7 years, 48% were men, 55% had hypertension, and 27% (by design) had type 2 diabetes. Serum creatinine was 91.7 +/- 19.0 micromol/L; creatinine clearance as estimated by the Cockroft-Gault formula was 72.5 +/- 13.7 mL/min/1.73 m(2), and the glomerular filtration rate (GFR) estimated by Levey's equation was 67.8 +/- 12.1 mL/min/1.73 m(2). Renal function was inversely associated with all-cause and with cardiovascular mortality. Relative risks (95% confidence intervals) were 1.08 (1.04 to 1.13) and 1.11 (1.07 to 1.16) per 5 micromol/L increase of serum creatinine; 1.07 (0.98 to 1.17) and 1.15 (1.01 to 1.31) for each decrease of 5 mL/min/1.73 m(2) creatinine clearance; and 1.15 (1.05 to 1.26) and 1.26 (1.12 to 1.42) for each decrease of 5 mL/min/1.73 m(2) of GFR. These associations remained after adjusting for age, sex, glucose tolerance status, hypertension, prior cardiovascular disease, low-density lipoprotein cholesterol, homocysteine, (micro)albuminuria, von Willebrand factor, soluble vascular adhesion molecule-1 and C-reactive protein. Analyses in diabetic and hypertensive subjects gave similar results.

CONCLUSION

Mild to moderate loss of renal function is strongly associated with an increased risk of cardiovascular mortality. The mechanism behind this association is unclear but does not appear to involve common risk factors such as hypertension, diabetes or hyperhomocysteinemia. Estimation of renal function by relatively simple methods therefore may be a valuable tool for cardiovascular risk assessment over and above that provided by conventional risk factors. Our results were obtained in a general middle-aged to elderly population, and thus have broad applicability.

Primary renal disease as a cardiovascular risk factor

Cardiovascular disease (CVD) is the No. 1 cause of death in patients with end-stage renal disease (ESRD) and is approximately 3 to 5 times that of non-uremic control subjects. Moreover, higher rates of CVD are seen in patients with moderate and even mild renal dysfunction, particularly if the patient has hypertension or diabetes. Recent studies have indicated that even modest elevations in serum creatinine and urinary albumin excretion are associated with increased CVD risk, not only in persons with diabetes or hypertension but also in the general population. In addition, recent studies have suggested that targeting the kidney and/or kidney specific endpoints (via the renin-angiotensin-aldosterone-kinin system) in the treatment of hypertension, diabetes, and heart failure slows progression of renal disease and reduces the risk of extra-renal micro- and macrovascular complications. We conclude that it is important to screen for renal disease in those with hypertension, diabetes, and other CVD risk factors because it predicts those who are at high risk for major CVD events.