Cardiovascular and mortality risk prediction and stratification using urinary albumin excretion in older adults ages 68–102: The cardiovascular Health Study

Association of urinary albumin-to-creatinine ratio with cardiometabolic risk markers and pre-diabetes in adults with normoglycemia, normoalbuminuria, and normotension with parental type 2 diabetes

INTRODUCTION

This is a post hoc analysis of urinary albumin-to-creatinine ratio (uACR) within the normoalbuminuric range in relation to cardiometabolic risk factors among initially normoglycemic, normotensive participants in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) Study.

RESEARCH DESIGN AND METHODS

308 healthy African American (AA) and European American (EA) participants in the POP-ABC Study underwent baseline assessments, including oral glucose tolerance test, anthropometry, urinary albumin-to-creatinine ratio (uACR), lipids, adipocytokines, insulin sensitivity and secretion. Participants were followed quarterly for 5.5 years (mean 2.62 years) for the primary outcome of incident pre-diabetes.

RESULTS

The cohort's mean fasting glucose was 92.1±6.90 mg/dL, 2-hour plasma glucose was 123±25.0 mg/dL, systolic blood pressure was 123±15.9 mm Hg, and diastolic blood pressure was 74±8.80 mm Hg. Baseline uACR levels (range 1-29 mg/g) were similar in AA versus EA participants (6.40 mg/g±4.80 vs 6.80±5.40 mg/g, p=0.52), higher in women than men (7.30 mg/g±5.30 vs 4.60±3.90 mg/g, p<0.0001), and showed significant associations with cardiometabolic risk factors, including age, insulin sensitivity, high-density lipoprotein cholesterol, and adiponectin levels (p=0.03-0.004). During 5.5 years of follow-up, 104 participants developed pre-diabetes and 204 maintained normoglycemia. Baseline uACR quartiles were associated with incident pre-diabetes (r=0.19, p=0.0011).

CONCLUSIONS

Baseline uACR levels were associated with cardiometabolic risk markers and incident pre-diabetes risk among adults with normoglycemia, normoalbuminuria and normotension with parental diabetes.

Effect of Urinary Albumin Creatinine Ratio on Cardiovascular Morbidity and Mortality in Diabetes Patients with Atherosclerotic Disease

Background

Diabetes mellitus (DM) patients with increased urinary albumin creatinine ratio (uACR) have higher risk of mortality, while it is unclear in DM patients with atherosclerotic cardiovascular disease (ASCVD).

Methods

We analysed 2832 DM patients with ASCVD in this multi-center registry cohort study Cardiorenal ImprovemeNt II (CIN-II) in 5 Chinese tertiary hospitals from 2007 to 2020. Patients were divided into 3 groups according to their uACR level (normal group: uACR <30mg/g, moderately increased group: 30mg/g≤ uACR <300mg/g, severely increased group: 300mg/g≤ uACR). The main outcome of the study was cardiovascular mortality and all-cause mortality.

Results

During a median follow-up of 2.1 years, among 2832 patients (mean age: 63.3 ± 9.9 years, 29.1% women), 434 patients (15.3%) had moderately increased uACR, and 203 patients (7.2%) had severely increased uACR. Compared to patients in normal group, patients had higher cardiovascular mortality in moderately increased group and severely increased group (2.5% vs 9.9% vs 16.7%, P < 0.001), as well as all-cause mortality. After adjusting confounders, the risk of cardiovascular mortality remained higher in moderately increased group (adjusted hazard ratio [aHR]: 3.13; 95% confidence interval [CI]: 2.04-4.81) and severely increased group (aHR: 4.54; 95% CI: 2.58-8.01) than in normal group, as well as all-cause mortality.

Conclusion

In our study, we found nearly a quarter of DM patients with ASCVD had increased uACR, and they have over 2- or 3-fold risk of cardiovascular mortality than those with normal uACR. UACR is a helpful indicator for risk stratification and treatment target for DM patients with ASCVD.

Postprandial glucagon-like peptide 1 secretion is associated with urinary albumin excretion in newly diagnosed type 2 diabetes patients

BACKGROUND

Microalbuminuria is an early and informative marker of diabetic nephropathy. Our study found that microalbuminuria developed in patients with newly diagnosed type 2 diabetes mellitus (T2DM).

AIM

To investigate the association between glucagon-like peptide 1 (GLP-1) and microalbuminuria in newly diagnosed T2DM patients.

METHODS

In total, 760 patients were recruited for this cross-sectional study. The GLP-1 levels during a standard meal test and urinary albumin-creatinine ratio (UACR) were determined.

RESULTS

Patients with microalbuminuria exhibited lower GLP-1 levels at 30 min and 120 min during a standard meal test than patients with normal albuminuria (30 min GLP-1, 16.7 ± 13.3 pmol vs 19.9 ± 15.6 pmol, P = 0.007; 120 min GLP-1, 16.0 ± 14.1 pmol vs 18.4 ± 13.8 pmol, P = 0.037). The corresponding area under the curve for active GLP-1 (AUCGLP-1) was also lower in microalbuminuria patients (2257, 1585 to 3506 vs 2896, 1763 to 4726, pmol × min, P = 0.003). Postprandial GLP-1 levels at 30 min and 120 min and AUCGLP-1 were negatively correlated with the UACR (r = 0.159, r = 0.132, r = 0.206, respectively, P < 0.001). The prevalence of microalbuminuria in patients with newly diagnosed T2DM was 21.7%, which decreased with increasing quartiles of AUCGLP-1 levels (27.4%, 25.3%, 18.9% and 15.8%). After logistic regression analysis adjusted for sex, age, hemoglobin A1c, body mass index, systolic blood pressure, estimated glomerular filtration rate, homeostasis model assessment of insulin resistance, AUC_glucose and AUC_glucagon, patients in quartile 4 of the AUCGLP-1 presented a lower risk of microalbuminuria compared with the patients in quartile 1 (odds ratio = 0.547, 95% confidence interval: 0.325-0.920, P = 0.01). A consistent association was also found between 30 min GLP-1 or 120 min GLP-1 and microalbuminuria.

CONCLUSION

Postprandial GLP-1 levels were independently associated with microalbuminuria in newly diagnosed Chinese T2DM patients.

Acarbose Reduces Low-Grade Albuminuria Compared to Metformin in Chinese Patients with Newly Diagnosed Type 2 Diabetes

PURPOSE

To assess the effect of acarbose in lowering low-grade albuminuria compared to metformin in newly diagnosed Chinese type 2 diabetes (T2DM) patients.

PATIENTS AND METHODS

The Metformin and AcaRbose Clinical Trial was a randomized, open-label trial in newly diagnosed T2DM patients. Participants received 48 weeks of monotherapy with acarbose (100 mg three times a day) or metformin (1500 mg once a day). As the hypoglycemic effect of acarbose and metformin has been evaluated in previous reports. This analysis studied the effect of the two antidiabetic drugs on reducing urinary albumin. The percent change in the urinary albumin/creatinine ratio (uACR) from baseline to week 48 was analyzed, and ANCOVA was employed to establish whether the effect in decreasing uACR was mediated by metabolic improvement.

RESULTS

Acarbose reduced the adjusted mean percent uACR by -31.5% (95% confidence interval [CI] -48.4 to -7.5) compared with metformin. When adjusting for changes in glycated hemoglobin, body weight, systolic blood pressure and triglycerides or changes in area under the curve of glucagon-like peptide 1 (AUCGLP-1) in the standard meal test, the uACR-lowering effect was not attenuated. If stratified by eGFR, blood glucose level, sex or uACR level, the effect of acarbose versus metformin was consistent across subgroups. The proportion of patients with a reduction in uACR of at least 70% was 48.6% in the acarbose group and 34.1% in the metformin group.

CONCLUSION

Acarbose lowered the uACR compared to metformin in newly diagnosed T2DM patients independent of improvements in hyperglycemia, blood pressure, body weight and triglycerides.

Metabolic Clusters and Outcomes in Older Adults: The Cardiovascular Health Study

BACKGROUND/OBJECTIVES

Few studies have the requisite phenotypic information to define metabolic patterns that may inform our understanding of the pathophysiology and consequences of diabetes in older adults. We sought to characterize clusters of older adults on the basis of shared metabolic features.

DESIGN

Population-based prospective cohort study.

SETTING

Four U.S. Cardiovascular Health Study field centers.

PARTICIPANTS

Individuals aged 65 and older taking no glucose-lowering agents (N = 2,231).

MEASUREMENTS

K-means cluster analysis of 11 metabolic parameters (fasting and postload serum glucose and plasma insulin, fasting C-peptide, body mass index, C-reactive protein (CRP), estimated glomerular filtration rate (eGFR), albuminuria, carboxymethyl lysine (an advanced glycation end-product), procollagen III N-terminal propeptide (a fibrotic marker)) and their associations with incident cardiovascular disease, diabetes, disability, and mortality over 8 to 14.5 years of follow-up and with measures of subclinical cardiovascular disease.

RESULTS

A 6-cluster solution provided robust differentiation into distinct, identifiable clusters. Cluster A (n = 739) had the lowest glucose and insulin and highest eGFR and the lowest rates of all outcomes. Cluster B (n = 419) had high glucose and insulin and intermediate rates of most outcomes. Cluster C (n = 118) had the highest insulin. Cluster D (n = 129) had the highest glucose with much lower insulin. Cluster E (n = 314) had the lowest eGFR and highest albuminuria. Cluster F (n = 512) had the highest CRP. Rates of CVD, mortality, and subclinical atherosclerosis were highest in clusters C, D, and E and were similar to rates in participants with treated diabetes. Incidence of disability was highest in Cluster C.

CONCLUSION

Clustering according to metabolic parameters identifies distinct phenotypes that are strongly associated with clinical and functional outcomes, even at advanced age.

Carotid Plaque Score and Risk of Cardiovascular Mortality in the Oldest Old: Results from the TOOTH Study

Aim: Accumulating evidence suggests that predictability of traditional cardiovascular risk factors declines with advancing age. We investigated whether carotid plaque scores (CPSs) were associated with cardiovascular disease (CVD) death in the oldest old, and whether asymmetrical dimethylarginine (ADMA), a marker of endothelial dysfunction, moderated the association between the CPS and CVD death.

Methods: We conducted a prospective cohort study of Japanese subjects aged ≥ 85 years without CVD at baseline. We followed this cohort for 6 years to investigate the association of CPS with CVD death via multivariable Cox proportional hazard analysis. We divided participants into three groups according to CPS (no, 0 points; low, 1.2–4.9 points; high, ≥5.0 points). The predictive value of CPS for estimating CVD death risk over CVD risk factors, including ADMA, was examined using C-statistics.

Results: We analyzed 347 participants (151 men, 196 women; mean age, 87.6 years), of which 135 (38.9%) had no carotid plaque at baseline, and 48 (13.8%) had high CPS. Of the total, 29 (8.4%) participants experienced CVD-related death during the study period. Multivariable analysis revealed a significant association of high CPS with CVD-related mortality relative to no CPS (hazard ratio, 3.90; 95% confidence interval: 1.47–10.39). ADMA was not associated with CVD death, but the significant association between CPS and CVD death was observed only in lower ADMA level. The addition of CPS to other risk factors improved the predictability of CVD death (p = 0.032).

Conclusions: High CPS correlated significantly with a higher CVD death risk in the oldest old with low cardiovascular risk. Ultrasound carotid plaque evaluation might facilitate risk evaluations of CVD death in the very old.

Low-grade albuminuria and incidence of cardiovascular disease and all-cause mortality in nondiabetic and normotensive individuals

BACKGROUND

Recent studies indicate that, in people with diabetes or hypertension and in the general population, low-grade albuminuria (LGA) below the microalbuminuria threshold is a predictor for incidence of cardiovascular disease (CVD) and mortality. However, it remains unclear whether LGA predicts the risk of CVD incidence and death in nondiabetic and normotensive individuals.

METHODS

A total of 3599 individuals aged not less than 40 years from the general population who are free of CVD in nondiabetic and normotensive individuals with preserved glomerular filtration rate were followed for CVD incidence and all-cause death. LGA was defined as urinary albumin to creatinine ratio (UACR) less than 30  mg/g. It was examined whether there is an association between LGA and CVD incidence or all-cause death.

RESULTS

During the average 5.9 years of follow-up, 61 individuals had first CVD events, and 85 individuals died. The hazard ratios (HRs) for CVD incidence and all-cause death after full adjustment by potential confounders increased significantly in the top tertile of LGA (UACR ≥ 9.6  mg/g for men, ≥ 12.0  mg/g for women) compared with the first tertile [HR = 2.79, 95% confidence interval (CI), 1.41-5.52, HR = 1.69, 95% CI, 1.00-2.84, respectively]. Population-attributable fractions of the top tertile of LGA for CVD incidence and all-cause death were 37.9 and 20.1%, respectively.

CONCLUSION

In apparently healthy individuals with optimal blood pressure and no diabetes, LGA independently predicts CVD incidence and all-cause death, particularly with the large contribution to the excessive incidence of CVD.

APOL1 Genotype, Kidney and Cardiovascular Disease, and Death in Older Adults

OBJECTIVE

We sought to evaluate the cardiovascular impact of coding variants in the apolipoprotein L1 gene APOL1 that protect against trypanosome infection but have been associated with kidney disease among African Americans.

APPROACH AND RESULTS

As part of the Cardiovascular Health Study, a population-based cohort of Americans aged ≥65 years, we genotyped APOL1 polymorphisms rs73885319 and rs71785153 and examined kidney function, subclinical atherosclerosis, and incident cardiovascular disease and death over 13 years of follow-up among 91 African Americans with 2 risk alleles, 707 other African Americans, and 4964 white participants. The high-risk genotype with 2 risk alleles was associated with 2-fold higher levels of albuminuria and lower ankle-brachial indices but similar carotid intima-media thickness among African Americans. Median survival among high-risk African Americans was 9.9 years (95% confidence interval [CI], 8.7-11.9), compared with 13.6 years (95% CI, 12.5-14.3) among other African Americans and 13.3 years (95% CI, 13.0-13.6) among whites (P=0.03). The high-risk genotype was also associated with increased risk for incident myocardial infarction (adjusted hazard ratio 1.8; 95% CI, 1.1-3.0) and mortality (adjusted hazard ratio 1.3; 95% CI 1.0-1.7). Albuminuria and risk for myocardial infarction and mortality were nearly identical between African Americans with 0 to 1 risk alleles and whites.

CONCLUSIONS

APOL1 genotype is associated with albuminuria, subclinical atherosclerosis, incident myocardial infarction, and mortality in older African Americans. African Americans without 2 risk alleles do not differ significantly in risk of myocardial infarction or mortality from whites. APOL1 trypanolytic variants may account for a substantial proportion of the excess risk of chronic disease in African Americans.

Prevention of Heart Failure in Patients with Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have heightened risk of developing heart failure (HF), yet few clinical studies have directly investigated the pathophysiologic underpinnings or therapeutic strategies to prevent HF. A wide range of clinically available cardiac and renal biomarkers can identify at-risk individuals who would benefit from dietary and lifestyle modifications (exercise prescription, smoking cessation), as well as risk factor modification (blood pressure, glucose, and lipid control). Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have the most consistent data for risk reduction, while other standard HF drugs such as beta-blockers and mineralocorticoid receptor antagonists have promising findings but no large-scale clinical trial evidence for their routine use to prevent the development and progression of HF in this vulnerable population.

Risk factors for cardiovascular disease across the spectrum of older age: the Cardiovascular Health Study

OBJECTIVE

The associations of some risk factors with cardiovascular disease (CVD) are attenuated in older age; whereas others appear robust. The present study aimed to compare CVD risk factors across older age.

METHODS

Participants (n = 4883) in the Cardiovascular Health Study free of prevalent CVD, were stratified into three age groups: 65-74, 75-84, 85+ years. Traditional risk factors included systolic blood pressure (BP), LDL-cholesterol, HDL-cholesterol, obesity, and diabetes. Novel risk factors included kidney function, C-reactive protein (CRP), and N-terminal pro-B-type natriuretic peptide (NT pro-BNP).

RESULTS

There were 1498 composite CVD events (stroke, myocardial infarction, and cardiovascular death) over 5 years. The associations of high systolic BP and diabetes appeared strongest, though both were attenuated with age (p-values for interaction = 0.01 and 0.002, respectively). The demographic-adjusted hazard ratios (HR) for elevated systolic BP were 1.79 (95% confidence interval: 1.49, 2.15), 1.59 (1.37, 1.85) and 1.10 (0.86, 1.41) in participants aged 65-74, 75-84, 85+, and for diabetes, 2.36 (1.89, 2.95), 1.55 (1.27, 1.89), 1.51 (1.10, 2.09). The novel risk factors had consistent associations with the outcome across the age spectrum; low kidney function: 1.69 (1.31, 2.19), 1.61 (1.36, 1.90), and 1.57 (1.16, 2.14) for 65-74, 75-84, and 85+ years, respectively; elevated CRP: 1.54 (1.28, 1.87), 1.33 (1.13, 1.55), and 1.51 (1.15, 1.97); elevated NT pro-BNP: 2.67 (1.96, 3.64), 2.71 (2.25, 3.27), and 2.18 (1.43, 3.45).

CONCLUSIONS

The associations of most traditional risk factors with CVD were minimal in the oldest old, whereas diabetes, eGFR, CRP, and NT pro-BNP were associated with CVD across older age.

Neutrophil lymphocyte ratio significantly improves the Framingham risk score in prediction of coronary heart disease mortality: insights from the National Health and Nutrition Examination Survey-III

BACKGROUND

Neutrophil lymphocyte ratio (NLR) has been shown to predict cardiovascular events in several studies. We sought to study if NLR predicts coronary heart disease (CHD) in a healthy US cohort and if it reclassifies the traditional Framingham risk score (FRS) model.

METHODS

We performed post hoc analysis of National Health and Nutrition Examination Survey-III (1998-94) including subjects aged 30-79 years free from CHD or CHD equivalent at baseline. Primary endpoint was death from ischemic heart disease. NLR was divided into four categories: <1.5, ≥1.5 to <3.0, 3.0-4.5 and >4.5. Statistical analyses involved multivariate Cox proportional hazards models as well as discrimination, calibration and reclassification.

RESULTS

We included 7363 subjects with a mean follow up of 14.1 years. There were 231 (3.1%) CHD deaths, more in those with NLR>4.5 (11%) compared to NLR<1.5 (2.4%), p<0.001. Adjusted hazard ratio of NLR>4.5 was 2.68 (95% CI 1.07-6.72, p=0.035). There was no significant improvement in C-index (0.8709 to 0.8713) or area under curve (0.8520 to 0.8531) with addition of NLR to FRS model. Model with NLR was well calibrated with Hosmer-Lemeshow chi-square of 8.57 (p=0.38). Overall net reclassification index (NRI) was 6.6% (p=0.003) with intermediate NRI of 10.1% (p<0.001) and net upward reclassification of 5.6%. Absolute integrated discrimination index (IDI) was 0.003 (p=0.039) with relative IDI of 4.3%.

CONCLUSIONS

NLR can independently predict CHD mortality in an asymptomatic general population cohort. It reclassifies intermediate risk category of FRS, with significant upward reclassification. NLR should be considered as an inflammatory biomarker of CHD.

Cubilin maintains blood levels of HDL and albumin

Cubilin is an endocytic receptor highly expressed in renal proximal tubules, where it mediates uptake of albumin and filtered forms of apoA-I/HDL. Cubilin deficiency leads to urinary loss of albumin and apoA-I; however, the consequences of cubilin loss on the homeostasis of blood albumin and apoA-I/HDL have not been studied. Using mice heterozygous for cubilin gene deletion (cubilin HT mice), we show that cubilin haploinsufficiency leads to reduced renal proximal tubular uptake of albumin and apoA-I and significantly increased urinary loss of albumin and apoA-I. Moreover, cubilin HT mice displayed significantly decreased blood levels of albumin, apoA-I, and HDL. The levels of albumin and apoA-I protein or mRNA expressed in the liver, kidney, or intestine of cubilin HT mice did not change significantly. The clearance rate of small HDL3 particles (density>1.13 g/ml) from the blood increased significantly in cubilin HT mice. In contrast, the rate of clearance of larger HDL2 particles from the blood did not change significantly, indicating a decreased half-life for HDL particles capable of filtering through the glomerulus. On the basis of these findings, we conclude that cubilin deficiency reduces renal salvage and delivery back to the blood of albumin and apoA-I, which decreases blood levels of albumin and apoA-I/HDL. These findings raise the possibility that therapeutic increase of renal cubilin expression might reduce proteinuria and increase blood levels of albumin and HDL.

2012 update of the Canadian Cardiovascular Society guidelines for the diagnosis and treatment of dyslipidemia for the prevention of cardiovascular disease in the adult

Many developments have occurred since the publication of the widely-used 2009 Canadian Cardiovascular Society (CCS) Dyslipidemia guidelines. Here, we present an updated version of the guidelines, incorporating new recommendations based on recent findings and harmonizing CCS guidelines with those from other Societies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used, per present standards of the CCS. The total cardiovascular disease Framingham Risk Score (FRS), modified for a family history of premature coronary disease, is recommended for risk assessment. Low-density lipoprotein cholesterol remains the primary target of therapy. However, non-high density lipoprotein cholesterol has been added to apolipoprotein B as an alternate target. There is an increased emphasis on treatment of higher risk patients, including those with chronic kidney disease and high risk hypertension. The primary panel has recommended a judicious use of secondary testing for subjects in whom the need for statin therapy is unclear. Expanded information on health behaviours is presented and is the backbone of risk reduction in all subjects. Finally, a systematic approach to statin intolerance is advocated to maximize appropriate use of lipid-lowering therapy. This document presents the recommendations and principal conclusions of this process. Along with associated Supplementary Material that can be accessed online, this document will be part of a program of knowledge translation. The goal is to increase the appropriate use of evidence-based cardiovascular disease event risk assessment in the management of dyslipidemia as a fundamental means of reducing global risk in the Canadian population.

Age and association of kidney measures with mortality and end-stage renal disease

CONTEXT

Chronic kidney disease (CKD) is prevalent in older individuals, but the risk implications of low estimated glomerular filtration rate (eGFR) and high albuminuria across the full age range are controversial.

OBJECTIVE

To evaluate possible effect modification (interaction) by age of the association of eGFR and albuminuria with clinical risk, examining both relative and absolute risks.

DESIGN, SETTING, AND PARTICIPANTS

Individual-level meta-analysis including 2,051,244 participants from 33 general population or high-risk (of vascular disease) cohorts and 13 CKD cohorts from Asia, Australasia, Europe, and North/South America, conducted in 1972-2011 with a mean follow-up time of 5.8 years (range, 0-31 years).

MAIN OUTCOME MEASURES

Hazard ratios (HRs) of mortality and end-stage renal disease (ESRD) according to eGFR and albuminuria were meta-analyzed across age categories after adjusting for sex, race, cardiovascular disease, diabetes, systolic blood pressure, cholesterol, body mass index, and smoking. Absolute risks were estimated using HRs and average incidence rates.

RESULTS

Mortality (112,325 deaths) and ESRD (8411 events) risks were higher at lower eGFR and higher albuminuria in every age category. In general and high-risk cohorts, relative mortality risk for reduced eGFR decreased with increasing age; eg, adjusted HRs at an eGFR of 45 mL/min/1.73 m2 vs 80 mL/min/1.73 m2 were 3.50 (95% CI, 2.55-4.81), 2.21 (95% CI, 2.02-2.41), 1.59 (95% CI, 1.42-1.77), and 1.35 (95% CI, 1.23-1.48) in age categories 18-54, 55-64, 65-74, and ≥75 years, respectively (P <.05 for age interaction). Absolute risk differences for the same comparisons were higher at older age (9.0 [95% CI, 6.0-12.8], 12.2 [95% CI, 10.3-14.3], 13.3 [95% CI, 9.0-18.6], and 27.2 [95% CI, 13.5-45.5] excess deaths per 1000 person-years, respectively). For increased albuminuria, reduction of relative risk with increasing age was less evident, while differences in absolute risk were higher in older age categories (7.5 [95% CI, 4.3-11.9], 12.2 [95% CI, 7.9-17.6], 22.7 [95% CI, 15.3-31.6], and 34.3 [95% CI, 19.5-52.4] excess deaths per 1000 person-years, respectively by age category, at an albumin-creatinine ratio of 300 mg/g vs 10 mg/g). In CKD cohorts, adjusted relative hazards of mortality did not decrease with age. In all cohorts, ESRD relative risks and absolute risk differences at lower eGFR or higher albuminuria were comparable across age categories.

CONCLUSIONS

Both low eGFR and high albuminuria were independently associated with mortality and ESRD regardless of age across a wide range of populations. Mortality showed lower relative risk but higher absolute risk differences at older age.

Identifying novel biomarkers for cardiovascular disease risk prediction

The primary prevention of cardiovascular disease relies on the ability to identify at-risk individuals long before the development of overt events. In the past decade, research into circulating, genetic and imaging biomarkers to augment traditional methods of risk prediction has only achieved modest success. Emerging technologies in the fields of genomics, metabolomics and proteomics are providing new platforms for biomarker discovery. Here, we review current concepts in the evaluation and discovery of cardiovascular biomarkers. Further research is needed to identify new biomarkers to successfully stratify risk of cardiovascular disease in low-risk populations, as well as to test whether management strategies informed by biomarker testing are better than standard of care.

Methodological evaluation and comparison of five urinary albumin measurements

BACKGROUND

Microalbuminuria is an indicator of kidney damage and a risk factor for the progression kidney disease, cardiovascular disease, and so on. Therefore, accurate and precise measurement of urinary albumin is critical. However, there are no reference measurement procedures and reference materials for urinary albumin.

METHODS

Nephelometry, turbidimetry, colloidal gold method, radioimmunoassay, and chemiluminescence immunoassay were performed for methodological evaluation, based on imprecision test, recovery rate, linearity, haemoglobin interference rate, and verified reference interval. Then we tested 40 urine samples from diabetic patients by each method, and compared the result between assays.

RESULTS

The results indicate that nephelometry is the method with best analytical performance among the five methods, with an average intraassay coefficient of variation (CV) of 2.6%, an average interassay CV of 1.7%, a mean recovery of 99.6%, a linearity of R=1.00 from 2 to 250 mg/l, and an interference rate of <10% at haemoglobin concentrations of <1.82 g/l. The correlation (r) between assays was from 0.701 to 0.982, and the Bland-Altman plots indicated each assay provided significantly different results from each other.

CONCLUSION

Nephelometry is the clinical urinary albumin method with best analytical performance in our study.

Microalbuminuria in Cerebrovascular Disease: A Modifiable Risk Factor?

Stroke is potentially preventable through risk factor modification. Over the past decade, there has been considerable interest on microalbuminuria as a risk factor for chronic diseases. The concept of microalbuminuria was originally introduced, about 25 years ago, to clinical practice as a useful marker of nephropathy. Since then various studies reported an association of microalbuminuria with the increased risk of cardiovascular events and all cause of mortality in subjects with or without diabetes. The presence of microalbuminuria was related to left ventricular dysfunction, stroke, and myocardial infarction. Microalbuminuria may be a predictor of stroke but further studies are required. However data on prognostic significance and therapeutic consequence, particularly in haemorrhagic stroke are lacking. This review focuses on the importance of microalbuminuria for cerebrovascular disease, stressing the clinical and therapeutic implications using antihypertensive therapy to control the urinary albumin excretion.

Additional value of carotid artery intima-media thickness in cardiovascular risk assessment by Framingham risk-score in Type 2 diabetes: a retrospective cohort study

BACKGROUND

The intima-media thickness (IMT) of the carotid artery is highly correlated with cardiovascular events in Type 2 diabetes mellitus (T2DM). The aim of the present study was to undertake a cardiovascular risk assessment in a group of patients (n = 102) who had been followed-up for 10 years.

METHODS

Framingham risk score (FRS), IMT, and various other clinical parameters were evaluated retrospectively using Student's t-test, regression analysis, and χ² tests. Primary endpoints were defined as cardiovascular death, non-fatal myocardial infarction, angina, and ischemic stroke.

RESULTS

The IMT (1.09 ± 0.32 vs 0.89 ± 0.25; P < 0.001) and percentage coronary risk as determined by the FRS (24.33 ± 11.07 vs 16.54 ± 8.35; P = 0.001) were significantly higher in patients presenting with any of the primary endpoints compared with patients in whom no cardiovascular morbidity or mortality was recorded. Other factors that significantly predicted cardiovascular mortality and morbidity included diastolic blood pressure and urinary albumin excretion (UAE; P < 0.001). The likelihood of primary endpoints could be predicted by UAE >30 mg/day, carotid artery IMT ≥0.9 mm, and FRS ≥20 (odds ratios 8.800, 3.377, and 2.807, respectively).

CONCLUSION

Although FRS predicts 10-year risk for cardiovascular mortality and morbidity in T2DM, we suggest that UAE and carotid artery IMT should also be considered in risk assessments.

Kidney function and estimated vascular risk in patients with primary dyslipidemia

Background:

Chronic kidney disease (CKD) is associated with increased vascular risk. Some studies suggested that considering markers of CKD might improve the predictive accuracy of the Framingham risk equation.

Aim:

To evaluate the links between kidney function and risk stratification in patients with primary dyslipidemia.

Methods:

Dyslipidemic patients (n = 156; 83 men) who were non-smokers, did not have diabetes mellitus or evident vascular disease and were not on lipid-lowering or antihypertensive agents were recruited. Creatinine clearance (CrCl) was estimated using the Cockcroft-Gault equation. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) equation. We estimated vascular risk using the Framingham equation.

Results:

In both men and women, there was a significant negative correlation between estimated Framingham risk and both eGFR and CrCl (p < 0.001 for all correlations). When men were divided according to creatinine tertiles, there were no significant differences in any parameter between groups. When men were divided according to either eGFR or CrCl tertiles, all estimated Framingham risks significantly increased as renal function declined (p<0.001 for all trends). When women were divided according to creatinine tertiles, all estimated Framingham risks except for stroke significantly increased as creatinine levels increased. When women were divided according to either eGFR or CrCl tertiles, all estimated Framingham risks significantly increased as renal function declined.

Conclusions:

Estimated vascular risk increases as renal function declines. The possibility that incorporating kidney function in the Framingham equation will improve risk stratification requires further evaluation.

Community-based population data indicates the significant alterations of insulin resistance, chronic inflammation and urine ACR in IFG combined IGT group among prediabetic population

AIMS

To investigate alterations of insulin resistance (IR), chronic inflammation and urine albumin-to-creatinine ratio (ACR) in Chinese community-based prediabetic population.

MATERIALS AND METHODS

252 prediabetics [prediabetes (PD), including impaired fasting glucose (IFG), 91; impaired glucose tolerance (IGT), 123; IFG+IGT, 38] and 38 newly diagnosed-diabetics (NDDM) aged over 35 years older were screened from 2336 community individuals. 123 age and gender matched individuals with normal glucose tolerance (NGT) were selected as controls. Serum adiponectin, interleukin-6 (IL-6) levels and urine ACR were determined, HOMA-IR and Gutt's index were calculated to evaluate IR and insulin sensitivity, respectively.

RESULTS

The data displayed significant difference of serum adiponectin, IL-6, ACR and Gutt's index among PD, NDDM and NGT groups. Adiponectin level and Gutt's index decreased, but IL-6 level and ACR increased gradually among NGT, PD and NDDM groups (P<0.01). Unlike adiponectin and IL-6, ACR analysis indicates a gradual increase from NGT, IFG, IGT, IFG+IGT to NDDM individuals (P<0.01). Gutt's index showed significant difference between IFG and NDDM, IFG+IGT and NDDM (P<0.01), but HOMA-IR index did not.

CONCLUSIONS

IR, chronic inflammation and endothelial dysfunction dose exist in prediabetic individuals, especially in IFG+IGT population. Gutt's index and ACR might seem to be more sensitive than adiponectin and HOMA-IR index as IR and chronic inflammation maker in prediabetic population.

Quantification of urinary albumin by using protein cleavage and LC-MS/MS

BACKGROUND

Urinary albumin excretion is a sensitive diagnostic and prognostic marker for renal disease. Therefore, measurement of urinary albumin must be accurate and precise. We have developed a method to quantify intact urinary albumin with a low limit of quantification (LOQ).

METHODS

We constructed an external calibration curve using purified human serum albumin (HSA) added to a charcoal-stripped urine matrix. We then added an internal standard, (15)N-labeled recombinant HSA ((15)NrHSA), to the calibrators, controls, and patient urine samples. The samples were reduced, alkylated, and digested with trypsin. The concentration of albumin in each sample was determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and linear regression analysis, in which the relative abundance area ratio of the tryptic peptides (42)LVNEVTEFAK(51) and (526)QTALVELVK(534) from albumin and (15)NrHSA were referenced to the calibration curve.

RESULTS

The lower limit of quantification was 3.13 mg/L, and the linear dynamic range was 3.13-200 mg/L. Replicate digests from low, medium, and high controls (n = 5) gave intraassay imprecision CVs of 2.8%-11.0% for the peptide (42)LVNEVTEFAK(51), and 1.9%-12.3% for the (526)QTALVELVK(534) peptide. Interassay imprecision of the controls for a period of 10 consecutive days (n = 10) yielded CVs of 1.5%-14.8% for the (42)LVNEVTEFAK(51) peptide, and 6.4%-14.1% for the (526)QTALVELVK(534) peptide. For the (42)LVNEVTEFAK(51) peptide, a method comparison between LC-MS/MS and an immunoturbidometric method for 138 patient samples gave an R(2) value of 0.97 and a regression line of y = 0.99x + 23.16.

CONCLUSIONS

Urinary albumin can be quantified by a protein cleavage LC-MS/MS method using a (15)NrHSA internal standard. This method provides improved analytical performance in the clinically relevant range compared to a commercially available immunoturbidometric assay.

Cardiovascular disease in chronic kidney disease

The presence of kidney disease, manifested by low glomerular filtration rates (GFR) and/or large amounts of protein in the urine, is independently associated with increased rates of cardiovascular disease (CVD). The severity of kidney disease is associated with graded increases in risk for CVD and death. Chronic kidney disease (CKD) should be recognized and treatment initiated early to maximize the chances for slowing nephropathy progression and reducing proteinuria. We recommend screening for CKD in all patients with CVD, including computing an estimated GFR and evaluating for proteinuria using a spot urine albumin:creatinine ratio. Aggressive management of traditional cardiovascular risk factors should be employed in this high-risk population, specifically rigorous hypertension control (including the use of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blocking agents (ARB)), management of hyperglycemia, hyperlipidemia and smoking cessation. Further studies are needed to identify the unique renal failure-related (non-traditional) risk factors that contribute to accelerated atherosclerosis in this population and performance of randomized trials to assess the effects of cardiovascular interventions in individuals with CKD.