Relationship between albuminuria and cardiovascular disease in Type 2 diabetes

Severely increased albuminuria in patients with type 2 diabetes mellitus is associated with increased subclinical atherosclerosis in femoral arteries with Na [18F]F activity as a proxy - The DETERMINE study

BACKGROUND AND AIMS

Sodium [18F]fluoride (Na [18F]F) positron emission tomography imaging allows detailed visualization of early arterial micro-calcifications. This study aims to investigate atherosclerosis manifested by micro-calcification, macro-calcification, and aortic stiffness in patients with type 2 diabetes mellitus (T2DM) with and without albuminuria and severely decreased kidney function.

METHODS

A cohort was stratified in four groups (N = 10 per group), based on KDIGO categories (G1-5 A1-3). G1-2A1 non-diabetic controls (median [IQR] estimated glomerular filtration rate (eGFR) in mL/min/1.73 m2 91 [81-104]), G1-2A1 with T2DM (eGFR 87 [84-93], and albumin-creatinin-ratio (ACR) in mg/mmol 0.35 [0.25-0.75]), G1-2A3 with T2DM (eGFR 85 [60-103], and ACR 74 [62-122], and G4A3 with T2DM (eGFR 19 [13-27] and ACR 131 [59-304]).

RESULTS

Na [18F]F femoral artery grading score differed significantly in the groups with the highest Na [18F]F activity in A3 groups with T2DM (G1-2A3 with T2DM 228 [100-446] and G4A3 with T2DM 198 [113-578]) from the lowest groups of the G1-2A1 with T2DM (33 [0-93]) and in G1-2A1 non-diabetic controls (75 [0-200], p = 0.001). Aortic Na [18F]F activity and femoral artery computed tomography (CT)-assessed macro-calcification was increased in G4A3 with T2DM compared with G1-2A1 with T2DM (47.5 [33.8-73.8] vs. 17.5 [8.8-27.5] (p = 0.006) and 291 [170-511] vs. 12.2 [1.41-44.3] mg (p = 0.032), respectively). Carotid-femoral pulse wave velocity (PWV)-assessed aortic stiffness was significantly higher in both A3 groups with T2DM compared with G1-2A1 with T2DM (11.15 and 12.35 vs. 8.86 m/s, respectively (p = 0.009)).

CONCLUSIONS

This study indicates that the presence of severely increased albuminuria in patients with T2DM is cross-sectionally associated with subclinical arterial disease in terms of micro-calcification and aortic stiffness. Additional decrease in kidney function was associated with advanced macro-calcifications.

Elevated urine albumin-to-creatinine ratio increases the risk of new-onset heart failure in patients with type 2 diabetes

BACKGROUND

Although albuminuria has been linked to heart failure in the general population, the relationship between urine albumin-to-creatinine ratio (uACR) and heart failure in type 2 diabetes patients is not well understood. We aimed to investigate the relationship between uACR and new-onset heart failure (HF) in type 2 diabetics.

METHODS

We included 9287 Chinese participants with type 2 diabetes (T2D) but no heart failure (HF) who were assessed with uACR between 2014 and 2016. The participants were divided into three groups based on their baseline uACR: normal (< 3 mg/mmol), microalbuminuria (3-30 mg/mmol), and macroalbuminuria (≥ 30 mg/mmol). The relationship between uACR and new-onset HF was studied using Cox proportional hazard models and restricted cubic spline. The area under the receiver operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to see if incorporating uACR into existing models could improve performance.

RESULTS

216 new-onset HF cases (2.33%) were recorded after a median follow-up of 4.05 years. When compared to normal uACR, elevated uACR was associated with a progressively increased risk of new-onset HF, ranging from microalbuminuria (adjusted HR, 2.21; 95% CI 1.59-3.06) to macroalbuminuria (adjusted HR, 6.02; 95% CI 4.11-8.80), and 1 standard deviation (SD) in ln (uACR) (adjusted HR, 1.89; 95% CI 1.68-2.13). The results were consistent across sex, estimated glomerular filtration rate, systolic blood pressure, and glycosylated hemoglobin subgroups. The addition of uACR to established HF risk models improved the HF risk prediction efficacy.

CONCLUSIONS

Increasing uACR, even below the normal range, is an independent risk factor for new-onset HF in a type 2 diabetic population. Furthermore, uACR may improve HF risk prediction in community-based T2D patients.

Traditional Chinese medicine body constitution predicts new-onset diabetic albuminuria in patients with type 2 diabetes: Taichung diabetic body constitution prospective cohort study

This prospective cohort study explored whether body constitution (BC) independently predicts new-onset albuminuria in persons with type 2 diabetes mellitus (T2DM) enrolled in the diabetes care management program (DCMP) of a medical center, providing evidence of integrating traditional Chinese medicine into DCMP for improving care quality. Persons with T2DM (n = 426) originally without albuminuria enrolled in DCMP were recruited in 2010 and were then followed up to 2015 for detecting new-onset albuminuria. The participants received urinalysis and blood test annually. Albuminuria was determined by an elevated urinary albumin/creatinine ratio (≥ 30 µg/mg), and poor glucose control was defined as Glycosylated hemoglobin above or equal to 7%. BC type (Yin deficiency, Yang deficiency, and phlegm stasis) was assessed using a well-validated body constitution questionnaire at baseline. Risk factors for albuminuria (sociodemographic factors, diabetes history, lifestyle behaviors, lipid profile, blood pressure, and kidney function) were also recorded. Hazard ratios (HR) of albuminuria for BC were estimated using multivariate Cox proportional hazards model. During the 4-year follow-up period, albuminuria occurred in 30.5% of participants (n = 130). The HR indicated that Yin deficiency was significantly associated with an increased risk of new-onset albuminuria in persons with T2DM and good glucose control after adjustment for other risk factors (HR = 2.09; 95% confidence interval = 1.05-4.17, P = .04), but not in those with poor glucose control. In persons with T2DM and poor glucose control, phlegm stasis was also significantly associated with a higher risk of albuminuria (2.26; 1.03-4.94, P = .04) after multivariate adjustment, but not in those with good glucose control. In addition to already-known risk factors, BC is an independent and significant factor associated with new-onset albuminuria in persons with T2DM. Our results imply Yin deficiency and phlegm stasis interacting with glucose control status may affect new-onset albuminuria in persons with T2DM.

Machine learning approach to predicting albuminuria in persons with type 2 diabetes: An analysis of the LOOK AHEAD Cohort

Albuminuria and estimated glomerular filtration rate (e-GFR) are early markers of renal disease and cardiovascular outcomes in persons with diabetes. Although body composition has been shown to predict systolic blood pressure, its application in predicting albuminuria is unknown. In this study, we have used machine learning methods to assess the risk of albuminuria in persons with diabetes using body composition and other determinants of metabolic health. This study is a comparative analysis of the different methods to predict albuminuria in persons with diabetes mellitus who are older than 40 years of age, using the LOOK AHEAD study cohort-baseline characteristics. Age, different metrics of body composition, duration of diabetes, hemoglobin A1c, serum creatinine, serum triglycerides, serum cholesterol, serum HDL, serum LDL, maximum exercise capacity, systolic blood pressure, diastolic blood pressure, and the ankle-brachial index are used as predictors of albuminuria. We used Area under the curve (AUC) as a metric to compare the classification results of different algorithms, and we show that AUC for the different models are as follows: Random forest classifier-0.65, gradient boost classifier-0.61, logistic regression-0.66, support vector classifier -0.61, multilayer perceptron -0.67, and stacking classifier-0.62. We used the Random forest model to show that the duration of diabetes, A1C, serum triglycerides, SBP, Maximum exercise Capacity, serum creatinine, subtotal lean mass, DBP, and subtotal fat mass are important features for the classification of albuminuria. In summary, when applied to metabolic imaging (using DXA), machine learning techniques offer unique insights into the risk factors that determine the development of albuminuria in diabetes.

Prevalence of Microalbuminuria and Its Association with Subclinical Carotid Atherosclerosis in Middle Aged, Nondiabetic, Low to Moderate Cardiovascular Risk Individuals with or without Hypertension

Microalbuminuria is closely associated with the risk of cardiovascular disease and all-cause mortality in the general population. Less is known about its relationship with subclinical atherosclerosis. We aimed to assess the prevalence of microalbuminuria and its relationship with subclinical atherosclerosis in middle-aged, nondiabetic, apparently healthy individuals (N = 187; 40.1% men, 59.9% women; aged 35–55 years) as well as to evaluate its potential associations with established risk modifiers, especially with the presence of carotid plaque. Clinical and laboratory parameters, the estimated 10-year fatal cardiovascular risk (SCORE), as well as circulating, functional (flow mediated vasodilation, ankle-brachial index, augmentation index, and pulse wave velocity), and morphological markers (mean carotid intima–media thickness, and carotid plaque) of subclinical atherosclerosis were analysed in group with vs. without microalbuminuria. Microalbuminuria was present in 3.8% of individuals with SCORE risk 0.43 ± 0.79%. Functional markers predominated in both groups. Carotid intima–media thickness (mean ± SD) in both groups was in range: 0.5–0.55 ± 0.09–0.14 mm. Carotid plaque was more frequent in group with (14.3%) vs. without (4.4%) microalbuminuria. Microalbuminuria had no statistically significant effect on most markers of subclinical atherosclerosis, but the increasing value of microalbuminuria was significantly associated with the occurrence of carotid plaque (p = 0.035; OR = 1.035; 95% CI = 1.002–1.07). Additional multiple logistic regression analysis, where variables belonged to microalbuminuria, number of risk factors, and family history, finally showed only two variables: microalbuminuria (p = 0.034; OR = 1.04; 95%CI = 1.003–1.09) and the number of risk factors (p = 0.006; OR = 2.15; 95% CI = 1.24–3.73) with independent and significant impact on the occurrence of carotid plaque. Our results may indicate an association of microalbuminuria with the presence of carotid atherosclerotic plaque; in addition, microalbuminuria and the number of risk factors appear to be possible predictors of the carotid plaque occurrence. Monitoring microalbuminuria may improve the personalized cardiovascular risk assessment in nondiabetic, low-to-moderate cardiovascular risk individuals with or without hypertension.

Increased Proteinuria is Associated with Increased Aortic Arch Calcification, Cardio-Thoracic Ratio, Rapid Renal Progression and Increased Overall and Cardiovascular Mortality in Chronic Kidney Disease

Background: Patients with chronic kidney disease (CKD) are associated with high prevalence rates of proteinuria, vascular calcification and cardiomegaly. In this study, we investigated relationships among proteinuria, aortic arch calcification (AoAC) and cardio-thoracic ratio (CTR) in patients with CKD stage 3A-5. In addition, we investigated correlations among proteinuria and decline in renal function, overall and cardiovascular (CV) mortality. Methods: We enrolled 482 pre-dialysis patients with CKD stage 3A-5, and determined AoAC and CTR using chest radiography at enrollment. The patients were stratified into four groups according to quartiles of urine protein-to-creatinine ratio (U_PCR). Results: The patients in quartile 4 had a lower estimated glomerular filtration rate (eGFR) slope, and higher prevalence rates of rapid renal progression, progression to commencement of dialysis, overall and CV mortality. Multivariable analysis showed that a high U_PCR was associated with high AoAC (unstandardized coefficient β: 0.315; p = 0.002), high CTR (unstandardized coefficient β: 1.186; p = 0.028) and larger negative eGFR slope (unstandardized coefficient β: -2.398; p < 0.001). With regards to clinical outcomes, a high U_PCR was significantly correlated with progression to dialysis (log per 1 mg/g; hazard ratio [HR], 2.538; p = 0.003), increased overall mortality (log per 1 mg/g; HR, 2.292; p = 0.003) and increased CV mortality (log per 1 mg/g; HR, 3.195; p = 0.006). Conclusions: Assessing proteinuria may allow for the early identification of high-risk patients and initiate interventions to prevent vascular calcification, cardiomegaly, and poor clinical outcomes.

Immune-unreactive urinary albumin as a predictor of cardiovascular events: the Hortega Study

BACKGROUND

We aimed to determine if immune-unreactive albumin excretion (IURAE) is associated with cardiovascular (CV) events in a representative sample of a general population from Spain.

METHODS

We included 1297 subjects (mean age ± standard error 48.0 ± 0.2 years, 48% females), who participated in the Hortega Follow-Up Study. The primary endpoint was incidence of fatal and non-fatal CV events. Urinary albumin excretion (UAE) was measured in spot voided urine, frozen at -80°C, by immunonephelometry [immune-reactive albumin excretion (IRAE)] and by high-performance liquid chromatography (HPLC) [total albumin excretion (AE)]. IURAE was calculated as the difference between HPLC measurements and IRAE. We estimated fully adjusted hazard ratios (HRs) of CV incidence by Cox regression for IRAE, IURAE and total AE.

RESULTS

After an average at-risk follow-up of 13 years, we observed 172 CV events. urinary albumin to creatinine ratio (UACR) of ≥30 mg/g assessed by IRAE, IURAE or total AE concentrations was observed in 74, 273 and 417 participants, respectively. Among discordant pairs, there were 49 events in those classified as micro- and macroalbuminuric by IURAE, but normoalbuminuric by IRAE. Only the IRAE was a significant independent factor for the incidence of CV events [HR (95% confidence interval) 1.15 (1.04-1.27)]. The association of UAE with CV events was mainly driven by heart failure (HF) [HR 1.33 (1.15-1.55) for IRAE; HR 1.38 (1.06-1.79) for IURAE; HR 1.62 (1.22-2.13) for total AE]. Those subjects who were micro- and macroalbuminuric by both IRAE and IURAE had a significant increase in risk for any CV event, and especially for HF.

CONCLUSIONS

IRAE, IURAE and AE were associated with an increased risk for CV events, but IRAE offered better prognostic assessment.

Review of biomarkers to assess the effects of switching from cigarettes to modified risk tobacco products

Context: One approach to reducing the harm caused by cigarette smoking, at both individual and population level, is to develop, assess and commercialize modified risk alternatives that adult smokers can switch to. Studies to demonstrate the exposure and risk reduction potential of such products generally involve the measuring of biomarkers, of both exposure and effect, sampled in various biological matrices.Objective: In this review, we detail the pros and cons for using several biomarkers as indicators of effects of changing from conventional cigarettes to modified risk products.Materials and methods: English language publications between 2008 and 2017 were retrieved from PubMed using the same search criteria for each of the 25 assessed biomarkers. Nine exclusion criteria were applied to exclude non-relevant publications.Results: A total of 8876 articles were retrieved (of which 7476 were excluded according to the exclusion criteria). The literature indicates that not all assessed biomarkers return to baseline levels following smoking cessation during the study periods but that nine had potential for use in medium to long-term studies.Discussion and conclusion: In clinical studies, it is important to choose biomarkers that show the biological effect of cessation within the duration of the study.

Role of Vitamin D in Uremic Vascular Calcification

The risk of cardiovascular death is 10 times higher in patients with CKD (chronic kidney disease) than in those without CKD. Vascular calcification, common in patients with CKD, is a predictor of cardiovascular mortality. Vitamin D deficiency, another complication of CKD, is associated with vascular calcification in patients with CKD. GFR decline, proteinuria, tubulointerstitial injury, and the therapeutic dose of active form vitamin D aggravate vitamin D deficiency and reduce its pleiotropic effect on the cardiovascular system. Vitamin D supplement for CKD patients provides a protective role in vascular calcification on the endothelium by (1) renin-angiotensin-aldosterone system inactivation, (2) alleviating insulin resistance, (3) reduction of cholesterol and inhibition of foam cell and cholesterol efflux in macrophages, and (4) modulating vascular regeneration. For the arterial calcification, vitamin D supplement provides adjunctive role in regressing proteinuria, reverse renal osteodystrophy, and restoring calcification inhibitors. Recently, adventitial progenitor cell has been linked to be involved in the vascular calcification. Vitamin D may provide a role in modulating adventitial progenitor cells. In summary, vitamin D supplement may provide an ancillary role for ameliorating uremic vascular calcification.

The renal tubular damage marker urinary N-acetyl-β-D-glucosaminidase may be more closely associated with early detection of atherosclerosis than the glomerular damage marker albuminuria in patients with type 2 diabetes

Background

To determine the association between urinary N-acetyl-β-d-glucosaminidase (NAG), a marker of renal tubulopathy, and carotid intima-media thickness (IMT) and plaques in patients with type 2 diabetes mellitus (T2D) and to compare the predictive value of NAG versus albuminuria, a marker of renal glomerulopathy.

Methods

A total of 343 participants were enrolled in this retrospective cross-sectional study. We recruited participants with T2D who were tested for blood glucose parameters, urinary NAG, and urinary albumin-to-creatinine ratio (ACR) and had been checked for carotid ultrasonography.

Results

We classified participants into a below-median urinary NAG group (Group I; n = 172) or an above-median group (Group II; n = 171). Mean, maximum, and mean of maximum carotid IMT and the proportion of patients with carotid plaques were significantly higher in Group II compared with Group I. In multiple linear regression analyses, high urinary NAG (Group II) was significantly associated with carotid IMT, independently of urinary ACR and other confounding factors. In terms of carotid plaques, both urinary NAG and ACR were significantly higher in participants with carotid plaques than in those without carotid plaques. After adjustment for confounding factors, both urinary NAG and ACR were significantly associated with the presence of carotid plaques.

Conclusions

Elevated urinary NAG, a marker of renal tubular damage, was related to increased carotid IMT and the presence of carotid plaques in patients with T2D. Urinary NAG may be a more sensitive biomarker than urinary albumin for early detection of atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0497-7) contains supplementary material, which is available to authorized users.

Childhood Albuminuria and Chronic Kidney Disease is Associated with Mortality and End-Stage Renal Disease

BACKGROUND

We do not yet fully grasp the significance of childhood albuminuria. Based on mass urinary screening (MUS) using albumin-specific dipsticks in school children, we studied the independent association of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in children with chronic kidney disease (CKD).

METHODS

A prospective cohort of 5351 children with albuminuria detected by school MSU during the period 1992-1996, followed up to 2009.

RESULTS

Cumulative mortality rate, prevalence of CKD, and ESRD were higher in children with albuminuria than those without. Albuminuria category was associated with the risk of mortality [hazard ratio (HR) 3.4] and ESRD (HR 3.24). Lower eGFR and albuminuria predicted mortality and ESRD among children with albuminuria and CKD. We found that being below a threshold of 45 mL/min/1.73 m(2) was significantly associated with ESRD. The highest renal function decline, along with the steepest slope of cumulative ESRD number, occurred in Stage 3, the critical point in renal progression. Risk factors for renal progression among different age groups with albuminuria were hypercholesterolemia and low serum albumin at 7-17 years of age. Beyond 18 years of age, besides the risk factor, a higher fasting blood sugar (BS) was also noted.

CONCLUSION

Childhood albuminuria is a risk factor for CKD in later life, albuminuria provides additional prognostic information, and complications of CKD should be defined in each case.

Increased detection of coronary atherosclerosis on 320-slice computed tomographic angiography with burden of cardiovascular risk factors and complications in patients with type 2 diabetes

AIMS

The cardiovascular risk factors and diabetic complications are related to coronary atherosclerosis. However, the evaluation of the prevalence of coronary atherosclerosis based on their accumulation remains to be determined.

METHODS

247 consecutive Chinese subjects with type 2 diabetes but without history of coronary heart disease (CHD) underwent 320-slice computed tomographic coronary angiography, including no coronary atherosclerosis, non-obstructive atherosclerosis (<50% stenosis) and obstructive atherosclerosis (≥50% stenosis). Conventional cardiovascular risk factors, albuminuria, renal dysfunction and diabetic retinopathy (DR) were determined. Framingham Risk Score (FRS) was used to assess the 10-year CHD risk.

RESULTS

Increase in burden of cardiovascular risk factors and diabetic complications were significantly associated with the likelihood of being a higher coronary atherosclerosis category. In the analysis for trend through the categories of burden score or FRS stratification, the percentage of obstructive atherosclerosis was increased and the percentage of no atherosclerosis decreased as the burden score and FRS increased (all p<0.005), respectively. The areas under the receiver operator curve for the burden score versus FRS were greater at predicting coronary atherosclerosis and obstructive atherosclerosis (p=0.004 and p=0.002), respectively.

CONCLUSIONS

The prevalence of coronary atherosclerosis was increased with the accumulation of cardiovascular risk factors and diabetic complications. The burden of these clinical and biochemical risk factors has increased ability for prediction of the presence and severity of coronary atherosclerosis over FRS in type 2 diabetic patients.

Endothelin

The endothelins comprise three structurally similar 21-amino acid peptides. Endothelin-1 and -2 activate two G-protein coupled receptors, ETA and ETB, with equal affinity, whereas endothelin-3 has a lower affinity for the ETA subtype. Genes encoding the peptides are present only among vertebrates. The ligand-receptor signaling pathway is a vertebrate innovation and may reflect the evolution of endothelin-1 as the most potent vasoconstrictor in the human cardiovascular system with remarkably long lasting action. Highly selective peptide ETA and ETB antagonists and ETB agonists together with radiolabeled analogs have accurately delineated endothelin pharmacology in humans and animal models, although surprisingly no ETA agonist has been discovered. ET antagonists (bosentan, ambrisentan) have revolutionized the treatment of pulmonary arterial hypertension, with the next generation of antagonists exhibiting improved efficacy (macitentan). Clinical trials continue to explore new applications, particularly in renal failure and for reducing proteinuria in diabetic nephropathy. Translational studies suggest a potential benefit of ETB agonists in chemotherapy and neuroprotection. However, demonstrating clinical efficacy of combined inhibitors of the endothelin converting enzyme and neutral endopeptidase has proved elusive. Over 28 genetic modifications have been made to the ET system in mice through global or cell-specific knockouts, knock ins, or alterations in gene expression of endothelin ligands or their target receptors. These studies have identified key roles for the endothelin isoforms and new therapeutic targets in development, fluid-electrolyte homeostasis, and cardiovascular and neuronal function. For the future, novel pharmacological strategies are emerging via small molecule epigenetic modulators, biologicals such as ETB monoclonal antibodies and the potential of signaling pathway biased agonists and antagonists.

Influence of Postprandial Hyperglycemic Conditions on Arterial Stiffness in Patients With Type 2 Diabetes

CONTEXT

Patients with type 2 diabetes (T2D) are at an increased risk of cardiovascular disease.

OBJECTIVE

The objective of the study was to determine whether postprandial hyperglycemia affects arterial function in T2D.

DESIGN

A single-center, open-label study of three groups of men were studied: 1) T2D patients with albuminuria (n = 22), 2) T2D patients without albuminuria (n = 24), and 3) nondiabetic controls (n = 25). Patients were randomized to a two-period crossover study schedule, ingesting breakfast, with or without insulin lispro (to induce low or high postprandial glycemia).

MAIN OUTCOME MEASURES

Arterial stiffness was assessed by calculating pulse wave velocity (PWV) and augmentation index using applanation tonometry, and endothelial dysfunction was assessed using peripheral arterial tonometry, 30 minutes before breakfast and up to 240 minutes after breakfast.

RESULTS

At baseline, arterial stiffness was increased in patients. When adjusted for age and body mass index, in a combined group of patients with and without albuminuria, brachial PWV was higher during low (P = .032) and high (P = .038) postprandial glycemia vs controls. These differences were driven by the albuminuria group vs controls during low (P = .014) and high (P = .018) postprandial glycemia. No differences were observed in aortic PWV, augmentation index, or peripheral arterial tonometry ratio between patients and controls. Endothelin-1 and IL-6 were higher, and superoxide dismutase was lower, during postprandial hyperglycemia in T2D patients vs controls.

CONCLUSIONS

In patients with T2D and albuminuria, brachial PWV was higher under postprandial hyperglycemic conditions, relative to controls. These data suggest that hyperglycemia induces an increase in stiffness of intermediate-sized arteries. We found no changes in other parts of the arterial bed.

Prognostic Value of Albuminuria on Cardiovascular Outcomes After Elective Percutaneous Coronary Intervention

Albuminuria is the most widely evaluated marker of kidney damage. Many previous studies have demonstrated an association between the presence of albuminuria and increased cardiovascular events. However, there are limited data regarding the impact of albuminuria in patients requiring coronary revascularization. This study investigated whether the urinary albumin excretion rate could predict cardiovascular events in such a population. We enrolled 698 consecutive patients who underwent elective percutaneous coronary intervention. The baseline urinary albumin-to-creatinine ratio (ACR; mg/gCr) was measured and patients were divided into those with normoalbuminuria (ACR <30 mg/gCr), microalbuminuria (ACR 30 to 300 mg/gCr), or macroalbuminuria (ACR >300 mg/gCr). We collected data on the incidences of cardiac death and/or nonfatal myocardial infarction. We identified 389, 230, and 79 patients with normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively. During follow-up (median: 1,564 days), 41 events occurred. The event-free survival rate was 89% in patients with macroalbuminuria, 92% in those with microalbuminuria, and 97% in those with normoalbuminuria, respectively (log-rank test p = 0.002). After adjustment for conventional risk factors, Cox analysis revealed hazard ratios for cardiac death and/or nonfatal myocardial infarction were 2.56 (95% CI 1.23 to 5.32, p = 0.01) in those with microalbuminuria and 4.02 (95% CI 1.59 to 10.12, p = 0.003) in those with macroalbuminuria compared with those with normoalbuminuria. In conclusion, an elevated urinary albumin excretion rate independently predicted adverse cardiovascular outcomes, with a gradual risk increase that progressed from microalbuminuria to macroalbuminuria in patients undergoing elective percutaneous coronary intervention.

An observational study of the association between microalbuminuria and increased N-terminal pro-B-type natriuretic peptide in patients with subarachnoid hemorrhage

BACKGROUND

The urinary albumin/creatinine ratio (ACR) is a significant neurologic prognostic predictor in patients with aneurysmal subarachnoid hemorrhage (SAH). B-type natriuretic peptide (BNP) plays an important role in body fluid regulation in patients with SAH. The present study was performed to determine whether ACR was independent predictor for unfavorable neurological outcome and ACR was associated with increased N-terminal pro-BNP (NT-pro-BNP) after SAH.

METHODS

We studied 61 patients undergoing surgery who were admitted within 48 h after aneurysmal SAH onset between July 2008 and June 2010. Hunt and Hess grade and Fisher grade were recorded at admission. The Glasgow Coma Scale (GCS) score was calculated at admission and daily for seven postoperative days. Arterial blood was sampled at admission and for seven postoperative days to determine the PaO2/FIO2 ratio, C-reactive protein level, troponin I level, and NT-pro-BNP level. Urine was sampled at admission and daily for seven postoperative days to determine ACR and vanillylmandelic acid/creatinine ratio (VMACR). Neurological outcomes were assessed at hospital discharge by using the Glasgow Outcome Scale. Receiver operating characteristic curves were constructed for the predictive variables of unfavorable neurological outcomes, and the area under the curve (AUC) was determined. Multivariate logistic regression analyses were performed for the significant predictors of unfavorable neurological outcomes after SAH. Associations with NT-pro-BNP were evaluated by using the Spearman rank correlation test.

RESULTS

Of the 61 patients, 24 had unfavorable outcomes. The prevalence rate of microalbuminuria was 85 % (52/61). The highest NT-pro-BNP levels were above the normal range in 57 of 61 patients (93 %). According to the AUC, the Hunt and Hess grade, GCS score, the highest ACR, and highest VMACR were significant predictors of neurological outcome. Multivariate logistic regression analyses showed that the highest ACR and Hunt and Hess grade are independent prognostic predictors of unfavorable neurological outcomes. The highest NT-pro-BNP significantly correlated with the highest troponin I, highest ACR, and VMACR on admission.

CONCLUSIONS

The highest ACR is an independent prognostic predictor of unfavorable neurological outcomes after SAH. Moreover, plasma NT-pro-BNP elevation may be associated with the development of microalbuminuria.

Vitamin D Associations With Renal, Bone, and Cardiovascular Phenotypes: African American-Diabetes Heart Study

CONTEXT

Vitamin D binding protein (DBP) is an important determinant of bioavailable vitamin D (BAVD) and may provide clues to racial variation in osteoporosis and atherosclerosis.

OBJECTIVE

The objective was to assess relationships between DBP, BAVD, 25-hydroxyvitamin D (25OHD), and 1,25 di-hydroxyvitamin D (1,25OH2D) with kidney, bone, adipose, and atherosclerosis phenotypes in African Americans with type 2 diabetes.

DESIGN

Cross-sectional (N = 545) and longitudinal (N = 288; mean 5.1 ± 0.9-year follow-up) relationships between vitamin D concentrations with renal phenotypes, vertebral bone mineral density, aorto-iliac, coronary artery, and carotid artery calcified plaque (CP), and adipose tissue volumes were studied.

SETTING

African American-Diabetes Heart Study.

PATIENTS

Participants were 56.7% female with mean ± standard deviation (sd) age 55.6 ± 9.6 years, diabetes duration 10.3 ± 8.2 years, and eGFR 90.9 ± 22.1 ml/min/1.73 m(2).

INTERVENTIONS

None.

MAIN OUTCOMES AND MEASURES

Associations tested between vitamin D and the previously mentioned phenotypes adjusting for age, sex, African ancestry proportion, diabetes duration, statins, smoking, changes in estimated glomerular filtration rate, body mass index, hemoglobin A1c, and blood pressure.

RESULTS

1,25OH2D was inversely associated with change in coronary artery CP (parameter estimate [β] -0.005, standard error [SE] 0.002; P = .037), with a trend for change in carotid artery CP (β -0.007, SE 0.004; P = .074). Further adjustment for renin-aldosterone-system blockade revealed inverse association between 1,25OH2D and change in albuminuria (β -0.004, SE 0.002; P = .037). DBP, BAVD, and 25OHD did not associate significantly with changes in albuminuria, CP, or bone mineral density. BAVD was inversely associated with visceral, subcutaneous, intermuscular, and pericardial adipose volumes.

CONCLUSIONS

In contrast to BAVD and 25OHD, only 1,25OH2D levels were significantly and inversely associated with changes in subclinical atherosclerosis and albuminuria in African Americans, suggesting potential beneficial effects.

High protein weight loss diets in obese subjects with type 2 diabetes mellitus

BACKGROUND AND AIM

Diets where carbohydrate has been partially exchanged for protein have shown beneficial changes in persons with type 2 diabetes but no studies have enrolled people with albuminuria. We aim to determine if a high protein to carbohydrate ratio (HPD) in an energy reduced diet has a beneficial effect on metabolic control and cardiovascular risk factors without negatively affecting renal function.

METHOD AND RESULTS

Adult, overweight participants with type 2 diabetes, with albuminuria (30-600 mg/24 h or an albumin-to-creatinine ratio of 3.0-60 mg/mmol), and estimated GFR of >40 ml/min/1.73 m(2) were enrolled. Participants were randomized to an HPD or an SPD. Protein:fat:carbohydrate ratio was 30:30:40% of energy for the HPD and 20:30:50% for the SPD. Main outcomes were renal function, weight loss, blood pressure, serum lipids and glycaemic control. We recruited 76 volunteers and 45 (35 men and 10 women) finished. There were no overall changes in renal function at 12 months and no significant differences in weight loss between groups (9.7 ± 2.9 kg and 6.6 ± 1.4 kg HPD and SPD group respectively; p = 0.32). Fasting blood glucose decreased significantly with no treatment effect. The decrease in HbA1c differed between treatments at 6 months (HPD -0.9 vs. SPD -0.3%; p = 0.039) but not at 12 months. HDL increased significantly with no treatment effects. There were no changes in LDL or blood pressure overall but DBP was lower in the HPD group (p = 0.024) at 12 months.

CONCLUSION

Weight loss improved overall metabolic control in this group of well controlled participants with type 2 diabetes regardless of diet composition.

Glomerular filtration rate and albuminuria predict mortality independently from coronary artery calcified plaque in the Diabetes Heart Study

Background

Risk stratification in individuals with type 2 diabetes (T2D) remains an important priority in the management of associated morbidity and mortality, including from cardiovascular disease (CVD). The current investigation examined whether estimated glomerular filtration rate (eGFR) and urine albumin:creatinine ratio (UACR) were independent predictors of CVD-mortality in European Americans (EAs) with T2D after accounting for subclinical CVD.

Methods

The family-based Diabetes Heart Study (DHS) cohort (n=1,220) had baseline measures of serum creatinine, eGFR, UACR and coronary artery calcified plaque (CAC) assessed by non-contrast computed tomography scan. Cox proportional hazards regression was performed to determine risk for all-cause mortality and CVD-mortality associated with indices of kidney disease after accounting for traditional CVD risk factors and CAC as a measure of subclinical CVD.

Results

Participants were followed for 8.2±2.6 years (mean±SD) during which time 247 (20.9%) were deceased, 107 (9.1%) from CVD. Univariate analyses revealed positive associations between serum creatinine (HR:1.56; 95% CI:1.37–1.80; p<0.0001) and UACR (1.59; 1.43–1.77; p>0.0001) and negative associations between serum albumin (0.74; 0.65–0.84; p<0.0001) and eGFR (0.66; 0.58–0.76; p<0.0001) with all-cause mortality. Associations remained significant after adjustment for traditional CVD risk factors, as well as for CAC. Similar trends were noted when predicting risk for CVD-mortality.

Conclusions

The DHS reveals that kidney function and albuminuria are independent risk factors for all-cause mortality and CVD-mortality in EAs with T2D, even after accounting for CAC.

Relationships between serum MCP-1 and subclinical kidney disease: African American-Diabetes Heart Study

Background

Monocyte chemoattractant protein-1 (MCP-1) plays important roles in kidney disease susceptibility and atherogenesis in experimental models. Relationships between serum MCP-1 concentration and early nephropathy and subclinical cardiovascular disease (CVD) were assessed in African Americans (AAs) with type 2 diabetes (T2D).

Methods

Serum MCP-1 concentration, urine albumin:creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and atherosclerotic calcified plaque (CP) in the coronary and carotid arteries and infrarenal aorta were measured in 479 unrelated AAs with T2D. Generalized linear models were fitted to test for associations between MCP-1 and urine ACR, eGFR, and CP.

Results

Participants were 57% female, with mean ± SD (median) age 55.6±9.5 (55.0) years, diabetes duration 10.3±8.2 (8.0) years, urine ACR 149.7±566.7 (14.0) mg/g, CKD-EPI eGFR 92.4±23.3 (92.0) ml/min/1.73m², MCP-1 262.9±239.1 (224.4) pg/ml, coronary artery CP 280.1±633.8 (13.5), carotid artery CP 47.1±132.9 (0), and aorta CP 1616.0±2864.0 (319.0). Adjusting for age, sex, smoking, HbA_1c, BMI, and LDL, serum MCP-1 was positively associated with albuminuria (parameter estimate 0.0021, P=0.04) and negatively associated with eGFR (parameter estimate −0.0003, P=0.001). MCP-1 remained associated with eGFR after adjustment for urine ACR. MCP-1 levels did not correlate with the extent of CP in any vascular bed, HbA_1c or diabetes duration, but were positively associated with BMI. No interaction between BMI and MCP-1 was detected on nephropathy outcomes.

Conclusions

Serum MCP-1 levels are associated with eGFR and albuminuria in AAs with T2D. MCP-1 was not associated with subclinical CVD in this population. Inflammation appears to play important roles in development and/or progression of kidney disease in AAs.

Coronary calcium score, albuminuria and inflammatory markers in type 2 diabetic patients: associations and prognostic implications

AIMS

To investigate the relationship of coronary artery calcium (CAC) scores with common carotid artery intima media thickness (CCA-IMT), albuminuria and inflammatory factors in type 2 diabetes.

METHODS AND RESULTS

128 asymptomatic type 2 diabetic patients, with at least one cardiovascular risk factor in addition to diabetes, were included in the study. CAC scores, carotid arteries plaque formation and CCA-IMT were assessed. The patients were followed for a mean period of 36.6 ± 3.3 months. Linear regression analysis identified the logarithmically transformed (Ln) albuminuria (β=0.32, P=0.007), age (β=0.04, P=0.001) and the uric acid (β=0.13, P=0.04) as independent determinants of the CAC score. During follow-up period, cardiovascular events occurred in 18 out of 46 patients with CAC score ≥100 compared with 5 out of 82 patients with CAC score <100 (log rank, P<0.0001). Multivariate Cox proportional hazards analysis identified LnCAC score (P<0.0001), LnAlbuminuria (P=0.01) and uric acid (P=0.03) as independent predictors for cardiovascular events.

CONCLUSIONS

There was a significant relationship between CAC score, albuminuria and inflammation in patients with type 2 diabetes. LnCAC score together with LnAlbuminuria and uric acid were identified as independent predictors of cardiovascular events in these patients.

Review of the Diabetes Heart Study (DHS) family of studies: a comprehensively examined sample for genetic and epidemiological studies of type 2 diabetes and its complications

The Diabetes Heart Study (DHS) is a genetic and epidemiological study of 1,443 European American and African American participants from 564 families with multiple cases of type 2 diabetes. Initially, participants were comprehensively examined for measures of subclinical cardiovascular disease (CVD) including computed tomography measurement of vascular calcified plaque, ultrasound imaging of carotid artery wall thickness, and electrocardiographic intervals. Subsequent studies have investigated the relationship between bone mineral density and vascular calcification, measures of adiposity, and biomarkers. Ongoing studies are carrying out an extensive evaluation of cerebrovascular disease using magnetic resonance imaging and cognitive assessment. A second, parallel study, the African American DHS, has expanded the sample of African Americans to investigate marked racial differences in subclinical CVD between European Americans and African Americans. Studies in development will evaluate the impact of social stress during the lifecourse on CVD risk, and the prevalence of gastroparesis in this diabetes enriched sample. In addition, the ongoing high mortality rate in DHS participants provides novel insights into the increased risks for type 2 diabetes affected individuals. A comprehensive genetic analysis of the sample is underway using the genome-wide association study (GWAS) approach. Data from this GWAS survey will complement prior family-based linkage data in the analysis of genetic contributors to the wide range of traits in the sample. To our knowledge the DHS family of studies has created the most comprehensively examined sample of individuals with type 2 diabetes yet available, and represents a unique resource for the study people with type 2 diabetes. The aim of this review is to provide a collective overview of the major results from the DHS family of studies, and relate them to the larger body of biomedical investigations of diabetes and its complications.

Association between coronary artery calcification progression and microalbuminuria: the MESA study

OBJECTIVES

This study sought to evaluate the relationship between microalbuminuria (MA) and the development and progression of atherosclerosis, as assessed by incident and progression of coronary artery calcification (CAC).

BACKGROUND

MA is associated with an increased risk of cardiovascular disease, but the mechanism by which MA imparts this increased risk is not known.

METHODS

The MESA (Multi-Ethnic Study of Atherosclerosis) study is a prospective cohort study of 6,814 self-identified White, African-American, Hispanic, or Chinese participants free of clinical cardiovascular disease at entry. Of the 6,775 individuals with available urine albumin data, we excluded 97 subjects with macroalbuminuria and 1,023 with missing follow-up CAC data. The final study population consists of 5,666 subjects.

RESULTS

At baseline, individuals with MA were more likely to have CAC >0 compared with those without MA (62% vs. 48%, p < 0.0001). During a mean follow-up of 2.4 +/- 0.8 years, those with MA and no CAC at baseline were more likely to develop CAC (relative risk [RR]: 2.05, 95% confidence interval [CI]: 1.41 to 3.02, p < 0.0001) as compared with those without MA in demographic-adjusted analyses. After multivariant adjustment, the relationship was attenuated but remained statistically significant (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005). Among those with CAC at baseline, those with versus those without MA had a 15 (95% CI: 8 to 22, p < 0.0001) volume units higher median increase in CAC in demographic-adjusted analyses. After multivariant adjustment, MA remained associated with incident CAC (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005) and with progression of CAC (median increase in CAC volume score of 9 [95% CI: 2 to 16, p = 0.009]), relative to those without MA.

CONCLUSIONS

This large multiethnic, population-based study of asymptomatic individuals demonstrates an increased risk of incident CAC as well as greater CAC progression among those with MA. Further study is needed to determine the degree to which MA precedes and predicts progression of atherosclerosis and how this information can be used to reduce cardiovascular events.

Reappraisal of the impact of race on survival in patients on dialysis

Racial differences in the cause, natural history, and effects of chronic kidney disease have long been the subject of investigation. Dialysis-dependent kidney failure occurs nearly 4 times more often in African Americans than European Americans. Despite this observation, studies repeatedly show that African Americans have a significant survival advantage after initiating dialysis therapy. Although this phenomenon has been attributed to environmental and socioeconomic factors, recent studies show that inherited factors strongly influence racial differences in the development of diverse kidney diseases and may affect the risk of nephropathy-associated cardiovascular disease. We review relevant studies and propose the hypothesis that inherited factors leading to organ-limited kidney diseases and a lower burden of systemic atherosclerosis contribute in part to the improved survival rates in African American patients on dialysis therapy.

The estimated GFR, but not the stage of diabetic nephropathy graded by the urinary albumin excretion, is associated with the carotid intima-media thickness in patients with type 2 diabetes mellitus: a cross-sectional study

Background

To study the relationship between the intima-media thickness (IMT) of the carotid artery and the stage of chronic kidney disease (CKD) based on the estimated glomerular filtration rate (eGFR) and diabetic nephropathy graded by the urinary albumin excretion (UAE) in the patients with type 2 diabetes mellitus.

Methods

A cross-sectional study was performed in 338 patients with type 2 diabetes mellitus. The carotid IMT was measured using an ultrasonographic examination.

Results

The mean carotid IMT was 1.06 ± 0.27 mm, and 42% of the subjects showed IMT thickening (≥ 1.1 mm). Cerebrovascular disease and coronary heart disease were frequent in the patients with IMT thickening. The carotid IMT elevated significantly with the stage progression of CKD (0.87 ± 0.19 mm in stage 1, 1.02 ± 0.26 mm in stage 2, 1.11 ± 0.26 mm in stage 3, and 1.11 ± 0.27 mm in stage 4+5). However, the IMT was not significantly different among the various stages of diabetic nephropathy. The IMT was significantly greater in the diabetic patients with hypertension compared to those without hypertension. The IMT positively correlated with the age, the duration of diabetes mellitus, and the brachial-ankle pulse wave velocities (baPWV), and negatively correlated with the eGFR. In a stepwise multivariate regression analysis, the eGFR and the baPWV were independently associated with the carotid IMT.

Conclusions

Our study is the first report showing a relationship between the carotid IMT and the renal parameters including eGFR and the stages of diabetic nephropathy with a confirmed association between the IMT and diabetic macroangiopathy. Our study further confirms the importance of intensive examinations for the early detection of atherosclerosis and positive treatments for hypertension, dyslipidaemia, obesity, as well as hyperglycaemia are necessary when a reduced eGFR is found in diabetic patients.

Potential effects of MYH9-associated nephropathy on dialysis and kidney transplant outcomes

Several related disorders comprise the spectrum of nonmuscle myosin heavy chain 9-associated (MYH9) nephropathy. The contribution of variants in this single MYH9 gene to ethnic differences in the incidence rates of end-stage renal disease is now clearly established. The importance of recognizing the role of MYH9 in these inherited kidney disorders goes beyond simple disease association; there may well be effects on clinical outcomes in patients on dialysis and after kidney transplantation. MYH9 polymorphisms may affect treatment outcomes in severe kidney disease and such gene effects are rarely encountered in practice.

Ethnic differences in the relationship between albuminuria and calcified atherosclerotic plaque: the African American-diabetes heart study

OBJECTIVE

Despite higher rates of nephropathy, calcified atherosclerotic plaque is less prevalent in African Americans with diabetes relative to European Americans. We explored ethnicity-specific relationships between albuminuria and calcified plaque involving the infrarenal aorta, coronary artery, and carotid artery in 835 European American and 393 African American subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Generalized estimating equations with exchangeable correlation and the sandwich estimator of the variance were used to test for association between the principal component of calcified plaque in the three vascular beds and urine albumin-to-creatinine ratio (ACR).

RESULTS

Mean +/- SD ages of African American and European American participants were 56.7 +/- 9.6 and 61.7 +/- 9.1 years, respectively, with diabetes duration of 10.4 +/- 7.4 and 10.0 +/- 7.3 years and median urine ACR of 17.5 and 13.4 mg/g. In African American and European American participants, respectively, median calcified plaque mass scores were 53.5 and 291 for coronary artery, 3 and 35.5 for carotid artery, and 761 and 3,237 for aorta. With adjustment for age, sex, glomerular filtration rate, and BMI, albuminuria was significantly associated with calcified plaque in European Americans (P = 3.4 x 10(-8)) but not in African Americans (P = 0.33), with significant ethnic interaction (P = 0.01). Ethnic differences in this relationship persisted after adjustment for blood pressure, smoking, lipids, and use of ACE inhibitors or angiotensin receptor blockers.

CONCLUSIONS

Albuminuria is strongly associated with severity of calcified plaque in European Americans with diabetes but not in African Americans. Disparities in this relationship may contribute to ethnic differences in the rates of cardiovascular disease that are observed in subjects with type 2 diabetes.

The role of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) as a prognostic marker in older people: the impact of reduced renal function

The N-terminal pro-brain natriuretic peptide (NT-pro-BNP) is released in response to volume expansion and/or increased tension on left ventricular myocytes. NT-pro-BNP is a useful diagnostic and prognostic biomarker both in patients with dyspnoea of unknown aetiology, and for risk assessment of patients with established heart failure. However, impaired kidney function – a common condition in older people as well as a strong risk factor for cardiovascular disease is associated with elevated circulating levels of NT-pro-BNP. Therefore, it is important to know the kidney function when interpreting an elevated NT-pro-BNP measurement obtained in older people in order to diagnose or stage congestive heart failure.

Association between atherosclerosis and newly classified chronic kidney disease stage for Japanese patients with type 2 diabetes

Using a new estimated glomerular filtration rate (eGFR) equation, we undertook a retrospective chart review to investigate the clinical significance of chronic kidney disease (CKD) stage for atherosclerosis in 653 Japanese patients with type 2 diabetes that were followed from January 2004 to December 2006 at Juntendo University Hospital. Diabetic patients with CKD stage 2 or 3 detected in 2004 or before had more history of cardiovascular disease (CVD) compared with those patients without CKD [ischemic heart disease (IHD): 25% vs. 9.3%, P<0.01 and stroke: 17.6% vs. 10.5%, P<0.05]. In Addition, the incidence of CVD through the observation period tended to increase with progression of CKD stage (0.9% in stage 0, 3.2% in stage 1 or 2, and 3.4% in stage > or =3, P=0.056), and patients with eGFR<75 had a higher incidence of IHD (2.5% vs. 0.3%) and IHD or Stroke (3.3% vs. 0.7%) compared with those who had eGFR > or =75. Patients with urinary albumin excretion rate (UACR) > or =20mg/g Cr also had a higher incidence of IHD or stroke compared to patients with UACR<20 (3.5% vs. 0.6%). In conclusion, diabetic patients with eGFR<75 and/or UACR > or =20 might be a high-risk population for CVD.

Nontraditional risk factors for cardiovascular disease in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) have a reduced lifespan, and a substantial proportion of these individuals die from cardiovascular disease. Although a large percentage of patients with CKD have traditional cardiac risk factors such as diabetes, hypertension and abnormalities in cholesterol, interventions to address these factors--which have significantly decreased cardiovascular mortality in the general population--have not shown such benefit in the CKD population. In addition, the severity and extent of cardiovascular complications in patients with CKD is disproportionate to the number and severity of traditional risk factors. This realization has focused attention on nontraditional cardiac risk factors that are particularly relevant to patients with CKD, including decreased hemoglobin levels, microalbuminuria, increased inflammation and oxidative stress, and abnormalities in bone and mineral metabolism. However, large prospective trials in patients with advanced CKD or in those requiring chronic dialysis have not shown that normalization of these nontraditional risk factors improves survival. Moreover, the mechanisms by which these nontraditional risk factors contribute to cardiovascular disease are unknown. Therefore, although current treatment of patients with CKD includes management of traditional and nontraditional risk factors, the value of modifying some nontraditional risk factors remains unclear.

Genetic epidemiology of subclinical cardiovascular disease in the diabetes heart study

A genome-wide linkage scan of 357 European American (EA) and 72 African American (AA) pedigrees multiplex for type 2 diabetes mellitus (T2DM) was performed with multipoint nonparametric QTL linkage analysis. Four subclinical measures of cardiovascular disease (CVD): coronary artery (CCP), carotid artery (CarCP), and abdominal aortic calcified plaque (AACP) and carotid artery intima-media thickness (IMT) were mapped. Analyses were adjusted for age, gender, body mass index, and (if appropriate) ethnicity and diabetes status. Evidence for linkage was observed in EA T2DM subjects to CarCP near 16p13 (LOD=4.39 at 8.4 cM; P = 0.00001). When all EA subjects were included, the LOD score was 2.52, suggesting an amplification of the linkage by diabetes. Linkage analysis of a principal components measure of vascular calcium (LOD = 3.85 at 9.3 cM on 16p in EA T2DM subjects) and bivariate analysis of CarCP X IMT (LOD = 3.77 at 9.3 cM on 16p in EA T2DM subjects) were consistent with this linkage. In addition, evidence for linkage was observed with CCP near D15S1515 (LOD = 2.34) in EAs. Additional loci on chromosomes 1, 2, 7, 10, 13, and 21 had LODs > 2.0. The identification of trait-determining polymorphisms underlying these linkages will help delineate risk factors for CVD in T2DM and the general population.

Relationship between albuminuria, low eGFR, and carotid atherosclerosis in Japanese women

In this cross-sectional study, we have investigated whether chronic kidney disease components were associated with carotid plaque and carotid intima-media thickening in women. Between April 2005 and May 2006, 830 women underwent general health screening including carotid ultrasonography and urinary albumin excretion, and were enrolled in the study. Of these individuals examined, 83 (10%) had albuminuria, 203 (24%) had low estimated GFR (eGFR), and 24 (3%) had both albuminuria and low eGFR. Univariate analysis showed that albuminuria, but not low eGFR, was associated with carotid plaque, and that both albuminuria and low eGFR were positively associated with carotid intima-media thickening. Age-adjusted logistic regression analysis showed that albuminuria was positively associated with carotid plaque with an odds ratio of 2.48 (95% CI 1.49-4.11, p < 0.001). On the other hand, association between albuminuria and carotid intima-media thickening was not statistically significant after age adjustment. Positive association between albuminuria and carotid plaque was present when either hypertension or high fasting glucose was absent. In conclusion, in Japanese women who underwent general health screening, albuminuria, but not low eGFR, was positively associated with carotid plaque.

The impact of the menopause on coronary artery calcification examined by multislice computed tomography scanning

BACKGROUND AND AIMS

To examine whether there is a difference in coronary artery calcification (CAC) scores between males and females aged above 50 years.

METHODS AND RESULTS

A total of 479 subjects aged between 40 and 70 years with no clinical or family history of cardiovascular disease (CVD) were enrolled for this study. All subjects were assessed by multislice CT scanning (MCTS), and the CAC scores obtained were assigned to one of four quartiles for further assessment and comparison. The main outcome evaluated was the percentage of high CAC scores and mean CAC scores, comparing males and females of different age groups. This study found that the percentage of high CAC scores increased markedly from 5% (40-49 age group) to 21.2% (50-59 age group) among females. The increase was significantly less when comparing males from different age groups (from 25% in the 40-49 age group to 31.2% in the 50-59 age group). Females had higher odds ratios (ORs) postmenopausally (4.3 in the 50-59 age group) than males in the same age group (1.6).

CONCLUSIONS

These initial findings seem to indicate that above 50 years of age, CAC is more dependent on age in females than in males, which might be due to the effect of the menopause.

Genome-wide linkage scans for renal function and albuminuria in Type 2 diabetes mellitus: the Diabetes Heart Study

AIMS/HYPOTHESIS

Glomerular filtration rate (GFR), end-stage renal disease and albuminuria are highly heritable. We performed a genome-wide linkage scan in 416 Diabetes Heart Study (DHS) families to detect loci that contributed to renal function and albuminuria.

MATERIALS AND METHODS

A total of 1067 individuals (900 with Type 2 diabetes mellitus) from 348 European American and 68 African American DHS families had measures of urine albumin : creatinine ratio (ACR), serum creatinine concentration and Modification of Diet in Renal Disease estimated GFR (eGFR). Variance components quantitative trait linkage analysis (using SOLAR) was computed.

RESULTS

Participants had mean +/- sd age 61.4 +/- 9.4 years; diabetes duration 10.5 +/- 7.4 years; eGFR 1.15 +/- 0.32 ml/sec; and urine ACR 15.8 +/- 67.2 mmol/l (median 1.4). In all families, significant evidence for linkage of GFR was observed on chromosome 2p16 (log of the odds; LOD = 4.31 at 72.0 cM, ATA47C04P/D2S1352) and 1p36 (LOD = 3.81 at 45.0 cM, D1S3669/D1S3720), with suggestive evidence on 7q21 (LOD = 2.42 at 99.0 cM, D7S820/D7S821) and 13q13 (LOD = 2.28 at 28.0 cM, D13S1493/D13S894). The evidence for linkage to ACR was far weaker, on 13q21-q22 (LOD = 1.84 at 50 cM, D13S1807/D13S800), 3p24-p23 (LOD = 1.81 at 58 cM, D3S3038/D3S2432) and 10p11 (LOD = 1.78 at 71.0 cM, D10S1208/D10S1221).

CONCLUSIONS/INTERPRETATIONS

The eGFR linkage peaks on 2p16, 7q21 and 13q13 closely overlap with nephropathy peaks identified in family studies enriched for severe kidney disease. These diabetes-enriched families provide an opportunity to map genes regulating renal function, potentially leading to the identification of genes producing nephropathy susceptibility in subjects with Type 2 diabetes.

Kidney volume associations with subclinical renal and cardiovascular disease: the Diabetes Heart Study

BACKGROUND

The prognostic significance of total kidney volume (TKV) in subjects with type 2 diabetes mellitus (T2DM) is unknown.

METHODS

One hundred and seventy unrelated Caucasians with T2DM underwent multidetector-row computed tomography of the neck, chest, and abdomen to measure calcified plaque in the coronary artery (CorCP), carotid artery (CarCP), and infrarenal aorta (AorCP). Spearman's rank correlation coefficients were used to assess associations between TKV and subclinical renal and cardiovascular disease. Partial correlation coefficients were computed to adjust for the potential confounding effects of age, sex, body mass index, glomerular filtration rate (GFR), diabetes duration, and hemoglobin A(1c). Values are expressed as mean +/- SD (median in parentheses).

RESULTS

The study group (51% female) had a mean age of 62.9 +/- 8.5 (62.3) years, a T2DM duration of 11.5 +/- 6.8 (10.0) years, a urinary albumin:creatinine ratio of 109.9 +/- 396 (17.6) mg/g, a GFR of 63.8 +/- 12.8 (63.2) ml/min, a TKV of 272.4 +/- 69.7 (261.9) cm(3), CorCP 2,170 +/- 3,394 (653), CarCP 374 +/- 673 (104), AorCP 14,569 +/- 17,480 (8,370), and a carotid artery intima-media thickness of 0.70 +/- 0.14 (0.68) mm. Adjusting for age, sex, body mass index, diabetes duration, GFR, and hemoglobin A(1c), the TKV was significantly associated with AorCP (r = 0.20, p = 0.016), but not with CorCP, CarCP, or carotid artery intima-media thickness (all p >or= 0.25). No significant associations were detected between TKV and blood pressure or albuminuria.

CONCLUSIONS

In Caucasians with T2DM, TKV and calcified atherosclerotic plaque in the infrarenal abdominal aorta are positively associated. Common mechanisms linking renal matrix deposition with aortic atherosclerosis may underlie this association and require further study.

Microalbuminuria and the metabolic syndrome and its components in the Chinese population

BACKGROUND

Microalbuminuria and the metabolic syndrome (MetS) have both been linked to chronic kidney disease and cardiovascular disease. This study investigated the association between urinary albumin-to-creatinine ratio (ACR) and MetS and its components.

MATERIALS AND METHODS

A total of 2311 subjects aged 40 years and over were recruited in 2004 in a metropolitan city in Taiwan. The biochemical indices, such as fasting glucose levels, urinary albumin, urinary creatinine and anthropometric indices, were measured. We defined microalbuminuria as a urinary ACR ranging from 30 to 300 mg g(-1) creatinine. MetS was defined using the American Heart Association and the National Heart, Lung and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF) definitions. The relationship between MetS and microalbuminuria was examined using multiple logistical regression analysis.

RESULTS

Subjects with microalbuminuria had higher age, body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose, triglycerides, total cholesterol (TCHOL)/high-density lipoprotein cholesterol (HDL-C) ratio, prevalence of diabetes mellitus and hypertension and lower HDL-C than subjects with normoalbuminuria. After adjusting for age and BMI, microalbuminuria was associated with the individual components of MetS, except in central obesity in women and elevated fasting glucose in men. After adjusting for age, BMI, smoking and alcohol consumption status, multiple logistical regressions revealed that microalbuminuria is strongly associated with MetS in both genders and according to both definitions. The odds ratio of having MetS using the AHA/NHLBI and IDF definition was 1.76 (1.16-2.67) and 1.73 (1.06-2.83) in men and 2.19 (1.38-3.50) and 2.09 (1.24-3.51) in women, respectively.

CONCLUSIONS

Microalbuminuria was strongly associated with MetS and its components. There is an increased likelihood of having MetS if subjects have microalbuminuria.

Mineral metabolism disturbances in patients with chronic kidney disease

BACKGROUND

Kidney disease, especially chronic kidney disease (CKD), is a worldwide public health problem with serious adverse health consequences for affected individuals. Secondary hyperparathyroidism, a disorder characterized by elevated serum parathyroid hormone levels, and alteration of calcium and phosphorus homeostasis are common metabolic complications of CKD that may impact cardiovascular health.

MATERIALS AND METHODS

Here, we systematically review published reports from recent observational studies and clinical trials that examine markers of altered mineral metabolism and clinical outcomes in patients with CKD.

RESULTS

Mineral metabolism disturbances begin early during the course of chronic kidney disease, and are associated with cardiovascular disease and mortality in observational studies. Vascular calcification is one plausible mechanism connecting renal-related mineral metabolism with cardiovascular risk. Individual therapies to correct mineral metabolism disturbances have been associated with clinical benefit in some observational studies; clinical trials directed at more comprehensive control of this problem are warranted.

CONCLUSIONS

There exists a potential to improve outcomes for patients with CKD through increased awareness of the Bone Metabolism and Disease guidelines set forth by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative. Future studies may include more aggressive therapy with a combination of agents that address vitamin D deficiency, parathyroid hormone and phosphorus excess, as well as novel agents that modulate circulating promoters and inhibitors of calcification.

Diabetic nephropathy: leveraging mouse genetics

PURPOSE OF REVIEW

Advances in mouse genetics have made this species particularly useful as a model for human disease. This review will summarize recent advances regarding the pathogenesis of diabetic nephropathy discovered in mice.

RECENT FINDINGS

Diabetic nephropathy has been characterized in novel genetic models of murine diabetes including the Akita, Ove26, and ICER-Igamma mice. Mutagenesis resources targeting every gene of the genome and the importance of inbred genetic background are discussed.

SUMMARY

Through the use of these resources mouse models should provide new insight into the pathogenesis of diabetic nephropathy, and complement human studies and validate the identity of candidate genes contributing to diabetic nephropathy.

Genetic determinants of the metabolic syndrome

Complex interactions between inherited factors and the environment determine an individual's susceptibility to type 2 diabetes mellitus and related syndromes. Insulin resistance, obesity, hypertension, and hyperlipidemia frequently precede the development of frank diabetes and aggregate in families. Several genome-wide scans have recently been performed in families with this constellation of findings, called the "metabolic syndrome." These analyses strongly support an inherited component to the syndrome. In this review, we provide an overview of the evidence in support of an inherited contribution to the metabolic syndrome and the search for causative genomic regions. When multiple genome scans involving different patient cohorts implicate a common genomic region as susceptible to the metabolic syndrome, it is highly likely that causative genes reside in that area. Identification of these genes will dramatically improve our understanding of the mechanisms that underlie the metabolic syndrome, and could lead to novel treatment strategies. It is hoped that these therapies will also prevent the future development of type 2 diabetes mellitus and atherosclerotic complications, both common among individuals affected by the metabolic syndrome.

Disordered Mineral Metabolism and Vascular Calcification in Nondialyzed Chronic Kidney Disease Patients

It is well established that abnormalities in mineral metabolism are apparent early in the course of chronic kidney disease (CKD) and result in clinically relevant consequences such as renal osteodystrophy. Furthermore, there is emerging evidence linking some of these abnormalities (hyperphosphatemia) to the high cardiovascular morbidity and mortality experienced by nondialyzed patients with CKD. Most studies have evaluated vascular calcification in patients with stage 5 CKD. Reports published over the last 2 years show that the process begins rather early in CKD and is particularly severe among elderly and type 2 diabetic patients. Furthermore, "calcium begets calcium", such that the calcification burden in early CKD is an important predictor of subsequent progression, including the rapid increase seen in stage 5 CKD. There is an increasing body of evidence that supports the thesis that elevated serum levels of phosphorus and calcium and deficiency of inhibitors of calcification (for example, fetuin-A) are important in the progression of vascular calcification in patients with end-stage renal disease. However, the concentrations of calcium and phosphorus shown to induce mineralization in cell culture studies are not observed in most patients until late in stage 4 or stage 5 CKD. Cross-sectional and longitudinal studies have also been unable to show a correlation between serum levels of markers of disordered mineral metabolism and severity of vascular calcification. Future studies should evaluate the pathogenetic role of phosphorus retention, which occurs early in the course of CKD, in the induction and/or progression of vascular calcification. Finally, there is a need to identify alternative pathogenetic mechanisms that may be important causes of the high calcification burden observed early in CKD.

The endothelin system and its antagonism in chronic kidney disease

The incidence of chronic kidney disease (CKD) is increasing worldwide. Cardiovascular disease (CVD) is strongly associated with CKD and constitutes one of its major causes of morbidity and mortality. Treatments that slow the progression of CKD and improve the cardiovascular risk profile of patients with CKD are needed. The endothelins (ET) are a family of related peptides, of which ET-1 is the most powerful endogenous vasoconstrictor and the predominant isoform in the cardiovascular and renal systems. The ET system has been widely implicated in both CVD and CKD. ET-1 contributes to the pathogenesis and maintenance of hypertension and arterial stiffness and more novel cardiovascular risk factors such as oxidative stress and inflammation. Through these, ET also contributes to endothelial dysfunction and atherosclerosis. By reversal of these effects, ET antagonists may reduce cardiovascular risk. In particular relation to the kidney, antagonism of the ET system may be of benefit in improving renal hemodynamics and reducing proteinuria. ET likely also is involved in progression of renal disease, and data are emerging to suggest a synergistic role for ET receptor antagonists with angiotensin-converting enzyme inhibitors in slowing CKD progression.

Hypertension and the Metabolic Syndrome

The cause of hypertension in the metabolic syndrome is complex and multifactorial and all of the elements of the metabolic syndrome, including obesity, insulin resistance, and the characteristic dyslipidemia probably are involved in mediating changes ultimately resulting in hypertension and modifying its course. Of these elements, obesity may play the most important and pivotal role in creating the conditions that lead to hypertension in the metabolic syndrome. This is not to say that the other elements of the syndrome are less important, and, as we gain more insight into the processes involved, we should be able to better manage the disease and tailor our therapeutic interventions appropriately.

The impact of ethnicity and sex on subclinical cardiovascular disease: the Diabetes Heart Study

AIMS/HYPOTHESIS

African-Americans with type 2 diabetes and access to adequate healthcare are at lower risk of clinical coronary artery disease than are white diabetic patients. We evaluated whether ethnic differences in subclinical cardiovascular disease, coronary and carotid artery calcified plaque and carotid artery intima-medial thickness (IMT) were present in members of The Diabetes Heart Study families.

SUBJECTS AND METHODS

In a bi-racial cohort of 1,180 individuals from families enriched for members with type 2 diabetes, we calculated coronary and carotid artery calcified plaque using fast-gated helical computed tomography, and measured carotid artery IMT and clinical risk factor profiles. Generalised estimating equations were used to test for an association between measures of subclinical cardiovascular disease and ethnicity and sex.

RESULTS

After adjustment for age, ethnicity and kidney function, African-Americans had significantly lower amounts of coronary artery calcified plaque (mean+/-SE) (866+/-158 vs 1,915+/-135, respectively; p=0.0466) and carotid artery calcified plaque (179+/-51 vs 355+/-27, respectively; p=0.0240) relative to whites, despite having increased carotid IMT (0.71+/-0.01 vs 0.67+/-0.004 cm, respectively; p=0.0007), and higher blood pressure, albuminuria and HbA1c. Sex-specific analyses revealed that African-American men had significantly lower coronary and carotid artery calcified atheroma than white men. In women, ethnic differences in calcified carotid artery plaque, but not coronary artery plaque, were observed.

CONCLUSIONS/INTERPRETATION

In families enriched for members with type 2 diabetes, African-American men had markedly lower levels of coronary and carotid artery calcified plaque than white men, despite increased carotid artery IMT and conventional risk factors. These findings suggest that susceptibility to subclinical cardiovascular disease differs markedly according to ethnicity and sex.