Determinants of urinary albumin excretion within the normal range in patients with type 2 diabetes: the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study

Effect of gender on transition of normo- to microalbuminuria under angiotensin receptor blocker therapy in diabetes

Highlights In normoalbuminuric diabetic patients at low cardiovascular risk, the risk of transition from normo- to microalbuminuria is lower in women, despite the nonprotective effects of the angiotensin receptor blocker olmesartan. Additional methods of assessment of albuminuria in clinical studies (eg, measurements of albumin and creatinine excretion rate) should be implemented or the actually accepted higher urine albumin creatinine ratio (UACR) cutoff values for microalbuminuria in women reconsidered.

Novel Risk Factors for Progression of Diabetic and Nondiabetic CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Identification of novel risk factors for chronic kidney disease (CKD) progression may inform mechanistic investigations and improve identification of high-risk subgroups. The current study aimed to characterize CKD progression across levels of numerous risk factors and identify independent risk factors for CKD progression among those with and without diabetes.

STUDY DESIGN

The Chronic Renal Insufficiency Cohort (CRIC) Study is a prospective cohort study of adults with CKD conducted at 7 US clinical centers.

SETTING & PARTICIPANTS

Participants (N=3,379) had up to 12.3 years of follow-up; 47% had diabetes.

PREDICTORS

30 risk factors for CKD progression across sociodemographic, behavioral, clinical, and biochemical domains at baseline.

OUTCOMES

Study outcomes were estimated glomerular filtration rate (eGFR) slope and the composite of halving of eGFR or initiation of kidney replacement therapy.

ANALYTICAL APPROACH

Stepwise selection of independent risk factors was performed stratified by diabetes status using linear mixed-effects and Cox proportional hazards models.

RESULTS

Among those without and with diabetes, respectively, mean eGFR slope was-1.4±3.3 and-2.7±4.7mL/min/1.73m² per year. Among participants with diabetes, multivariable-adjusted hazard of the composite outcome was approximately 2-fold or greater with higher levels of the inflammatory chemokine CXCL12, the cardiac marker N-terminal pro-B-type natriuretic peptide (NT-proBNP), and the kidney injury marker urinary neutrophil gelatinase-associated lipocalin (NGAL). Among those without diabetes, low serum bicarbonate and higher high-sensitivity troponin T, NT-proBNP, and urinary NGAL levels were all significantly associated with a 1.5-fold or greater rate of the composite outcome.

LIMITATIONS

The observational study design precludes causal inference.

CONCLUSIONS

Strong associations for cardiac markers, plasma CXCL12, and urinary NGAL are comparable to that of systolic blood pressure≥140mm Hg, a well-established risk factor for CKD progression. This warrants further investigation into the potential mechanisms that these markers indicate and opportunities to use them to improve risk stratification.

Detection of Lower Albuminuria Levels and Early Development of Diabetic Kidney Disease Using an Artificial Intelligence-Based Rule Extraction Approach

The aim of the present study was to determine the lowest cut-off value for albuminuria levels, which can be used to detect diabetic kidney disease (DKD) using the urinary albumin-to-creatinine ratio (UACR). National Health and Nutrition Examination Survey (NHANES) data for US adults were used, and participants were classified as having diabetes or prediabetes based on a self-report and physiological measures. The study dataset comprised 942 diabetes and 524 prediabetes samples. This study clarified the significance of the lower albuminuria (UACR) levels, which can detect DKD, using an artificial intelligence-based rule extraction approach. The diagnostic rules (15 concrete rules) for both samples were extracted using a recursive-rule eXtraction (Re-RX) algorithm with continuous attributes (continuous Re-RX) to discriminate between prediabetes and diabetes datasets. Continuous Re-RX showed high test accuracy (77.56%) and a large area under the receiver operating characteristics curve (75%), which derived the two cut-off values (6.1 mg/g Cr and 71.00 mg/g Cr) for the lower albuminuria level in the UACR to detect early development of DKD. The early cut-off values for normoalbuminuria (NA) and microalbuminuria (MA) will be determined to help detect CKD and DKD, and to detect diabetes before MA develop and to prevent diabetic complications.

Clinical Trials on Diabetic Nephropathy: A Cross-Sectional Analysis

INTRODUCTION

Treatment options and decisions are often based on the results of clinical trials. We have evaluated the public availability of results from completed, registered phase III clinical trials on diabetic nephropathy and current treatment options.

METHODS

This was a cross-sectional analysis in which STrengthening the Reporting of OBservational studies in Epidemiology criteria were applied for design and analysis. In June 2017, 34 completed phase III clinical trials on diabetic nephropathy in the ClinicalTrials. gov registry were identified and matched to publications in the ClinicalTrials.gov registry and to those in the PubMed and Google Scholar databases. If no publication was identified, the principal investigator was contacted. The ratio of published and non-published studies was calculated. Various parameters, including study design, drugs, and comparators provided, were analyzed.

RESULTS

Drugs/supplements belonged to 26 different categories of medications, with the main ones being angiotensin-converting enzyme inhibitors, angiotensin-II receptors blockers, and dipeptidyl-peptidase-4-inhibitors. Among the trials completed before 2016 (n = 32), 22 (69%) were published, and ten (31%) remained unpublished. Thus, data on 11 different interventions and more than 1000 patients remained undisclosed. Mean time to publication was 26.5 months, which is longer than the time constrictions imposed by the U.S. Food and Drug Administration Amendments Act. Most trials only showed weak effects on micro- and macroalbuminuria, with an absolute risk reduction of 1.0 and 0.3%, respectively, and the number needed to treat varied between 91 and 333, without any relevant effect on end-stage-renal disease by intensive glucose-lowering treatment. Comparison of the results, however, was difficult since study design, interventions, and the renal outcome parameters vary greatly between the studies.

CONCLUSION

Despite the financial and human resources involved and the relevance for therapeutic guidelines and clinical decisions, about one-third of phase III clinical trials on diabetic nephropathy remain unpublished. Interventions used in published trials showed a low efficacy on renal outcome.

FUNDING

Deutsche Forschungsgemeinschaft (DFG): SFB 1118.

Renin angiotensin aldosterone inhibition in the treatment of cardiovascular disease

A collective century of discoveries establishes the importance of the renin angiotensin aldosterone system in maintaining blood pressure, fluid volume and electrolyte homeostasis via autocrine, paracrine and endocrine signaling. While research continues to yield new functions of angiotensin II and angiotensin-(1-7), the gap between basic research and clinical application of these new findings is widening. As data accumulates on the efficacy of angiotensin converting enzyme inhibitors and angiotensin II receptor blockers as drugs of fundamental importance in the treatment of cardiovascular and renal disorders, it is becoming apparent that the achieved clinical benefits is suboptimal and surprisingly no different than what can be achieved with other therapeutic interventions. We discuss this issue and summarize new pathways and mechanisms effecting the synthesis and actions of angiotensin II. The presence of renin-independent non-canonical pathways for angiotensin II production are largely unaffected by agents inhibiting renin angiotensin system activity. Hence, new efforts should be directed to develop drugs that can effectively block the synthesis and/or action of intracellular angiotensin II. Improved drug penetration into cardiac or renal sites of disease, inhibiting chymase the primary angiotensin II forming enzyme in the human heart, and/or inhibiting angiotensinogen synthesis would all be more effective strategies to inhibit the system. Additionally, given the role of angiotensin II in the maintenance of renal homeostatic mechanisms, any new inhibitor should possess greater selectivity of targeting pathogenic angiotensin II signaling processes and thereby limit inappropriate inhibition.

All Components of Metabolic Syndrome Are Associated with Microalbuminuria in a Chinese Population

BACKGROUND AND AIM

Albuminuria is a well-known predictor of poor renal and cardiovascular outcomes and associated with increased risk of all-cause mortality. The study aimed to evaluate the associations between metabolic characteristics and the presence of albuminuria.

METHODS

This cross-sectional study included 18,384 adult Chinese who participated in health examinations during 2013-2014. Differences in clinical characteristics were compared for microalbuminuria (MAU) and albuminuria, and between genders. Potential risk factors associated with the risk of developing MAU and albuminuria were analyzed using univariate logistic regression. Multiple logistic regression was applied to further identify the independent associations between different levels of risk factors and the presence of MAU and albuminuria. The area under the ROC curve (AUC) was used to determine the discriminatory ability of metabolic risk factors in detecting albuminuria.

RESULTS

There were significant gender differences in clinical characteristics according to albuminuria status. Risk for the presence of albuminuria was significantly associated with age, male gender, waist circumference (WC), waist-to-height ratio (WHtR), hypertension, fasting plasma glucose (FPG), and triglycerides to high-density lipoprotein cholesterol ratio (TG/HDL-C) in univariate logistic regression. Multiple logistic regression analysis indicated that the factors significantly associated with the presence of MAU were WC > 90cm, WHtR at 0.6-0.7, hypertension, FPG > 6.1 mmole/L, and TG/HDL-C ratio > 1.6. The optimal cutoffs for risk factors of metabolic syndrome (MetS) to predict albuminuria in males and females were: WC, 90.8 vs. 80.0 cm; WHtR, 0.53 vs. 0.52; MAP, 97.9 vs. 91.9 mmHg; FPG, 5.40 vs. 5.28 mmole/L; and TG/HDL-C, 1.13 vs. 1.08.

CONCLUSION

MetS and all its components were associated with the presence of MAU in a health check-up population in China. Gender specific and optimal cutoffs for MetS components associated with the presence of MAU were determined.

Assessment of oxidative stress and inflammation in prediabetes-A hospital based cross-sectional study

BACKGROUND AND AIM

Prediabetes is associated with dysglycemia, obesity, inflammation and endothelial dysfunction, contributing towards the pathogenesis of cardiovascular diseases rendering them vulnerable for the same. The current study intended to explore the risk of cardiovascular disease (CVD) related with prediabetes by assessing oxidative stress and inflammation using serum interleukin-6 (IL-6), myeloperoxidase (MPO) and urine microalbumin (MA) and their correlation with fasting plasma glucose (FPG) and physical measurements.

MATERIALS AND METHODS

Based on FPG values, 80 subjects were grouped into prediabetes and healthy controls. IL-6 and MPO were estimated in serum sample whereas MA was estimated in random urine sample.

RESULTS

Prediabetes group had significantly increased (p<0.05) mean anthropometric measurements and IL-6, MPO and MA as compared to healthy controls. MPO had significant correlation with FPG (r-0.388) in the prediabetes group. IL-6 and MPO showed a positive correlation with body mass index (BMI (r-0.339, r-0.327)), waist circumference (WC (r-484, r-0.493)) and waist-to-hip ratio (WHR (r-0.430, r-0.493)) while MA did not correlate with FPG and anthropometric measurements.

CONCLUSION

This study suggests that prediabetes is associated with central adiposity, inflammation and oxidative stress predisposing them to an increased risk for CVD.

Independent correlates of urinary albumin excretion within the normoalbuminuric range in patients with type 2 diabetes: The Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study

AIMS

Within the normoalbuminuric range, low albuminuria (LA, 10-29 mg/24 h) is associated with higher adverse cardiovascular and renal outcomes than normal albuminuria (NA, <10 mg/24 h). This cross-sectional analysis of the cohort from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study was aimed at assessing the independent correlates of LA versus NA in patients with type 2 diabetes.

METHODS

This analysis involved 11,538 normoalbuminuric patients (73.2 % of the entire RIACE cohort): 6023 (52.2 %) with NA and 5515 (47.8 %) with LA. Binary logistic regression analysis with backward conditional variable selection was applied to assess the independent correlates of LA versus NA.

RESULTS

Compared with NA subjects, LA patients were more frequently males, older and with family history of hypertension, had longer diabetes duration, lower HDL cholesterol, and higher haemoglobin (Hb) A1c, triglycerides, and blood pressure (BP), use of anti-hyperglycaemic and anti-hypertensive drugs, and prevalence of metabolic syndrome, retinopathy, chronic kidney disease, any cardiovascular disease, myocardial infarction, and coronary and peripheral events. Men with LA were also more frequently current or former smokers and had higher body mass index, waist circumference, and non-HDL cholesterol. Independent correlates of LA were age (OR 1.018), family history of hypertension (OR 1.321), smoking status (former, OR 1.158; current, OR 1.237), HbA1c (OR 1.062), waist circumference (OR 1.050), triglycerides (OR 1.001), and diastolic BP (OR 1.014), together with use of anti-hyperglycaemic and anti-hypertensive agents.

CONCLUSIONS

Several risk factors are associated with increased albuminuria within the normoalbuminuric range. As most of these factors are potentially modifiable, treating them aggressively might reduce the excess risk associated with LA.

TRIAL REGISTRATION

NCT00715481; www.ClinicalTrials.gov .

High-normal urinary albumin-to-creatinine ratio is independently associated with metabolic syndrome in Chinese patients with type 2 diabetes mellitus: A cross-sectional community-based study

Aims/Introduction

Microalbuminuria is positively related to metabolic syndrome (MetS). Our aim was to investigate whether urinary albumin-to-creatinine ratio (UACR) within the normal range is independently associated with MetS in Chinese community-based patients with type 2 diabetes.

Materials and Methods

A total of 514 participants (206 males and 308 females; mean age 66 years) with UACR less than 3.5 mg/mmol were enrolled from two downtown areas of Shanghai. The participants were stratified into quartiles according to UACR levels. The prevalence of MetS was assessed and compared among the four groups by binary logistic regression.

Results

Compared with participants with UACRs in the first quartile, the other quartiles had a higher prevalence of MetS (65.9%, 74.4% and 81.3%, respectively, P = 0.001) after adjustment for sex and age. After adjusting for potential confounders, participants in the second to the fourth quartile group had a 1.36-, 1.84- and 2.73-fold risk of MetS, respectively, relative to those in the lowest quartile. Furthermore, UACR, whether as quartile groups or as a continuous variable, is an independent predictor of MetS after fully adjusting for other variables.

Conclusions

These results suggest that UACR even within the normal range is independently associated with MetS in Chinese community-based patients with type 2 diabetes mellitus.

Normal range albuminuria and metabolic syndrome in South Korea: the 2011-2012 Korean National Health and Nutrition Examination Survey

Background

It is well-known that there is a close relationship between metabolic syndrome (MetS) and microalbuminuria. However, some recent studies have found that even normal range albuminuria was associated with MetS and cardiometabolic risk factors. The purpose of this study is to analyze the relationship between MetS and normal range albuminuria and to calculate the cutoff value for albuminuria that correlates with MetS in the representative fraction of Korean population.

Methods

Data were obtained from the 2011–2012 Korea National Health and Nutrition Examination Survey and included 9,650 subjects aged ≥19 years. We measured metabolic parameters: fasting blood glucose, waist circumference, blood pressure, and lipids, and albumin-to-creatinine ratio (ACR). The optimal ACR cutoff points for MetS were examined by the receiver operating characteristic curve. Multivariate logistic regression was used to obtain the prevalence of MetS and its components according to the ACR levels.

Results

The first cutoff value of ACR were 4.8 mg/g for subjects with ≥3 components of MetS. There was a graded association between ACR and prevalence of MetS and its components. If ACR was <4 mg/g, there was no significant increase in the prevalence of MetS or its components. From the ACR level of 4–5 mg/g, the prevalence of MetS significantly increased after adjusting for age, sex, body mass index, smoking, alcohol intake, exercise, and medications for diabetes mellitus and hypertension (odds ratio; 95% confidence intervals = 1.416; 1.041–1.926).

Conclusions

Albuminuria within the normal range (around 5 mg/g) was associated with prevalence of MetS in the Korean population.

Glycated peptides are associated with the variability of endothelial dysfunction in the cerebral vessels and the kidney in type 2 diabetes mellitus patients: a cross-sectional study

BACKGROUND

Diabetic atherosclerosis and microangiopathy parallel diabetic nephropathy. The aim of our study was to evaluate the pattern of endothelial dysfunction in two vascular territories, the kidney and the brain, both affected by diabetic vasculopathic complications. The endothelial variability was evaluated in relation to advanced glycation end-products modified peptides.

METHODS

Seventy patients with type 2 diabetes mellitus and 11 healthy subjects were assessed concerning urine albumin: creatinine ratio, plasma and urinary advanced glycation end-products, plasma asymmetric dimethyl-arginine, serum cystatin C, intima-media thickness in the common carotid arteries, the pulsatility index, the resistance index in the internal carotid arteries and the middle cerebral arteries, the cerebrovascular reactivity through the breath-holding test.

RESULTS

The breath-holding index correlated with asymmetric dimethyl-arginine (R²=0.151; p<0.001), plasma advanced glycation end-products (R²=0.173; p<0.001), C-reactive protein (R²=0.587; p<0.001), duration of diabetes mellitus (R²=0.146; p=0.001), cystatin C (R²=0.220; p<0.001), estimated glomerular filtration rate (R²=0.237; p=0.001). Urine albumin: creatinine ratio correlated with urinary advanced glycation end-products (R²=0.257; p<0.001), but not with asymmetric dimethyl-arginine (R²=0.029; p=0.147).

CONCLUSIONS

In type 2 diabetic patients endothelial dysfunction in the cerebral vessels appears to be dissociated from glomerular endothelial dysfunction in early diabetic nephropathy. Advanced glycation end-products could impact both the cerebral vessels and the glomerular endothelium.

Glycated peptides are associated with proximal tubule dysfunction in type 2 diabetes mellitus

BACKGROUND

Advanced glycation end-products have been involved in the pathogenesis of proximal tubule dysfunction which characterizes diabetic tubulopathy.

METHODS

A total of 76 Type 2 diabetes mellitus patients and 28 healthy controls were evaluated concerning a potential association of glycated peptides with proximal tubule dysfunction by assessing urine albumin:creatinine ratio, urinary alpha1-microglobulin, urinary neutrophil gelatinase-associated lipocalin, plasma and urinary advanced glycation end-products, plasma asymmetric dimethyl-arginine, serum cystatin C. Fully automated chip-nanoelectrospray ionization and high-capacity ion trap multistage mass spectrometry characterized the urinary proteomic profile.

RESULTS

The urinary glycated proteins displayed a molecular weight of 15,121.4 Da in normoalbuminuric patients and of 30,180.4 Da in microalbuminuric patients. Urinary alpha1-microglobulin and neutrophil gelatinase-associated lipocalin correlated with urinary advanced glycation end-products (R(2)=0.586; R(2)=0.415), urine albumin: creatinine ratio (R(2)=0.292; R(2)=0.116), estimated glomerular filtration rate (R(2)=0.172; R(2)=0.135), serum cystatin C (R(2)=0.146; R(2)=0.129), but not with asymmetric dimethyl-arginine. In multivariable regression analysis models, the correlations for urinary alpha1-microglobulin and neutrophil gelatinase-associated lipocalin remained significant with urine albumin: creatinine ratio, urinary advanced glycation end-products, estimated glomerular filtration rate (P<0.0001, R(2)=0.674; P<0.0001, R(2)=0.551; P<0.0001, R(2)=0.482).

CONCLUSIONS

In patients with Type 2 diabetes mellitus urinary glycated peptides are associated with proximal tubule dysfunction. The proteomic patterns of urinary glycated peptides could differentiate normo- from microalbuminuric patients and may explain a potential relation between the size and the glycation status of glycated peptides, and the extent of proximal tubule dysfunction. The lack of correlation between parameters of endothelial dysfunction and proximal tubule dysfunction cannot exclude glomerular involvement in early diabetic nephropathy.

Proximal tubule dysfunction is associated with podocyte damage biomarkers nephrin and vascular endothelial growth factor in type 2 diabetes mellitus patients: a cross-sectional study

BACKGROUND

There is an ongoing debate as to whether early diabetic nephropathy in Type 2 diabetes mellitus may be attributed to the glomerulus or to the proximal tubule. Urinary excretion of nephrin and vascular endothelial growth factor may increase even in the normoalbuminuria stage. In the course of diabetic nephropathy, the proximal tubule may be involved in the uptake of urinary nephrin and vascular endothelial growth factor.

MATERIALS AND METHODS

Two groups of consecutive Type 2 diabetes mellitus outpatients (38 normo-, 32 microalbuminuric) and 21 healthy subjects were enrolled in a cross-sectional study and evaluated concerning the relation of proximal tubule dysfunction with the podocyte biomarkers excretion, assessed by ELISA methods. The impact of advanced glycation end-products on this relation was also queried.

RESULTS

Urinary alpha1-microglobulin and kidney injury molecule-1 correlated with urinary albumin:creatinine ratio (R2 = 0.269; p < 0.001; R2 = 0.125; p < 0.001), nephrinuria (R2 = 0.529; p<0.001; R2 = 0.203; p < 0.001), urinary vascular endothelial growth factor (R2 = 0.709; p < 0.001; R2 = 0.360; p < 0.001), urinary advanced glycation end-products (R2 = 0.578; p < 0.001; R2 = 0.405; p < 0.001), serum cystatin C (R2 = 0.130; p < 0.001; R2 = 0.128; p<0.001), and glomerular filtration rate (R2 = 0.167; p < 0.001; R2 = 0.166; p < 0.001); nephrinuria and urinary vascular endothelial growth factor correlated with urinary albumin:creatinine ratio (R2 = 0.498; p < 0.001; R2 = 0.227; p<0.001), urinary advanced glycation end-products (R2 = 0.251; p < 0.001; R2 = 0.308; p < 0.001), serum cystatin C (R2 = 0.157; p < 0.001; R2 = 0.226; p < 0.001), and glomerular filtration rate (R2 = 0.087; p = 0.007; R2 = 0.218; p < 0.001).

CONCLUSIONS

In Type 2 diabetes mellitus there is an association of proximal tubule dysfunction with podocyte damage biomarkers, even in the normoalbuminuria stage. This observation suggests a potential role of the proximal tubule in urinary nephrin and urinary vascular endothelial growth factor processing in early diabetic nephropathy, a fact which could be related to advanced glycation end-products intervention. Podocyte damage and proximal tubule dysfunction biomarkers could be validated as a practical approach to the diagnosis of early diabetic nephropathy by further studies on larger cohorts.

Targeting nocturnal hypertension in type 2 diabetes mellitus

Several studies in different populations have suggested that nighttime blood pressure (BP) is a stronger predictor of cardiovascular events than daytime BP. Consequently, treatment strategies to target nighttime BP have come into focus. The aim of the present study was to investigate the effect of change of administration time of antihypertensive drugs. We included 41 patients with type 2 diabetes mellitus and nocturnal hypertension (nighttime systolic BP >120 mm Hg) in an open-label, crossover study. Patients were randomized to 8 weeks of either morning or bedtime administration of all of the individual's once-daily antihypertensive drugs, followed by 8 weeks of switched dosing regimen. Bedtime administration of antihypertensive drugs resulted in a significant reduction in nighttime (7.5 mm Hg; P<0.001) and 24-hour (3.1 mm Hg; P=0.014) systolic BP, with a nonsignificant reduction in daytime (1.3 mm Hg; P=0.336) systolic BP. We did not find morning BP surge to be different between dosing regimens. Levels of C-reactive protein were significantly lower with bedtime administration, which may indicate an effect on low-grade inflammation. We found no difference in urinary albumin excretion, regardless of albuminuria status. Urinary sodium/creatinine was significantly increased and urinary osmolality significantly reduced with bedtime administration, which can be interpreted as increased nocturnal natriuresis. In patients with type 2 diabetes mellitus and nocturnal hypertension, administration of once-daily antihypertensive drugs at bedtime may be favorable. The increased nocturnal natriuresis may reflect increased effect of bedtime-administered thiazides and renin-angiotensin system inhibitors, suggesting a potential mechanism of the observed effects on BP with chronotherapeutic intervention.

Genome-wide association study of urinary albumin excretion rate in patients with type 1 diabetes

AIMS/HYPOTHESIS

An abnormal urinary albumin excretion rate (AER) is often the first clinically detectable manifestation of diabetic nephropathy. Our aim was to estimate the heritability and to detect genetic variation associated with elevated AER in patients with type 1 diabetes.

METHODS

The discovery phase genome-wide association study (GWAS) included 1,925 patients with type 1 diabetes and with data on 24 h AER. AER was analysed as a continuous trait and the analysis was stratified by the use of antihypertensive medication. Signals with a p value <10(-4) were followed up in 3,750 additional patients with type 1 diabetes from seven studies.

RESULTS

The narrow-sense heritability, captured with our genotyping platform, was estimated to explain 27.3% of the total AER variability, and 37.6% after adjustment for covariates. In the discovery stage, five single nucleotide polymorphisms in the GLRA3 gene were strongly associated with albuminuria (p < 5 × 10(-8)). In the replication group, a nominally significant association (p = 0.035) was observed between albuminuria and rs1564939 in GLRA3, but this was in the opposite direction. Sequencing of the surrounding genetic region in 48 Finnish and 48 UK individuals supported the possibility that population-specific rare variants contribute to the synthetic association observed at the common variants in GLRA3. The strongest replication (p = 0.026) was obtained for rs2410601 between the PSD3 and SH2D4A genes. Pathway analysis highlighted natural killer cell mediated immunity processes.

CONCLUSIONS/INTERPRETATION

This study suggests novel pathways and molecular mechanisms for the pathogenesis of albuminuria in type 1 diabetes.

Microalbuminuria as a risk predictor in diabetes: the continuing saga

OBJECTIVE The rationale for this study was to review the data on microalbuminuria (MA), an amount of albumin in the urine of 30-299 mg/day, in patients with diabetes in the context of cardiovascular risk and development of kidney disease. The objective was to review the pathophysiology of MA in patients with diabetes and review the data from trials regarding MA in the context of risk for cardiovascular events or kidney disease progression. RESEARCH DESIGN AND METHODS Data sources were all PubMed-referenced articles in English-language peer-reviewed journals since 1964. Studies selected had to have a minimum 1-year follow-up and be either a randomized trial linking MA to cardiovascular or kidney disease outcome, a meta-analysis/systematic review, or a large observational cohort study. RESULTS The data suggest that MA is a risk marker for cardiovascular events and possibly for kidney disease development. Its presence alone, however, does not indicate established kidney disease, especially if the estimated glomerular filtration rate is >60 mL/min/1.73 m(2). An increase in MA, when blood pressure and other risk factors are controlled, portends a poor prognosis for kidney outcomes over time. Early in the course of diabetes, aggressive risk factor management focused on glycemic and blood pressure goals is important to delay kidney disease development and reduce cardiovascular risk. CONCLUSIONS MA is a marker of cardiovascular disease risk and should be monitored per guidelines once or twice a year for progression to macroalbuminuria and kidney disease development, especially if plasma glucose, lipids, and blood pressure are at guideline goals.

Proteinuria and its relation to cardiovascular disease

Chronic kidney disease (CKD) and its associated morbidity pose a worldwide health problem. As well as risk of endstage renal disease requiring renal replacement therapy, cardiovascular disease is the leading cause of premature death among the CKD population. Proteinuria is a marker of renal injury that can often be detected earlier than any tangible decline in glomerular filtration rate. As well as being a risk marker for decline in renal function, proteinuria is now widely accepted as an independent risk factor for cardiovascular morbidity and mortality. This review will address the prognostic implications of proteinuria in the general population as well as other specific disease states including diabetes, hypertension and heart failure. A variety of pathophysiological mechanisms that may underlie the relationship between renal and cardiovascular disease have been proposed, including insulin resistance, inflammation, and endothelial dysfunction. As proteinuria has evolved into a therapeutic target for cardiovascular risk reduction in the clinical setting we will also review therapeutic strategies that should be considered for patients with persistent proteinuria.

High-normal albuminuria predicts metabolic syndrome in middle-aged Korean men: a prospective cohort study

OBJECTIVE

High-normal albuminuria has recently been associated with an elevated risk of cardiovascular disease. However, it is uncertain whether high-normal albuminuria is associated with metabolic syndrome (MetS). The objective of this prospective cohort study was to investigate whether a temporal relationship exists between a high-normal urine albumin-to-creatinine ratio (UACR) and the development of MetS.

STUDY DESIGN

A total of 4338 healthy Korean men who had their UACRs and MetS components assessed in 2005 were enrolled in the study. A MetS-free cohort of 1364 individuals, who did not have any conditions that would have excluded them from the study, was followed up until 2010.

MAIN OUTCOME MEASURE

MetS was defined according to the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention.

RESULTS

Cox proportional hazards models were used to estimate the hazard ratio (HR) associated with normal UACR values stratified into following tertiles: <3.12 μg/mg, ≥3.12, <4.87 μg/mg, and ≥4.87 μg/mg. The UACR was categorised into the following tertiles. During 4470.6 person-years of follow-up, 247 incident cases of MetS developed between 2006 and 2010. The third UACR tertile was associated with the development of MetS after adjusting for multiple baseline covariates (HR 1.57; 95% confidence interval: 1.14-2.18).

CONCLUSIONS

On the basis of our 5-year follow-up study, a high-normal UACR predicts the development of MetS in Korean men.

ANGIOTENSIN II RECEPTOR ANTAGONISTS AND NEPHROPROTECTION: PLACE OF OLMESARTAN

The paper presents the results of experimental studies and clinical trials which demonstrate nephroprotective effects of olmesartan. 

Low-Grade Albuminuria Is Associated with Metabolic Syndrome and Its Components in Middle-Aged and Elderly Chinese Population

BACKGROUND

Micro-albuminuria has been well established as one of the risk factors of metabolic syndrome (MetS). However, the association of MetS and its components with low-grade albuminuria among those with normal urinary albumin excretion has not been clearly elucidated in Chinese population.

METHODOLOGY AND FINDINGS

A cross-sectional study was conducted among 9,579 participants with normal urinary albumin excretion, who were recruited from Jia Ding District, Shanghai, China. The single-void first morning urine sample was collected for urinary albumin and creatinine measurements, and urinary albumin-to-creatinine ratio (UACR) was calculated as urinary albumin divided by creatinine. Low-grade albuminuria was classified as sex-specific upper UACR quartile in this population. MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. The prevalence of MetS and its components increased across the UACR quartiles (all P trend <0.01). A multivariable adjusted logistic regression analysis revealed that the prevalence of MetS was gradually elevated according to the UACR quartiles (adjusted odds ratios [ORs] were 1.14, 1.24 and 1.59 for UACR quartiles 2, 3 and 4, compared with the lowest quartile; P trend<0.0001). In the further stratified logistic regression analyses, the associations between low-grade albuminuria and MetS were significant in both sex strata (male and female), both age strata (<60 and ≥60 years), both body mass index strata (<24 and ≥24 kg/m(2)), and both diabetes strata (yes and no). Compared to the lowest UACR quartile, the participants in the highest quartile of UACR had the highest prevalence of central obesity (OR = 1.43; 95%CI = 1.25-1.63), high blood pressure (OR = 1.64; 95%CI = 1.43-1.87), hyperglycemia (OR = 1.52; 95%CI = 1.30-1.78) and high triglycerides (OR = 1.19; 95%CI = 1.04-1.37).

CONCLUSIONS AND SIGNIFICANCE

Low-grade albuminuria was significantly associated with the increasing prevalence of MetS and its components in the middle-aged and elderly Chinese population with normal urinary albumin excretion.

Update on the ROADMAP clinical trial report: olmesartan for the prevention or delay of microalbuminuria development in type 2 diabetes

Albuminuria is associated with renal disease progression and cardiovascular disease development or cardiovascular complications in individuals at low, medium and high risk for these outcomes. Furthermore, in patients with vascular disease, changes in albuminuria independently predict mortality and cardiovascular and renal outcomes, and drug-induced lowering of albuminuria with the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers confers long-term cardiovascular and renal protection. However, few studies have directly examined whether these agents might also prevent the development of albuminuria and whether this translates into protection from cardiovascular disease events. The ROADMAP trial was conducted in an attempt to give answers to these questions. The results provide evidence that pharmacological blockade of angiotensin II receptors is effective in reducing the risk of new-onset albuminuria in type 2 diabetic patients. The study was not able to determine if this will also lead to a long-term reduction of cardiovascular morbidity and mortality.

Antihypertensive agents for preventing diabetic kidney disease

BACKGROUND

Various blood pressure-lowering agents, and particularly inhibitors of the renin-angiotensin system (RAS), are widely used for people with diabetes to prevent the onset of diabetic kidney disease (DKD) and adverse cardiovascular outcomes. This is an update of a Cochrane review first published in 2003 and updated in 2005.

OBJECTIVES

This systematic review aimed to assess the benefits and harms of blood pressure lowering agents in people with diabetes mellitus and a normal amount of albumin in the urine (normoalbuminuria).

SEARCH METHODS

In January 2011 we searched the Cochrane Renal Group's Specialised Register through contact with the Trials Search Co-ordinator.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any antihypertensive agent with placebo or another agent in hypertensive or normotensive patients with diabetes and no kidney disease (albumin excretion rate < 30 mg/d) were included.

DATA COLLECTION AND ANALYSIS

Two investigators independently extracted data on kidney and other patient-relevant outcomes (all-cause mortality and serious cardiovascular events), and assessed study quality. Analysis was by a random effects model was applied to analyse results which were expressed as risk ratio (RR) and 95% confidence intervals (CI).

MAIN RESULTS

We identified 26 studies that enrolling 61,264 participants. Angiotensin-converting enzyme inhibitors (ACEi) reduced the risk of new onset of microalbuminuria, macroalbuminuria or both when compared to placebo (8 studies, 11,906 patients: RR 0.71, 95% CI 0.56 to 0.89), with similar benefits in people with and without hypertension (P = 0.74), and when compared to calcium channel blockers (5 studies, 1253 participants: RR 0.60, 95% CI 0.42 to 0.85). ACEi reduced the risk of death when compared to placebo (6 studies, 11,350 participants: RR 0.84, 95% CI 0.73 to 0.97). No effect was observed for angiotensin receptor blockers (ARB) when compared to placebo for new microalbuminuria, macroalbuminuria or both (5 studies, 7653 participants: RR 0.90, 95% CI 0.68 to 1.19) or death (5 studies, 7653 participants: RR 1.12, 95% CI 0.88 to 1.41); however, meta-regression suggested possible benefits from ARB for preventing kidney disease in high risk patients. There was a trend towards benefit from use of combined ACEi and ARB for prevention of DKD compared with ACEi alone (2 studies, 4171 participants: RR 0.88, 95% CI 0.78 to 1.00).The risk of cough was significantly increased with ACEi when compared to placebo (6 studies, 11,791 patients: RR 1.84, 95% CI 1.24 to 2.72), however there was no significant difference in the risk of headache or hyperkalaemia. There was no significant difference in the risk of cough, headache or hyperkalaemia when ARB was to placebo. On average risk of bias was judged to be either low (27% to 69%) or unclear (i.e. no information available) (8% to 73%). Blinding of participants, incomplete outcome data and selective reporting were judged to be high in 23%, 31% and 31% of studies, respectively.

AUTHORS' CONCLUSIONS

ACEi were found to prevent new onset DKD and death in normoalbuminuric people with diabetes, and could therefore be used in this population. More data are needed to clarify the role of ARB and other drug classes in preventing DKD.

Resting heart rate and the risk of microvascular complications in patients with type 2 diabetes mellitus

Background

A higher resting heart rate is associated with an increased probability of cardiovascular complications and premature death in patients with type 2 diabetes mellitus. The impact of heart rate on the risk of developing microvascular complications, such as diabetic retinopathy and nephropathy, is, however, unknown. The present study tests the hypothesis that a higher resting heart rate is associated with an increased incidence and a greater progression of microvascular complications in patients with type 2 diabetes mellitus.

Methods and Results

The relation between baseline resting heart rate and the development of a major microvascular event was examined in 11 140 patients who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. Major microvascular events were defined as a composite of new or worsening nephropathy or new or worsening retinopathy. Patients with a higher baseline heart rate were at increased risk of a new major microvascular complication during follow-up (adjusted hazard ratio: 1.13 per 10 beats per minute; 95% confidence interval: 1.07–1.20; P<0.001). The excess hazard was evident for both nephropathy (adjusted hazard ratio: 1.16 per 10 beats per minute; 95% confidence interval: 1.08–1.25) and retinopathy (adjusted hazard ratio: 1.11 per 10 beats per minute; 95% confidence interval: 1.02–1.21).

Conclusion

Patients with type 2 diabetes mellitus who have a higher resting heart rate experience a greater incidence of new-onset or progressive nephropathy and retinopathy.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00145925. http://www.advance-trial.com/static/html/prehome/prehome.asp

Preventing cardiovascular events with angiotensin II receptor blockers: a closer look at telmisartan and valsartan

Angiotensin II receptor blockers (ARBs) inhibit the renin-angiotensin system. As a result, these agents provide beneficial effects in terms of cardiovascular (CV) and renal protection, independent of their blood pressure-lowering effects. Telmisartan and valsartan are the most intensively studied ARBs for the effects on CV outcomes. Randomized clinical trials assessing morbidity and mortality end points have included a range of patient types, including those with hypertension, hypertension with Type 2 diabetes, high CV risk without hypertension, ischemic heart disease, stroke and heart failure. Few head-to-head comparisons between telmisartan and valsartan have been performed. However, some blood pressure-independent properties of these two ARBs can be scrutinized from separate studies in the available literature.

L/N-type calcium channel blocker cilnidipine reduces plasma aldosterone, albuminuria, and urinary liver-type fatty acid binding protein in patients with chronic kidney disease

Cilnidipine inhibits both L- and N-type calcium channels and has been shown to dilate efferent arterioles as effectively as afferent arterioles. We conducted an open-label, randomized trial to compare the effects of cilnidipine against those of amlodipine on blood pressure (BP), albuminuria, and plasma aldosterone concentration in hypertensive patients with mild- to moderate-stage chronic kidney disease. Patients with BP ≥130/80 mmHg, an estimated glomerular filtration rate of 90-30 ml/min/1.73 m(2), and albuminuria ≥30 mg/g, despite treatment with the maximum recommended dose of angiotensin II receptor blockers, were randomly assigned to two groups. Patients received either 10 mg/day cilnidipine (increased to 20 mg/day; n = 35) or 2.5 mg/day amlodipine (increased to 5 mg/day; n = 35). After 48 weeks of treatment, a significant and comparable reduction in systolic and diastolic BP was observed in both groups. The percent reduction in the urinary albumin to creatinine ratio and liver-type fatty acid binding protein (L-FABP) in the cilnidipine group was significantly greater than in the amlodipine group. Although plasma renin activity did not differ between the two groups, the plasma aldosterone level was significantly decreased in the cilnidipine group. Cilnidipine therefore appears to reduce albuminuria, urinary L-FABP, and plasma aldosterone levels more than amlodipine, and these effects are independent of BP reduction.

Body Mass Index or Microalbuminuria, Which One is More Important for the Prediction and Prevention of Diastolic Dysfunction in Non-diabetic Hypertensive Patients?

BACKGROUND

Numerous studies have now demonstrated that heart failure with a normal ejection fraction (HFnlEF) is common. Hypertension is also the most commonly associated cardiac condition in patients with HFnlEF. Despite the observed link between microalbuminuria, obesity, and cardiovascular disorders, this question has remained - 'Which is more important for the prediction and prevention of diastolic dysfunction in non-diabetic hypertensive patients?'

METHODS

The current study was a cross-section study conducted on a total of 126 non-diabetic hypertensive patients screened to identify those with hypertension. Urine creatinine was measured by the picric acid method and urine albumin content was measured by a sensitive, nephelometric technique. The urinary albumin/creatinine ratio (UACR) was determined as an indicator of microalbuminuria. Complete two-dimensional, doppler, and tissue-doppler echocardiography was performed and the recording of the diastolic function parameters was carried out.

RESULTS

High body mass index and high systolic blood pressure were positively correlated with the appearance of left ventricular hypertrophy, whereas, the UACR index had no significant relationship with hypertrophy. Multivariable analysis also showed that advanced age and systolic blood pressure were significantly associated with the E/E annulus parameter.

CONCLUSION

According to our investigation obesity is more important than microalbuminuria for the prediction and prevention of diastolic dysfunction in non-diabetic hypertensive patients.

Early angiotensin-converting enzyme inhibition in Alport syndrome delays renal failure and improves life expectancy

Alport syndrome inevitably leads to end-stage renal disease and there are no therapies known to improve outcome. Here we determined whether angiotensin-converting enzyme inhibitors can delay time to dialysis and improve life expectancy in three generations of Alport families. Patients were categorized by renal function at the initiation of therapy and included 33 with hematuria or microalbuminuria, 115 with proteinuria, 26 with impaired renal function, and 109 untreated relatives. Patients were followed for a period whose mean duration exceeded two decades. Untreated relatives started dialysis at a median age of 22 years. Treatment of those with impaired renal function significantly delayed dialysis to a median age of 25, while treatment of those with proteinuria delayed dialysis to a median age of 40. Significantly, no patient with hematuria or microalbuminuria advanced to renal failure so far. Sibling pairs confirmed these results, showing that earlier therapy in younger patients significantly delayed dialysis by 13 years compared to later or no therapy in older siblings. Therapy significantly improved life expectancy beyond the median age of 55 years of the no-treatment cohort. Thus, Alport syndrome is treatable with angiotensin-converting enzyme inhibition to delay renal failure and therapy improves life expectancy in a time-dependent manner. This supports the need for early diagnosis and early nephroprotective therapy in oligosymptomatic patients.

Pioglitazone delays proximal tubule dysfunction and improves cerebral vessel endothelial dysfunction in normoalbuminuric people with type 2 diabetes mellitus

AIM

The renal and cerebral protective effects of pioglitazone were assessed in normoalbuminuric patients with type 2 diabetes mellitus (DM).

METHODS

A total of 68 normoalbuminuric type 2 DM patients were enrolled in a one-year open-label randomized controlled trial: 34 patients (pioglitazone-metformin) vs. 34 patients (glimepiride-metformin). All patients were assessed concerning urinary albumin: creatinine ratio (UACR), urinary alpha1-microglobulin, urinary beta2-microglobulin, plasma asymmetric dymethyl-arginine (ADMA), GFR, hsC-reactive protein, fibrinogen, HbA1c; pulsatility index, resistance index in the internal carotid artery and middle cerebral artery, intima-media thickness in the common carotid artery; cerebrovascular reactivity was evaluated through the breath-holding test.

RESULTS

At 1 year there were differences between groups regarding ADMA, urinary beta2-microglobulin, urinary alpha1-microglobulin, parameters of inflammation, serum creatinine, GFR, UACR, the cerebral haemodynamic indices. Significant correlations were found between alpha 1-microglobulin-UACR (R(2)=0.143; P=0.001) and GFR (R(2)=0.081; P=0.01); beta2-microglobulin-UACR (R(2)=0.241; P=0.0001) and GFR (R(2)=0.064; P=0.036); ADMA-GFR (R(2)=0.338; P=0.0001), parameters of inflammation, HbA1c, duration of DM, cerebral indices. There were no correlations between ADMA-UACR, urinary alpha1-microglobulin and beta2-microglobulin.

CONCLUSION

Proximal tubule (PT) dysfunction precedes albuminuria and is dissociated from endothelial dysfunction in patients with type 2 DM. Pioglitazone delays PT dysfunction and improves cerebral vessels endothelial dysfunction in normoalbuminuric patients with type 2 DM.

Circadian blood pressure variation in patients with type 2 diabetes--relationship to macro- and microvascular subclinical organ damage

AIMS

To explore the association between nocturnal blood pressure (BP) dipper status and macro- and microvascular organ damage in type 2 diabetes.

METHODS

Cross-sectional data from 663 patients with type 2 diabetes, aged 55-66 years, were analysed. Nurses measured office BP and ambulatory BP during 24h. Individuals with ≥ 10% difference in nocturnal systolic blood pressure (SBP) relative to daytime values were defined as dippers. Non-dippers were defined as <10% nocturnal decrease in SBP. Estimated glomerular filtration rate (GFR) was calculated and microalbuminuria was measured by albumin:creatinine ratio (ACR). Aortic pulse wave velocity (PWV) was measured with applanation tonometry over the carotid and femoral arteries.

RESULTS

We identified 433 dippers and 230 subjects with a nocturnal non-dipping pattern. Nocturnal SBP dipping was independently of office SBP associated with decreased PWV (p = 0.008), lower ACR (p = 0.001) and NT-proBNP (p = 0.001) and increased GFR (p<0.001).

CONCLUSIONS

We conclude that diurnal BP variation provides further information about early macro- and microvascular subclinical organ damage that goes beyond standardized office BP measurements in patients with type 2 diabetes.

Effects of olmesartan medoxomil, an angiotensin II type 1 receptor antagonist, on plasma concentration of B-type natriuretic peptide, in hypertensive patients with type 2 diabetes mellitus: a preliminary, observational, open-label study

BACKGROUND AND OBJECTIVE

Angiotensin II type 1 (AT1) receptor antagonists (angiotensin receptor blockers [ARBs]) are widely used for the treatment of not only hypertension but also cardiac dysfunction. B-type natriuretic peptide (BNP) is secreted mainly by the cardiac ventricle and plays an important role in the regulation of blood pressure (BP) and body fluid. It has been established that the plasma level of BNP is increased in patients with chronic heart failure in proportion to the severity of cardiac dysfunction. Because cardiac dysfunction is closely associated with a high risk of mortality in patients with diabetes mellitus, early identification and prevention of cardiac dysfunction are important. The objective of this study was to determine the effects of olmesartan medoxomil, a novel ARB, on the plasma level of BNP in hypertensive patients with type 2 diabetes.

METHODS

This was a preliminary, prospective, observational, open-label study. Sixty-eight type 2 diabetic patients with hypertension (systolic BP [SBP]≥140 mmHg or diastolic BP [DBP]≥90 mmHg) received olmesartan medoxomil 10–20 mg/day for 24 weeks. Plasma levels of BNP, as well as several clinical parameters of glycaemic control and lipid metabolism, were compared before and after 24 weeks of treatment. Another group consisting of 22 age- and body mass index-matched subjects not treated with olmesartan medoxomil was observed for reference purposes.

RESULTS

In the olmesartan medoxomil group, mean±SD SBP decreased from 152.8±16.4 at baseline to 146.8±14.4 mmHg after 24 weeks' treatment (p<0.05); similarly, mean±SD DBP decreased from 85.6±10.5 to 81.3±11.6 mmHg (p<0.05). In 53 subjects in whom plasma levels of BNP could be measured both before and after treatment, mean±SD BNP decreased from 41.3±49.9 to 32.5±36.3 pg/mL (p<0.05). Change in plasma BNP level over the 24-week treatment period in the olmesartan medoxomil group was not correlated with change in SBP or DBP. Multiple regression analysis revealed that change in plasma BNP level was not correlated with baseline value of or change in any other parameters. No other parameters in the olmesartan medoxomil group, and no parameters in the non-olmesartan medoxomil reference group, showed significant changes.

CONCLUSION

The current preliminary study showed that olmesartan medoxomil treatment might decrease plasma BNP levels, independent of its BP-lowering effect, in hypertensive patients with type 2 diabetes.

Which anthropometric parameter is best related with urinary albumin excretion and creatinine clearance in type 2 diabetes: body mass index, waist circumference, waist-to-hip ratio, or conicity index?

OBJECTIVE

We analyzed the relationships between body mass index (BMI), waist circumference (WC), waist-to-hip ratio, and conicity index and 24-hour urinary albumin excretion rate (UAER) and creatinine clearance.

DESIGN

Cross-sectional study.

SETTING

Patients presenting to a state hospital.

PATIENTS

Study involved patients with type 2 diabetes.

METHODS

Study participants underwent medical history examination, measurement of office blood pressure (BP), measurement of anthropometric factors and calculations (including BMI, WC, waist-to-hip ratio, and conicity index), physical examination, biochemical analysis, and 24-hour urine specimen collection to determine creatinine clearance and UAER.

RESULTS

In all, 202 patients with type 2 diabetes (male/female: 91/111, aged: 58.4 ± 10.1 years) were included. It was found that 24-hour UAER correlated with WC (rho: +0.176, P = .012), serum albumin (rho: -0.324, P < .0001), and systolic BP (rho: +0.153, P = .029), whereas creatinine clearance correlated with age (rho: -0.152, P = .031), BMI (rho: +0.191, P = .007), albumin level (rho: +0.365, P < .0001), and uric acid level (rho: -0.369, P < .0001). The stepwise linear regression analysis revealed that WC (P = .012), glycosylated hemoglobin (P = .018), and systolic BP (P = .043) were found to be independently related to logarithmically converted 24-hour UAER, whereas creatinine clearance was found to be related to duration of diabetes (P = .001), BMI (P = .008), presence of peripheral arterial disease (P = .021), fasting serum glucose level (P = .003), and uric acid level (P < .0001). However, after correction for body surface area, BMI was no longer associated with creatinine clearance.

CONCLUSION

Among the anthropometric parameters, only an increase in WC was found to be independently related to 24-hour UAER. Although BMI was associated with creatinine clearance, this association was lost after creatinine clearance was corrected for body surface area.

CUBN is a gene locus for albuminuria

Identification of genetic risk factors for albuminuria may alter strategies for early prevention of CKD progression, particularly among patients with diabetes. Little is known about the influence of common genetic variants on albuminuria in both general and diabetic populations. We performed a meta-analysis of data from 63,153 individuals of European ancestry with genotype information from genome-wide association studies (CKDGen Consortium) and from a large candidate gene study (CARe Consortium) to identify susceptibility loci for the quantitative trait urinary albumin-to-creatinine ratio (UACR) and the clinical diagnosis microalbuminuria. We identified an association between a missense variant (I2984V) in the CUBN gene, which encodes cubilin, and both UACR (P = 1.1 × 10(-11)) and microalbuminuria (P = 0.001). We observed similar associations among 6981 African Americans in the CARe Consortium. The associations between this variant and both UACR and microalbuminuria were significant in individuals of European ancestry regardless of diabetes status. Finally, this variant associated with a 41% increased risk for the development of persistent microalbuminuria during 20 years of follow-up among 1304 participants with type 1 diabetes in the prospective DCCT/EDIC Study. In summary, we identified a missense CUBN variant that associates with levels of albuminuria in both the general population and in individuals with diabetes.

Immune-related effects in hypertension and target-organ damage

PURPOSE OF REVIEW

Several studies published in the past three decades have suggested that inflammation and activation of immunity are central features in the pathogenesis of atherosclerosis, ischemic myocardial injury, and also in hypertension-induced target organ damage. A better understanding of this field could help us to explain the increased cardiovascular risk in patients with chronic inflammation.

RECENT FINDINGS

Recent studies have demonstrated that macrophages and various T-cell subtypes play a pivotal role in the regulation of blood pressure and target organ damage. Hypertensive stimuli such as the effector molecule of the renin-angiotensin system, angiotensin II, not only regulate vascular tone and sodium balance, but also activate immune cells and promote cell infiltration into target organs. Experimental and clinical evidence show that adaptive transfer of immune cells, rendering mice deficient for a certain subset of immune cells, or immunosuppressive treatment affects blood pressure and ameliorates target organ damage.

SUMMARY

The aim of this review is to summarize and discuss some of the more recent insights as to how immune cells might affect the regulation of blood pressure and the pathogenesis of hypertension-induced target organ damage.

Urinary albumin excretion is associated with nocturnal systolic blood pressure in resistant hypertensives

Microalbuminuria is a known marker of subclinical organ damage. Its prevalence is higher in patients with resistant hypertension than in subjects with blood pressure at goal. On the other hand, some patients with apparently well-controlled hypertension still have microalbuminuria. The current study aimed to determine the relationship between microalbuminuria and both office and 24-hour ambulatory blood pressure. A cohort of 356 patients (mean age 64 ± 11 years; 40.2% females) with resistant hypertension (blood pressure ≥ 140 and/or 90 mm Hg despite treatment with ≥ 3 drugs, diuretic included) were selected from Spanish hypertension units. Patients with estimated glomerular filtration rate <30 mL/min/1.73 m(2) were excluded. All patients underwent clinical and demographic evaluation, complete laboratory analyses, and good technical-quality 24-hour ambulatory blood pressure monitoring. Urinary albumin/creatinine ratio was averaged from 3 first-morning void urine samples. Microalbuminuria (urinary albumin/creatinine ratio ≥ 2.5 mg/mmol in males or ≥ 3.5 mg/mmol in females) was detected in 46.6%, and impaired renal function (estimated glomerular filtration rate <60 mL/min/1.73 m(2)) was detected in 26.8%. Bivariate analyses showed significant associations of microalbuminuria with older age, reduced estimated glomerular filtration rate, increased nighttime systolic blood pressure, and elevated daytime, nighttime, and 24-hour diastolic blood pressure. In a logistic regression analysis, after age and sex adjustment, elevated nighttime systolic blood pressure (multivariate odds ratio, 1.014 [95% CI, 1.001 to 1.026]; P=0.029) and reduced estimated glomerular filtration rate (multivariate odds ratio, 2.79 [95% CI, 1.57 to 4.96]; P=0.0005) were independently associated with the presence of microalbuminuria. We conclude that microalbuminuria is better associated with increased nighttime systolic blood pressure than with any other office and 24-hour ambulatory blood pressure monitoring parameters.

Renin inhibition and microalbuminuria development: meaningful predictor of kidney disease progression

PURPOSE OF REVIEW

Microalbuminuria is an indicator of increased cardiovascular disease risk. Herein, we review microalbuminuria as a predictor of the onset and progression of renal disease in people with and without diabetes. We evaluate the data on the use of direct renin inhibitors (DRIs) for treatment of hypertension with microalbuminuria.

RECENT FINDINGS

It is known that DRIs have an antiproteinuric effect, whether used alone or with an angiotensin receptor blocker (ARB), independent of its hypotensive effects in patients with type 2 diabetes. A current study will determine if adding the DRI aliskiren to an angiotensin-converting enzyme inhibitor (ACEi) or an ARB will reduce cardiovascular and renal risk in patients with type 2 diabetes.

SUMMARY

DRIs are the latest addition to the class of renin-angiotensin-aldosterone system (RAAS) inhibitors available for patients with hypertension and kidney disease. Whether these drugs can improve upon the reduction of cardiovascular and renal risk with an ACEi or an ARB is unknown. Microalbuminuria is a surrogate marker for both cardiovascular and possibly renal endpoints. However, an ongoing issue is that the majority of patients with microalbuminuria will die of cardiovascular events before the onset of end-stage renal disease, limiting the value of using longitudinal measures of microalbuminuria progression as a measure of therapeutic benefit with newer RAAS-blocking drugs such as DRIs.

Role of olmesartan in combination therapy in blood pressure control and vascular function

Angiotensin receptor blockers have emerged as a first-line therapy in the management of hypertension and hypertension-related comorbidities. Since national and international guidelines have stressed the need to control blood pressure to <140/90 mmHg in uncomplicated hypertension and <130/80 mmHg in those with associated comorbidities such as diabetes or chronic kidney disease, these goal blood pressures can only be achieved through combination therapy. Of several drugs that can be effectively combined to attain the recommended blood pressure goals, fixed-dose combinations of angiotensin receptor blockers and the calcium channel blocker amlodipine provide additive antihypertensive effects associated with a safe profile and increased adherence to therapy. In this article, we review the evidence regarding the beneficial effects of renin–angiotensin system blockade with olmesartan medoxomil and amlodipine in terms of blood pressure control and improvement of vascular function and target organ damage.