The association between atherosclerotic risk factors and renal function in the general population

Harnessing a simple ratiometric fluorescent probe for albumin recognition and beyond

A commercially available naphthalene fluorophore serves as a ratiometric indicator for albumin, showcasing its applications in albumin-based supramolecular recognition.

A microenvironment-sensitive red emissive probe with a large Stokes shift for specific recognition and quantification of serum albumin in complex biofluids and live cells

Human serum albumin (HSA) is regarded as a useful biomarker for rapid medical diagnosis of various disorders mainly related to the kidneys and liver. Hence, it is crucial to identify and monitor the HSA level in complex biofluids (urine and blood samples) using a simple approach. Herein, we have designed and synthesized an intramolecular charge transfer (ICT) based environment-sensitive fluorescent molecular probe, (E)-2-(3-(2-(5-methoxy-1H-indol-3-yl)vinyl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (DCI-MIN), that can selectively interact with HSA in PBS buffer solution and exhibit a ∼78-fold enhancement in fluorescence intensity with a significant Stokes shift (∼126 nm), which is important to avoid interference from the excitation light. The significant red fluorescence response can be attributed to the suppression of free intramolecular rotation of the DCI-MIN probe inside the hydrophobic binding cavity of HSA and the low polar microenvironment present within HSA. According to the 3σ/slope method, the detection limit was found to be 1.01 nM (0.0671 mg L-1) in aqueous solutions, which is significantly lower than the normal level of HSA in healthy urine and blood serum, indicating its high sensitivity. DCI-MIN has the ability to exhibit useful applications, including the detection and quantification of HSA concentration in complex biofluids (human urine and blood samples) as well as the imaging of serum albumin in living cells.

Rational design of a FA1-targeting anti-interference fluorescent probe for the point-of-care testing of albuminuria

Albuminuria is a crucial urine biomarker of human unhealthy events such as kidney diseases, cardiovascular diseases, and diabetes. However, the accurate diagnosis of albuminuria poses a significant challenge owing to the severe interference from urine fluorescence and urine drugs. Here, we report a novel flavone-based fluorescent probe, DMC, by incorporating the FA1-targeting methylquinazoline group into a flavone skeleton with the extend π-conjugation. DMC exhibited a rapid response time, high sensitivity, and selectivity towards human serum albumin (HSA) in urine. Moreover, the red-shifted fluorescence and the FA1-targeted HSA-binding of DMC efficiently mitigated the interference from both urine fluorescence and urine drug metabolites. Furthermore, the establishment of a portable testing system highlighted the potential for point-of-care testing, offering a user-friendly and accurate approach to diagnose A2-level and A3-level albuminuria. We expect that the success of this DMC-based diagnostic platform in real urine samples can signify a significant advancement in early clinical diagnosis of albuminuria and its associated diseases.

The Association of Smoking and Hyperuricemia with Renal Arteriolosclerosis in IgA Nephropathy

The combination effects of smoking (SMK) and hyperuricemia (HU) on renal arteriolosclerosis in patients with IgA nephropathy remain unknown. We examined the cross-sectional association between smoking (current or former) and renal arteriolar hyalinosis and wall thickening with or without HU [uric acid (UA) level ≥ 7 and ≥5 mg/dL in men and women] in 87 patients with IgA nephropathy who underwent renal biopsy. Arteriolar hyalinosis and wall thickening were assessed by the semiquantitative grading of arterioles. The SMK/HU subgroup showed the highest indices for hyalinosis and wall thickening, followed by the non-SMK/HU, SMK/non-HU, and non-SMK/non-HU subgroups. Multiple logistic analysis showed that SMK/HU, but not SMK/non-HU, was significantly associated with an increased risk of higher-grade renal arteriolar wall thickening. However, this did not occur with hyalinosis compared to non-SMK/non-HU. The adjusted odds ratio (95% confidence interval, p value) for SMK/HU was 12.8 (1.36-119, p < 0.05) for wall thickening. An association between SMK and renal arteriolar wall thickening might be prevalent only among patients with HU and in patients with IgA nephropathy. Further prospective studies are needed to determine whether patients with HU and SMK history exhibit rapid eGFR deterioration.

Novel insights in classic versus relative glomerular hyperfiltration and implications on pharmacotherapy

PURPOSE OF REVIEW

Glomerular filtration rate (GFR) assessment and its estimation (eGFR) is a long-lasting challenge in medicine and public health. Current eGFR formulae are indexed for standardized body surface area (BSA) of 1.73 m2, ignoring persons and populations wherein the ratio of BSA or metabolic rate to nephron number might be different, due to increased BSA, increased metabolic rate or reduced nephron number. These equations are based on creatinine, cystatin C or a combination of the two, which adds another confounder to eGFR assessment. Unusually high GFR values, also known as renal hyperfiltration, have not been well defined under these equations.

RECENT FINDINGS

Special conditions such as solitary kidney in kidney donors, high dietary protein intake, obesity and diabetes are often associated with renal hyperfiltration and amenable to errors in GFR estimation. In all hyperfiltration types, there is an increased intraglomerular pressure that can be physiologic, but its persistence over time is detrimental to glomerulus leading to progressive glomerular damage and renal fibrosis. Hyperfiltration might be underdiagnosed due to BSA standardization embedded in the formula. Hence, timely intervention is delayed. Reducing intraglomerular pressure in diabetes can be achieved by SGLT2 inhibitors or low protein diet to reverse the glomerulopathy process.

SUMMARY

Accurate identification of glomerular hyperfiltration as a pre-CKD condition needs accurate estimation of GFR in the above normal range should establish a threshold for timely intervention.

Rapid Point-of-Care Quantification of Human Serum Albumin in Urine Based on Ratiometric Fluorescence Signaling Driven by Intramolecular H-Bonding

Human serum albumin exerts multifunctions, such as maintaining the oncotic pressure of plasma, carrying hydrophobic molecules, and acting as the most important antioxidant in the blood. Lower serum albumin levels are linked to several cardiovascular diseases, and dysfunction of albumin reabsorption in the kidney is linked to liver disease, renal disorder, and diabetes. Albumin is thus a powerful diagnostic and prognostic marker; however, its quantification in urine by readily affordable tools is challenging owing to its very low concentration. To address this issue, we developed a ratiometric fluorescent probe with multiple advantages through a systematic structure variation of a benzocoumarin fluorophore and, further, a prototype of a smartphone-based point-of-care device. We determined albumin levels in urine and observed that a smoking person has notably higher urine albumin than a nonsmoking person. The cheap device provides a promising tool for albumin-associated disease diagnosis in communities with limited resources.

Population-Based Limits of Urine Creatinine Excretion

Introduction

The validity of a timed urine collection is typically judged by measurement of urine creatinine excretion, but prevailing limits may be unreliable. We sought to empirically derive population-based limits of excretion for evaluating the validity of a timed urine collection.

Methods

Covariate and 24-hour urine data were obtained from 3582 participants in the Chronic Renal Insufficiency Cohort (CRIC) study, 814 participants in the Modification of Diet in Renal Disease (MDRD) study, 1010 participants in the Jackson Heart Study (JHS), and 8536 participants in the Prevention of Renal Vascular End Stage Disease (PREVEND) study. Weight, height, age, sex, and serum creatinine concentrations were evaluated as potential predictors of urine creatinine excretion using Akaike Information Criteria, R-squared values, and deviance. Bias and precision of the fitted models were assessed by analyses of residuals. Agreement between 24-hour creatinine clearance and 125I-iothalamate clearance was assessed before and after exclusion of potentially invalid urine samples.

Results

A best-fitting model to predict 24-hour urine creatinine excretion among the 9199 discovery cohort members included sex-specific terms for weight, height, and age (R-squared = 0.328). This model had a median bias of +4.3 mg creatinine/day (95% confidence interval -5.6, +13.3 mg/day) in 4599 validation cohort members, and 82% of observed values were within 30% of predicted model. Serum creatinine concentrations only marginally improved model precision but reduced bias in persons with advanced chronic kidney disease (CKD).

Conclusion

The limits of urine creatinine excretion derived here represent the most valid and representative data for appraising the adequacy of a timed urine collection.

Randomized clinical trial to determine the effectiveness of CO-oximetry and anti-smoking brief advice in a cohort of kidney transplant patients who smoke

Background: measure the efficacy of exhaled carbon monoxide (CO) measurement plus brief advisory sessions to reduce smoking exposure and smoking behaviour in kidney transplant recipients. Methods: Randomized, controlled, open-label clinical trial at a Spanish hospital.Smoking kidney transplant recipients giving their consent to participate were randomized to control (brief advice, n=63) or intervention group (brief advisory session plus measuring exhaled CO, n=59). Measurements: Sociodemographic characteristics, cardiovascular risk factors, treatment, rejection episodes, infections, self-reported smoking, drug use, level of dependence and motivation to stop smoking (Fagerström's and Richmond's test) and stage of change (Prochaska and DiClemente's Stages). Efficacy was assessed at 3, 6, 9 and 12 months as: cotinine test, CO levels in exhaled air, nicotine dependence, motivational stages of change, motivation to stop smoking, pattern of tobacco use and smoking cessation rates. Logistic regression models were computed. Results: At 12 months of follow-up, differences were found in exhaled CO between the intervention and control group(6.1±6.8vs.10.2±9.7ppm;p=0.028). Carboxyhemoglobin levels were lower in the intervention group as well as the positive cotinine test (1.2±1.2%vs.2.0±2.4%;p=0.039),(53.4%vs.74.2%). At 12 months, intervention reduces the probability of a positive urine test by 28%. Conclusions: Co-oximetry is a clinically relevant intervention for reduction of tobacco exposure in kidney transplant recipients.

Glomerular Filtration Rate, its Association with Risk Factors and Cardiovascular Diseases. The Results of the ESSE-RF-2 Study

Aim. To study the influence of social determinants on the frequency of glomerular filtration rate (GFR) categories of various levels, as well as associations with a number of cardiovascular diseases (CVD) and cardiovascular risk factors among the population of four Russian regions included in the ESSE-RF-2.

Material and methods. The study was performed as part of a multicenter epidemiological study “Epidemiology of cardiovascular diseases in the regions of the Russian Federation. The second study (ESSE-RF-2)”. In total, 6681 people 25-64 years old from 4 regions of Russian Federation were included in the analysis. The CKD-EPI formula was used to calculate GFR by blood creatinine level. Groups with normal GFR (≥90 ml/min/1.73 m²), with an initial decrease in GFR (<90 ml/min/1.73 m²), and with a decrease in GFR (<60 ml/min/1.73 m²) were distinguished for statistical analysis. Generalized linear/nonlinear analysis (GLM) was used for multivariate assessment and adjustment of results to socio-demographic characteristics.

Results. The average GFR level in the total sample was 97.8±16.6 ml/min/1.73 m2 ; 29.0% of individuals had an initial decrease in GFR, 1.6% had a reduced GFR. Age was significantly associated with GFR. A statistically significant association with an initial decrease in GFR was found for: hypercholesterolemia (odds ratio [OR] 1.22; 95% clearance interval [95%CI] 1.14-1.30), hypertriglyceridemia (OR 1.09; 95%CI 1.02-1.17), hyperuricemia (OR 1.51; 95%CI 1.39-1.63), no smoking (OR 0.79; 95%CI 0.73-0.85), history of kidney disease (OR 1.13; 95%CI 1.04-1.22). A more pronounced decrease in GFR was associated with the following factors and diseases: arterial hypertension (OR 1.48; 95%CI 1.07-2.05), low level of high-density lipoproteins (OR 1.36; 95%CI 1.04-1.79), hypertriglyceridemia (OR 1.37; 95%CI 1.08-1.76), hyperuricemia (OR 2.49; 95%CI 1.97-3.16), hyperglycemia (OR 1.35; 95%CI 1.01-1.80), a history of myocardial infarction (OR 1.63; 95%CI 1.13-2.36) and kidney disease (OR 1.50; 95%CI 1.16-1.93).

Conclusion. The results of the study indicate a greater number of factors and diseases associated with low GFR compared with the initial decrease, which emphasizes the need for early detection of signs of chronic kidney disease, especially in the elderly, in people with metabolic syndrome, hypertension or diabetes mellitus, as well as a history of kidney disease.

Macronutrients, micronutrients intake and inflammation in hemodialysis patients

Inflammation in hemodialysis patients occurs since before undergoing hemodialysis. Inflammation is associated with an increase in oxidative stress. Hemodialysis patients are at risk for macronutrients and micronutrients deficiencies which can influence the increase in oxidative stress and inflammation. The purpose of this study was to evaluate the intake of micronutrients and inflammatory status in hemodialysis patients. This study was a cross-sectional study with 76 hemodialysis patients (40 male and 36 female) who attended in two hemodialysis centers of Kendal, Indonesia. After obtaining the written consent, then patients were interviewed food intake consisting of macronutrient and micronutrient intake. Macronutrient and micronutrient intake are obtained by the semi quantitative food frequency method and classified as a deficit (<100% adequacy level) and normal/ more (≥100% adequacy level), according to specific recommendations for individuals undergoing dialysis. Serum albumin was examined using the Brom Cresol Purple (BCP) method with a low category (<3.5 mg.dL-1) and normal (3.5 – 4.5 mg.dL-1). The hs-CRP serum was examined using the ELISA method and categorized as low (<1 mg.L-1), moderate (1 – 3 mg.L-1) and high (> 3 mg.L-1). A descriptive analysis was performed. The results of this study showed that 88.2% deficit energy intake, 84.2% deficit protein intake, 85.5% deficit of vitamin A intake, 85.5% deficit of vitamin C intake, 100% deficit of vitamin E intake, 98, 7% deficit zinc intake , 92.1% deficit copper intake. 63.2% subjects are low level of serum albumin and 61.8% subjects is high level of hs-CRP serum. Macronutrient and micronutrient intake in most hemodialysis patients shows deficit. The serum albumin of most hemodialysis patients shows low level. Serum hs-CRP most hemodialysis patients show high level.

Prevalence of and risk factors for chronic kidney disease of unknown aetiology in India: secondary data analysis of three population-based cross-sectional studies

OBJECTIVES

To assess whether chronic kidney disease of unknown aetiology (CKDu) is present in India and to identify risk factors for it using population-based data and standardised methods.

DESIGN

Secondary data analysis of three population-based cross-sectional studies conducted between 2010 and 2014.

SETTING

Urban and rural areas of Northern India (states of Delhi and Haryana) and Southern India (states of Tamil Nadu and Andhra Pradesh).

PARTICIPANTS

12 500 individuals without diabetes, hypertension or heavy proteinuria.

OUTCOME MEASURES

Mean estimated glomerular filtration rate (eGFR) and prevalence of eGFR below 60 mL/min per 1.73 m2 (eGFR <60) in individuals without diabetes, hypertension or heavy proteinuria (proxy definition of CKDu).

RESULTS

The mean eGFR was 105.0±17.8 mL/min per 1.73 m2. The prevalence of eGFR <60 was 1.6% (95% CI=1.4 to 1.7), but this figure varied markedly between areas, being highest in rural areas of Southern Indian (4.8% (3.8 to 5.8)). In Northern India, older age was the only risk factor associated with lower mean eGFR and eGFR <60 (regression coefficient (95% CI)=-0.94 (0.97 to 0.91); OR (95% CI)=1.10 (1.08 to 1.11)). In Southern India, risk factors for lower mean eGFR and eGFR <60, respectively, were residence in a rural area (-7.78 (-8.69 to -6.86); 4.95 (2.61 to 9.39)), older age (-0.90 (-0.93 to -0.86); 1.06 (1.04 to 1.08)) and less education (-0.94 (-1.32 to -0.56); 0.67 (0.50 to 0.90) for each 5 years at school).

CONCLUSIONS

CKDu is present in India and is not confined to Central America and Sri Lanka. Identified risk factors are consistent with risk factors previously reported for CKDu in Central America and Sri Lanka.

Predictive Value of Baseline High-Sensitivity C-Reactive Protein Level and Renal Function for Patients With Acute Coronary Syndrome Undergoing Aggressive Lipid-Lowering Therapy: A Subanalysis of HIJ-PROPER

The systematic inflammatory response might confound renal impairment, and both have been reported to affect clinical outcomes after acute coronary syndrome. We examined the impacts of the high-sensitivity C-reactive protein (hsCRP) level and estimated glomerular filtration rate level on the prognosis for acute coronary syndrome patients who underwent aggressive lipid-lowering therapy in contemporary practice. This was a subanalysis of the HIJ-PROPER study, and 1,734 patients were enrolled. Patients were divided into 4 groups using an hsCRP value of 10mg/L and an estimated glomerular filtration rate value of 60 ml/min/1.73 m² as the cut-off points. Groups were defined as follows: group A, low hsCRP and normal or mild renal impairment; group B, low hsCRP and renal impairment; group C, high hsCRP and normal or mild renal impairment; and group D, high hsCRP and renal impairment. The primary end point was defined as the composite of all-cause death, nonfatal myocardial infarction, nonfatal stroke, and unstable angina or coronary revascularizations. The median follow-up period was 3.9years, and the follow-up rate was 99%. Compared with group A, the 2 higher hsCRP groups (groups C and D) showed a significantly higher incidence of primary end points (hazard ratio 1.36, 95% confidence interval 1.12 to 1.65, p = 0.002; and hazard ratio 1.40, 95% CI 1.10 to 1.80, p = 0.008). Such a difference was not found compared with group B. In conclusion, patients with higher hsCRP levels had worse prognoses regardless of renal impairment and aggressive lipid-lowering therapy.

Mild Albuminuria Is a Risk Factor for Faster GFR Decline in the Nondiabetic Population

INTRODUCTION

A minimal increase in the albumin-to-creatinine ratio (ACR) predicts cardiovascular disease and mortality, but whether it predicts kidney function loss in nondiabetic persons is unclear. We investigated the association between ACR in the optimal or high-normal range and the rate of glomerular filtration rate (GFR) decline in a cohort from the general population without diabetes, cardiovascular, or chronic kidney disease.

METHODS

In the Renal Iohexol Clearance Survey, we measured GFR using iohexol clearance in 1567 middle-aged nondiabetic individuals with an ACR <3.40 mg/mmol (30.0 mg/g) at baseline. The ACR was measured in unfrozen morning urine samples collected on 3 days before the GFR measurements. A total of 1278 (81%) participants had follow-up with GFR measurements after a median of 5.6 years.

RESULTS

The median ACR at baseline was 0.22 mg/mmol (interquartile range: 0.10-0.51 mg/mmol), the mean ± SD GFR was 104.0 ± 20.1 ml/min, and the mean ± SD GFR decline rate was -0.95 ± 2.23 ml/min per year. Higher baseline ACR levels were associated with a steeper GFR decline in adjusted linear mixed models. Study participants with ACR levels of 0.11 to 0.45 and 0.46 ± 3.40 mg/mmol had a 0.25 ml/min per year (95% confidence interval [95% CI]: -0.03 to 0.53) and 0.31 ml/min per year (95% CI: 0.02-0.60) steeper rate of decline than those with ACR ≤0.10 mg/mmol in multivariable-adjusted analyses. Among study participants with an ACR of <1.13 mg/mmol (defined as the optimal range), those with an ACR of 0.11 to 1.12 mg/mmol (n = 812) had a 0.28 ml/min per year (95% CI: 0.04-0.52) steeper rate of GFR decline than those with an ACR of ≤0.10 mg/mmol (n = 655).

CONCLUSION

A mildly increased ACR is an independent risk factor for faster GFR decline in nondiabetic individuals.

The association between high-density lipoproteins and estimated glomerular filtration rate in patients without severe kidney disease

PURPOSE

Several studies investigated the association between the estimated glomerular filtration rate (eGFR) and the concentration of high-density lipoproteins (HDL) in patients without severely damaged kidney function. As results of those studies were inconclusive and contradictory, we wanted to investigate this association in multiple cardiovascular disease (CVD) risk patients without severe kidney disease or renal failure.

METHODS

We enrolled a cohort of 187 patients with intermediate and high CVD risk without severe renal disease. We grouped them based on their eGFR into: group 1 (≥ 30 < 60 ml/min/1.73 m²), group 2 (≥ 60 < 90 ml/min/1.73 m²) and group 3 (≥ 90 ml/min/1.73 m²). We analyzed the difference between their HDL levels and assessed the association of HDL and eGFR in three regression models with the following predictors: model 1 (age and gender), model 2 (model 1 plus smoking status, hs-CRP and diabetes mellitus) and model 3 (model 2 plus excessive weight and obesity, hypertension, hypercholesterolemia, hypertriglyceridemia, family history of CVD and medications they used).

RESULTS

Patients with the lowest eGFR had the lowest HDL values (P = 0.013). In multiple linear regression, HDL was an independent predictor of eGFR (β = 0.189, P = 0.025) which was also shown in multinomial regression for all three models: model 1 [odds ratio (OR) 0.05; 95% confidence interval (CI) 0.007-0.331; P = 0.002], model 2 (OR 0.052; 95% CI 0.006-0.428; P = 0.006) and model 3 (OR 0.2; 95% CI 0.001-0.309; P = 0.005).

CONCLUSIONS

Low HDL is an independent predictor of lower eGFR in intermediate and high CVD risk patients without severe kidney disease. In such patients, low HDL could be one of the early indicators of renal failure.

White-coat and masked hypertension are associated with albuminuria in a general population: the Hisayama Study

Epidemiological and clinical studies have investigated the influence of hypertension on chronic kidney disease (CKD), but limited data are available for the associations of white-coat hypertension (WCHT), masked hypertension (MHT) and sustained hypertension (SHT) with kidney dysfunction in general populations. We examined the associations of these types of hypertension with CKD (albuminuria and reduction in estimated glomerular filtration rate (eGFR)) in a cross-sectional survey of 2974 community-dwelling Japanese aged ⩾40 years. The types of hypertension were defined based on combined measurements of clinic and home blood pressures. Albuminuria was determined as urinary albumin-creatinine ratio (UACR) levels ⩾30.0 mg g^-1. The eGFR was calculated using the Japanese equation. The age- and sex-adjusted geometric mean of the UACR values was significantly higher in the subjects with WCHT (20.2 mg g^-1), MHT (19.6 mg g^-1) and SHT (31.6 mg g^-1) than in those with normotension (NT) (12.5 mg g^-1) (all P<0.001). Compared with NT, all types of hypertension were significantly associated with an increased likelihood of albuminuria (the age- and sex-adjusted prevalence of albuminuria; NT 14.1%, WCHT 26.3%, MHT 26.4% and SHT 43.3%; all P<0.001). These associations remained significant even after adjustment for other risk factors. However, the age- and sex-adjusted mean of eGFR and the prevalence of low eGFR (<60 ml min^-1 per 1.73 m²) did not differ between NT and the three hypertension types. The associations of the types of hypertension with the likelihood of CKD were similar to those for albuminuria. Our findings suggest that WCHT, MHT and SHT are associated with albuminuria in the general Japanese population.

Central obesity associates with renal hyperfiltration in the non-diabetic general population: a cross-sectional study

Background

Obesity is a risk factor for end-stage renal disease. Renal hyperfiltration, defined as an abnormally high glomerular filtration rate (GFR), is a link in the causal chain between diabetes and chronic kidney disease. Whether obesity is associated with hyperfiltration in the non-diabetic general population, remains unresolved due to a lack of consensus regarding the definition of hyperfiltration and the limited precision of high-range GFR estimations with creatinine and/or cystatin C.

Methods

1555 middle-aged participants without diabetes, renal or cardiovascular disease were enrolled from the general population in the Renal Iohexol Clearance Survey from the 6th Tromsø Study (RENIS-T6) between 2007 and 2009. Obesity was assessed using the body mass index (BMI), waist circumference (WC) and the waist-hip ratio (WHR). GFR was measured by iohexol clearance. Dichotomous variables for hyperfiltration were based on two alternative definitions using unadjusted GFR (mL/min) above the 90th percentile. The 90th percentile was age-, sex- and height-specific in one definition and age-, sex-, height- and weight-specific in the other.

Results

In multivariable adjusted logistic regression models, only WHR was consistently associated with hyperfiltration based on both definitions. For the definition based on the age-, sex-, height- and weight-specific 90th percentile, the association with the WHR (odds ratios (95 % confidence intervals)) for hyperfiltration was 1.48 (1.08–2.02) per 0.10 WHR increase.

Conclusions

Central obesity is associated with hyperfiltration in the general population. The WHR may serve as a better indicator of the renal effects of obesity than BMI or WC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0386-4) contains supplementary material, which is available to authorized users.

[Consensus document for the detection and management of chronic kidney disease]

La enfermedad renal crónica (ERC) es un importante problema de salud pública que puede afectar en sus diferentes estadios a cerca del 10% de la población española y que supone una elevada morbimortalidad, así como un importante consumo de recursos al Sistema Nacional de Salud. Diez sociedades científicas involucradas en el manejo del paciente renal nos hemos puesto de acuerdo para hacer una puesta al día del anterior documento de consenso sobre ERC de 2007. El presente es la edición abreviada del documento general extenso, que puede ser consultado en las páginas Web de cada una de las sociedades firmantes. Contiene los siguientes aspectos: definición, epidemiología y factores de riesgo de la ERC; criterios de diagnóstico, evaluación y estadificación de la ERC, albuminuria y estimación del filtrado glomerular; concepto y factores de progresión; criterios de derivación a nefrología; seguimiento del paciente, actitudes y objetivos por especialidad; prevención de la nefrotoxicidad; detección del daño cardiovascular; actitudes, estilo de vida y tratamiento: manejo de la hipertensión arterial, dislipidemia, hiperglucemia, tabaquismo, obesidad, hiperuricemia, anemia, alteraciones del metabolismo mineral y óseo; seguimiento coordinado por atención primaria-otras especialidades-nefrología; manejo del paciente en tratamiento renal sustitutivo, hemodiálisis, diálisis peritoneal y trasplante renal; tratamiento paliativo de la uremia terminal. Esperamos que sirva de gran ayuda en el manejo multidisciplinar del paciente con ERC, a la vista de las recomendaciones más actualizadas.

[Consensus document for the detection and management of chronic kidney disease]

Chronic kidney disease (CKD) is an important global health problem, involving to 10% of the Spanish population, promoting high morbidity and mortality for the patient and an elevate consumption of the total health resources for the National Health System. This is a summary of an executive consensus document of ten scientific societies involved in the care of the renal patient, that actualizes the consensus document published in 2007. The central extended document can be consulted in the web page of each society. The aspects included in the document are: Concept, epidemiology and risk factors for CKD. Diagnostic criteria, evaluation and stages of CKD, albuminuria and glomerular filtration rate estimation. Progression factors for renal damage. Patient remission criteria. Follow-up and objectives of each speciality control. Nephrotoxicity prevention. Cardio-vascular damage detection. Diet, life-style and treatment attitudes: hypertension, dyslipidaemia, hyperglycemia, smoking, obesity, hyperuricemia, anemia, mineral and bone disorders. Multidisciplinary management for Primary Care, other specialities and Nephrology. Integrated management of CKD patient in haemodialysis, peritoneal dialysis and renal transplant patients. Management of the uremic patient in palliative care. We hope that this document may be of help for the multidisciplinary management of CKD patients by summarizing the most updated recommendations.

Subclinical cardiovascular disease is associated with a high glomerular filtration rate in the nondiabetic general population

A reduced glomerular filtration rate (GFR) in chronic kidney disease is a risk factor for cardiovascular disease. However, evidence indicates that a high GFR may also be a cardiovascular risk factor. This issue remains unresolved due to a lack of longitudinal studies of manifest cardiovascular disease with precise GFR measurements. Here, we performed a cross-sectional study of the relationship between high GFR measured as iohexol clearance and subclinical cardiovascular disease in the Renal Iohexol Clearance Survey in Tromsø 6 (RENIS-T6), a representative sample of the middle-aged general population. A total of 1521 persons without cardiovascular disease, chronic kidney disease, diabetes, or micro- or macroalbuminuria were examined with carotid ultrasonography and electrocardiography. The GFR in the highest quartile was associated with an increased odds ratio of having total carotid plaque area greater than the median of non-zero values (odds ratio 1.56, 95% confidence interval 1.02-2.39) or electrocardiographic signs of left ventricular hypertrophy (odds ratio 1.62, 95% confidence interval 1.10-2.38) compared to the lowest quartile. The analyses were adjusted for cardiovascular risk factors, urinary albumin excretion, and fasting serum glucose. Thus, high GFR is associated with carotid atherosclerosis and left ventricular hypertrophy and should be investigated as a possible risk factor for manifest cardiovascular disease in longitudinal studies.

Estimating the glomerular filtration rate in the general population using different equations: effects on classification and association

BACKGROUND/AIMS

Several formulas for glomerular filtration rate (GFR) estimation, based on serum creatinine or cystatin C, have been proposed. We assessed the impact of some of these equations on estimated GFR (eGFR) and chronic kidney disease (CKD) prevalence, and on the association with cardiovascular risk factors, in a general population sample characterized by a young mean age.

METHODS

We studied 1,199 individuals from three Alpine villages enrolled into the MICROS study. eGFR was obtained with the 4- and 6-parameter MDRD study equations, the Virga equation, and with the three CKD-EPI formulas for creatinine, cystatin C, and the combination of creatinine and cystatin C. We assessed the concordance between quantitative eGFR levels, CKD prevalence, and in terms of association with total, LDL, and HDL cholesterol.

RESULTS

The highest and lowest eGFR levels corresponded to the cystatin C-based and MDRD-4 equations, respectively. CKD prevalence varied from 1.8% (Virga) to 5.8% (MDRD-4). The CKD-EPI based on creatinine showed the highest agreement with all other equations. Agreement between methods was higher at lower eGFR levels, older age, and in the presence of diabetes and hypertension. Creatinine-based estimates of eGFR were associated with total and low-density lipoprotein but not high-density lipoprotein cholesterol. The opposite was observed for the cystatin C-based GFR.

CONCLUSION

GFR estimation is strongly affected by the chosen equation. Differences are more pronounced in healthy and younger individuals. To identify CKD risk factors, the choice of the equation is of secondary importance to the choice of the biomarker used in the formula. If eGFR is not calibrated to a gold standard GFR in the general population, reports about CKD prevalence should be considered with caution.

The impact of pay for performance on the control of blood pressure in people with chronic kidney disease stage 3-5

BACKGROUND

The implementation of national estimated glomerular filatration rate reporting and the inclusion of renal-specific indicators in a primary care pay for performance (P4P) system since April 2006 has promoted identification and better management of risk factors related to chronic kidney disease (CKD). In the UK, the P4P framework is known as the Quality and Outcomes Framework (QOF). One of the key targets for intervention in primary care was hypertension. It is clear that hypertension is a major predictor of development and progression of CKD; thus, targeting better blood pressure control is likely to have a positive impact on outcomes in CKD. The aim of this study was to evaluate the effectiveness of renal indicators outlined in P4P on the management of hypertension in primary care. To estimate the cost implications of the resulting changes in prescribing patterns of antihypertensive medication following introduction of such indicators.

METHODS

We performed a prospective cohort study using a large primary care database. This cohort was taken from a database collated as part of a clinical decision support system used to assist the management of CKD in primary care. We investigated a total population of 90 250 individuals on general practitioner (GP) registers with a valid serum creatinine estimation in the 6-year study period. A total of 10 040 patients had confirmed stage 3-5 CKD in the 2 years pre-QOF and formed the study cohort. Patients were studied over three time periods, pre-QOF (1 April 2004 to 31 March 2006), 2 years post-QOF (1 April 2006 to 31 March 2008) and finally the two subsequent years (1 April 2008 to 31 March 2010). The mean systolic and diastolic blood pressures (BP) together with antihypertensive medication were analysed over the three time periods. Cost calculation was based on 2009 British National Formulary list prices for antihypertensives.

RESULTS

The mean age of the cohort at the start of the study period was 64.8 years, 55% were female. In those patients with stage 3-5 CKD 83.9% were hypertensive, defined by a pre-P4P BP of >140/85 or currently taking antihypertensive medication. The proportion of patients with CKD 3-5 attaining the BP target of 145/80 increased from 41.5% in the pre-QOF period to 50.0% in the post-QOF period. This increase was even more marked for those with hypertension in the pre-QOF period (28.8-45.1%). In the hypertensive patients, mean BP fell from 146/79 mmHg to 140/76 in the first 2 years post-P4P [P < 0.01, analysis of variance (ANOVA)]. This BP reduction was sustained in the last 2 years of the study, 139/75 (P < 0.01, ANOVA). The proportion of hypertensive patients taking angiotensin-converting enzyme inhibitors or angiotensin blockers increased, this was also sustained in the third time period. An increase in the prescribing of diuretics, calcium channel blockers and β-blockers was also observed. The additional cost of increased prescribing was calculated to be €25.00 per hypertensive patient based on GP prescription data.

CONCLUSIONS

Population BP control has improved since the introduction of P4P renal indicators, and this improvement has been sustained. This was associated with a significant increase in the use of antihypertensive medication, resulting in increased prescription cost. Longer-term follow-up will establish whether or not this translates to improved outcomes in terms of progression of CKD, cardiovascular disease and patient mortality.

Association between cystatin C and arteriosclerosis in the absence of chronic kidney disease

AIM

Chronic kidney disease (CKD) is a known risk factor for cardiovascular disease (CVD). Cystatin C was recently reported to be an endogenous surrogate of kidney function, and a high level of cystatin C is reported to be a strong predictor of CVD; however, the association between cystatin C and arteriosclerosis in a non-CKD population is unclear. This study aimed to clarify the association between cystatin C and arteriosclerosis in a non-CKD population.

METHODS

Of the 637 Japanese adults (264 men, 373 women) enrolled, we analyzed 446 participants with an estimated glomerular filtration rate (eGFR) >60 mL/min and no proteinuria (177 men, 269 women) without a history of CVD. Kidney function was evaluated according to serum cystatin C levels and eGFR. Arteriosclerosis was evaluated on the basis of the cardio-ankle vascular index (CAVI) and carotid intima-media thickness (CIMT).

RESULTS

The mean age of our subjects was 67.0±10.0 years. No variables showed any significant differences according to gender. The results of multiple linear regression analysis showed a significant correlation between serum cystatin C and CAVI only in women, but not CIMT.

CONCLUSION

We observed a significant correlation between cystatin C and CAVI, which is a marker of early-stage arteriosclerosis, in women in a non-CKD population with no proteinuria and eGFR>60 mL/min.

Association between younger age when first overweight and increased risk for CKD

There is little information on how the duration of overweight or obesity during life affects the risk for CKD. To investigate whether prolonged exposure to overweight during adult life increases the risk of later CKD in a cumulative manner, we analyzed data from the Medical Research Council National Survey of Health and Development, a socially stratified sample of 5362 singleton children born in 1 week in March 1946 in England, Scotland, and Wales. Multiple imputation expanded the analysis sample from the initial 1794 participants with complete data to 4584. This study collected self-reported body mass index (BMI) at ages 20 and 26 years and measured BMI at ages 36, 43, 53, and 60-64 years. The outcome of interest was CKD at age 60-64 years, suggested by estimated GFR (eGFR) <60 ml/min per 1.73 m(2) and/or urine albumin-to-creatinine ratio (UACR) ≥ 3.5 mg/mmol. In analyses adjusted for childhood and adulthood social class, first becoming overweight at younger ages was associated with higher odds of developing CKD by age 60-64 years. Compared with those who first became overweight at age 60-64 years or never became overweight, those first overweight at age 26 or 36 years had approximately double the odds of developing CKD. The strength of this association decreased with increasing age when first overweight (P for trend <0.001). These associations were consistent for creatinine-based eGFR, cystatin C-based eGFR, and UACR. Taken together, these results suggest that preventing overweight in early adulthood may have a considerable effect on the prevalence of CKD in the population.

Associations of estimated glomerular filtration rate and albuminuria with mortality and renal failure by sex: a meta-analysis

OBJECTIVE

To assess for the presence of a sex interaction in the associations of estimated glomerular filtration rate and albuminuria with all-cause mortality, cardiovascular mortality, and end stage renal disease.

DESIGN

Random effects meta-analysis using pooled individual participant data.

SETTING

46 cohorts from Europe, North and South America, Asia, and Australasia.

PARTICIPANTS

2,051,158 participants (54% women) from general population cohorts (n=1,861,052), high risk cohorts (n=151,494), and chronic kidney disease cohorts (n=38,612). Eligible cohorts (except chronic kidney disease cohorts) had at least 1000 participants, outcomes of either mortality or end stage renal disease of ≥ 50 events, and baseline measurements of estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology Collaboration equation (mL/min/1.73 m(2)) and urinary albumin-creatinine ratio (mg/g).

RESULTS

Risks of all-cause mortality and cardiovascular mortality were higher in men at all levels of estimated glomerular filtration rate and albumin-creatinine ratio. While higher risk was associated with lower estimated glomerular filtration rate and higher albumin-creatinine ratio in both sexes, the slope of the risk relationship for all-cause mortality and for cardiovascular mortality were steeper in women than in men. Compared with an estimated glomerular filtration rate of 95, the adjusted hazard ratio for all-cause mortality at estimated glomerular filtration rate 45 was 1.32 (95% CI 1.08 to 1.61) in women and 1.22 (1.00 to 1.48) in men (P(interaction)<0.01). Compared with a urinary albumin-creatinine ratio of 5, the adjusted hazard ratio for all-cause mortality at urinary albumin-creatinine ratio 30 was 1.69 (1.54 to 1.84) in women and 1.43 (1.31 to 1.57) in men (P(interaction)<0.01). Conversely, there was no evidence of a sex difference in associations of estimated glomerular filtration rate and urinary albumin-creatinine ratio with end stage renal disease risk.

CONCLUSIONS

Both sexes face increased risk of all-cause mortality, cardiovascular mortality, and end stage renal disease with lower estimated glomerular filtration rates and higher albuminuria. These findings were robust across a large global consortium.

Physical exercise, fasting glucose, and renal hyperfiltration in the general population: the Renal Iohexol Clearance Survey in Tromsø 6 (RENIS-T6)

BACKGROUND AND OBJECTIVES

Abnormally elevated GFR, or hyperfiltration, is a proposed mechanism for kidney injury in diabetes, prediabetes, and obesity. This study investigated whether lack of physical exercise is associated with hyperfiltration and whether exercise modifies the positive association between fasting glucose and measured GFR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Renal Iohexol Clearance Survey in Tromsø 6 measured GFR as single-sample plasma iohexol clearance in 1506 members of the general population (age 50-62 years) without diabetes, cardiovascular disease, or kidney disease. Leisure-time physical exercise was assessed by a self-administered questionnaire. Hyperfiltration was defined as GFR above the 90th percentile after adjustment for sex, age, weight, height, and use of renin-angiotensin system inhibitors.

RESULTS

High-intensity exercise was associated with lower adjusted odds of hyperfiltration in men (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.28-0.80) but not in women (OR, 1.02; 95% CI, 0.60-1.72). In both sexes, high-intensity exercise modified the association between fasting glucose and GFR. A fasting glucose level 1 mmol/L higher was associated with a GFR that was 7.3 (95% CI, 4.0-10.6) and 6.2 (95% CI, 3.4-9.0) ml/min per 1.73 m(2) higher in men and women who never exercised or exercised with low intensity. There was no association between fasting glucose and GFR in men and women who exercised with high intensity (interaction, P<0.001).

CONCLUSIONS

High-intensity exercise was associated with lower odds of hyperfiltration in men and modified the association between glucose and GFR of both sexes in a population without diabetes.

Variation in APOL1 Contributes to Ancestry-Level Differences in HDLc-Kidney Function Association

Low levels of high-density cholesterol (HDLc) accompany chronic kidney disease, but the association between HDLc and the estimated glomerular filtration rate (eGFR) in the general population is unclear. We investigated the HDLc-eGFR association in nondiabetic Han Chinese (HC, n = 1100), West Africans (WA, n = 1497), and African Americans (AA, n = 1539). There were significant differences by ancestry: HDLc was positively associated with eGFR in HC (β = 0.13, P < 0.0001), but negatively associated among African ancestry populations (WA: -0.19, P < 0.0001; AA: -0.09, P = 0.02). These differences were also seen in nationally-representative NHANES data (among European Americans: 0.09, P = 0.005; among African Americans -0.14, P = 0.03). To further explore the findings in African ancestry populations, we investigated the role of an African ancestry-specific nephropathy risk variant, rs73885319, in the gene encoding HDL-associated APOL1. Among AA, an inverse HDLc-eGFR association was observed only with the risk genotype (-0.38 versus 0.001; P = 0.03). This interaction was not seen in WA. In summary, counter to expectation, an inverse HDLc-eGFR association was observed among those of African ancestry. Given the APOL1 × HDLc interaction among AA, genetic factors may contribute to this paradoxical association. Notably, these findings suggest that the unexplained mechanism by which APOL1 affects kidney-disease risk may involve HDLc.

Relation of reduction in urinary albumin excretion to ten-year cardiovascular mortality in patients with type 2 diabetes and systemic hypertension

Microalbuminuria is one of the strongest predictors of both adverse renal and cardiovascular disease (CVD) outcomes in patients with type 2 diabetes mellitus. Although measurement of urinary albumin excretion (UAE) is widely recommended, limited data are available to suggest that reducing UAE translates into a reduction in long-term cardiovascular mortality, particularly among patients without overt nephropathy, who constitute most patients with type 2 diabetes worldwide. We assessed whether changes in the UAE at 1 year were associated with cardiovascular mortality in 393 patients with hypertension and type 2 diabetes during a 10-year period. On univariate analysis, CVD history, age, diabetes duration, and change in UAE at 1 year were associated with cardiovascular mortality risk (hazard ratio 2.60 for those with CVD history, 95% confidence interval [CI] 1.47 to 4.62; hazard ratio 1.59 per 10 years of diabetes duration, 95% CI 1.12 to 2.25; and hazard ratio 1.49 per log UAE increase, 95% CI 1.13 to 1.96). In a stepwise Cox regression model that included baseline UAE and CVD history, the 10-year predicted mortality of those with a decrease in UAE of 2 logs at 1 year was 4.7% (95% CI 1.4% to 7.8%). For those with an increase in UAE of 2 logs at 1 year, it was 24.5% (95% CI 10.1% to 36.5%). In conclusion, these data support current guideline recommendations to screen for UAE in all patients with type 2 diabetes, even in the absence of nephropathy, and suggest that serial UAE measurements even after the initiation of antihypertensive therapy has prognostic value independent of traditional cardiovascular risk factors.

Implications of proteinuria: CKD progression and cardiovascular outcomes

In this review, we summarize the evidence for the associations of proteinuria with incident CKD, progression of kidney disease, development of kidney failure, as well as the association with surrogates of cardiovascular disease (CVD), clinical cardiovascular outcomes, and all-cause mortality. Results reveal that proteinuria is a powerful and independent risk factor for kidney and cardiovascular outcomes, and that these relationships are independent of the level of glomerular filtration rate. Furthermore, these associations are true in populations at high, medium, and low risk for kidney disease progression and development of CVD. We show data which demonstrate that the associations with CVD are present even at levels of proteinuria below current cutoffs for microalbuminuria, and that changes in proteinuria may be a useful predictor of future outcomes. Finally, we provide some theories as to why proteinuria may be a risk factor for development of CVD.

Estimated GFR associates with cardiovascular risk factors independently of measured GFR

Estimation of the GFR (eGFR) using creatinine- or cystatin C-based equations is imperfect, especially when the true GFR is normal or near-normal. Modest reductions in eGFR from the normal range variably predict cardiovascular morbidity. If eGFR associates not only with measured GFR (mGFR) but also with cardiovascular risk factors, the effects of these non-GFR-related factors might bias the association between eGFR and outcome. To investigate these potential non-GFR-related associations between eGFR and cardiovascular risk factors, we measured GFR by iohexol clearance in a sample from the general population (age 50 to 62 years) without known cardiovascular disease, diabetes, or kidney disease. Even after adjustment for mGFR, eGFR associated with traditional cardiovascular risk factors in multiple regression analyses. More risk factors influenced cystatin C-based eGFR than creatinine-based eGFR, adjusted for mGFR, and some of the risk factors exhibited nonlinear effects in generalized additive models (P<0.05). These results suggest that eGFR, calculated using standard creatinine- or cystatin C-based equations, partially depends on factors other than the true GFR. Thus, estimates of cardiovascular risk associated with small changes in eGFR must be interpreted with caution.

The clinical significance of hyperfiltration in diabetes

Glomerular filtration rate is commonly elevated in early diabetes and patients with this symptom are arbitrarily considered to have hyperfiltration. The prevalence of hyperfiltration in type 1 diabetes varies from less than 25% to more than 75%. The corresponding figures in type 2 diabetes are significantly lower, ranging between 0% and more than 40%. Several factors, methodological and biological, may contribute to the wide variation in estimates of hyperfiltration prevalence. Methodological differences in measurement and evaluation of GFR apply in particular to the handling of plasma disappearance curves of filtration markers. Biological factors that may influence GFR in the hyperfiltration range include glycaemic control, diabetes duration, BMI, sex, pubertal status in type 1 diabetes and age in type 2 diabetes. Hyperglycaemia may influence GFR and albuminuria, and may therefore confound the evaluation of hyperfiltration as an independent risk factor for diabetic nephropathy. Adequate assessment of the relationship between glycaemic control, GFR and AER therefore requires serial measurements of all three variables followed by multivariate analysis. A recent meta-analysis of ten type 1 diabetes studies concluded that the presence of hyperfiltration at baseline more than doubled the risk of developing micro- or macroalbuminuria at follow-up. However, not all studies allowed for confounding factors or regression dilution bias. Future studies will therefore need to address the independent role of hyperfiltration, not only in the evolution of albuminuria, but also in the subsequent decline of GFR.

Lower HDL-C and apolipoprotein A-I are related to higher glomerular filtration rate in subjects without kidney disease

Animal experiments show that the kidney contributes to apolipoprotein (apo)A-I catabolism. We tested relationships of HDL cholesterol (HDL-C) and apo-I with kidney function in subjects without severe chronic kidney disease. Included was a random sample of the general population (part of the PREVEND cohort). Kidney function [estimated glomerular filtration rate (e-GFR) by two well-established equations and creatinine clearance], HDL-C, triglycerides, apoA-I and insulin resistance (HOMAir) were measured in 2,484 fasting subjects (e-GFR>or=45 ml/min/1.73 m2) without macroalbuminuria, cardiovascular disease, diabetes, or the use of anti-hypertensives and/or lipid-lowering agents. HDL-C (r=-0.056 to -0.102, P<0.01 to <0.001) and apo A-I (r=-0.096 to -0.126, P<0.001) were correlated inversely with both GFR estimates and creatinine clearance in univariate analyses. Multiple linear regression analyses also demonstrated inverse relationships of HDL-C and apoA-I with all measures of kidney function even after adjustment for age, sex, waist circumference, HOMAir, triglycerides, and urinary albumin excretion (P=0.053 to 0.004). In conclusion, HDL-C and apoA-I are inversely related to e-GFR and creatinine clearance in subjects without severely compromised kidney function, which fits the concept that the kidney contributes to apoA-I regulation in humans. High glomerular filtration rate may be an independent determinant of a pro-atherogenic lipoprotein profile.

“Does chronic kidney disease define a particular risk pattern of cerebral vessels modifications in patients with symptomatic ischemic cerebrovascular disease?”

Cardiovascular complications, including stroke, may be attributed the highest rate of morbidity and mortality in patients with chronic kidney disease (CKD). The aim of our study was to evaluate the prevalence of CKD in patients with symptomatic ischaemic cerebrovascular disease and to establish of whether CKD may define a particular risk pattern of cerebral vessels modifications in this category of patients. The prevalence of CKD was evaluated in 590 consecutive patients with symptomatic ischaemic cerebrovascular disease admitted to a department of neurology. The types of stroke, the vascular territories, the vascular modifications and the haemodynamic changes (resistance index- RI) found by neurosonology (extracranial and transcranial Doppler ultrasound) were analysed in relation to classic and non-classic cerebrovascular risk factors, as well as to stages of CKD (defined by estimated glomerular filtration rate-eGFR-MDRD4 formula-K/DOQI 2002). The prevalence of CKD in the studied patients was 70.84%. Atherosclerosis in a diffuse pattern was detected in 79.7% of CKD patients, while carotid artery stenoses were found in 10% of cases, occlusions- 5.3%, stenoses + occlusions-1.2%, and multiple stenoses- 3.8% of cases. The RI evaluated in the internal carotid arteries correlated with fibrinogen(P<0.0001) and GFR(P<0.0001), while IR in the middle cerebral arteries correlated with fibrinogen(P<0.05), C-reactive protein(P<0.0001), and GFR(P<0.0001). There is a strong relation between symptomatic cerebrovascular disease and CKD, a fact demonstrated by the increased prevalence of CKD in these patients and by the severity of the cerebral vessels lesions.

Microalbuminuria in Cerebrovascular Disease: A Modifiable Risk Factor?

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

Ultra-fast carotid CT-angiography: low versus standard volume contrast material protocol for a 128-slice CT-system

OBJECTIVES

Noninvasive imaging is increasingly accepted for the evaluation of atherosclerotic disease of the carotid arteries. We sought to evaluate the feasibility of a low-contrast media volume protocol for carotid computed tomography angiography (CTA) using a 128-slice-spiral-computed tomography scanner with a gantry rotation time of 300 milliseconds.

METHODS AND MATERIALS

Thirty consecutive patients underwent CTA for the evaluation of the carotid vessels, with a 128-section scanner. Fifteen patients were examined with a standard volume contrast injection protocol (group A): 80 mL of contrast material (CM) were injected at 5 mL/s using the test bolus method to assess individual transit time. Another 15 patients were examined with a low-volume contrast media protocol (group B): 30 mL CM were injected at 4 mL/s using bolus tracking to trigger the CTA acquisition. In both groups, contrast administration was followed by a saline flush. Image quality and segmental vascular enhancement as well as the presence and degree of arterial stenosis were independently evaluated by 2 radiologists. Venous enhancement and streak artifacts at the thoracic inlet because of highly concentrated CM in the subclavian veins were evaluated in both groups. Kappa statistic and Pearson correlation coefficient were used to quantify interobserver variability. Qualitative data were compared using the Wilcoxon signed rank test and student t test was used to investigate differences in segmental vessel attenuation.

RESULTS

All studies were of diagnostic quality in both groups. Interobserver agreement was high (kappa = 0.82, group A; kappa = 0.78, group B). Attenuation measurement showed excellent interobserver correlation in both groups (r > 0.9). Mean enhancement values were slightly higher in group A, but without statistical significance when averaged for all segments (P = 0.06). Streak artifacts impaired evaluation of 13 adjacent arterial segments in 8 patients at the level of the thoracic inlet in group A. In group B, only 1 segment was rated insufficient by both radiologists. Venous enhancement was significantly lower in group B (P = 0.04). The low-contrast protocol proved to be the more robust method with constant high arterial enhancement, less streak artifacts at the thoracic inlet, and less venous overlay.

CONCLUSION

Using the latest CT technology, optimal depiction of the craniocervical arteries can be archived with a low-volume (30 mL) CM protocol.

How should proteinuria be detected and measured?

Proteinuria is a classic sign of kidney disease and its presence carries powerful prognostic information. Although proteinuria testing is enshrined in clinical practice guidelines, there is surprising variation among such guidelines as to the definition of clinically significant proteinuria. There is also poor agreement as to whether proteinuria should be defined in terms of albumin or total protein loss, with a different approach being used to stratify diabetic and non-diabetic nephropathy. Further, the role of reagent strip devices in the detection and assessment of proteinuria is unclear. This review explores these issues in relation to recent national and international guidelines on chronic kidney disease (CKD) and epidemiological evidence linking proteinuria and clinical outcome. The authors argue that use of urinary albumin measurement as the front-line test for proteinuria detection offers the best chance of improving the sensitivity, quality and consistency of approach to the early detection and management of CKD.

The effect of ethnicity on the prevalence of diabetes and associated chronic kidney disease

BACKGROUND

The effect of ethnicity on the prevalence of diabetes mellitus (DM) and associated chronic kidney disease (CKD) is unknown.

AIM

To establish the impact of ethnicity on the prevalence and severity of diabetes mellitus and associated CKD.

DESIGN

Cross-sectional study of 34 359 adult diabetic patients in three primary care trusts in the UK.

METHODS

Read coded data from general practice computers was used to analyse the relationship between ethnicity, DM and CKD.

RESULTS

The prevalence of DM was 3.5% for Whites, 11% for South Asians and 8% for Black groups. The prevalence of CKD (stages 3-5) among diabetics was 18%. CKD stage 3 was more prevalent in Whites compared to South Asians--OR 0.79 (95% CI: 0.71-0.87) and Blacks--OR 0.49 (95% CI: 0.43-0.57). Among all CKD patients severity (CKD stages 4, 5) was associated with Black (OR 1.39, 95% CI: 1.06-1.81) and South Asian (OR 1.54, 95% CI: 1.26-1.88) ethnicity compared to Whites. Less than 50% of diabetics with CKD met the target blood pressure (BP) of 130/80 mmHg. The prevalence of a blood pressure > 150/90 mmHg in diabetics with CKD was South Asian 15.6%, White 13.9%, Black 21.8% (P < 0.001). Proteinuria was present in 8.6% of all diabetic patients. However, this increased to 18.6% in patients with CKD, and was more frequent in Black (22.6%) and South Asian (21%) patients compared to White patients (14.1%) (P < 0.001).

CONCLUSION

Significant disparities exist between the major ethnic groups in both disease prevalence and management. Future studies examining the management of CKD need to take variation by ethnicity into account.