Microalbuminuria in the US population: third National Health and Nutrition Examination Survey

Reference values for urinary protein, albumin, beta 2-microglobulin, and the alpha 1-microglobulin-to-creatinine ratio in Japanese children

BACKGROUND

The importance of the ratio of creatinine to urinary protein, albumin, and low-molecular weight protein as a urinary marker in chronic kidney disease patients is widely recognized. However, no reference values have hitherto been established for these markers in Japanese children. The present study aimed to establish the reference values for these urinary markers in Japanese children.

METHODS

The first morning urine was randomly collected from 1712 pupils aged ≥ 3 to < 18 years during school and kindergarten mass urinary screenings. The upper limit of the reference values was set at the 97.5th percentile of the creatinine ratio per marker.

RESULTS

The urinary protein-to-creatinine ratio (PCR), urinary albumin-to-creatinine ratio (ACR), urinary beta 2-microglobulin-to-creatinine ratio (BMCR), and urinary alpha 1-microglobulin-to-creatinine ratio (AMCR) showed an age-related decrease at the 50th percentile reflecting an age-related increase in urinary creatinine. The appropriate reference value for the PCR and ACR was 0.12 g/gCr and 35 mg/gCr, respectively, in the entire cohort. The appropriate reference value for the BMCR was 0.5 μg /mgCr for age ≥ 3 to < 6 years and 0.35 μg/mgCr for age 6 years or older. The appropriate reference value for the AMCR was 5.0 μg/mgCr for age ≥ 3 to < 6 years and 3.5 μg /mgCr for age 6 years or older.

CONCLUSION

The present study was the first to determine appropriate reference values for the PCR, ACR, BMCR, and AMCR based on an analysis of the first morning urine samples of a large number of children.

The relationships between sediment findings and culture results and the presence of proteinuria in canine urine samples

OBJECTIVES

To assess relationships between urine sediment and microbial culture findings and the presence of proteinuria in canine urine samples, and to assess the change in the percentage of proteinuric samples and urine protein-to-creatinine ratio when urine abnormalities resolve.

MATERIALS AND METHODS

Canine urine samples collected via cystocentesis and submitted for culture and contemporaneous urinalysis (including urine protein-to-creatinine ratio) were retrospectively identified. Dogs receiving corticosteroids were excluded. Associations between haematuria (red blood cells>5/high-power field), pyuria (white blood cells>5/high-power field), presence of microorganisms on microscopy, active sediment, and positive culture and proteinuria (urine protein-to-creatinine ratio>0.5) were investigated. Patient characteristics were considered possible confounders. In dogs with repeat urinalysis, the associations between active sediment and positive culture resolution on proteinuria and urine protein-to-creatinine ratio were assessed.

RESULTS

One hundred and ninety-two of 491 samples were proteinuric (39.1%). Age was positively associated with proteinuria. In the multivariable analysis corrected for age, active sediment was the only variable significantly associated with proteinuria (adjusted odds ratio: 2.12; 95% confidence interval: 1.44 to 3.11); however, only 49.8% of samples with active sediment were proteinuric. Neither resolution of active sediment nor positive culture were associated with reduced proportions of proteinuric samples (from 57.9% to 42.1% and from 40.0% to 25.0%, respectively) or significant reductions in urine protein-to-creatinine ratio (median change: -0.16 and -0.14, respectively).

CLINICAL SIGNIFICANCE

Attributing proteinuria to urinalysis abnormalities or a positive urine culture in canine cystocentesis samples is not supported by our findings, and could result in alternative causes of proteinuria (e.g. renal proteinuria) being overlooked.

Albuminuria and markers for cardiovascular risk in 12-year-olds from the general Dutch population: a cross-sectional study

In adults, albuminuria represents a risk factor for cardiovascular disease and is associated with hypertension and obesity. Pediatric data from the general population are inconsistent and largely based on randomly collected urine. A possible association between antenatal programming and albuminuria at school age has still to be investigated. The purpose of this study is to assess albuminuria in first morning void urine samples in a population-based pediatric cohort and to investigate cross-sectionally the association with factors related to cardiovascular risk. Moreover, we investigate the possible association of antenatal factors with albuminuria. A first morning void urine sample was collected in the population-based GECKO (Groningen Expert Center for Kids with Obesity) Drenthe cohort at the age of 12 years. We investigated cross-sectionally associations between albuminuria and body mass index (BMI), waist circumference (WC), blood pressure (BP) and antenatal factors. The prevalence of UACR (urinary albumin-creatinine ratio) ≥ 3 mg/mmol was 3.3% (95%CI 2.3-4.2). In a multivariate linear regression model, UAC was negatively associated with z-BMI (β-0.08, p = 0.013) and positively with z-systolic BP (β 0.09, p = 0.006), model significance p = 0.002. UACR was negatively associated with z-BMI (β - 0.13, p < 0.001) and positively with z-diastolic BP (β 0.09, p = 0.003), model significance p = 0.001. Albuminuria was not significantly associated with antenatal factors such as gestational age and standardized birth weight.

CONCLUSIONS

 Albuminuria in first morning void urine in 12-year-olds has a lower prevalence than previously reported by randomly collected samples. A negative association between albuminuria and BMI is confirmed. A positive association with blood pressure, but no association with antenatal factors was found.

WHAT IS KNOWN

• While, in adults, albuminuria is a recognized risk factor for cardiovascular disease and is associated with hypertension and obesity, pediatric data are inconsistent and largely based on randomly collected urine. • A possible association between antenatal programming and albuminuria at school age has still to be investigated.

WHAT IS NEW

• In this population study on first morning void urine samples from 12-year-olds of the general population, albuminuria is negatively associated with body mass index, and positively associated with blood pressure, while there is no association with antenatal factors. • The prevalence of albuminuria at 12 years is lower than previously reported in studies based on randomly collected urine samples, probably due to elimination of orthostatic proteinuria.

Clinical Significance of Altered Vascular Morphology and Function in Normotension

PURPOSE OF REVIEW

To review current literature examining the presence of subclinical micro- and macrovascular alterations in normotensive individuals and their clinical significance in terms of hypertension prediction. Emphasis is placed on alterations that can be detected in peripheral vascular beds using non-invasive, easily applicable methodology, as these are in general easier to capture and evaluate in clinical practice compared to more complex invasive or functional tests.

RECENT FINDINGS

Arterial stiffness, increased carotid intima-media thickness, and altered retinal microvascular diameters predict the progression from the normotensive to the hypertensive state. By contrast, there is substantial lack of relevant prospective studies for skin microvascular alterations. Although conclusions regarding causality cannot be safely deduced from available studies, detection of morphological and functional vascular alterations in normotensive individuals emerges as a sensitive indicator of progression to hypertension and hence increased CVD risk. An increasing amount of evidence suggests that early detection of subclinical micro- and macrovascular alterations would be clinically useful for the early identification of individuals at high risk for future hypertension onset. Methodological issues and gaps in knowledge need to be addressed before detection of such changes could guide the development of strategies to prevent new-onset hypertension in normotensive individuals.

Do not forget the kidney in graves' disease

PURPOSE

To investigate the prevalence of microalbuminuria and factors associated with microalbuminuria in Graves' Disease (GD).

METHODS

This cross-sectional and single-center study included 99 patients with GD and 47 healthy controls (HC). Exclusion criteria such as active infection, uncontrolled diabetes, and chronic kidney disease were applied to the participants. The participants' clinical findings, comorbidities, drug use, laboratory tests, and thyroid antibody levels were recorded. Spot urine samples were collected and stored at - 80 ℃ to analyze the presence of microalbuminuria.

RESULTS

The prevalence of microalbuminuria in patients with GD was 12.1%. The median microalbumin/creatinine ratio in spot urine (UACR) in patients with GD (9.49 mg/g [5.09-18.10]) was higher than in the HC group (7.99 mg/g [3.48-12.88], p = 0.033). UACR was correlated with thyroid-stimulating hormone receptor antibody (TRAb), thyroid-stimulating hormone (TSH), and free triiodothyronine (FT3) levels (p = 0.020, p = 0.006, p = 0.009 respectively). In the regression analysis, only the relationship between TRAb level and UACR remained (p = 0.040).

CONCLUSION

This study demonstrates an increased prevalence of microalbuminuria in patients with GD. There was a significant correlation between microalbuminuria and TRAb level in patients with GD. This relationship suggests that one of the underlying mechanisms of microalbuminuria seen in patients with GD may be autoimmunity.

Longitudinal relationship between albuminuria in infancy and childhood

BACKGROUND

Mildly increased albuminuria is common in the general adult population and is a strong predictor for cardiovascular events, even in otherwise healthy individuals. The underlying pathophysiological process could be endothelial dysfunction. Previously, we reported that increased albuminuria can also be found in 2-year-olds from the general population. We hypothesized that some individuals have constitutionally higher levels of albuminuria, possibly as an expression of early or inborn endothelial dysfunction. The aim of this study is to evaluate longitudinal persistence of albuminuria from infancy into school age.

METHODS

In the population-based GECKO (Groningen Expert Center for Kids with Obesity) cohort, urine was collected from 816 children at the age of 2 years as well as 12 years (random urine and first morning void urine, respectively). We evaluated prevalence and persistence of increased albuminuria (UACR ≥ 3 mg/mmol) at the two time points.

RESULTS

The prevalence of UACR ≥ 3 mg/mmol at 2 and 12 years of age was 31.9% (95% CI 28.7-35.2) and 3.1% (95% CI 2.0-4.5), respectively. UACR < 3 mg/mmol at both 2 and 12 years of age was present in 540 children (66.2%). Only 9 children (3.5%) of the 260 children with an UACR ≥ 3 mg/mmol at 2 years had an UACR ≥ 3 mg/mmol at 12 years (p < 0.001).

CONCLUSION

Albuminuria in 2-year-olds does largely not persist until the age of 12, indicating that albuminuria at 2 years of age is not a marker for constitutional endothelial dysfunction in this cohort. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association between serum iron and liver transaminases based on a large adult women population

BACKGROUND

Studies are being focused on the potential roles of iron in various diseases, but remain unclear for the association between serum iron and liver injury, especially in adult women.

METHODS

Based on the National Health and Nutrition Examination Survey, we investigated the relationship between serum iron and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among 19,185 adult women.

RESULTS

Using weighted multivariate regression analyses, subgroup analyses, and threshold effect analyses, we found that serum iron was independently and positively correlated with ALT and AST. These associations differed in various age or race. Additionally, we found turning points in the curves of the relationship between serum iron and ALT in all women and the non-pregnant women. Using sensitivity analyses, we further found that the associations between serum iron and the liver transaminases remained positive in the non-pregnant women after adjusting for various covariates, but not in pregnant women. Besides, the positive associations between them kept present after excluding the women with high blood pressure, diabetes, and chronic kidney disease.

CONCLUSION

The present study indicated a positive association between serum iron and liver transaminases, indicating that serum iron may be a potential biomarker of liver function.

Urine alpha 1-microglobulin-to-creatinine ratio and beta 2-microglobulin-to-creatinine ratio for detecting CAKUT with kidney dysfunction in children

BACKGROUND

The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known.

METHODS

The present observational study analyzed data on children with CAKUT (stage 2-4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated.

RESULTS

In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/-, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3-4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data.

CONCLUSION

AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association between urinary albumin creatinine ratio and cardiovascular disease

INTRODUCTION

The association between microalbuminuria and cardiovascular disease (CVD) is accumulating in various patient populations. However, when stratified by sex, the relationship between microalbuminuria and CVD remains unclear.

METHOD

We obtained data from the 2011-2014 and 2019-2020 Korea National Health and Nutrition Examination Survey (KNHANES). Microalbuminuria was measured based on spot urine albumin-creatinine ratio (UACR). The Framingham risk score (FRS) model was implemented to evaluate the CVD risk. Linear and logistic regression models were used to identify the associations of microalbuminuria status with cardiometabolic predictors and CVD status determined by the FRS score.

RESULTS

Among 19,340 representative Korean participants, the (UACR) in Korean women and men with history of CVD was higher than in those without history of CVD. Among patients without history of CVD, multivariate regression analysis showed that a high UACR was related to older age, lower high-density lipoprotein cholesterol level, higher total cholesterol level, higher systolic blood pressure, higher prevalence of current smoking, higher prevalence of diabetes, and higher anti-hypertensive medication use in both women and men. The UACR showed a positive linear correlation with the Framingham risk score in both women and men.

CONCLUSION

The presence of microalbuminuria was significantly associated with the cardiometabolic risk factors and the increased risk of CVD evaluated by FRS model in both women and men in a nationally representative sample of Korea.

Homocysteine concentrations in overweight children and adolescents

OBJECTIVE

The aim of this study was to describe homocysteine concentrations in overweight and obese children and adolescents and relate them to blood pressure levels, renal function, and insulin resistance.

METHODS

This is a cross-sectional and observational study with 64 overweight children and adolescents (mean age: 11.6±3.5 years) in outpatient follow-up. The following parameters were evaluated: body mass index z-score, waist-to-height circumference ratio, pubertal stage, blood pressure, serum homocysteine, glycemia, insulin, lipid profile, renal function, high-sensitivity C-reactive protein, microalbuminuria, and creatinuria. Statistical analysis: analysis of variance and logistic regression (dependent variable: homocysteine) (p<0.05).

RESULTS

The mean body mass index z-score was 2.9±1.1. The mean homocysteine concentrations were 8.6±2.2 μmol/L (10th and 90th percentiles: 6.6 and 11.2 μmol/L, respectively), with no difference when compared with children with severe obesity and obesity/overweight (p=0.431). High values of waist-to-height ratio (93.8%), systolic blood pressure (18.8%), diastolic blood pressure (12.5%), glycemia (4.7%), low-density lipoprotein cholesterol (31.1%), triglycerides (35.9%), non-high-density lipoprotein cholesterol (34.4%), and microalbuminuria (21.9%) were obtained. The mean glomerular filtration rate was 122.9±24.6 mL/min/1.73 m². Homocysteine concentrations were not associated with any of the studied variables (R²=0.095).

CONCLUSION

Homocysteine concentrations in overweight children and adolescents (mean 8.6±2.2 μmol/L) were not associated with body mass index z-score, blood pressure, renal function, and insulin resistance.

The Effects of TRPC6 Knockout in Animal Models of Kidney Disease

Diseases that induce a loss of renal function affect a substantial portion of the world's population and can range from a slight decline in the glomerular filtration rate or microalbuminuria to complete kidney failure. Kidney disorders can be acute or chronic, but any significant reduction in renal function is associated with increased all-cause morbidity and mortality, especially when the conditions become chronic. There is an urgent need for new therapeutic approaches to slow or halt the progression of kidney disease. One potential target of considerable interest is the canonical transient receptor potential-6 (TRPC6) channel. TRCP6 is a cationic channel with a significant permeability to Ca2+. It is expressed in several tissues, including in multiple cell types of the kidney in glomeruli, microvasculature, and tubules. Here, we will describe TRPC6 channels and their roles in signal transduction, with an emphasis on renal cells, and the studies implicating TRPC6 channels in the progression of inherited and acquired kidney diseases. We then describe studies using TRPC6 knockout mice and rats subjected to treatments that model human diseases, including nephrotic syndromes, diabetic nephropathy, autoimmune glomerulonephritis, and acute kidney injuries induced by renal ischemia and by obstruction of the urinary tract. TRPC6 knockout has been shown to reduce glomerular manifestations of disease in several of these models and reduces renal fibrosis caused by urinary tract obstruction. TRPC6 knockout has proven to be less effective at reducing diabetic nephropathy in mouse and rat models. We also summarize the implications of these studies for drug development.

Tangled relationship between insulin resistance and microalbuminuria in children with obesity

Childhood obesity represents a complex disease with a well-known cardiometabolic burden including fatty liver, type 2 diabetes, metabolic syndrome, and cardiovascular disease. From a pathogenic point of view, insulin resistance (IR) represents the key factor underlying the spectrum of these obesity consequences. As observed in adults, recent data supported the occurrence of microalbuminuria (MA) as marker of early kidney dysfunction and its potential link with cardiometabolic factors also in children with obesity. In fact, a well-documented pathophysiological hypothesis both in adults and children supported an intimate correlation with the major feature of obesity such as IR through the influence of insulin on renal hemodynamics. Based on the clinical and prognostic relevance of this relationship in daily practice (including an increased risk of chronic kidney disease development overtime), more scientific attention needs to be paid to the evaluation of early kidney damage in children with obesity. In this paper, we attempt to address three debated questions regarding the intriguing liaison between IR and MA in children with obesity: (1) What is the prevalence of pediatric MA? (2) What is the state of art of MA in children with obesity? and (3) Is there a link between IR and MA in children with obesity?

The association between serum ferritin and blood pressure in adult women: a large cross-sectional study

BACKGROUND

Studies on the relationships between ferritin and blood pressure remain limited, especially in adult women. The aim of the present study was to investigate the associations between serum ferritin and blood pressure among adult women.

METHODS

Using the National Health and Nutrition Examination Survey, a cross-sectional study, including 5521 adult women, was performed. Weighted multivariate regressions, subgroup analyses, threshold effect analyses, and sensitivity analysis were used.

RESULTS

The authors found that serum ferritin was independently and positively correlated to diastolic blood pressure (DBP), and this positive correlation kept present among women who are 26-30 years old, non-pregnant women, Mexican American women, and women of other races in the subgroup analyses. Additionally, no significant association was found between serum ferritin and systolic blood pressure (SBP), except in women aged 26-30, Mexican American women, and women of other races. In pregnant women, the association between serum ferritin and SBP was an inverted U-shaped curve with an inflection point at 39.5 ng/mL.

CONCLUSIONS

The authors demonstrated that serum ferritin was positively correlated to DBP in adult women, which may provide a novel reference for clinical management.

High Normal Urinary Albumin-Creatinine Ratio Is Associated With Hypertension, Type 2 Diabetes Mellitus, HTN With T2DM, Dyslipidemia, and Cardiovascular Diseases in the Chinese Population: A Report From the REACTION Study

Background

Albuminuria has been widely considered a risk factor for cardiovascular diseases (CVDs), which is associated with hypertension (HTN), type 2 diabetes mellitus (T2DM), HTN with T2DM, and dyslipidemia. However, the associations between albuminuria and HTN, T2DM, HTN with T2DM, dyslipidemia, and CVDs are still unclear. Thus, this study aimed to explore the association of albuminuria thoroughly, especially within the normal range, with the abovementioned diseases in the Chinese population.

Methods

This study included 40,188 participants aged over 40 years from seven centers across China. Urinary albumin-creatinine ratio (UACR) was firstly divided into the ≥30-mg/g group, indicating kidney damage, and <30-mg/g group. Furthermore, UACR was divided into five groups: the <20%, 20%-39%, 40%-59%, 60%-79%, and ≥80% groups, according to the quintile division of participants within the normal range. Propensity score matching was used to reduce bias, and multiple logistic regression models were conducted to examine the association between UACR and HTN, T2DM, HTN with T2DM, dyslipidemia, and CVDs.

Results

Multivariable regression analysis revealed that UACR, even within the normal range, is significantly associated with HTN, T2DM, HTN with T2DM, dyslipidemia, and CVDs, and the association between UACR and HTN with T2DM was the most significant in model 3 even after adjusting for confounding factors (HTN: OR = 1.56 (95% CI = 1.45-1.68), p < 0.0001; T2DM: OR = 1.78 (95% CI = 1.60-1.97), p < 0.0001; HTN with T2DM: OR = 1.76 (95% CI = 1.59-1.95), p < 0.0001; dyslipidemia: OR = 1.08 (95% CI = 1.01-1.14), p = 0.0146; CVDs: OR = 1.12 (95% CI = 1.00-1.25), p = 0.0475). In the stratified analysis, high normal UACR was significantly associated with HTN, T2DM, HTN with T2DM, and dyslipidemia in subgroups.

Conclusions

In summary, we observe a higher prevalence of HTN, T2DM, HTN with T2DM, dyslipidemia, and CVDs in abnormal UACR and reveal a significant association of UACR, even within the normal range, with HTN, T2DM, HTN with T2DM, dyslipidemia, and CVDs.

Visceral adiposity index is closely associated with urinary albumin-creatinine ratio in the Chinese population with prediabetes

AIMS

Visceral obesity is a major health issue and is a risk factor for an atherogenic state. Visceral obesity has been reported to be a crucial link between albuminuria and cardiovascular diseases (CVD). This study attempted to explore the association between visceral obesity and albuminuria in prediabetic individuals.

METHODS

This cross-sectional study included 24871 prediabetic participants over 40 years of age from seven centres across China (REACTION study). The visceral adiposity index (VAI) was determined based on the measurements of anthropometric indices and lipid parameters. Increased albuminuria was defined as a urinary albumin-creatinine ratio (UACR) ≥30 mg/g, indicating kidney damage. Propensity score matching was used to reduce bias, and a multiple logistic regression model was performed to evaluate the association between visceral obesity and albuminuria in the population with prediabetes.

RESULTS

Participants with increased UACR exhibited increased VAI, age, blood pressure, triglycerides, poor glycaemic control, CVD events, and decreased estimated glomerular filtration rate (eGFR). Multiple logistic regression analysis demonstrated that VAI quartiles were positively associated with an increased risk of albuminuria (Q2: odds rate [OR]: 1.10, 95% confidence intervals [CI] 0.96-1.25; Q3: OR: 1.16, 95% CI 1.01-1.32; Q4: OR: 1.26, 95% CI 1.10-1.44, p for trend = 0.001). Stratified analysis revealed that the association of VAI level with increased albuminuria risk also occurred in people who were young, women, overweight or obese, with poor control of blood pressure, and eGFR ≥90 ml/min per 1.73 m² .

CONCLUSIONS

Visceral obesity assessed by VAI is significantly associated with increased UACR in a Chinese population with prediabetes.

Effects of TRPC6 Inactivation on Glomerulosclerosis and Renal Fibrosis in Aging Rats

Canonical transient receptor potential 6 (TRPC6) channels have been implicated in familial and acquired forms of focal and segmental glomerulosclerosis (FSGS) in patients and animal models, as well as in renal fibrosis following ureteral obstruction in mice. Aging also evokes declines in renal function owing to effects on almost every renal compartment in humans and rodents. Here, we have examined the role of TRPC6 in driving inflammation and fibrosis during aging in Sprague-Dawley rats. This was assessed in rats with non-functional TRPC6 channels owing to CRISPR-Cas9 deletion of a portion of the ankyrin repeat domain required for the assembly of functional TRPC6 channels (Trpc6^del/del rats). Wild-type littermates (Trpc6^wt/wt rats) were used as controls. Animals were evaluated at 2 months and 12 months of age. There was no sign of kidney disease at 2 months of age, regardless of genotype. However, by 12 months of age, all rats examined showed declines in renal function associated with albuminuria, azotemia and increased urine excretion of β2-microglobulin, a marker for proximal tubule pathology. These changes were equally severe in Trpc6^wt/wt and Trpc6^del/del rats. We also observed age-related increases in renal cortical expression of markers of fibrosis (α-smooth muscle actin and vimentin) and inflammation (NLRP3 and pro-IL-1β), and there was no detectable protective effect of TRPC6 inactivation. Tubulointerstitial fibrosis assessed from histology also appeared equally severe in Trpc6^wt/wt and Trpc6^del/del rats. By contrast, glomerular pathology, blindly scored from histological sections, suggested a significant protective effect of TRPC6 inactivation, but only within the glomerular compartment.

The importance of low HbA1c during childhood on glycaemic control in adulthood and the risk of late complications

AIM

To evaluate whether a very low glycated haemoglobin A (HbA1c) (<48 mmol/mol, 6.5%) during childhood compared to higher HbA1c values further decreases the risk for microvascular complications.

METHODS

Data were included from the 5116 patients with type 1 diabetes transferred from the Swedish paediatric diabetes quality registry to the Swedish National Diabetes Register (NDR), until 2014. All HbA1c values ever registered in the paediatric registry were used to divide patients into six groups based on the mean HbA1c. Values were compared with HbA1c registered in 2013 and 2014 in NDR, together with data on retinopathy, micro- and macroalbuminuria, age at onset and duration of diabetes.

RESULTS

The group with lowest mean-HbA1c during childhood had also the lowest mean as young adults during 2013 and 2014. The most common complication as young adults was retinopathy. The proportion with macroalbuminuria was 3% in the lowest HbA1c group during childhood and 3.9% in the highest group, and lower in the groups in between. Microalbuminuria had the same pattern. Retinopathy increased with each HbA1c group.

CONCLUSION

Children with the lowest HbA1c values had the lowest HbA1c values as adults. HbA1c was associated with retinopathy but the relationship with albuminuria was not obvious.

Association between Frailty and Albuminuria among Older Chinese Inpatients

OBJECTIVES

Older adults with frailty are vulnerable to cardiovascular event and subsequent mortality. Frailty and albuminuria share atherosclerotic risk factors. The present study investigated the association of frailty and albuminuria among elderly Chinese inpatients.

DESIGN

Cross-sectional study.

SETTINGS AND PARTICIPANTS

A total of 202 patients aged over 60 years from the Center of Gerontology and Geriatric, West China Hospital.

MEASUREMENTS

Frailty was defined using the five-item FRAIL scale. This included measurements of fatigue, resistance, ambulation, illness, and loss of weight. We further determined the random urine albumin/creatinine ratio (UACR) of all patients. Random UACR ≥30 mg/g was defined as albuminuria, and < 30mg/g as normoalbuminuria. The relationship between albuminuria and frailty was assessed through multiple regression analysis.

RESULTS

The 202 participants (156 men, 77.2%) had an average age of 78.99±7.60 years, which ranged from 60 to 95. Compared to those without albuminuria, elderly patients with albuminuria were of an older age, had a higher prevalence of diabetes and poorer renal function. The prevalence of frailty, pre-frailty and ambulation (one of the FRAIL components) were higher in the albuminuria group than the normoalbuminuria group (23.9% vs. 12.2%, 47.9% vs.37.4%, 33.8% vs. 16.0%, respectively, P<0.05). Following the adjustment for age, eGFR, hypertension, diabetes and using ACEI/ARB, being frail or pre-frail led to an enhanced risk of albuminuria (OR frail 2.60, 95% CI frail 1.01-6.72; OR pre-frail 2.14, 95% CI pre-frail 1.03-4.44).

CONCLUSIONS

Frailty is independently associated with albuminuria when adjusted for classic cardiovascular risk factors.

Relationship between High Blood Pressure and Microalbuminuria in Children Aged 6-9 Years in a South African Population

Though the association between high blood pressure and microalbuminuria is well established in adults, there is a paucity of information on microalbuminuria in children. This study investigated the relationship between high blood pressure and microalbuminuria in 6-9-year-old children. A cross-sectional study, which included 306 primary school children of age 6-9 years old from urban areas (n = 154) and rural areas (n = 152) of the Eastern Cape Province of South Africa, was conducted. Participants' anthropometric data were determined and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and converted to BP percentiles for age, sex and height. Creatinine and albumin concentrations were assayed in early morning midstream urine and the albumin to creatinine ratio (ACR) was calculated. There was a 42.8% prevalence of elevated blood pressure/high blood pressure (E-BP/H-BP) and a 10.1% prevalence of microalbuminuria. Among the 131 children with E-BP/H-BP, 17 had elevated ACR with a prevalence of 13.95%. SBP and HR increased with increasing range of ACR and, furthermore, SBP was significantly (p < 0.05) higher in children with moderately and severely increased ACR. SBP was associated with ACR and increased SBP predicted microalbuminuria (R2 = 0.42, adj R2 = 0.039, B: 0.120, p = < 0.05). In conclusion, microalbuminuria was present in 6-9-year-old South African children of African Ancestry and a weak association was observed with SBP in children.

Chronic Kidney Disease in Adolescents after Surgery for Congenital Heart Disease

BACKGROUND

The onset of chronic kidney disease (CKD) is an important prognostic factor in young adults with congenital heart disease (CHD). Although it is likely that CKD is manifest early in CHD patients, the prevalence among adolescents is still unknown. The National Kidney Foundation's Kidney Disease Improving Global Outcomes guidelines 2012 recommend new equations for the estimated glomerular filtration rate (eGFR) and highlight the importance of albuminuria for CKD screening. The objective of the present study was to estimate the prevalence of CKD in CHD adolescents.

METHODS

This observational cross-sectional study included 115 patients aged 10-18 years attending the cardiologic outpatient clinic at our institution as a follow-up after cardiac surgery in infancy related to various CHDs. CKD assessment used the CKD criteria 2012, including eGFR equations based on serum creatinine and cystatin C, and measurement of albuminuria.

RESULTS

No patient had an eGFR <60 mL min-1 1.73 m-2. However, 28.7% of all patients (95% CI 20.7-37.9) had eGFRbetween 60 and 89 mL min-1 1.73 m-2 when estimated by the bedside Schwartz creatinine-based equation,and 17.4% (95% CI 11.2-24.1) had eGFRbetween 60 and 89 mL min-1 1.73 m-2 when estimated by the Zappitelli equation, combining creatinine and cystatin C. Of all patients, 20.0% (95% CI 12.1-26.7) had orthostatic proteinuria, and none had persistent albuminuria.

CONCLUSIONS

There was no evidence of CKD in the present population aged 10-18 years. The significance of an eGFR between 60 and 90 mL min-1 1.73 m-2 is not concordant for this age range and requires further investigations.

Renal abnormalities and its associated factors among school-aged children living in Schistosoma mansoni endemic communities in Northwestern Tanzania

Background

In sub-Saharan Africa, renal abnormalities are a major public health concern, especially in children living in Schistosoma haematobium endemic areas. However, there is a dearth of data on renal abnormalities among children living in Schistosoma mansoni endemic areas. The objective of the study was to assess the prevalence of renal abnormalities among school children in a Schistosoma mansoni endemic community in Northwestern Tanzania.

Methods

A cross-sectional study was conducted between January and March 2017 among school children aged 6–13 years, attending three primary schools located along the shoreline of Lake Victoria. A single urine sample was collected from each child and screened for S. mansoni using circulating cathodic antigen and for S. haematobium eggs using a urine filtration technique. A urine dipstick was used to screen for urine protein levels, creatinine levels, microalbuminuria, and red blood cells. Venous blood was obtained for estimation of creatinine level and for malaria diagnosis. The primary outcomes were the prevalence of renal abnormalities, defined by the presence of low estimated glomerular filtration rate (eGFR), proteinuria or microalbuminuria, and hematuria in urine.

Results

Of 507 children included in the final analysis, 49.9% (253/507) were male with a mean age of 8.51 ± 1.3 years. Overall, 64.0% (326/507) of the children were infected with S. mansoni, and 1.6% (8/507) of the children were infected with S. haematobium. A total of 71 (14%) of the children had proteinuria, 37 (7.3%) had hematuria, and 8 (1.6%) had a low estimated glomerular filtration rate (eGFR). Overall prevalence of renal abnormalities was 22.9%. Renal abnormalities (proteinuria) were associated with S. mansoni infection (OR = 4.9, 95% CI 2.1–11.2, p < 0.001) and having red blood cells in urine (OR = 5.3, 95% CI 2.5–11.2, p < 0.001).

Conclusion

Twenty-two percent of school children who participated in this study had renal abnormalities associated with S. mansoni infection. Given the high prevalence of S. mansoni, longitudinal epidemiological surveillance is warranted to measure the burden of renal abnormalities and assess the impact of the praziquantel treatment on these abnormalities.

Association between Pro12Ala polymorphism and albuminuria in type 2 diabetic nephropathy

AIMS/INTRODUCTION

Diabetic nephropathy (DN) is a complication of diabetes mellitus that is characterized by the gradual loss of kidney function, which results in increased levels of albumin in the urine. The Pro12Ala polymorphism in the peroxisome proliferator-activated receptor-γ2 gene has been confirmed to improve insulin sensitivity, but its association with susceptibility to DN in patients with type 2 diabetes remains inconclusive.

MATERIALS AND METHODS

To examine whether the Pro12Ala polymorphism leads to the development of DN, a case-control study was carried out in 554 patients with type 2 diabetes. The genotypes of Pro12Ala polymorphism of the peroxisome proliferator-activated receptor gamma 2 gene were analyzed by real-time polymerase chain reaction with TaqMan® probe genotyping assay in all patients.

RESULTS

The mean age of the study population was 57.7 ± 8.8 years, with average diabetes duration of 12.8 ± 6.9 years. The prevalence of albuminuria was 43.5%. The frequency of genotype Pro12Pro, Pro12Ala and Ala12Ala genotype were 92.6%, 7.0%, 0.4% in our study population, and 90.4%, 8.9% and 0.7% in normal urinary albumin-to-creatinine ratio group, respectively. The Ala carriers (Pro12Ala + Ala12Ala) had significantly lower urinary albumin-to-creatinine ratio (15.0 vs 20.5 mg/g, P = 0.001) and better renal function (estimated glomerular filtration rate 81.8 [69.8-97.6] vs 78.7 mL/min/1.73 m2 [61.6-96.2]; P = 0.05) compared with those with the genotype Pro12Pro. After adjustment for age, sex and other confounders, the odds ratio of albuminuria for the Ala12 allele was 0.428 (95% confidence interval 0.195-0.940, P = 0.034]).

CONCLUSIONS

Our results suggest that the peroxisome proliferator-activated receptor gamma 2 Ala12 variant has significant protective effects against albuminuria and DN.

Risk of Kidney Injury among Construction Workers Exposed to Heat Stress: A Longitudinal Study from Saudi Arabia

Saudi Arabia (SA) is one of the hottest countries in the world. This study was conducted to assess the impact of summer heat stress in Southeastern SA on short-term kidney injury (KI) among building construction workers and to identify relevant risk factors. Measurements of urinary albumin-creatinine ratio (ACR), height, weight, hydration, symptoms, daily work and behavioral factors were collected in June and September of 2016 from a cohort of construction workers (n = 65) in Al-Ahsa Province, SA. KI was defined as ACR ≥ 30 mg/g. Multivariate linear regression analysis was used to assess factors related to cross-summer changes in ACR. A significant increase in ACR occurred among most workers over the study period; incidence of KI was 18%. Risk factors associated with an increased ACR included dehydration, short sleep, and obesity. The findings suggest that exposure to summer heat may lead to the development of KI among construction workers in this region. Adequate hydration and promotion of healthy habits among workers may help reduce the risk of KI. A reduction in work hours may be the most effective intervention because this action can reduce heat exposure and improve sleep quality.

Chronic Kidney Disease: A Vicarious Relation to Premature Cell Senescence

Chronic kidney disease (CKD), commonly fostering nonrenal complications, themselves more life threatening than renal pathology, remains enigmatic. Despite more than a century of intense research, therapeutic options to halt or reverse renal disease are rather limited. Recently, similarity between manifestations of progressive CKD and aging kidney has attracted investigative attention that revealed senescent cells and secreting proinflammatory and profibrotic mediators in all renal compartments, even at young age, in patients with kidney maladies. The overlapping features of these categories have been noticed previously and are briefly summarized herein. I propose two hypothetical scenarios for interactive association of kidney diseases and cell senescence, both culminating in progressive deterioration of renal function. Persistence of senescent cells is considered as a critical contributor to this association; and the mechanisms explaining persistence, such as activation of cell cycle regulators, anti-apoptotic stimuli, metabolic aberrations, and their interactions, are discussed. The mutual encroachment of underlying kidney disease and cell senescence bring about the conclusion that both entities merge along the natural history of the disease. This putative interpretation of vicarious relation between cell senescence and CKD may expand the arsenal of pharmacotherapy to include the judicious use of senotherapeutics in the management of renal disease.

Association of Urinary Albumin:Creatinine Ratio with Outcome of Children with Sepsis

Objective

The aim of the study was to investigate the association of urinary albumin:creatinine ratio (ACR) with regard to the outcome of sepsis patients and to study the trends of ACR with severity of disease, organ dysfunction, microcirculation status, the use of inotrope, and mechanical ventilation use, and length of pediatric intensive care unit (PICU) stay.

Materials and methods

In the prospective observational study, the patients with varying categories of sepsis admitted in the PICU with stay >24 hours were enrolled consecutively. Urine samples were collected at the time of admission (ACR1), 12 hours (ACR2), and 24 hours (ACR3).

Results

One hundred and thirty-eight patients including 56 cases of sepsis, 31 of severe sepsis, 22 of septic shock, and 29 of multiorgan dysfunction syndrome (MODS) cases were analyzed. There were 29 (21%) deaths. ACR (median, IQR) was significantly higher in nonsurvivors [ACR1 198.9 (111.2–329.4) vs 124.5 (59.37–294.5), p 0.03], [ACR2 213.8 (112.5–350) vs 117.8 (62.6–211.9) p 0.008], [ACR3 231.8 (99.9–441.2 vs 114.4 (44.1–240.3), p 0.005]. The ACR is increased progressively with the increasing severity of sepsis (p < 0.001). The performance of ACR operative characteristics was compared with that of PRISM and PELOD scores. In deceased, ACR was significantly correlated with blood pH, lactate, and base deficit. A cutoff value of ACR 102.7 mg/g had sensitivity 86.2%, specificity 40.4%, positive predictive value 27.8%, and negative predictive value 91.7%. The use of inotropes, mechanical ventilation (>48 hours), and mortality was significantly higher in patients with ACR >102 mg/g. The probability of death varied from 17.6 to 19% in the first 24 hours of admission. ACR was significantly cheaper as compared to PRISM score and PELOD score estimations.

Conclusion

Urinary ACR, a cost-effective tool, correlates with the severity of sepsis and associated morbidity and mortality in children.

How to cite this article

Sachdev A, Raheja K, Gupta N, Chugh P. Association of Urinary Albumin:Creatinine Ratio with Outcome of Children with Sepsis. Indian J Crit Care Med 2020;24(6):465–472.

Length of gestation and birth weight are associated with indices of combined kidney biomarkers in early childhood

Infants born prematurely or with low birth weights are more susceptible to kidney dysfunction throughout their lives. Multiple proteins measured in urine are noninvasive biomarkers of subclinical kidney damage, but few studies have examined the joint effects of multiple biomarkers. We conducted an exploratory study of 103 children in the Programing Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) longitudinal birth cohort, and measured nine proteins selected a priori in banked spot urine samples collected at ages 4-6. The goal of our study was to explore the combined effects of kidney damage biomarkers previously associated with birth outcomes. To do this, we generated kidney biomarker indices using weighted quantile sum regression and assessed associations with length of gestation or birth weight. A decile increase in each kidney biomarker index was associated with 2-day shorter gestations (β = -2.0, 95% CI: -3.2, -0.9) and 59-gram lower birth weights (β = -58.5, 95% CI: -98.3, -18.7), respectively. Weights highlighting the contributions showed neutrophil gelatinase-associated lipocalin (NGAL) (60%) and osteopontin (19%) contributed most to the index derived for gestational age. NGAL (66%) and beta-2-microglobulin (10%) contributed most to the index derived for birth weight. Joint analyses of multiple kidney biomarkers can provide integrated measures of kidney dysfunction and improved statistical assessments compared to biomarkers assessed individually. Additionally, shorter gestations and lower birth weights may contribute to subclinical kidney damage measurable in childhood.

Relation of short-term blood pressure variability to early renal effects in hypertensive patients with controlled blood pressure

INTRODUCTION

Microalbuminuria is a common early hypertension-mediated organ damage, which correlates with the overall cardiovascular risk and development of end-stage renal damage. Lately, blood pressure variability has shown an additive value over traditional BP measurement in prediction of cardiovascular and renal involvement.

AIM

Investigate the relation between short-term blood pressure variability and microalbuminuria in controlled hypertensive patients.

PATIENTS AND METHODS

Ninety non-diabetic hypertensive patients with controlled blood pressure and normal estimated glomerular filtration rate had 24-hour ambulatory blood pressure monitoring with calculation of short-term blood pressure variability indices (SD, coefficient of variation and average reading variability of systolic and diastolic blood pressure for 24-hour, daytime and nighttime], and measurement of the albumin/creatinine ratio.

RESULTS

Patients were classified into group 1 (61 patients without microalbuminuria) and group 2 (29 patients with microalbuminuria). No significant difference was observed between both groups regarding age, sex, body mass index, office blood pressure, average 24-hour ambulatory blood pressure monitoring readings and dipping status, but significantly longer duration of hypertension in group 2. All blood pressure variability indices were significantly higher in group 2, which showed strong positive correlations with microalbuminuria level. Multivariate analysis represented an average reading variability of 24-hour systolic blood pressure as the most powerful independent predictor for microalbuminuria (r = 0.516, P = 0.001). Receiver operating characteristic curve analysis revealed that average reading variability of 24-hour systolic blood pressure (>12.55) could predict microalbuminuria (sensitivity = 89.7%, specificity = 88.5%, area under curve = 0.949, P = 0.001).

CONCLUSION

Short-term blood pressure variability correlated well with early renal effects in controlled hypertensive patients. Average reading variability of 24-hour systolic blood pressure was the strongest predictor for microalbuminuria in such patients.

Microalbuminuria and cardiorenal risk: old and new evidence in different populations

Since the association of microalbuminuria (MAU) with cardiovascular (CV) risk was described, a huge number of reports have emerged. MAU is a specific integrated marker of CV risk and targets organ damage in patients with hypertension, chronic kidney disease (CKD), and diabetes and its recognition is important for identifying patients at a high or very high global CV risk. The gold standard for diagnosis is albumin measured in 24-hour urine collection (normal values of less than 30 mg/day, MAU of 30 to 300 mg/day, macroalbuminuria of more than 300 mg/day) or, more practically, the determination of urinary albumin-to-creatinine ratio in a urine morning sample (30 to 300 mg/g). MAU screening is mandatory in individuals at risk of developing or presenting elevated global CV risk. Evidence has shown that intensive treatment could turn MAU into normoalbuminuria. Intensive treatment with the administration of an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker, in combination with other anti-hypertensive drugs and drugs covering other aspects of CV risk, such as mineralocorticoid receptor antagonists, new anti-diabetic drugs, and statins, can diminish the risk accompanying albuminuria in hypertensive patients with or without CKD and diabetes.

Association of neutrophil-to-lymphocyte ratio and microalbuminuria in patients with normal eGFR

AIMS

The aim of this study was to evaluate the association between neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and microalbuminuria in patients with normal estimated glomerular filtration rate (eGFR).

METHODS

174 patients who had eGFR ≥ 60 mL/min/1.73 m2 were studied. Patients were divided into two groups according to the urinary albumin excretion as microalbuminuric group (n = 105) and normoalbuminuric group (n = 69). NLR and PLR levels were calculated.

RESULTS

NLR was significantly higher (p < 0.05) in microalbuminuric patients (1.91 ± 0.70) compared with normoalbuminuric patients (1.63 ± 0.53). A positive correlation was found between urine albumin excretion and NLR in the whole study group (r = 0.214, p < 0.005).

CONCLUSIONS

Higher NLR levels were found in microalbuminuric patients with normal eGFR. Also a significant positive correlation was observed between albuminuria and NLR.

Individual and Environmental Factors Associated with Proteinuria in Korean Children: A Multilevel Analysis

Proteinuria is a significant sign of childhood renal disorders. However, little is known about how sociodemographic and environmental factors are related to the presence of proteinuria among children and adolescents. This paper focuses on the prevalence of proteinuria and its risk factors among children and adolescents. This study conducted a secondary analysis of data from the 2016 Sample Schools Raw Data of Health Examination for School Students (SSRDHESS). Data collected from 27,081 students who had undergone a health screening were analyzed using Chi-square tests, independent t-tests, and multilevel logistic regression analysis. The prevalence of proteinuria was higher in the thin group than in the normal weight group (adjusted odds ratio (aOR) = 1.77; 95% confidence interval (CI) = 1.34–2.33) and lower in the overweight/obese group (aOR = 0.64; 95% CI = 0.51–0.80). Additionally, those in metropolitan and small–medium sized cities had a proteinuria prevalence about 1.5-fold higher than that of those in rural areas (95% CI = 1.08–2.02, 95% CI = 1.19–1.92, respectively). Proteinuria was associated with environmental pollution, including smoking rate, ambient particulate matter and heavy metals in drinking water (aOR = 1.10; 95% CI = 1.01–1.20; aOR = 1.06; 95% CI = 1.01–1.11, aOR = 1.001; 95% CI = 1.0001–1.0015). These results suggest that to improve health management effectiveness, kidney disease prevention efforts for children and adolescents should focus on geographical area and environmental pollution, as well as body weight as individual factors.

Association of Albuminuria With Major Adverse Outcomes in Adults With Congenital Heart Disease: Results From the Boston Adult Congenital Heart Biobank

Importance

Albuminuria is associated with adverse outcomes in diverse groups of patients, but the importance of albuminuria in the emerging population of increasingly complex adults with congenital heart disease (ACHD) remains unknown.

Objective

To assess the prevalence, risk factors, and prognostic implications of albuminuria in ACHD.

Design, Setting, and Participants

This prospective study assessed a cohort of ambulatory patients aged 18 years and older who were examined at an ACHD referral center and enrolled in the Boston ACHD Biobank between May 17, 2012, to August 5, 2016. Albuminuria was defined as an urine albumin-to-creatinine (ACR) ratio of 30 mg/g or more.

Main Outcomes and Measures

Death or nonelective cardiovascular hospitalization, defined as overnight admission for heart failure, arrhythmia, thromboembolic events, cerebral hemorrhage, and/or disease-specific events.

Results

We measured the ACR of 612 adult patients with CHD (mean [SD] age, 38.6 [13.4] years; 308 [50.3%] women). Albuminuria was present in 106 people (17.3%) and was associated with older age (patients with ACR <30 mg/g: mean [SD]: 37.5 [13.2] years; vs patients with ACR ≥30 mg/g: 43.8 [13.1] years; P < .001), presence of diabetes mellitus (ACR <30 mg/g: 13 of 506 [2.6%]; vs ≥30 mg/g: 11 of 106 [10.4%]; P < .001), lower estimated glomerular filtration rate (ACR <30 mg/g: median [interquartile range (IQR)]: 103.3 [90.0-116.4] mL/min/1.73 m2; ACR ≥30 mg/g: 99.1 [78.8-108.7] mL/min/1.73 m2; P = .002), and cyanosis (ACR <30 mg/g: 23 of 506 [5.1%]; vs ACR ≥30 mg/g: 21 of 106 [22.6%]; P < .001). After a mean (SD) follow-up time of 270 (288) days, 17 patients (2.5%) died, while 68 (11.1%) either died or experienced overnight inpatient admission. Albuminuria predicted outcome, with 30 of 106 patients with albuminuria (28.3%) affected vs 38 of 506 patients without albuminuria (7.5%; hazard ratio [HR], 3.0; 95% CI, 1.9-4.9; P < .001). Albuminuria was also associated with increased mortality (11 of 106 [10.4%]; vs 6 of 506 [1.2%] in patients with and without albuminuria, respectively; HR, 6.4; 95% CI, 2.4-17.3; P < .001). Albuminuria was associated with the outcomes only in patients with a biventricular circulation (HR, 4.5; 95% CI, 2.5-8.0) and not those with single-ventricle circulation (HR, 1.0; 95% CI, 0.4-2.8; P = 0.01 compared with biventricular circulation group). Among 133 patients (21.7%) in NYHA functional class 2, albuminuria was strongly associated with death or nonelective hospitalization.

Conclusions and Relevance

Albuminuria is common and is associated with increased risk for adverse outcome in patients with ACHD with biventricular circulation. Albuminuria appears especially useful in stratifying risk in patients categorized as NYHA functional class 2.

Hypertension is associated with increased post-exercise albuminuria, which may be attenuated by an active lifestyle

Albuminuria is a known marker for endothelial dysfunction and cardiovascular events, even below the threshold of moderately increased albuminuria (MIA). Post-exercise increased albuminuria may precede the appearance of rest MIA, enabling detection of early injury. Modifying lifestyle for a population at risk for MIA is therefore of interest. Our aim was to evaluate post-exercise albuminuria in hypertensive compared with normotensive individuals and to analyze the effect of an active lifestyle on rest and post-exercise albumin excretion. The study cohort consisted of 3931 adults who participated in a health-screening program. Albuminuria was measured as urine albumin-to-creatinine ratio (ACR). Lifestyle was divided into three groups: non-active, less-active, and active according to regular sport activity, categorized as follows: none, <2.5 and ≥2.5 hours per week. Mean age was 47.7 years, and 31.2% (n = 1228) were diagnosed with hypertension. Both rest and post-exercise ACR were higher in hypertensive compared to normotensive participants. Rest ACR was higher in non-active compared to less-active and active hypertensive participants. Hypertensive participants with an active lifestyle had significantly lower post-exercise and delta ACR compared to less-active and non-active hypertensive participants. Parameters related to delta ACR in hypertensive participants were increased age, BMI, and diabetes, while active lifestyle and fitness (measured as METS achieved by a stress test) were protective. In conclusion, there is an association between hypertension and increased albumin excretion post-exercise, which can be attenuated with an active lifestyle.

Protein supplement use and prevalence of microalbuminuria in gym members

BACKGROUND

Protein supplement use is common in bodybuilders because protein supplements are thought to increase muscle mass by preventing protein catabolism during exercise routines. Information on the consequences of protein supplement use is scarce and contradictory. Therefore, the identification of a kidney damage marker, such as microalbuminuria, could be transcendent in preventing probable organ compromise in healthy persons. The aim of this study is to determine the presence of microalbuminuria in gym members and whether there is an associated risk with protein supplement use.

METHODS

An analytic, descriptive, cross-sectional study was conducted. It included gym members whose clinical and nutritional histories were taken, identifying protein supplement use. Microalbuminuria was then determined through a random urine sample. Descriptive and inferential statistics were used for the data analysis. The objective was to determine the presence of microalbuminuria in gym members and whether there is an associated risk with protein supplement use.

RESULTS

A total of 107 gym members, 71 men and 36 women, that met the inclusion criteria of the study were analyzed. Their mean age was 35±13 years, and the prevalence of microalbuminuria was 9.34%. There was active protein supplement use in 58% of the study participants, with a mean consumption duration of 16±22 months. No association with the presence of microalbuminuria was found (P=0.35).

CONCLUSIONS

The prevalence of microalbuminuria in gym members was higher than that of the general healthy population and was not associated with protein supplement use.

Urinary Albumin Excretion, Estimated Glomerular Filtration Rate, and Prevalence of Microalbuminuria in Obese Nondiabetic and Nonhypertensive Adults: A Cross-Sectional Study

Context:

Obesity even in absence of diabetes and hypertension increases the risk for microalbuminuria (MAU), glomerular hyperfiltration, and therefore nephropathy.

Aims:

This study aims to assess the urinary albumin excretion (UAE), prevalence of MAU, and values of estimated glomerular filtration rate (eGFR) in obese nondiabetic and nonhypertensive patients, vis a vis thin healthy subjects, and attempts to correlate anthropometric measurements with UAE and eGFR.

Setting and Design:

Cross-sectional analytical study on 60 cases who were obese according to Asia Pacific guidelines and 60 nonobese controls. Patients with diabetes, hypertension, ischemic heart disease, and established renal disease were excluded.

Methods and Material:

Albuminuria was assessed in each patient by quantitative immunoturbidimetry method on a spot urine sample. eGFR was calculated by Cockcroft–Gault formula.

Statistical Analysis:

Data was analyzed using SPSS (2015 version). Mann–Whitney U-test, Fisher Exact test, and Spearman's correlation coefficient was used for various variables.

Results:

The mean age of cases was 31.90 ± 6.32 years. About 78.33% were in class 1 and 21.66% in class 2 obese groups. The mean UAE at 21.20 ± 26.82 mg/g creatinine was higher in the case group. The prevalence of MAU was 11.66% and 3.33% in case and control groups, respectively. The cases had a significantly higher mean eGFR of 123.29 ± 20.49 mL/min/kg as compared with controls who had a mean eGFR of 106.59 ± 10.15 mL/min/kg. There was moderate correlation between anthropometric measurements and eGFR.

Conclusion:

Younger, class 1 obese patients had a higher UAE, eGFR, and three times higher MAU prevalence, even in absence of diabetes and hypertension, with a correlation between anthropometry and eGFR as compared with nonobese individuals.

Beyond chronic kidney disease: the diagnosis of Renal Disease in the Elderly as an unmet need. A position paper endorsed by Italian Society of Nephrology (SIN) and Italian Society of Geriatrics and Gerontology (SIGG)

The dramatic increase in prevalence of chronic kidney disease (CKD) with ageing makes the recognition and correct referral of these patients of paramount relevance in order to implement interventions preventing or delaying the development of CKD complications and end-stage renal disease. Nevertheless, several issues make the diagnosis of CKD in the elderly cumbersome. Among these are age related changes in structures and functions of the kidney, which may be difficult to distinguish from CKD, and multimorbidity. Thus, symptoms, clinical findings and laboratory abnormalities should be considered as potential clues to suspect CKD and to suggest screening. Comprehensive geriatric assessment is essential to define the clinical impact of CKD on functional status and to plan treatment. Correct patient referral is very important: patients with stage 4-5 CKD, as well as those with worsening proteinuria or progressive nephropathy (i.e. eGFR reduction > 5 ml/year) should be referred to nephrologist. Renal biopsy not unfrequently may be the key diagnostic exam and should not be denied simply on the basis of age. Indeed, identifying the cause(s) of CKD is highly desirable to perform a targeted therapy against the pathogenetic mechanisms of CKD, which complement and may outperform in efficacy the general measures for CKD.

Renal function in prepubertal children born with very low birthweight

OBJECTIVES

The objective of this study was to evaluate estimated glomerular filtration rates (eGFR) and markers of renal function in very low birthweight (VLBW) children and to relate these parameters to current nutritional status.

METHODS

A cross-sectional and controlled study was performed with prepubertal children between ages 5 and 10, including 44 VLBW participants and 30 healthy participants born at full term with an adequate birthweight (control group). The following data were collected: perinatal history; current weight, height and waist circumference; blood pressure (three measures); blood creatinine, urea, uric acid, cystatin-C, and neutrophil gelatinase-associated lipocalin levels; and urine albumin, creatinine, and calcium levels.

RESULTS

Blood pressure, eGFR, albuminuria, concentrations of cystatin-C, neutrophil gelatinase-associated lipocalin, uric acid, urea, creatinine, and fractional calcium excretion did not differ between VLBW and control groups. Regarding the VLBW group, there was no difference in eGFR, albuminuria, and other markers of renal injury in overweight or obese children compared with children with a normal body mass index.

CONCLUSIONS

Prepubertal children born with VLBW did not have altered renal function, regardless of their current nutritional status.

Electrochemical Quantification of Glycated and Non-glycated Human Serum Albumin in Synthetic Urine

A polymer-based electrode capable of specific detection of human serum albumin, and its glycated derivatives, is described. The sensor is constructed from a glass microscope slide coated with a synthesized, polythiophene film bearing a protected, iminodiacetic acid motif. The electrode surface is then further elaborated to a functional biosensor through deprotection of the iminodiacetic acid, followed by metal-affinity immobilization of a specific and high-affinity, albumin ligand. Albumin was then quantified in buffer and synthetic urine via electrochemical impedance spectroscopy. Glycated albumin was next bound to a boronic acid-modified, single-cysteine dihydrofolate reductase variant to quantify glycation ratios by square-wave voltammetry. The platform offers high sensitivity, specificity, and reproducibility in an inexpensive arrangement. The detection limits exceed the requirements for intermediate-term glycemic control monitoring in diabetes patients at 5 and 1 nM for albumin and its glycated forms, respectively.

A narrative review of proteinuria and albuminuria as clinical biomarkers in children

Proteinuria is an important biomarker commonly used to detect and manage kidney disease in children. There are now a variety of methods available to measure urinary protein loss, and physicians are faced with several contrasting strategies: 24-h or timed collection versus spot samples (first-morning or random), measurement of total urinary protein versus selective measurement of urinary albumin, unadjusted urine protein concentration versus protein-to-creatinine ratio and the use of dipstick versus laboratory-based methods. In this review, we will discuss the advantages and disadvantages of these different approaches. We will then summarise the evidence base for proteinuria as a clinical biomarker in different settings, including discussion of the current and potential role of measuring low-level albuminuria. Finally, we will highlight gaps in the literature and opportunities for further research into proteinuria among children.

Frequency and Risk Factors of Kidney Alterations in Children and Adolescents who Are Overweight and Obese in a Primary Health-care Setting

OBJECTIVE

Obesity is clearly associated to kidney disease in adult population; however, there is scarce evidence in children and adolescents. The aim was to compare frequency of renal damage according to the presence of overweight-obesity in children and adolescents, as well as to compare nutritional and biochemical risk factors, according to the presence of kidney alterations.

METHODS

Cross-sectional study; 172 children and adolescents, 6-16 years old, without malnutrition, diabetes mellitus, hypertension and independent comorbid conditions associated to obesity or kidney disease, as well as transitory causes of microalbuminuria (MA) from a Primary Health-Care Unit were included. Clinical, biochemical, anthropometric and dietetic evaluations were measured in all subjects; subsequently they were classified as normal weight, overweight and obesity groups according to sex- and age-adjusted body mass index (BMI). Glomerular filtration rate (GFR, estimated by Schwartz equation) and albuminuria (albumin/creatinine ratio) were determined. Presence of kidney alterations was measured as decreased GFR (<90 mL/min/1.73m²), hyperfiltration (>170 mL/min/1.73m²) and MA (30-300 mg/g).

RESULTS

Compared with controls, subjects with overweight-obesity had significantly (P<.05) abdominal obesity (0 vs 69%), hypertension (19 vs 26%), hypertriglyceridemia (11 vs 47%), high low-density lipoprotein cholesterol (2 vs 8%) and low high-density lipoprotein cholesterol (HDL-cholesterol; 2 vs 28%), hyperuricemia (11 vs 28%) and hyperinsulinemia (8 vs 70%). Hyperfiltration and MA were present in 5 and 4 subjects with overweight/obesity, respectively, whereas decreased GFR was present in only 1 subject with obesity. Normal weight subjects had no kidney alterations. In multivariate analysis, kidney alterations were significantly predicted by higher BMI and lower HDL-cholesterol.

CONCLUSIONS

Kidney alterations were observed only in subjects with overweight (3.6%) and obesity (9.9%), who additionally, displayed cardiometabolic and kidney disease risk factors more frequently than normal weight subjects.

New Areas of Interest: Is There a Role for Omega-3 Fatty Acid Supplementation in Patients With Diabetes and Cardiovascular Disease?

PURPOSE OF REVIEW

Summarize studies on omega-3 fatty acids in prevention of albuminuria in subjects with diabetes.

RECENT FINDINGS

Several small, short-term trials suggested benefit on albuminuria in subjects with diabetes; however, results were not definitive. Welty et al. showed that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for 1 year slowed progression of early-stage albuminuria in subjects with diabetes with clinical coronary artery disease on an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker, the majority of whom had an albumin/creatinine ratio (ACR) < 30 μg/mg. Moreover, significantly more (3-fold) subjects on EPA and DHA had a decrease in ACR compared to control, and three on EPA and DHA had a change in category from > 30 μg/mg to < 30 μg/mg, whereas no controls did. Potential mechanisms for benefit are discussed. These results suggest that there is benefit and perhaps even reversal of albuminuria with EPA and DHA at an early stage of disease in those with ACR < 30 μg/mg and those with microalbuminuria (ACR > 30).

Iron handling by the human kidney: glomerular filtration and tubular reabsorption both contribute to urinary iron excretion

In physiological conditions, circulating iron can be filtered by the glomerulus and is almost completely reabsorbed by the tubular epithelium to prevent urinary iron wasting. Increased urinary iron concentrations have been associated with renal injury. However, it is not clear whether increased urinary iron concentrations in patients are the result of increased glomerular iron filtration and/or insufficient tubular iron reabsorption and if these processes contribute to renal injury. We measured plasma and urine iron parameters and urinary tubular injury markers in healthy human subjects ( n = 20), patients with systemic iron overload ( n = 20), and patients with renal tubular dysfunction ( n = 18). Urinary iron excretion parameters were increased in both patients with systemic iron overload and tubular dysfunction, whereas plasma iron parameters were only increased in patients with systemic iron overload. In patients with systemic iron overload, increased urinary iron levels were associated with elevated circulating iron, as indicated by transferrin saturation (TSAT), and increased body iron, as suggested by plasma ferritin concentrations. In patients with tubular dysfunction, enhanced urinary iron and transferrin excretion were associated with distal tubular injury as indicated by increased urinary glutathione S-transferase pi 1-1 (GSTP1-1) excretion. In systemic iron overload, elevated urinary iron and transferrin levels were associated with increased injury to proximal tubules, indicated by increased urinary kidney injury marker 1 (KIM-1) excretion. Our explorative study demonstrates that both glomerular filtration of elevated plasma iron levels and insufficient tubular iron reabsorption could increase urinary iron excretion and cause renal injury.

Albuminuria and glomerular filtration rate in obese children and adolescents

OBJECTIVE

To describe the frequency of albuminuria in overweight and obese children and adolescents and to relate it to the severity of obesity, pubertal staging, associated morbidities and the glomerular filtration rate.

METHOD

Cross-sectional study including 64 overweight and obese children and adolescents between 5 and 19 years of age.

DATA COLLECTED

weight, height, waist circumference and systemic arterial pressure.

LABORATORY TESTS

lipid profile; glycemia and insulin, used to calculate the Homeostasis Model Assessment (HOMA-IR); C-reactive protein; glutamic-pyruvic transaminase and albuminuria in an isolated urine sample (cutoff <30 mg/g). Creatinine was used to calculate the estimated glomerular filtration rate (eGFR, mL/min/1.73 m2).

RESULTS

The mean age was 11.6 ± 3.4 years, 32 (50%) and 29 (45.3%) were male and prepubertal. Forty-six (71.9%) had severe obesity. The frequency and median (min/max) of the observed values for albuminuria (> 30 mg/g) were 14 (21.9%) and 9.4 mg/g (0.70, -300.7 mg/g). The mean eGFR was 122.9 ± 24.7 mL/min/1.73 m2. There was no significant correlation between body mass index, pubertal staging, insulin and HOMA-IR with albuminuria values and neither with eGFR. Children with albuminuria tended to have higher values of diastolic blood pressure (75.0 ± 12.2 vs. 68.1 ± 12.4, p = 0.071).

CONCLUSION

Albuminuria, although frequent in children and adolescents with obesity, was not associated with other morbidities and the glomerular filtration rate in these patients.

Dipstick proteinuria predicts all-cause mortality in general population: A study of 17 million Korean adults

Objective

A quantitative basis for the use of dipstick urinalysis for risk assessment of all-cause mortality is scarce. Therefore, we investigated the association between dipstick proteinuria and all-cause mortality in a general population and evaluated the effect of confounders on this association.

Methods

The study population included 17,342,956 adults who underwent health examinations between 2005 and 2008 under the National Health Insurance System. Proteinuria was determined using a single dipstick urinalysis, and the primary outcome of this study was all-cause mortality. The prognostic impact of proteinuria was assessed by constructing a multivariable Cox model.

Results

The mean age of the study population (53.24% male) was 46.06 years; 724,681 deaths from all causes occurred over a median follow-up period of 9.34 years (interquartile range 8.17–10.16), and the maximum follow-up was 12.12 years. After full adjustment for covariates, a higher level of dipstick proteinuria indicated a higher risk of all-cause death [Hazard ratios (95% confidence intervals); 1.22 (1.20–1.24), 1.47 (1.45–1.49), 1.81 (1.77–1.84), 2.32 (2.24–2.41), 2.74 (2.54–2.96); trace to 4+, respectively], and various subgroup analyses did not affect the main outcome for the total population. ≥1+ proteinuria in the group without metabolic diseases (hypertension, diabetes, dyslipidemia, or obesity) resulted in higher hazard ratios than those in the group with metabolic diseases and negative or trace proteinuria.

Conclusions

Our study showed a strong association between dipstick proteinuria and all-cause mortality in this nationwide population-based cohort in South Korea.

Estimating Time to ESRD in Children With CKD

RATIONALE & OBJECTIVE

The KDIGO (Kidney Disease: Improving Global Outcomes) guideline for chronic kidney disease (CKD) presented an international classification system that ranks patients' risk for CKD progression. Few data for children informed guideline development.

STUDY DESIGN

Observational cohort study.

SETTINGS & PARTICIPANTS

Children aged 1 to 18 years enrolled in the North American Chronic Kidney Disease in Children (CKiD) cohort study and the European Effect of Strict Blood Pressure Control and ACE Inhibition on the Progression of CRF in Pediatric Patients (ESCAPE) trial.

PREDICTOR

Level of estimated glomerular filtration rate (eGFR) and proteinuria (urine protein-creatinine ratio [UPCR]) at study entry.

OUTCOME

A composite event of renal replacement therapy, 50% reduction in eGFR, or eGFR<15mL/min/1.73m2. eGFR was estimated using the CKiD-derived "bedside" equation.

ANALYTICAL APPROACH

Accelerated failure time models of the composite outcome using a conventional generalized gamma distribution. Likelihood ratio statistics of nested models were used to amalgamate levels of similar risk.

RESULTS

Among 1,232 children, median age was 12 (IQR, 8-15) years, median eGFR was 47 (IQR, 33-62) mL/min/1.73m2, 60% were males, and 13% had UPCRs>2.0mg/mg at study entry. 6 ordered stages with varying combinations of eGFR categories (60-89, 45-59, 30-44, and 15-29mL/min/1.73m2) and UPCR categories (<0.5, 0.5-2.0, and >2.0mg/mg) described the risk continuum. Median times to event ranged from longer than 10 years for eGFRs of 45 to 90mL/min/1.73m2 and UPCRs<0.5mg/mg to 0.8 years for eGFRs of 15 to 30mL/min/1.73m2 and UPCRs>2mg/mg. Children with glomerular disease were estimated to have a 43% shorter time to event than children with nonglomerular disease. Cross-validation demonstrated risk patterns that were consistent across the 10 subsample validation models.

LIMITATIONS

Observational study, used cross-validation rather than external validation.

CONCLUSIONS

CKD staged by level of eGFR and proteinuria characterizes the timeline of progression and can guide management strategies in children.

Screening for kidney disease in Indigenous Canadian children: The FINISHED screen, triage and treat program

Background

Indigenous populations are disproportionately affected by kidney failure at younger ages than other ethnic groups in Canada. As symptoms do not occur until disease is advanced, early kidney disease risk is often unrecognized.

Objectives

We sought to evaluate the yield of community-based screening for early risk factors for kidney disease in youth from rural Indigenous communities in Canada.

Methods

The FINISHED project screened 11 rural First Nations communities in Manitoba, Canada after community and school engagement. The results for the 10- to 17-year olds are reported here. Body mass index (BMI), blood pressure, estimated glomerular filtration rate (eGFR), hemoglobin A1c's (HbA1c) and urine albumin-to-creatinine ratios (ACR) were assessed. All children were triaged and referred to either primary or tertiary care, depending on risk.

Results

A total of 353 were screened (estimated 22.4% of population). The median age was 12 years (IQR 10 to 13), 55% were female and 55% were overweight or obese. Overall, 21.8% of children had at least one abnormality. Hypertension was identified in 5.4% and 11.9% had prehypertension. None of the children had an eGFR < 60 ml/min/1.73 m² however 10.5% had an ACR > 3 mg/mmol and 6.2% had an eGFR < 90 ml/min/1.73 m² suggestive of early kidney disease. Diabetes was identified in 1.4%, and 1.4% had HbA1c's between 6.1% and 6.49%.

Conclusions

Risk factors for chronic kidney disease are highly prevalent in rural Indigenous children. More research is required to confirm the persistence of these findings, and to evaluate the efficacy of screening children to prevent or delay progression to kidney failure.

CKD and ESRD in US Hispanics

Hispanics are the largest racial/ethnic minority group in the United States, and they experience a substantial burden of kidney disease. Although the prevalence of chronic kidney disease (CKD) is similar or slightly lower in Hispanics than non-Hispanic whites, the age- and sex-adjusted prevalence rate of end-stage renal disease is almost 50% higher in Hispanics compared with non-Hispanic whites. This has been attributed in part to faster CKD progression among Hispanics. Furthermore, Hispanic ethnicity has been associated with a greater prevalence of cardiovascular disease risk factors, including obesity and diabetes, as well as CKD-related complications. Despite their less favorable socioeconomic status, which often leads to limited access to quality health care, and their high comorbid condition burden, the risk for mortality among Hispanics appears to be lower than for non-Hispanic whites. This survival paradox has been attributed to a complex interplay between sociocultural and psychosocial factors, as well as other factors. Future research should focus on evaluating the long-term impact of these factors on patient-centered and clinical outcomes. National policies are needed to improve access to and quality of health care among Hispanics with CKD.

Evidence of chronic kidney disease in veterans with incident diabetes mellitus

While chronic kidney disease (CKD) is regularly evaluated among patients with diabetes, kidney function may be significantly impaired before diabetes is diagnosed. Moreover, disparities in the severity of CKD in such a population are likely. This study evaluated the extent of CKD in a national cohort of 36,764 US veterans first diagnosed with diabetes between 2003 and 2013 and prior to initiating oral antidiabetic therapy. Evidence of CKD (any stage) at the time of diabetes diagnosis was determined using eGFR and urine-albumin-creatinine ratios, the odds of which were assessed using logistic regression controlling for patient characteristics. CKD was evident in 31.6% of veterans prior to being diagnosed with diabetes (age and gender standardized rates: 241.8 per 1,000 adults [overall] and 247.7 per 1,000 adult males), over half of whom had at least moderate kidney disease (stage 3 or higher). The odds of CKD tended to increase with age (OR: 1.88; 95% CI: 1.82-1.93), hemoglobin A1C (OR: 1.05; 95% CI: 1.04-1.06), systolic blood pressure (OR: 1.04; 95% CI: 1.027-1.043), and BMI (OR: 1.016; 95% CI: 1.011-1.020). Both Asian Americans (OR: 1.53; 95% CI: 1.15-2.04) and African Americans (OR: 1.11; 95% CI: 1.03-1.20) had higher adjusted odds of CKD compared to whites, and prevalence was highest in the Upper Midwest and parts of the Mid-South. Results suggest that evidence of CKD is common among veterans before a diabetes diagnosis, and certain populations throughout the country, such as minorities, may be afflicted at higher rates.

Ambulatory blood pressure in the dash diet trial: Effects of race and albuminuria

We evaluated whether low-grade albuminuria or black race modulates ambulatory blood pressure (BP) or nocturnal BP response to the DASH diet. Among 202 adults enrolled in the DASH multicenter trial who were fed the DASH or control diet for 8 weeks, reductions in 24-hour daytime and nighttime SBP and DBP were significantly larger for DASH compared to control. Median changes in nocturnal BP dipping were not significant. Compared to urine albumin excretion of <7 mg/d, ≥7 mg/d was associated with larger significant median reductions in 24-hour SBP (-7.3 vs -3.1 mm Hg), all measures of DBP (24-hour: -5.9 vs -1.8 mm Hg; daytime: -9.9 vs -4.0 mm Hg; nighttime -9.0 vs -2.0 mm Hg), and with increased nocturnal SBP dipping (2.3% vs -0.5%). Black race was associated with larger median reduction in 24-hour SBP only (-5.5 vs -2.4 mm Hg). This analysis suggests greater effect of DASH on ambulatory BP in the presence of low-grade albuminuria.