Obesity and change in estimated GFR among older adults

Age and estimated glomerular filtration rate in Chinese older adults: a cohort study from 2014 to 2020

Objectives

This study aimed to fill the data gap of the course of renal function decline in old age and explore changes in renal function across different health states with increasing age.

Methods

This observational, retrospective, single-center cohort study included 5,112 Chinese older adults (3,321 men and 1,791 women, range 60-104 years). The individual rate of estimated glomerular filtration rate (eGFR) decline was analyzed using linear mixed-effects model to account for repeated measures over the years.

Results

The median age was 66 years, median BMI was 24.56 kg/m2, and median eGFR was 89.86 mL/min.1.73 m2. For every 1-year increase in age, women's eGFR decreased by 1.06 mL/min/1.73 m2 and men's by 0.91 mL/min/1.73 m2. We observed greater age-related eGFR decline in men and women with high systolic blood pressure (SBP). Men with high triglyceride (TG), high low-density lipoprotein cholesterol (LDL-C), and low high-density lipoprotein cholesterol (HDL-C), had greater age-related eGFR decline. In women, different BMI groups showed significant differences in age-related eGFR decline, with the highest decline in those with obesity. Additionally, participants with normal baseline eGFR had a faster age-related decline than those with low baseline eGFR.

Conclusion

The eGFR declined linearly with age in Chinese older adults, with women exhibiting a slightly faster decline than men. Both men and women should be cautious of SBP. Older adults with normal baseline renal function experienced a faster eGFR decline. Men with high TG, LDL-C, and low HDL-C levels, as well as obese women, should be vigilant in monitoring renal function.

Association between Neck Circumference and Chronic Kidney Disease in Korean Adults in the 2019-2021 Korea National Health and Nutrition Examination Survey

Chronic kidney disease (CKD) is a major public health problem and a leading cause of cardiovascular disease and death. Early recognition and management of CKD risk factors are necessary to prevent its onset and progression. Neck circumference (NC) is a non-invasive and easily accessible anthropometric measure associated with central obesity and subcutaneous fat accumulation in the upper body. Our study aimed to explore the relationship between NC and the prevalence of CKD using data from the nationally representative Korea National Health and Nutrition Examination Survey (2019-2021). We analyzed data from 10,219 subjects (age > 19 years, no missing values). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Logistic regression analysis was performed, which revealed a significant association between NC and CKD prevalence even after adjusting for confounding factors, both when NC was considered a continuous variable (OR [95% CI], 1.11 [1.03-1.19]) and in quartiles (Q1 as reference; Q2 OR [95% CI], 1.23 [0.91-1.67]; Q3 OR [95% CI], 1.59 [1.16-2.18]; Q4 OR [95% CI], 1.70 [1.16-2.50]). Our findings suggest that NC could be a simple and effective anthropometric measurement for identifying individuals at risk for CKD.

Modifiable kidney disease risk factors among nondiabetic adults with obesity from the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

It is unknown whether weight change or physical fitness is associated with chronic kidney disease (CKD) risk among nondiabetic adults with obesity.

METHODS

This was a prospective, longitudinal cohort study of adults with obesity without baseline CKD or diabetes enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). Linear mixed-effects and multistate models were adjusted for demographics, time-varying covariates including blood pressure, and comorbidities these were used to examine associations of weight change and slow walking pace (<2 miles/h) with (i) rate of annual estimated glomerular filtration rate (eGFR) decline and (ii) incident CKD, defined as eGFRCr-Cys  < 60 mL/min/1.73 m2 , and tested for interaction by baseline hypertension status.

RESULTS

Among 1208 included MESA participants (median BMI 33.0 kg/m2 [interquartile range 31.2-35.9]), 15% developed CKD. Slow walking pace was associated with eGFR decline (-0.27 mL/min/1.73 m2 /year; 95% CI: -0.42 to -0.12) and CKD risk (adjusted hazard ratio 1.48; 95% CI: 1.08 to 2.01). Weight gain was associated with CKD risk (adjusted hazard ratio 1.34; 95% CI: 1.02 to 1.78 per 5 kg weight gain from baseline). There was no significant interaction by baseline hypertension status.

CONCLUSIONS

Slow walking pace and weight gain were associated with CKD risk among adults with obesity who did not have diabetes at baseline.

Association Between Plasma Levels of ANGPTL3, 4, 8 and the Most Common Additional Cardiovascular Risk Factors in Patients with Hypertension

Background

ANGPTL3, 4 and 8 have been reported to be involved in the regulation of lipid and glucose metabolism. The aim of this study was to investigate the expression of ANGPTL3, 4, 8 in hypertensive patients with or without overweight/obesity, T2D, and hyperlipidemia, and the possible association between their expression and the status of the aforementioned comorbidities.

Methods

Plasma levels of ANGPTL3, 4, and 8 in 87 hospitalized patients with hypertension were measured using ELISA kits. Associations between circulating ANGPTLs levels and the most common additional cardiovascular risk factors were assessed using multivariate linear regression analyses. Pearson's correlation analysis was used to examine the association between ANGPTLs and clinical parameters.

Results

In the context of hypertension, (1) although not statistically significant, circulating ANGPTL3 levels were higher in the overweight/obese group than in the normal weight group; (2) circulating levels of ANGPTL3 and ANGPTL8 were significantly lower in patients with T2D than in non-diabetic patients; (3) circulating ANGPTL3 levels were significantly higher in the hyperlipidemic group than in the non-hyperlipidemic group. ANGPTL3 was associated with T2D and hyperlipidemia status, whereas ANGPTL8 was independently associated with T2D status. In addition, circulating ANGPTL3 levels were positively correlated with TC, TG, LDL-C, HCY, and ANGPTL8, and circulating ANGPTL4 levels were positively correlated with UACR and BNP.

Conclusion

Changes in circulating ANGPTL3 and ANGPTL8 levels have been observed in hypertensive patients with the most common additional cardiovascular risk factors, suggesting a role in the common comorbidities of hypertension and cardiovascular disease. Hypertensive patients with overweight/obesity or hyperlipidemia may benefit from therapies targeting ANGPTL3.

Kidney-Function Trajectories From Young Adulthood to Midlife: Identifying Risk Strata and Opportunities for Intervention

Introduction

Understanding normative patterns of change in kidney function over the life course may allow targeting of early interventions to slow or prevent the onset of kidney disease, but knowledge about kidney functional change before middle age is limited. This study used prospective longitudinal data from a representative birth cohort to examine common patterns of change from young to midadulthood and to identify risk factors and outcomes associated with poorer trajectories.

Methods

We used group-based trajectory modeling in the Dunedin study birth cohort (n = 857) to identify the following: (i) common kidney function trajectories between the ages 32 and 45 years, (ii) early-life factors associated with those trajectories, (iii) modifiable physical and psychosocial factors across adulthood associated with differences in trajectory slope, and (iv) links between trajectories and kidney-related outcomes at age 45 years.

Results

Three trajectory groups were identified and could be differentiated by age 32 years as follows: normal (58% of participants), low-normal (36%), and high-risk (6%) groups. Those from low socioeconomic backgrounds had higher odds of following a high-risk (vs. normal) trajectory. Modifiable factors (blood pressure, body mass index, inflammation, glycated hemoglobin, smoking, and socioeconomic status) across adulthood were associated with steeper age-related declines in kidney function, particularly among those in the low-normal and high-risk groups. Those in the low-normal and high-risk groups also had more adverse kidney-related outcomes at age 45 years.

Conclusion

The current findings could be used to inform the development of early interventions and point to socioeconomic conditions across the life course and health-related risk factors and behaviors in adulthood as kidney health promotion targets.

Body roundness index is related to the low estimated glomerular filtration rate in Chinese population: A cross-sectional study

BACKGROUND

Kidney disease is related to visceral obesity. As a new indicator of obesity, body roundness index (BRI) has not been fully revealed with kidney disease. This study's objective is to assess the relationship between estimated glomerular filtration rate (eGFR) and BRI among the Chinese population.

METHODS

This study enrolled 36,784 members over the age of 40, they were from 7 centers in China by using a random sampling method. BRI was computed using height and waist circumference, eGFR ≤ 90 mL/min/1.73 m² was considered to indicate low eGFR. To lessen bias, propensity score matching was employed, multiple logistic regression models were utilized to examine the connection between low eGFR and BRI.

RESULTS

The age, diabetes and coronary heart disease rates, fasting blood glucose, and triglycerides were all greater in participants with low eGFR. The BRI quartile was still positively connected with low eGFR after controlling for confounding variables, according to multivariate logistic regression analysis. (OR [95%CI] Q2:1.052 [1.021-1.091], OR [95%CI] Q3:1.189 [1.062-1.284], OR [95%CI] Q4:1.283 [1.181-1.394], P trend < 0.001). Stratified research revealed that the elders, women, habitual smokers, and those with a history of diabetes or hypertension experienced the connection between BRI level and low eGFR. According to ROC, BRI was able to detect low eGFR more accurately.

CONCLUSION

Low eGFR in the Chinese community is positively connected with BRI, which has the potential to be used as an effective indicator for screening kidney disease to identify high-risk groups and take appropriate measures to prevent subsequent complications.

Aging and hypertension in kidney function decline: A 10 year population-based study

Background

Aging is associated with a physiological decline in kidney function (KFD). In this study, we aimed to describe the impact of age on the rate of KFD and its interplay with risk factors for chronic kidney disease (CKD), considering mainly hypertension (HT), in the general population.

Materials and methods

Participants of European descent, aged 35-75, were recruited from a populational cohort in Lausanne, Switzerland. Participants with a 10 year follow-up were selected. KFD was defined as the difference in estimated glomerular filtration rate (eGFR) between baseline and follow-up, divided by the observation period. Multivariate linear regressions were used with KFD as the outcome and age as the main predictor. HT was tested as a modifying factor.

Results

We included 4,163 participants with mean age 52.2 ± 10.4, 44.7% men, 31.9% HT, and 5.0% diabetics. Mean baseline eGFR was 85.9 ± 14.6 ml/min/1.73 m². Mean KFD was -0.49 ± 1.08 ml/min/1.73 m² per year with 70% of participants decreasing their eGFR during follow-up. The relationship between age and KFD was non-linear and age was divided in tertiles. Old participants had faster rates of KFD as compared to young and middle-age participants (p < 0.001). A significant interaction was found between age and HT on KFD prediction (p < 0.001). In HT participants, KFD was significantly different across tertiles of age (p < 0.001). On contrary, KFD was not different across tertiles of age in non-HT participants.

Conclusion

A physiological KFD is present over time in the general population. Age contributes non-linearly to the rate of this decline with older subjects declining the fastest. The presence of HT is a major contributing factor in this setting as KFD worsened with age only in hypertensive participants. Thus, HT represents an important pathological factor aggravating the age-related physiological decline in eGFR in the general population.

Severity of Periodontal Disease in Chronic Kidney Disease Patients: A Hospital-Based Study

Background

Periodontal disease is a chronic inflammatory condition of multifactorial origin. The inflammatory mediators released during the progression of disease may affect all the organs of the body. Renal disease is a chronic systemic disease which may influence the progression of periodontal disease. Therefore, this study was conducted to evaluate and compare the prevalence of periodontal disease among individuals with chronic kidney disease undergoing maintenance hemodialysis with healthy individuals.

Methodology

In this cross-sectional study including 150 participants, 75 patients with different renal diseases undergoing hemodialysis (Group I) and 75 healthy controls (Group II) were included. The general examination of the patients was done. Blood pressure, pulse, and body mass index were recorded, followed by biochemical investigations, in which serum urea, serum creatinine, and random blood sugar were evaluated for each participant. Plaque Index (PI) and Gingival Index (GI) scores were recorded. Probing pocket depth (PPD) and gingival recession GR were measured, and clinical attachment level (CAL) was calculated based on the obtained values. The subjects were then categorized into three groups, namely, no/mild, moderate, and severe periodontitis.

Results

Out of the total study participants, 68% were men and 32% were women, with a mean age of 47 years. Serum markers were significantly elevated in Group I compared to Group II. Poor oral hygiene and periodontitis were observed to be much higher in dialysis patients compared to the control group. The two groups also significantly differed in PI, GI, PPD, GR, and CAL, all of which were higher in Group I.

Conclusions

The results suggest that patients with renal disease must be screened for periodontal disease.

Obesity, Weight Loss, Lifestyle Interventions, and Autosomal Dominant Polycystic Kidney Disease

Obesity remains a growing public health concern in industrialized countries around the world. The prevalence of obesity has also continued to rise in those with chronic kidney disease. Epidemiological data suggests those with overweight and obesity, measured by body mass index, have an increased risk for rapid kidney disease progression. Autosomal dominant polycystic kidney disease causes growth and proliferation of kidney cysts resulting in a reduction in kidney function in the majority of adults. An accumulation of adipose tissue may further exacerbate the metabolic defects that have been associated with ADPKD by affecting various cell signaling pathways. Lifestyle interventions inducing weight loss might help delay disease progression by reducing adipose tissue and systematic inflammation. Further research is needed to determine the mechanistic influence of adipose tissue on disease progression.

Associations of endogenous androgens and sex hormone-binding globulin with kidney function and chronic kidney disease

INTRODUCTION

The role of endogenous androgens in kidney function and disease has not been extensively explored in men and women.

RESEARCH DESIGN AND METHODS

We analyzed data from the observational KORA F4 study and its follow-up examination KORA FF4 (median follow-up time 6.5 years) including 1293 men and 650 peri- and postmenopausal women, not using exogenous sex hormones. We examined the associations between endogenous androgens (testosterone [T], dihydrotestosterone [DHT], free T [fT], free DHT [fDHT], and T/DHT), with estimated glomerular filtration rate (eGFR) at baseline and follow-up, prevalent, and incident chronic kidney disease (CKD) adjusting for common CKD risk factors.

RESULTS

At baseline, 73 men (5.7%) and 54 women (8.4%) had prevalent CKD. Cross-sectionally, no significant associations between androgens and kidney function were observed among men. In women, elevated T (β=-1.305, [95% CI -2.290; -0.320]) and fT (β=-1.423, [95% CI -2.449; -0.397]) were associated with lower eGFR. Prospectively, 81 men (8.8%) and 60 women (15.2%) developed incident CKD. In women, a reverse J-shaped associations was observed between DHT and incident CKD (P_non-linear=0.029), while higher fDHT was associated with lower incident CKD risk (odds ratio per 1 standard deviation=0.613, [95% CI 0.369; 0.971]. Among men, T/DHT (β=-0.819, [95% CI -1.413; -0.226]) and SHBG (P_non-linear=0.011) were associated with eGFR at follow-up but not with incident CKD. Some associations appeared to be modified by type 2 diabetes (T2D).

CONCLUSION

Suggestive associations are observed of androgens and SHBG with kidney impairment among men and women. However, larger well-phenotyped prospective studies are required to further elucidate the potential of androgens, SHBG, and T2D as modifiable risk factors for kidney function and CKD.

Determinants of the Evolution of Kidney Function With Age

Introduction

Kidney function declines with age, but its determinants in the general population remain incompletely understood. We investigated the rate and determinants of kidney function decline in the general population.

Methods

Participants with information on kidney function were selected from a population-based cohort study. Joint models were used to investigate the evolution of the estimated glomerular filtration rate (eGFR, expressed in ml/min per 1.73 m² per year) and the urine albumin-to-creatinine ratio (ACR, expressed in mg/g per year) with age. We stratified for 8 potential determinants of kidney function decline, including sex, cardiovascular risk factors, and cardiovascular disease.

Results

We included 12,062 participants with 85,922 eGFR assessments (mean age 67.0 years, 58.7% women) and 3522 participants with 5995 ACR measurements. The annual eGFR decline was 0.82 and the ACR increase was 0.05. All determinants appeared detrimental for eGFR and ACR, except for prediabetes and higher body mass index which proved only detrimental for ACR. In participants without the determinants, eGFR decline was 0.75 and ACR increase was 0.002. Higher baseline eGFR but faster eGFR decline with age was detected in men (0.92 vs. 0.75), smokers (0.90 vs. 0.75), and participants with diabetes (1.07 vs. 0.78).

Conclusion

We identify prediabetes, smoking, and blood pressure as modifiable risk factors for kidney function decline. As with diabetes, hyperfiltration seems important in accelerated kidney function decline in men and smokers. The interpretation of kidney function decline may require adjustment for age and sex to prevent overdiagnosis of chronic kidney disease in aging populations.

Kidney disease risk factors do not explain impacts of low dietary protein on kidney function and structure

The kidneys balance many byproducts of the metabolism of dietary components. Previous studies examining dietary effects on kidney health are generally of short duration and manipulate a single macronutrient. Here, kidney function and structure were examined in C57BL/6J mice randomized to consume one of a spectrum of macronutrient combinations (protein [5%–60%], carbohydrate [20%–75%], and fat [20%–75%]) from weaning to late-middle age (15 months). Individual and interactive impacts of macronutrients on kidney health were modeled. Dietary protein had the greatest influence on kidney function, where chronic low protein intake decreased glomerular filtration rates and kidney mass, whereas it increased kidney immune infiltration and structural injury. Kidney outcomes did not align with cardiometabolic risk factors including glucose intolerance, overweight/obesity, dyslipidemia, and hypertension in mice with chronic low protein consumption. This study highlights that protein intake over a lifespan is an important determinant of kidney function independent of cardiometabolic changes.

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Chronic high macronutrient intake from any source increases kidney function (GFR)

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Low protein intake led to greater kidney tubular structural injury and inflammation

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Lower protein intake decreased kidney mass and glomerular filtration capacity

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Kidney outcomes did not align with longevity or cardiometabolic outcomes

Association between metabolic syndrome components and chronic kidney disease among 37,533 old Chinese individuals

Background

Chronic kidney disease (CKD) has become a worldwide health problem among aging populations. However, epidemiological information on Chinese elderly people with CKD is still lacking. This study aimed to investigate the epidemiological features and associated risk factors of CKD in aging population in China.

Methods

In this cross-sectional study, a total of 37,533 individuals aged ≥ 65 years were enrolled in Binhai from January to December 2018. The crude and standardized prevalence of CKD were calculated. Associations of metabolism-related indicators with CKD were examined using univariate and multivariate analyses.

Results

The overall prevalence of CKD was 17.7% (95% confidence interval 17.3–18.1%) in this Chinese elderly population. The prevalence was 17.5% among men (95% CI 17.0–18.1%) and 17.8% among women (95% CI 17.3–18.4%). The mean eGFR was 84.22 (SD ± 12.87) mL/min/1.73 m², with the median value higher for women than for men.

Conclusion

Our study shows a high prevalence of CKD among Chinese elderly population. Aging, pre-HTN, HTN, elevated triglyceride, and FBG were associated with the risk of CKD. More attention should be paid to metabolic diseases to prevent CKD in the elderly.

Association between socioeconomic position and cystatin C in the Heinz Nixdorf Recall Study

Social inequalities in health and disease are well studied. Less information is available on inequalities in biomarker levels indicating subclinical stages of disease such as cystatin C, an early diagnostic marker of renal dysfunction and predictor for cardiovascular disease. We evaluated the relationship between cystatin C, socioeconomic position (SEP) and established cardiovascular risk factors in a population-based study. In 4475 men and women aged 45–75 years participating in the baseline examination of the Heinz Nixdorf Recall Study cystatin C was measured from serum samples with a nephelometric assay. SEP was assessed by education and household income. Linear regression models were used to analyse the association between SEP and cystatin C as well as the impact of cardiovascular risk factors (i.e., body mass index, blood pressure, blood glucose, diabetes mellitus, blood lipids, C-reactive protein, smoking) on this association. After adjustment for age and sex cystatin C decreased by 0.019 mg/l (95% confidence interval (CI) − 0.030 to − 0.008) per five years of education. While using a categorical education variable cystatin C presented 0.039 mg/l (95% CI 0.017–0.061) higher in men and women in the lowest educational category (≤ 10 years of education) compared to the highest category (≥ 18 years). Concerning income, cystatin C decreased by 0.014 mg/l (95% CI − 0.021 to − 0.006) per 1000 € after adjustment for age and sex. For men and women in the lowest income quartile cystatin C was 0.024 mg/l (95% CI 0.009–0.038) higher compared to the highest income quartile. After adjusting for established cardiovascular risk factors the observed associations were substantially diminished. Social inequalities seem to play a role in subclinical stages of renal dysfunction, which are also related to development of cardiovascular disease. Adjustment for traditional cardiovascular risk factors showed that these risk factors largely explain the association between SEP and cystatin C.

Factors predicting decline in renal function and kidney volume growth in autosomal dominant polycystic kidney disease: a prospective cohort study (Japanese Polycystic Kidney Disease registry: J-PKD)

BACKGROUND

Factors affecting decline in renal function and cyst growth in patients with autosomal polycystic kidney disease (ADPKD) are not fully described, particularly in Japan.

METHODS

This was the first multi-facility, prospective, observational cohort study conducted in ADPKD patients at 14 centers in Japan. Patients in the J-PKD registry were assessed from December 2009 to June 2012 (follow-up until June 2017). Patients' data including estimated glomerular filtration rate (eGFR) and total kidney volume (TKV) were assessed initially and a maximum of five times annually. Contributing factors to eGFR decline and TKV growth were identified using multiple linear regression analysis.

RESULTS

Of the 340 patients in the J-PKD registry, data analysis was performed for 192 patients in whom serial changes for both eGFR and TKV were obtained. eGFR slope, eGFR change, and TKV change values were as follows: - 2.7 (- 4.2 to - 1.5) (ml/min/1.73 m²/year), - 5.0 (- 9.6 to - 2.3) (%/year), and 4.78 (0.86-8.22) (%/year), respectively. Lower high-density lipoprotein (HDL) cholesterol was an independent predictor of eGFR decline, using both eGFR slope and change (P = 0.04, P = 0.02, respectively), whereas lower hemoglobin and higher uric acid were significantly associated with greater eGFR change only (P = 0.02, P = 0.002, respectively). Younger age and higher fasting blood sugar were independent predictors of greater TKV change (P = 0.01, P = 0.02, respectively).

CONCLUSIONS

This real-world study in Japan identified risk factors for renal function decline in ADPKD patients. These included lower HDL cholesterol, lower hemoglobin and higher uric acid for eGFR decline, and youth and higher blood sugar levels for TKV growth.

Is trimethoprim/sulfamethoxazole-associated increase in serum creatinine a pseudo-elevation or true nephrotoxicity?

INTRODUCTION

The aim of this study was to determine the rates of trimethoprim/sulfamethoxazole (TMP/SMX)-associated pseudo-elevation and true nephrotoxicity by comparison of creatinine-estimated and cystatin C-estimated GFRs (glomerular filtration rates) before and after TMP/SMX administrations.

METHODS

Patients in whom serum creatinine and cystatin C were simultaneously measured are the cohort of this study. A decreasing of creatinine-estimated GFR posterior to TMP/SMX by ≥ 20% and a decreasing of cystatine C-estimated GFR posterior to TMP/SMX by ≥ 20% were defined as true nephrotoxicity. A decreasing of creatinine-estimated GFR posterior to TMP/SMX by ≥ 20% and a decreasing of cystatine C-estimated GFR posterior to TMP/SMX by < 20% were defined as pseudo-elevation.

RESULTS

A total of 66 patients were enrolled. Within the 19 patients in whom serum creatinine and cystatin C were measured simultaneously both before and after TMP/SMX administrations, 10 patients (52.6%) had nephrotoxicity. Fewer random error and systematic bias between creatinine- and cystatine C-estimated GFR were observed after TMP/SMX than before TMP/SMX by Bland-Altman analysis.

CONCLUSIONS

Using cystatin C, we reveled TMP/SMX-associated nephrotoxicity is not uncommon. We should equally pay attention to TMP/SMX-associated nephrotoxicity and pseudo-elevation. In spite of pseudo-elevation, creatinine-estimated GFR after receiving TMP/SMX is ironically reliable as surrogate maker for renal clearance.

Management of Obesity in Adults with CKD

Obesity is a leading public health problem that currently affects over 650 million individuals worldwide. Although interest in the adverse effects of obesity has grown exponentially in recent years, less attention has been given to studying its management in individuals with CKD. This relatively unexplored area should be considered a high priority because of the rapid growth and high prevalence of obesity in the CKD population, its broad impact on health and outcomes, and its modifiable nature. This article begins to lay the groundwork in this field by providing a comprehensive overview that critically evaluates the available evidence related to obesity and kidney disease, identifies important gaps in our knowledge base, and integrates recent insights in the pathophysiology of obesity to help provide a way forward in establishing guidelines as a basis for managing obesity in CKD. Finally, the article includes a kidney-centric algorithm for management of obesity that can be used in clinical practice.

Association between Neck Circumference and the Risk of Decreased Estimated Glomerular Filtration Rate in the General Population of China: A Cross-Sectional Study

Background

The burden of chronic kidney disease is increasing substantially worldwide. Neck circumference (NC), an anthropometric index for upper-body adiposity, has been recognized as an indicator of cardiometabolic diseases. However, the association between NC and renal dysfunction has not been fully disclosed.

Objectives

The aim of this study was to investigate the association between NC and estimated glomerular filtration rate (eGFR) in the general population in China.

Methods

A total of 8805 participants (3322 men and 5483 women) were enrolled in this study. Logistic regression analysis was conducted to examine the association between NC and eGFR. The male and female subjects were divided into four groups according to the NC quartiles. The primary outcome was defined as an eGFR ≤ 90 mL/min/1.73 m².

Results

Logistic regression analysis revealed that in both sexes, higher NC was significantly associated with a higher risk of decreased eGFR even after fully adjusting for age, other anthropometric indexes, traditional risk factors for chronic kidney diseases, and sociologic risk factors (quartile 1 as a reference; the odds ratios [95% confidence intervals] were as follows: quartile 2, 1.26 [0.99-1.59]; quartile 3, 1.40 [1.07-1.83]; and quartile 4, 1.71 [1.22-2.38], in men; quartile 2, 1.14 [0.95-1.37]; quartile 3, 1.31 [1.03-1.66]; and quartile 4, 1.32 [1.04-1.68], in women). Stratified analyses suggested that the association was significant among subjects with prediabetes or normal serum uric acid levels and those without cardiovascular diseases (CVD). Among subjects with CVD, the association persisted only in males. When the subjects were stratified according to blood pressure or BMI, the association persisted among male subjects with abnormal blood pressure and was strengthened among male subjects who were overweight/obese, while the association disappeared among female subjects.

Conclusions

NC is independently associated with the risk of decreased eGFR in the general population in China, indicating that NC could contribute to renal dysfunction risk assessment.

Childhood socioeconomic status, comorbidity of chronic kidney disease risk factors, and kidney function among adults in the midlife in the United States (MIDUS) study

Background

There is a lack of empirical effort that systematically investigates the clustering of comorbidity among known risk factors (obesity, hypertension, diabetes, hypercholesterolemia, and elevated inflammation) of chronic kidney disease (CKD) and how different types of comorbidity may link differently to kidney function among healthy adult samples. This study modeled the clustering of comorbidity among risk factors, examined the association between the clustering of risk factors and kidney function, and tested whether the clustering of risk factors was associated with childhood SES.

Methods

The data were from 2118 participants (ages 25–84) in the Midlife in the United States (MIDUS) Study. Risk factors included obesity, elevated blood pressure (BP), high total cholesterol levels, poor glucose control, and increased inflammatory activity. Glomerular filtration rate (eGFR) was estimated from serum creatinine, calculated with the CKD-EPI formula. The clustering of comorbidity among risk factors and its association with kidney function and childhood SES were examined using latent class analysis (LCA).

Results

A five-class model was optimal: (1) Low Risk (class size = 36.40%; low probability of all risk factors), (2) Obese (16.42%; high probability of large BMI and abdominally obese), (3) Obese and Elevated BP (13.37%; high probability of being obese and having elevated BP), (4) Non-Obese but Elevated BP (14.95%; high probability of having elevated BP, hypercholesterolemia, and elevated inflammation), and (5) High Risk (18.86%; high probability for all risk factors). Obesity was associated with kidney hyperfiltration, while comorbidity between obesity and hypertension was linked to compromised kidney filtration. As expected, the High Risk class showed the highest probability of having eGFR < 60 ml/min/1.73 m² (P = .12; 95%CI = .09–.17). Finally, higher childhood SES was associated with reduced probability of being in the High Risk rather than Low Risk class (β = − 0.20, SE = 0.07, OR [95%CI] = 0.82 [0.71–0.95]).

Conclusion

These results highlight the importance of considering the impact of childhood SES on risk factors known to be associated with CKD.

Anti-inflammatory action of β-hydroxybutyrate via modulation of PGC-1α and FoxO1, mimicking calorie restriction

β-Hydroxybutyrate (HB) is a ketone body used as an energy source that has shown anti-inflammatory effects similar to calorie restriction (CR); Here, PGC-1α, an abundantly expressed co-factor in the kidney, was reported to interact with both FoxO1 and NF-κB although the definitive interactive mechanism has not yet been reported. In this study, we investigated whether renal aging-related inflammation is modulated by HB. We compared aged rats administered with HB to calorie restricted rats and examined the modulation of FoxO1 and the NF-κB pathway through interactions with PGC-1α. We found that in aged rats treated with HB, pro-inflammatory signaling changes were reversed and showed effects comparable to CR. As FoxO1 and its target genes catalase/MnSOD were upregulated by HB treatment and PGC-1α selectively interacted with FoxO1, not with NF-κB, and ameliorated the renal inflammatory response. These findings were further confirmed using FoxO1 overexpression and siRNA transfection in vitro. Our findings suggest that HB suppressed aging-related inflammation as a CR mimetic by enabling the co-activation and selective interaction between FoxO1 and PGC-1α. This study demonstrates the potential therapeutic role of HB as a CR mimetic, which ameliorates inflammation by a novel mechanism where FoxO1 outcompetes NF-κB by interacting with PGC-1α in aging kidneys.

The anti-inflammatory and antioxidant effects of pigmented rice consumption in an obese cohort

The development of lifestyle diseases in the obese has been attributed to higher levels of inflammation and free radical mediated oxidative stress. The antioxidant and anti-inflammatory properties of polyphenols in pigmented rice varieties could have potential to neutralize oxidative stress and modulate inflammatory responses in the obese. A cross-over dietary intervention human clinical trial was conducted with three pigmented rice varieties chosen from previous chemical and in vitro antioxidant and anti-inflammatory screening. Obese (n = 22, BMI > 30) sedentary participants consumed one cup of pigmented rice (Reiziq (brown), Purple (purple) and Yunlu29 (red)). Blood samples were collected prior consumption (baseline) and at set time points of 30 minutes, 1 hour, 2 hours and 4 hours post rice consumption. The collected blood samples were analysed for antioxidant and inflammatory biomarkers. Total antioxidant activity increased (p < 0.001) at the 1 hour time point by 40.3% post purple rice consumption. The red rice variety, Yunlu29 increased antioxidant activity at the 30 minute (p < 0.001) and 1 hour (p < 0.01) time point by 29.5% and 21.2% respectively. Lipid peroxidation biomarker, malondialdehyde (MDA), decreased (p < 0.05) at the 30 minute time point by 6.8% post purple rice consumption. At the 4 hour time point MDA levels was significantly reduced (p < 0.001) by the red rice variety Yunlu29, by 9.6%. Pro-inflammatory cytokine, interleukin-10 (IL-10), was significantly (p < 0.0001) reduced by 3.1% 30 minutes post purple rice consumption. In contrast, Yunlu29 (red) reduced interleukin-6 levels by 13.6% and 11.0% at the 30 minute and 1 hour time points respectively. Both the purple (p < 0.01) and red (p < 0.001) varieties significantly reduced interleukin-12p70 concentrations at 30 minutes by 8.7% and 10.3% respectively. Reiziq (brown) did not affect any of the biomarkers analysed in this study. The outcomes of this study highlight that polyphenols found in pigmented rice may play a key role in targeting specific therapeutic pathways in obesity-related oxidative stress and inflammation.

Body mass index is an independent predictive factor for kidney function evaluated by glomerular filtration rate in a community-dwelling population

BACKGROUND

The effects of overweight and obesity on kidney function have since been identified and become a subject of increased study and concern. But the association between body mass index (BMI) and estimated glomerular filtration rate (eGFR) is not well characterized. The aim of this study was to determine the relationship between BMI and eGFR.

METHODS

To better understand the relationship between BMI and kidney function, we investigated the association between BMI and eGFR using both the baseline BMI level and the follow-up eGFR level and investigated the relationship between the change in BMI and the change in eGFR in 1447 patients from a 4.8-year prospective study in Beijing, People's Republic of China.

RESULTS

In multiple linear regression analysis, age, antihypertensive treatment, and BMI were negatively associated with the follow-up eGFR levels in all participants (R = -0.622, -0.926, and -0.266, respectively; P < 0.05), or in the elderly (R = -0.883, -1.035, and -0.630, respectively; P < 0.05); sex was found to be associated with the follow-up eGFR levels independently not only in all participants (R = 6.783; P < 0.001), but also in the elderly (R = 3.518; P < 0.05). In addition, the change in eGFR levels was positively related to age, the change in LDL-C, the change in TC, and the change in SBP, but negatively related to the change in BMI and the change in HDL-C (all P < 0.05).

CONCLUSIONS

The present study clearly indicated that BMI is an independent predictive factor for kidney function evaluated by the eGFR level during a median 4.8 years of follow-up in Chinese population.

LEVEL OF EVIDENCE

Level III, prospective cohort study.

The Association between Obesity Phenotypes and Early Renal Function Decline in Adults without Hypertension, Dyslipidemia, and Diabetes

Background

The prevalence of chronic kidney disease is increasing worldwide. Several studies have suggested that obesity is associated with early renal dysfunction. However, little is known about the relationship between obesity phenotypes and early renal function decline. Therefore, this study aimed to identify the relationship between obesity phenotypes and early renal function decline in adults without hypertension, dyslipidemia, and diabetes.

Methods

We conducted a cross-sectional analysis of clinical and anthropometric data from 1,219 patients who underwent a routine health checkup in 2014. We excluded adults with cardiovascular disease, renal disease, diabetes, hypertension, dyslipidemia, or low glomerular filtration rate (<60 mL/min/1.73 m²). Renal function was determined according to the estimated glomerular filtration rate calculated using the Chronic Kidney Disease Epidemiology Collaboration creatinine-cystatin C equation.

Results

Age, sex, body mass index, waist circumference, triglyceride, low-density lipoprotein, and fasting glucose had an association with the estimated glomerular filtration rate. After adjusting for age, sex, smoking status, and alcohol intake, the odds ratios of the metabolically abnormal normal weight and metabolically abnormal obese phenotypes for the presence of low estimated glomerular filtration rates were 1.807 (95% confidence interval, 1.009– 3.236) and 1.834 (95% confidence interval, 1.162–2.895), compared with the metabolically healthy normal weight phenotype. However, the metabolically healthy obese phenotype did not show a significant association with early renal function decline.

Conclusion

In this cross-sectional study, we confirmed the association between the metabolically abnormal normal weight and metabolically abnormal obese phenotypes and early kidney function decline in adults without hypertension, dyslipidemia, and diabetes.

Inhibition of PAI-1 attenuates perirenal fat inflammation and the associated nephropathy in high-fat diet-induced obese mice

Plasminogen activator inhibitor-1 (PAI-1) is increasingly recognized as a mediator in extracellular matrix (ECM) accumulation in diabetic nephropathy. Previous studies have implicated PAI-1 in adipose tissue (AT) expansion, while also contributing to insulin resistance. As inflammation is also known to occur in perirenal AT during obesity, we hypothesized that in a high-fat diet (HFD)-induced obese mouse model, PAI-1 contributes to macrophage-mediated inflammation and diabetic nephropathy. The HFD mice showed increased expression of PAI-1 in perirenal fat and also displayed increased fat weight and macrophage numbers. We found that the macrophage polarization, proinflammatory macrophage-M1-phenotype, including CD11c, IL-6, and monocyte chemoattractant protein-1, were increased by an HFD and decreased by either the genetic depletion of PAI-1 or treatment with the PAI-1 inhibitor, PAI-039. Similarly, an enhanced anti-inflammatory M2-phenotype, including CD206 and IL-10, was accompanied by either the genetic deletion of PAI-1 or PAI-039 treatment. Furthermore, the inhibition of PAI-1 reduced HFD-induced renal histological lesions and abated profibrotic/extracellular-matrix protein. Collectively, our findings provide support that PAI-1 contributes to the development of inflammation in perirenal fat and correlates with the development of diabetic nephropathy in HFD-induced obesity.

Coloured rice-derived polyphenols reduce lipid peroxidation and pro-inflammatory cytokines ex vivo

Rice-derived polyphenols have been demonstrated to alleviate obesity-related oxidative stress and inflammation. The aim of the study was to investigate if coloured rice polyphenol extracts (PE) reduce malondialdehyde, interleukin-6 and tumour necrosis factor-α (TNF-α) levels in obese individuals ex vivo. Malondialdehyde and pro-inflammatory cytokines were quantified using high-performance liquid chromatography and flow cytometry respectively. Fasting blood samples were treated with PE from three coloured rice varieties (purple, red and brown rice) at varying concentrations (10, 20, 50, 100, 200 and 500 μg mL-1). PE treatment demonstrated a dose-dependent reduction in malondialdehyde and TNF-α levels. Purple PE reduced plasma malondialdehyde concentration by 59% compared to red (21%) and brown (25.5%) rice PE. Brown rice PE at 50 μg mL-1 reduced TNF-α levels by 98% compared to red (80%) and purple rice PE (74%). Rice PE did not modulate plasma interleukin-6 concentrations. Coloured rice may be of therapeutic benefit as a potential functional food alternative in targeting specific pathways associated with obesity.

Changes of Percent Body Fat as a Useful Surrogate for Risk of Declined Renal Function

The association between anthropometric indices with chronic kidney disease (CKD) was examined previously. However, the effect of body fat on renal function was not determined clearly. Our aim was to investigate the association of percent body fat (PBF) and renal function in adult population from health examination in Tri-Service General Hospital (2010–2016). 35087 participants aged 20 years and older were enrolled in the study. PBF was measured by bioelectrical impedance analysis (BIA). Estimation of renal function was performed by Taiwanese MDRD equation. Optimal cut-off values of PBF was accessed by a receiver–operator characteristic (ROC) curve analysis. Multivariate regression models were used in the relationship among changes of PBF, renal function, and future CKD. In terms of baseline PBF for CKD, optimal cut-off values of PBF in males and females were 21.55 and 40.75. The changes of PBF were more closely associated with renal function decline than waist circumference (WC) with β values of −0.173 (95% CI: −0.233, −0.112) and −0.077 (95% CI: −0.104, −0.049), respectively. After stratified by gender, this relationship remained significant in male population with β values of −0.276 (95% CI: −0.371, −0.181) and −0.159 (95% CI: −0.207, −0.112), respectively. Female subjects with increased baseline PBF over cut-off values had increased risk for predicting the future CKD with odd ratios (ORs) of 2.298 (95% CI: 1.006–5.252). Body fat had detrimental impact on renal function and development of CKD in adult population. Measurement of PBF for surveillance of renal function impairment was warranted.

Modeling the impact of obesity on the lifetime risk of chronic kidney disease in the United States using updated estimates of GFR progression from the CRIC study

Rationale & objective

As the prevalence of obesity continues to rise in the United States, it is important to understand its impact on the lifetime risk of chronic kidney disease (CKD).

Study design

The CKD Health Policy Model was used to simulate the lifetime risk of CKD for those with and without obesity at baseline. Model structure was updated for glomerular filtration rate (GFR) decline to incorporate new longitudinal data from the Chronic Renal Insufficiency Cohort (CRIC) study.

Setting and population

The updated model was populated with a nationally representative cohort from National Health and Nutrition Examination Survey (NHANES).

Outcomes

Lifetime risk of CKD, highest stage and any stage.

Model, perspective, & timeframe

Simulation model following up individuals from current age through death or age 90 years.

Results

Lifetime risk of any CKD stage was 32.5% (95% CI 28.6%–36.3%) for persons with normal weight, 37.6% (95% CI 33.5%–41.7%) for persons who were overweight, and 41.0% (95% CI 36.7%–45.3%) for persons with obesity at baseline. The difference between persons with normal weight and persons with obesity at baseline was statistically significant (p<0.01). Lifetime risk of CKD stages 4 and 5 was higher for persons with obesity at baseline (Stage 4: 2.1%, 95% CI 0.9%–3.3%; stage 5: 0.6%, 95% CI 0.0%–1.1%), but the differences were not statistically significant (stage 4: p = 0.08; stage 5: p = 0.23).

Limitations

Due to limited data, our simulation model estimates are based on assumptions about the causal pathways from obesity to CKD, diabetes, and hypertension.

Conclusions

The results of this study indicate that obesity may have a large impact on the lifetime risk of CKD. This is important information for policymakers seeking to set priorities and targets for CKD prevention and treatment.

CKD Self-management: Phenotypes and Associations With Clinical Outcomes

BACKGROUND

To slow chronic kidney disease (CKD) progression and its complications, patients need to engage in self-management behaviors. The objective of this study was to classify CKD self-management behaviors into phenotypes and assess the association of these phenotypes with clinical outcomes.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Adults with mild to moderate CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. 3,939 participants in the CRIC Study recruited between 2003 and 2008 served as the derivation cohort and 1,560 participants recruited between 2013 and 2015 served as the validation cohort.

PREDICTORS

CKD self-management behavior phenotypes.

OUTCOMES

CKD progression, atherosclerotic events, heart failure events, death from any cause.

MEASUREMENTS

Latent class analysis stratified by diabetes was used to identify CKD self-management phenotypes based on measures of body mass index, diet, physical activity, blood pressure, smoking status, and hemoglobin A1c concentration (if diabetic); Cox proportional hazards models.

RESULTS

3 identified phenotypes varied according to the extent of implementation of recommended CKD self-management behaviors: phenotype I characterized study participants with the most recommended behaviors; phenotype II, participants with a mixture of recommended and not recommended behaviors; and phenotype III, participants with minimal recommended behaviors. In multivariable-adjusted models for those with and without diabetes, phenotype III was strongly associated with CKD progression (HRs of 1.82 and 1.49), death (HRs of 1.95 and 4.14), and atherosclerotic events (HRs of 2.54 and 1.90; each P < 0.05). Phenotype II was associated with atherosclerotic events and death among those with and without diabetes.

LIMITATIONS

No consensus definition of CKD self-management; limited to baseline behavior data.

CONCLUSIONS

There are potentially 3 CKD self-management behavior phenotypes that distinguish risk for clinical outcomes. These phenotypes may inform the development of studies and guidelines regarding optimal self-management.

Abdominal obesity and reduction of glomerular filtration

The objective was to evaluate the association between nutritional status and the glomerular filtration rate (GFR) in remaining quilombolas. Cross-sectional study carried out on 32 remaining quilombola communities in the municipality of Alcântara-MA. The nutritional indicators (IN) used were: body mass index (BMI); Waist circumference (WC); Waist-to-hip ratio (WHR); Waist-to-height ratio (WHtR); conicity index (CI) and estimated visceral adipose tissue (VAT). GFR was estimated from the CKD-EPI creatinine-cystatin C formula. The Shapiro Wilk test was used to evaluate the normality of the quantitative variables. In order to compare the second IN sex, the chi-square test was applied. The Anova or Kruskal-Wallis tests were used to verify the association between IN and GFR. Of the 1,526 remaining quilombolas studied, 89.5% were black or brown, 51.2% were women, 88.6% belonged to economic classes D and E and 61.2% were farmers or fishermen. Clinical investigation revealed 29.2% of hypertensive patients, 8.5% of diabetics and 3.1% with reduced GFR. The BMI revealed 45.6% of the remaining quilombolas with excess weight. When compared to men, women presented a higher prevalence of overweight by BMI (56.6% vs 33.8%, p <0.001) and abdominal obesity CC (52.3% vs 4.3%), WHR (76,5% vs 5.8%), WHtR (82.3% vs 48.9%) and VAT (27.1% vs 14.5%) (p <0.001). Comparing the means of IN according to the GFR, it was observed that the higher the mean value of the IN lower the GFR (p <0.05). The GFR reduced with increasing mean values of nutritional indicators of abdominal obesity, regardless of sex.

Impairment of PPARα and the Fatty Acid Oxidation Pathway Aggravates Renal Fibrosis during Aging

Defects in the renal fatty acid oxidation (FAO) pathway have been implicated in the development of renal fibrosis. Although, compared with young kidneys, aged kidneys show significantly increased fibrosis with impaired kidney function, the mechanisms underlying the effects of aging on renal fibrosis have not been investigated. In this study, we investigated peroxisome proliferator-activated receptor α (PPARα) and the FAO pathway as regulators of age-associated renal fibrosis. The expression of PPARα and the FAO pathway-associated proteins significantly decreased with the accumulation of lipids in the renal tubular epithelial region during aging in rats. In particular, decreased PPARα protein expression associated with increased expression of PPARα-targeting microRNAs. Among the microRNAs with increased expression during aging, miR-21 efficiently decreased PPARα expression and impaired FAO when ectopically expressed in renal epithelial cells. In cells pretreated with oleic acid to induce lipid stress, miR-21 treatment further enhanced lipid accumulation. Furthermore, treatment with miR-21 significantly exacerbated the TGF-β-induced fibroblast phenotype of epithelial cells. We verified the physiologic importance of our findings in a calorie restriction model. Calorie restriction rescued the impaired FAO pathway during aging and slowed fibrosis development. Finally, compared with kidneys of aged littermate controls, kidneys of aged PPARα^-/- mice showed exaggerated lipid accumulation, with decreased activity of the FAO pathway and a severe fibrosis phenotype. Our results suggest that impaired renal PPARα signaling during aging aggravates renal fibrosis development, and targeting PPARα is useful for preventing age-associated CKD.

Overweight and Obesity Are Predictors of Progression in Early Autosomal Dominant Polycystic Kidney Disease

The association of overweight/obesity with disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD) remains untested. We hypothesized that overweight/obesity associates with faster progression in early-stage ADPKD. Overall, 441 nondiabetic participants with ADPKD and an eGFR>60 ml/min per 1.73 m² who participated in the Halt Progression of Polycystic Kidney Disease Study A were categorized on the basis of body mass index (BMI; calculated using nonkidney and nonliver weight) as normal weight (18.5-24.9 kg/m²; reference; n=192), overweight (25.0-29.9 kg/m²; n=168), or obese (≥30 kg/m²; n=81). We evaluated the longitudinal (5-year) association of overweight/obesity with change in total kidney volume (TKV) by magnetic resonance imaging using linear regression and multinomial logistic regression models. Among participants, mean±SD age was 37±8 years, annual percent change in TKV was 7.4%±5.1%, and BMI was 26.3±4.9 kg/m² The annual percent change in TKV increased with increasing BMI category (normal weight: 6.1%±4.7%, overweight: 7.9%±4.8%, obese: 9.4%±6.2%; P<0.001). In the fully adjusted model, higher BMI associated with greater annual percent change in TKV (β=0.79; 95% confidence interval [95% CI], 0.18 to 1.39, per 5-unit increase in BMI). Overweight and obesity associated with increased odds of annual percent change in TKV ≥7% compared with <5% (overweight: odds ratio, 2.02; 95% CI, 1.15 to 3.56; obese: odds ratio, 3.76; 95% CI, 1.81 to 7.80). Obesity also independently associated with greater eGFR decline (slope) versus normal weight (fully adjusted β =-0.08; 95% CI, -0.15 to -0.02). In conclusion, overweight and, particularly, obesity are strongly and independently associated with rate of progression in early-stage ADPKD.

Effect of weight loss on renal function in overweight and obese patients with heart failure

AIMS

The effect of intentional weight loss on glomerular filtration rate (GFR) in overweight and obese patients with heart failure (HF), diabetes mellitus (DM) and/or metabolic syndrome (MS) has not been studied. The purpose of the present study is to assess the short term effects of intentional weight loss on renal function in this population.

MATERIALS AND METHODS

Fifty nine patients were recruited to participate in a 3-month intensive behavioral weight management intervention and received one of two standard structured energy-restricted meal plans (1200 or 1500kcal/day) based on their computed calorie deficit. Weight and renal function (serum creatinine, BUN and estimated glomerular filtration rate based on two formulas - Modification in Renal Disease Study (MDRD), and modified version of Cockcroft-Gault formula reported by Salazar Corcoran for obese patients (absolute and relative formulas) - were evaluated at baseline and at 3 months.

RESULTS

Participants had eGFR in the normal range at baseline and lost an average of 7.56±14.9 pounds (p<0.0001) over 3 months; however, there was no significant reduction in serum creatinine, BUN or eGFR.

CONCLUSION

This study provides evidence that intentional weight loss in overweight and obese patients with HF along with DM, and/or MS and normal baseline renal function does not adversely affect renal function overtime.

The Clinical Usefulness of Measurement of Visceral Fat Area Using Multi-Frequency Bioimpedance: The Association with Cardiac and Renal Function In General Population with Relatively Normal Renal Function

Background: This study was performed to determine the clinical usefulness of measurement of visceral fat area (VFA) using bioimpedance analysis in relation with left ventricular hypertrophy (LVH), diastolic dysfunction parameters, and decreased estimated glomerular filtration rate (eGFR). Methods: A cross-sectional analysis was performed on 1028 patients with eGFR≥60 ml/min/1.73m², aged 40 - 64 years, and who underwent routine health check-ups. Subjects were divided into tertiles based on their VFA. Associations of VFA with echocardiographic parameters and eGFR were evaluated. Results: Across the VFA teriltes, there was a significant trend for increasing left ventricular mass index (LVMi), left atrial diameter (LAD), and ratio of early mitral inflow velocity to peak mitral annulus velocity (E/E' ratio) and that for decreasing ratio of early to late mitral inflow peak velocities (E/A ratio) and eGFR. In multivariate linear regression analysis, log-transformed VFA was significantly associated with increased LVMi, LAD, and E/E' ratio, and with decreased E/A ratio and eGFR. After adjustment for body mass index, log-transformed VFA remained as a significant determinant for E/A ratio. Conclusion: VFA may be associated with LV structure and diastolic function, and decreased eGFR in middle-aged adults with normal or mildly impaired renal function.

Underweight Is an Independent Risk Factor for Renal Function Deterioration in Patients with IgA Nephropathy

Studies on the relationship between body mass index (BMI) and renal progression in IgA Nephropathy (IgAN) were limited, especially for underweight patients with IgAN. To elucidate the clinical features and effect of underweight on renal function deterioration in this disease, we recruited IgAN patients with diagnostic age ≥18 years old and a baseline estimated glomerular filtration rate (eGFR) ≥15 ml/min/1.73m² from our center between 1985 and 2014. Patients secondary to systemic diseases or follow-up less than 6 months were excluded. All patients’ clinical data at renal biopsy and during follow-up were recorded. Renal outcome was defined as end-stage kidney disease (ESRD). Baseline body mass index (BMI) was calculated by weight (kg) over squared height (m²). According to WHO Asian guideline, BMI was categorized as follows: <18.5kg/m² (underweight), 18.5–22.99kg/m² (normal weight), 23–27.49kg/m² (overweight) and obese (≥27.5 kg/m²). Of 930 primary IgAN patients enrolled in this study, mean age at renal biopsy was 37.6 years and 49.2% were men. Totally, 114 (12.3%) ESRD occurred after a mean follow-up of 47.1 months. More ESRD happened in underweight patients (17.3%) compared to patients with normal weight (13.2%), overweight (11.0%) or obesity (9.5%). By multivariate Cox regression analysis, underweight was independently associated with a higher risk of ESRD after adjustment for demographic characteristics and clinical variables (HR: 3.5, 95% CI: 1.3–9.5, P = 0.01) comparing to normal weight. Underweight patients had lower hemoglobin, serum uric acid, triglycerides, cholesterol and lymphocyte counts than patients with normal weight. Furthermore, BMI was positively correlated with serum C3 (r = 0.25, p <0.001). Our research finds that underweight is an independent risk factor for kidney disease progression in IgAN, which might be associated with malnutrition status and decreased C3 levels.

Risk Factors for Rapid Kidney Function Decline Among African Americans: The Jackson Heart Study (JHS)

BACKGROUND

Racial differences in rapid kidney function decline exist, but less is known regarding factors associated with rapid decline among African Americans. Greater understanding of potentially modifiable risk factors for early kidney function loss may help reduce the burden of kidney failure in this high-risk population.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,653 African American participants enrolled in the Jackson Heart Study (JHS) with kidney function data from 2 of 3 examinations (2000-2004 and 2009-2013). Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine using the CKD-EPI creatinine equation.

PREDICTORS

Demographics, socioeconomic status, lifestyle, and clinical risk factors for kidney failure.

OUTCOMES

Rapid decline was defined as a ≥30% decline in eGFR during follow-up. We quantified the association of risk factors with rapid decline in multivariable models.

MEASUREMENTS

Clinical (systolic blood pressure and albuminuria [albumin-creatinine ratio]) and modifiable risk factors.

RESULTS

Mean age was 54±12 (SD) years, 37% were men, average body mass index was 31.8±7.1kg/m(2), 19% had diabetes mellitus (DM), and mean eGFR was 96.0±20mL/min/1.73m(2) with an annual rate of decline of 1.27mL/min/1.73m(2). Those with rapid decline (11.5%) were older, were more likely to be of low/middle income, and had higher systolic blood pressures and greater DM than those with nonrapid decline. Factors associated with ≥30% decline were older age (adjusted OR per 10 years older, 1.51; 95% CI, 1.34-1.71), cardiovascular disease (adjusted OR, 1.53; 95% CI, 1.12-2.10), higher systolic blood pressure (adjusted OR per 17mmHg greater, 1.22; 95% CI, 1.06-1.41), DM (adjusted OR, 2.63; 95% CI, 2.02-3.41), smoking (adjusted OR, 1.60; 95% CI, 1.10-2.31), and albumin-creatinine ratio > 30mg/g (adjusted OR, 1.55; 95% CI, 1.08-1.21). Conversely, results did not support associations of waist circumference, C-reactive protein level, and physical activity with rapid decline.

LIMITATIONS

No midstudy creatinine measurement at examination 2 (2005-2008).

CONCLUSIONS

Rapid decline heterogeneity exists among African Americans in JHS. Interventions targeting potentially modifiable factors may help reduce the incidence of kidney failure.

Association between Obese Phenotype and Mildly Reduced eGFR among the General Population from Rural Northeast China

Obesity contributes to reduced kidney function; however, whether this is due to obesity itself or the metabolic abnormalities that accompany it is unclear. Besides, most previous studies enrolled participants with moderate or severe stage of chronic kidney disease. In the present study, we aim to investigate the possible relationship between obesity, metabolic abnormalities and mildly reduced estimated glomerular filtration rate (eGFR). A total of 11,127 Chinese participants (age ≥ 35 years) were enrolled in a survey conducted from January 2012 to August 2013. eGFR 60–90 mL/min/1.73 m² was defined as mildly reduced eGFR. Obese phenotype was divided into four types: metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically abnormal non-obese (MANO) and metabolically abnormal obese (MAO). Among all participants, 1941 (17.4%) of them had mildly reduced eGFR (16.7% for men and 18.1% for women, p = 0.025). The prevalence of obese phenotype was 22.5% for MHNO, 9.1% for MHO, 32.1% for MANO and 36.4% for MAO. The prevalence of mildly reduced eGFR was 9.0% among MHNO, 7.0% among MHO, 22.6% among MANO and 20.7% among MAO (p < 0.001). Multivariate logistic regression analysis revealed that obese phenotype did not statically contributed to mildly reduced eGFR (MHO: OR = 1.107, p = 0.662; MANO: OR = 0.800, p = 0.127; MAO: OR = 1.119, p = 0.525). However, gender (OR = 1.475, p < 0.001), aging (OR = 1.283, p < 0.001), dyslipidemia (OR = 1.544, 95%CI: 1.315, 1.814, p < 0.001) and hyperglycemia (OR = 1.247, 95%CI: 1.068, 1.455, p = 0.005) was associated with increased risk of mild reduced eGFR. Among the general population from rural Northeast China, mildly reduced eGFR was associated with metabolic disorders like dyslipidemia and hyperglycemia, but not obesity.

Relationship of the American Heart Association's Impact Goals (Life's Simple 7) With Risk of Chronic Kidney Disease: Results From the Atherosclerosis Risk in Communities (ARIC) Cohort Study

BACKGROUND

As part of its 2020 Impact Goals, the American Heart Association developed the Life's Simple 7 metric for cardiovascular health promotion. The relationship between the Life's Simple 7 metric and incident chronic kidney disease (CKD) is unknown.

METHODS AND RESULTS

We estimated the association between Life's Simple 7 and incident CKD in 14 832 Atherosclerosis Risk in Communities study participants. Ideal levels of Life's Simple 7 health factors were the following: nonsmoker or quit >1 year ago; body mass index <25 kg/m(2); ≥150 minutes/week of physical activity; healthy dietary pattern (high in fruits and vegetables, fish, and fiber-rich whole grains; low in sodium and sugar-sweetened beverages); total cholesterol <200 mg/dL; blood pressure <120/80 mm Hg; and fasting blood glucose <100 mg/dL. At baseline, mean age was 54 years, 55% were women, and 26% were African American. There were 2743 incident CKD cases over a median follow-up of 22 years. Smoking, body mass index, physical activity, blood pressure, and blood glucose were associated with CKD risk (all P<0.01), but diet and blood cholesterol were not. CKD risk was inversely related to the number of ideal health factors (P-trend<0.001). A model containing the Life's Simple 7 health factors was more predictive of CKD risk than the base model including only age, sex, race, and estimated glomerular filtration rate (Life's Simple 7 health factors area under the ROC curve: 0.73, 95% CI: 0.72, 0.74 versus base model area under the ROC curve: 0.68, 95% CI: 0.67, 0.69; P<0.001).

CONCLUSIONS

The AHA's Life's Simple 7 metric, developed to measure and promote cardiovascular health, predicts a lower risk of CKD.

Anthropometric measurements and markers of renal function in adults and older adults

Objective: To determine whether anthropometric indicators are associated with markers of renal function in adults and older adults. Methods: This cross-sectional study included 279 adults and older adults attending eight primary healthcare units in eastern Goiânia, Góias. Sociodemographic, lifestyle, and clinical data were collected using a standard questionnaire. Body mass index was categorized as overweight (≥25 kg/m²) or non-overweight. Waist circumference was classified as normal or high; chronic kidney disease was defined as a glomerular filtration rate below 60 mL/minutes/1.73 m²; micro/macroalbuminuria was defined as an albumin/creatinine ratio above 30 mg/g. The association between anthropometric indicators and renal function markers was assessed by multiple linear regression analysis. Results: Chronic kidney disease was present in 8.9% and micro/macroalbuminuria in 34.8% of the sample. The prevalence of overweight was 57.0%. Waist circumference and body mass index were positively associated with glomerular filtration rate, characterized as glomerular hyperfiltration. Microalbuminuria was positively associated with body mass index in women. Conclusion: The prevalences of chronic kidney disease and overweight were high in the study population. Overweight was positively associated with glomerular filtration rate.

Influence of Weight-Age Normalization on Glomerular Filtration Rate Values of Renal Patients: A STROBE-Compliant Article

To explore whether weight-age (W-A) could be applied in clinical practice, this study was designed to verify the normalization ability of W-A by the data from another medical center, and to access the influence of the normalization on glomerular filtration rate (GFR) values in renal patients.Both plasma clearance (pGFR) and camera-based (gGFR), which were separately scaled to W-A and body surface area (BSA), were measured for patients with diffuse renal diseases. The patients (n = 298) were stratified according to the Chinese body mass index (BMI) criteria and were staged according to the Kidney Disease Outcome Quality Initiatives guideline based on gGFR and pGFR separately.The indices of intraclass correlation coefficient (ICC), concordance correlation coefficient (CCC), and ratio of residual standard deviation to pooled standard deviation (RSD/PSD) suggested that, for all patients and each BMI stratum, W-A was obviously better than BSA in scaling GFR. Both under pGFR or gGFR renal stages, only small amount of the patients encountered stage migrations from BSA to W-A scaled stages. The differences between any 2 of the unscaled, BSA scaled, and W-A scaled gGFR (or pGFR) were not obviously changed. Additionally, in some strata, W-A normalization is better than BSA normalization in decreasing the median bias between pGFR and gGFR.W-A is better than BSA in scaling GFR without obvious modifying GFR values and can be applied in routine clinical practice.

Obesity-Related Chronic Kidney Disease-The Role of Lipid Metabolism

Obesity is an independent risk factor for chronic kidney disease (CKD). The mechanisms linking obesity and CKD include systemic changes such as high blood pressure and hyperglycemia, and intrarenal effects relating to lipid accumulation. Normal lipid metabolism is integral to renal physiology and disturbances of renal lipid and energy metabolism are increasingly being linked with kidney disease. AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) are important regulators of fatty acid oxidation, which is frequently abnormal in the kidney with CKD. A high fat diet reduces renal AMPK activity, thereby contributing to reduced fatty acid oxidation and energy imbalance, and treatments to activate AMPK are beneficial in animal models of obesity-related CKD. Studies have found that the specific cell types affected by excessive lipid accumulation are proximal tubular cells, podocytes, and mesangial cells. Targeting disturbances of renal energy metabolism is a promising approach to addressing the current epidemic of obesity-related kidney disease.

Metabolic syndrome and its components associated with chronic kidney disease

Background:

There is limited information on the relationship between metabolic syndrome (MetS) and chronic kidney disease (CKD) in the Iranian population, a group that has a high prevalence of CKD and obesity. The aim of present study was to determine the relationship between MetS and CKD in West of Iran.

Materials and Methods:

A total of 800 subjects aged more than 35 years admitted from 2011 to 2013 were enrolled in the study. MetS was defined based on the Adult Treatment Panel III criteria, and CKD was defined from the Kidney Disease Outcomes Quality Initiative practice guidelines. Waist circumference and body mass index were calculated, as well, blood samples were taken and lipid profile, plasma glucose levels, and serum creatinine were measured. Data were analyzed with SPSS version 17 (SPSS Inc., Chicago, IL, USA).

Results:

CKD was seen in 14.8% patients with MetS and 8.3% individuals without MetS. MetS was associated with an increased odds ratio (OR) for a glomerular filtration rate <60 ml/min/1.73 m² (OR: 1.91; 95% confidence interval [CI]: 1.22-2.99; P = 0.004). Individuals with 2, 3, 4, and 5 components of the MetS had an increased OR for CKD: 2.19 (95% CI: 0.95-3.62), 2.65 (95% CI: 1.03-4.71), 2.86 (95% CI: 1.08-5.53), and 5.03 (95% CI: 1.80-8.57), respectively, compared with individuals with none of the components.

Conclusion:

We found a high prevalence of CKD in patients with MetS compared with the subject without MetS. Our observations raised major clinical and public health concerns in Iran, where both the MetS and kidney diseases are becoming common.

Individualizing pharmacotherapy in patients with renal impairment: the validity of the Modification of Diet in Renal Disease formula in specific patient populations with a glomerular filtration rate below 60 ml/min. A systematic review

Background

The Modification of Diet in Renal Disease (MDRD) formula is widely used in clinical practice to assess the correct drug dose. This formula is based on serum creatinine levels which might be influenced by chronic diseases itself or the effects of the chronic diseases. We conducted a systematic review to determine the validity of the MDRD formula in specific patient populations with renal impairment: elderly, hospitalized and obese patients, patients with cardiovascular disease, cancer, chronic respiratory diseases, diabetes mellitus, liver cirrhosis and human immunodeficiency virus.

Methods and Findings

We searched for articles in Pubmed published from January 1999 through January 2014. Selection criteria were (1) patients with a glomerular filtration rate (GFR) < 60 ml/min (/1.73m²), (2) MDRD formula compared with a gold standard and (3) statistical analysis focused on bias, precision and/or accuracy. Data extraction was done by the first author and checked by a second author. A bias of 20% or less, a precision of 30% or less and an accuracy expressed as P₃₀% of 80% or higher were indicators of the validity of the MDRD formula. In total we included 27 studies. The number of patients included ranged from 8 to 1831. The gold standard and measurement method used varied across the studies. For none of the specific patient populations the studies provided sufficient evidence of validity of the MDRD formula regarding the three parameters. For patients with diabetes mellitus and liver cirrhosis, hospitalized patients and elderly with moderate to severe renal impairment we concluded that the MDRD formula is not valid. Limitations of the review are the lack of considering the method of measuring serum creatinine levels and the type of gold standard used.

Conclusion

In several specific patient populations with renal impairment the use of the MDRD formula is not valid or has uncertain validity.

Exploring associations between anthropometric indices and graft function in patients receiving renal transplant

BACKGROUND

The aim of the present study was to identify indicators of malnutrition, as obtained by anthropometric measurements, that might be potential predictors of transplant outcomes.

METHODS

One hundred and three patients receiving a graft from a living or a deceased donor were included in this prospective study. Body mass index (BMI) based on pretransplant dry body weight, triceps skinfold, mid-arm muscle circumference and corrected mid-arm muscle area were measured. Post-transplant data on delayed graft function (DGF) and glomerular filtration rate (GFR) at discharge were collected until patient discharge.

RESULTS

Delayed graft function developed in 36.9% of the patients. BMI was the only anthropometric variable associated with a higher likelihood of DGF (odds ratio = 1.25, 95% confidence interval = 1.07-1.47) after adjusting for age, gender, donor group, donor age and years of dialysis before transplantation. Obesity was associated with a higher frequency of DGF (83.3% versus 31.1%, P = 0.001) compared to normal weight. GFR at discharge was negatively associated with BMI [β = -0.014 (0.005), P = 0.004], being overweight [β = -0.151 (0.041), P < 0.001] and obesity [β = -0.188 (0.053), P = 0.001], after adjusting for age, gender, donor group, donor age and years of dialysis, but was not associated with indices of muscle reserves.

CONCLUSIONS

The likelihood of DGF was higher among obese patients, whereas GFR at discharge was negatively associated with being overweight and obesity.

Healthy lifestyle and risk of kidney disease progression, atherosclerotic events, and death in CKD: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

In general populations, healthy lifestyle is associated with fewer adverse outcomes. We estimated the degree to which adherence to a healthy lifestyle decreases the risk of renal and cardiovascular events among adults with chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

3,006 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.

PREDICTORS

4 lifestyle factors (regular physical activity, body mass index [BMI] of 20-<25kg/m(2), nonsmoking, and "healthy diet"), individually and in combination.

OUTCOMES

CKD progression (50% decrease in estimated glomerular filtration rate or end-stage renal disease), atherosclerotic events (myocardial infarction, stroke, or peripheral arterial disease), and all-cause mortality.

MEASUREMENTS

Multivariable-adjusted Cox proportional hazards.

RESULTS

During a median follow-up of 4 years, we observed 726 CKD progression events, 355 atherosclerotic events, and 437 deaths. BMI≥25kg/m(2) and nonsmoking were associated with reduced risk of CKD progression (HRs of 0.75 [95% CI, 0.58-0.97] and 0.61 [95% CI, 0.45-0.82] for BMIs of 25 to <30 and ≥30kg/m(2), respectively, versus 20 to <25kg/m(2); HR for nonsmoking of 0.68 [95% CI, 0.55-0.84] compared to the current smoker reference group) and reduced risk of atherosclerotic events (HRs of 0.67 [95% CI, 0.46-0.96] for BMI of 25-<30 vs 20-<25kg/m(2) and 0.55 [95% CI, 0.40-0.75] vs current smoker). Factors associated with reduced all-cause mortality were regular physical activity (HR, 0.64 [95% CI, 0.52-0.79] vs inactive), BMI≥30kg/m(2) (HR, 0.64 [95% CI, 0.43-0.96] vs 20-<25kg/m(2)), and nonsmoking (HR, 0.45 [95% CI, 0.34-0.60] vs current smoker). BMI<20kg/m(2) was associated with increased all-cause mortality risk (HR, 2.11 [95% CI, 1.13-3.93] vs 20-<25kg/m(2)). Adherence to all 4 lifestyle factors was associated with a 68% lower risk of all-cause mortality compared to adherence to no lifestyle factors (HR, 0.32; 95% CI, 0.11-0.89).

LIMITATIONS

Lifestyle factors were measured only once.

CONCLUSIONS

Regular physical activity, nonsmoking, and BMI≥25kg/m(2) were associated with lower risk of adverse outcomes in this cohort of individuals with CKD.

The association between body composition and cystatin C in South Asians: results from the MASALA study

While South Asians have high rates of obesity and kidney disease, little is known about the effect of regional body composition on kidney function. We investigated the association between body composition measures and cystatin C-based estimated glomerular filtration rate (eGFRcysC) in 150 immigrant South Asians. The inverse association between overall adiposity and eGFRcysC was attenuated by C-reactive protein (CRP), while the association of ectopic fat was completely attenuated by metabolic covariates and CRP. In immigrant South Asians, the associations between overall adiposity and ectopic fat with decreased kidney function are largely explained by metabolic alterations and inflammation.

The association of adiposity with kidney function decline among HIV-infected adults: findings from the Fat Redistribution and Metabolic Changes in HIV Infection (FRAM) study

OBJECTIVES

The aim of the study was to investigate the association of adiposity with longitudinal kidney function change in 544 HIV-infected persons in the Study of Fat Redistribution and Metabolic Change in HIV infection (FRAM) cohort over 5 years of follow-up.

METHODS

The regional distribution of muscle and adipose tissue was quantified by whole-body magnetic resonance imaging (MRI), and total adiponectin and leptin levels were measured in serum. Kidney function was assessed using the estimated glomerular filtration rate from serum cystatin C (eGFRCys), obtained at baseline and follow-up. Rapid kidney function decline was defined as annual loss of eGFRCys ≥ 3 mL/min/1.73 m(2) , and incident chronic kidney disease (CKD) was defined as eGFRCys <60 mL/min/1.73 m(2) . Multivariate regression analysis was adjusted for age, race, gender, glucose, antihypertensive use, serum albumin, baseline and change in HIV viral load.

RESULTS

At baseline, mean age was 43 years, mean eGFRCys was 86 mL/min/1.73 m(2) , and 21% of patients had albuminuria. The mean (± standard deviation) eGFRCys decline was -0.11 ± 4.87 mL/min/1.73 m(2) per year; 23% of participants had rapid kidney function decline, and 10% developed incident CKD. The lowest tertile of visceral adipose tissue and the highest tertile of adiponectin were both marginally associated with annual kidney function decline of -0.5 mL/min/1.73 m(2) each, but these associations were not statistically significant after adjustment. We found no statistically significant associations of MRI-measured regional adiposity or serum adipokines with rapid kidney function decline or incident CKD (all P-values>0.1 in adjusted models).

CONCLUSIONS

Contrary to findings in the general population, adiposity did not have a substantial association with longitudinal change in kidney function among HIV-infected persons.