Association between obesity and kidney disease: a systematic review and meta-analysis

Association between weight change across adulthood and risk of chronic kidney disease: NHANES 1999-2020

BACKGROUND

Obesity is a recognized risk factor for chronic kidney disease (CKD), but whether weight change is associated with CKD remains unclear. This research aimed to investigate the relationship between weight change patterns across adulthood and the risk of CKD.

METHODS

Data for 34,187 adults participating in the National Health and Nutrition Examination Survey 1999-2020 were analyzed. The weight change patterns of participants were assessed across different time intervals, including transitions from obesity to non-obesity, non-obesity to obesity, and remaining stable obesity. Absolute weight changes were also analyzed, categorizing participants into various weight gain and loss groups. Furthermore, stratified analyses were conducted to explore potential interactions between age, sex, and smoking status about CKD risk.

RESULTS

The study found that individuals transitioning from obesity to non-obesity, non-obesity to obesity, and remaining stable obesity had an elevated risk of developing CKD throughout adulthood compared to those maintaining stable non-obesity weight patterns. Moreover, a J-shaped or U-shaped relationship was observed between CKD risk and absolute weight changes, with both extreme weight gain (≥20 kg) and substantial weight loss (>2.5 kg) associated with increased CKD risk. Stratified analyses revealed that age and sex played significant roles in these associations, with stronger effects observed among participants under 60 years at baseline.

CONCLUSIONS

This study underscores the link between weight change across adulthood and the risk of CKD. Maintaining a stable weight and avoiding extreme weight fluctuations may reduce CKD risk. These insights can be considered when developing CKD prevention and management strategies.

Global, regional, and national burden of chronic kidney disease among adolescents and emerging adults from 1990 to 2021

BACKGROUND AND AIMS

There are limited studies on the epidemiology of chronic kidney disease (CKD) burden among adolescents and emerging adults. We aimed to assess the global, regional, and national trends in CKD burden among adolescents and emerging adults.

METHODS

The Global Burden of Disease 2021 study was utilized to evaluate the incidence, prevalence, mortality, disability-adjusted life years (DALYs) and average annual percentage changes (AAPC) in CKD among populations aged 15 to 29 years from 1990 to 2021.

RESULTS

From 1990 to 2021, age-standardized incidence (AAPC: 0.85%, 95% uncertainty interval [95% UI]: 0.81%-0.88%), prevalence (AAPC: 0.22%, 95% UI: 0.19%-0.25%), and mortality (AAPC: 0.18%, 95% UI: 0.04%-0.32%) rates of CKD have risen globally among adolescents and emerging adults. In 2021, Southeast Asia had the highest age-standardized prevalence (5370.39 [95% UI: 4060.97-6929.79] per 100,000 population), while Central sub-Saharan Africa had the highest mortality rate (5.05 [95% UI: 3.49-7] per 100,000 population). In 2021, glomerulonephritis and 'other and unspecified causes' accounted for 94% of new cases, 83% of prevalent cases, and 92% of mortality cases. Frontier analyses suggest that regions at varying stages of development still hold substantial potential for further improvements in addressing CKD.

CONCLUSION

Globally, the burden of CKD among adolescents and emerging adults continues to rise, with Southeast Asia and sub-Saharan Africa bearing a disproportionate burden. Nevertheless, there remain substantial opportunities across all levels of the development spectrum to alleviate the CKD burden through enhanced health interventions and resource allocation.

Kidney consequences of obesity

Herein, we review the devastating consequences of the worldwide obesity epidemic on kidney health and outcomes. We submit that the obesity epidemic is the most pressing public health crisis facing the nephrology community today. A historical approach has been undertaken, wherein major breakthroughs in the recognition and understanding of obesity-related kidney disease (ORKD) are highlighted. We begin with a description of the worldwide obesity epidemic followed by an account of the discovery and characterization of ORKD. A detailed summary of the pathophysiology of ORKD disease is presented, wherein we set forth the following two propositions: first, ORKD is due to a maladaptive response to caloric surplus; and second, this maladaptive response causes kidney damage via hemodynamic (hyperfiltration), hormonal (adipokine dysregulation), and lipotoxic pathways. Each of these pathways is described, with particular emphasis on the relatively recent discovery that the final stage of cellular injury in ORKD is mitochondrial oxidative damage. The prevention and treatment of ORKD are then discussed, including environmental, behavioral, pharmacologic, and surgical options. Finally, we conclude with suggestions for future research to improve early recognition and treatment of ORKD.

Risk stratification of metabolic disorder-associated kidney disease

During the last 20 years, the disease burden attributable to metabolic disorders increased by 49.4%. Metabolic disorders are established risk factors for both chronic kidney disease (CKD) and cardiovascular disease (CVD). A concept of cardiovascular-kidney-metabolic (CKM) syndrome has recently been proposed to underscore the pathophysiological interrelatedness of the metabolic risk factors, CKD, and CVD. Two major adverse outcomes of the metabolic disorder-associated kidney disease are cardiovascular disease and, to a less extent, kidney failure. This review aims to briefly summarize the traditional metabolic risk factors for kidney disease; to introduce the concept of CKM health; to present the methods for risk assessment for CKD progression and CVD, with focus on validated and clinically applicable prediction tools; and to discuss the key gaps in the current tools for the risk stratification. In summary, in general clinical settings, the CKM health and associated risk in patients with the metabolic disorder-associated kidney disease can be assessed by combining the CKM staging model, the CKD Prognosis Consortium equations for CKD progression, and the Predicting Risk of CVD Events (PREVENT) equations for CVD. More efficient risk prediction tools, potentially incorporating multimodal data, are needed for more accurate and early identification of individuals at high risk and better personalized management of the disease.

Elevation of p53 sensitizes obese kidney to adriamycin-induced aberrant lipid homeostasis via repressing HNF4α-mediated FGF21 sensitivity

INTRODUCTION

Lipid metabolism disorders have been confirmed to be closely related to kidney injury caused by adriamycin (ADR) and obesity, respectively. However, it has not been explored whether lipid metabolism disorders appear progressively more severe after ADR-based chemotherapy in the obese state, and the specific molecular mechanism needs to be further clarified.

OBJECTIVES

This study was designed to examine the role of p53-fibroblast growth factor 21 (FGF21) axis in ADR-induced renal injury aggravated by high-fat diet (HFD).

METHODS

We engineered Fgf21 KO mice and used long-term (4 months) and short-term (0.5 months) HFD feeding, and ADR-injected mice, as well as STZ-induced type 1 diabetic mice and type 2 (db/db) diabetic mice to produce an in vivo model of nephrotoxicity. The specific effects of p53/FGF21 on the regulation of lipid metabolism disorders and its downstream mediators in kidney were subsequently elucidated using a combination of functional and pathological analysis, RNA-sequencing, molecular biology, and in vitro approaches.

RESULTS

Long-term HFD feeding mice exhibited compromised effects of FGF21 on alleviation of renal dysfunction and lipid accumulation following ADR administration. However, these impairments were reversed by p53 inhibitor (pifithrin-α, PFT-α). PFT-α sensitized FGF21 actions in kidney tissues, while knockout of Fgf21 impaired the protective effects of PFT-α on lipid metabolism. Mechanistically, p53 impaired the renal expression of FGF receptor-1 (FGFR1) and thereby developed gradually into FGF21 resistance via inhibiting hepatocyte nuclear factor 4 alpha (HNF4α)-mediated transcriptional activation of Fgfr1. More importantly, exogenous supplementation of FGF21 or PFT-α could not only alleviate ADR-induced lipid metabolism disorder aggravated by HFD, but also reduce lipid accumulation caused by diabetic nephropathy.

CONCLUSION

Given the difficulties in developing the long-acting recombinant FGF21 analogs for therapeutic applications, sensitizing obesity-impaired FGF21 actions by suppression of p53 might be a therapeutic strategy for maintaining renal metabolic homeostasis during chemotherapy.

Obesity: pathophysiology and therapeutic interventions

Over the past few decades, obesity has transitioned from a localized health concern to a pressing global public health crisis affecting over 650 million adults globally, as documented by WHO epidemiological surveys. As a chronic metabolic disorder characterized by pathological adipose tissue expansion, chronic inflammation, and neuroendocrine dysregulation that disrupts systemic homeostasis and impairs physiological functions, obesity is rarely an isolated condition; rather, it is frequently complicated by severe comorbidities that collectively elevate mortality risks. Despite advances in nutritional science and public health initiatives, sustained weight management success rates and prevention in obesity remain limited, underscoring its recognition as a multifactorial disease influenced by genetic, environmental, and behavioral determinants. Notably, the escalating prevalence of obesity and its earlier onset in younger populations have intensified the urgency to develop novel therapeutic agents that simultaneously ensure efficacy and safety. This review aims to elucidate the pathophysiological mechanisms underlying obesity, analyze its major complications-including type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVD), non-alcoholic fatty liver disease (NAFLD), obesity-related respiratory disorders, obesity-related nephropathy (ORN), musculoskeletal impairments, malignancies, and psychological comorbidities-and critically evaluate current anti-obesity strategies. Particular emphasis is placed on emerging pharmacological interventions, exemplified by plant-derived natural compounds such as berberine (BBR), with a focus on their molecular mechanisms, clinical efficacy, and therapeutic advantages. By integrating mechanistic insights with clinical evidence, this review seeks to provide innovative perspectives for developing safe, accessible, and effective obesity treatments.

Weight-adjusted-waist index is associated with urinary albumin-creatinine ratio in normal body mass index adults: a cross-sectional study from NHANES 2001-2018

Obesity promotes chronic kidney disease and albuminuria. Whether weight-adjusted-waist index (WWI) is correlated with albuminuria reflected by urinary albumin-to-creatinine ratio (UACR) in normal body mass index (BMI) population and the effect of hypertension and hyperglycemia on the association remain unclear. This cross-sectional study included adults with complete WWI and UACR data in the National Health and Nutrition Examination Survey (NHANES) database from 2001 to 2018. WWI was defined as waist circumference (WC) divided by the square root of weight. Linear regression, restricted cubic splines (RCS) curve and logistic regression were performed to evaluate the relationship between WWI and albuminuria risk. The relationship in different blood pressure and glucose subgroups were further investigated. 10,105 participants were finally included. The prevalence of albuminuria was 5.05%. WWI in albuminuria group was higher. RCS curve analysis showed the relationship between WWI and albuminuria risk increased linearly in patients with hypertension or hyperglycemia, while a U-shaped curve relationship in normoglycemic or non-hypertensive individuals. Logistic regression results indicated increased WWI was an independent risk factor for albuminuria reflected by UACR in normal BMI population even after adjusting for confounding factors, especially in males. When patients only had hypertension with normal blood glucose, WWI was still independently associated with albuminuria. Elevated WWI increased albuminuria risk in normal BMI adults, especially in males and patients with hypertension or hyperglycemia, even in hypertension patients without hyperglycemia. Assessment of WWI to identify early renal dysfunction should be emphasized.

Association of Obesity, Visceral Fat Accumulation, and Dyslipidemia with the Risk of Chronic Kidney Disease

Objective Although chronic kidney disease (CKD) is independently associated with hypertension or hyperglycemia, there is no consensus on the thresholds of obesity, dyslipidemia, or visceral fat accumulation to predict CKD onset and progression. Methods We performed a multivariable logistic regression analysis for the association of the subsequent rate of estimated glomerular filtration rate (eGFR) decline with body mass index (BMI), blood high-density lipoprotein (HDL) cholesterol and triglycerides (TG) levels on 308,174 subjects who underwent health examinations conducted by the Public Health Research Center Foundation from 2015 to 2022. In addition, a Poisson regression analysis was used to evaluate the association between the appearance of urinary protein in participants without baseline urinary protein levels and eGFR decline. Results The median age of the subjects was 46 years old, and the median observation period was approximately 3 years. An eGFR decline rate of ≥5%/year was significantly associated with low HDL-cholesterol levels (<40 mg/dL), independent of the BMI and TG levels. A high baseline BMI (≥25 kg/m2) or waist circumference (≥85 cm for men and ≥90 cm for women), high TG levels (≥150 mg/dL), and low HDL-cholesterol levels were significantly associated with new-onset proteinuria. Furthermore, the higher the baseline BMI, the higher the incidence rate ratio of new-onset proteinuria. Conclusion Independent of hyperglycemia and hypertension, dyslipidemia according to the Japanese metabolic syndrome criteria and an elevated BMI were associated with a high risk of new-onset proteinuria, and a low HDL-cholesterol level was significantly associated with a rapid eGFR decline.

The association of thyroid hormone levels and incidence of chronic kidney disease: the Tehran thyroid study (TTS)

BACKGROUND

Evidence regarding the relationship between thyroid hormone levels within the normal range and the incidence of chronic kidney disease (CKD) in adults is scarce. This study aimed to identify the association between thyrotropin (TSH) and free thyroxine (FT4) levels with the incidence of CKD in a large cohort study over long-term follow-up.

METHODS

This prospective cohort study, with an 18-year follow-up, included 4118 adults without CKD from the Tehran thyroid Study (TTS). Participants were categorized by tertiles of normal TSH levels (low-normal, middle-normal, and high-normal) and abnormal TSH. The study outcome was incident CKD, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) for CKD incidence based on thyroid hormone levels.

RESULTS

The HR for CKD development was 1.08 (95%CI: 1.01-1.15) per 1 SD increase in the TSH levels. Compared with participants with low-normal TSH levels, those with high-normal (HR:1.37; 95%CI: 1.03-1.84) and abnormal TSH (HR:1.24; 95%CI: 1.05-1.46) had a significantly higher risk of developing CKD. In subgroup analyses, the association between TSH level and CKD was significant in participants younger than 60 years, females, non-obese, non-smokers, and those without diabetes and hypertension. No association was observed between FT4 levels and incident CKD (HR: 0.92; 95%CI: 0.79-1.09). However, a significant association was observed between FT4 levels within the normal range and CKD development in those younger than 60 years old (HR: 0.77; 95% CI: 0.61-0.98).

CONCLUSION

Increased TSH levels, even within the normal range, linearly increased the risk of CKD even after adjustment for important risk factors. As a result, TSH may potentially be an independent risk factor for incident CKD.

Overweight Status, Obesity, and Progression to ESKD in Patients with Autosomal Dominant Polycystic Kidney Disease

Key Points

Higher body mass index increased risk of progression to ESKD in patients with early-stage autosomal dominant polycystic kidney disease. Higher body mass index did not increase the risk of progression to ESKD in patients with late-stage autosomal dominant polycystic kidney disease.

Background

Prior research has linked higher body mass index (BMI) and greater visceral adiposity with more rapid progression of early-stage autosomal dominant polycystic kidney disease (ADPKD). We now evaluate the association between overweight and obesity in patients with early- and late-stage ADPKD with progression to ESKD.

Methods

Participants with early-stage ADPKD (study A; N =556; eGFR: 91±17 ml/min per 1.73 m2) and late-stage ADPKD (study B; N =483; eGFR: 48±12 ml/min per 1.73 m2) who participated in the Halt Progression of Polycystic Kidney Disease (HALT) polycystic kidney disease trials were categorized by BMI as normal weight (18.5–24.9 kg/m2; ref; n =357), overweight (25.0–29.9 kg/m2; n =384), or obese (≥30 kg/m2; n =298). Kaplan–Meier survival analysis and multivariate Cox proportional hazard models were used to determine the association of baseline BMI as a continuous and categorical variable with risk of ESKD (according to the United States Renal Data System) over a median (interquartile range) follow-up period of 12.2 (7.5–13.3; study A) and 7.3 (5.1–11.7; study B) years (primary outcome). All-cause mortality (National Death Index) was also considered as a competing risk (Fine and Gray method).

Results

The number of ESKD events was greater with overweight (n =24) and obesity (n =23) in HALT study A versus normal weight (n =12) but not in HALT study B (normal weight: n =89, overweight: n =102, obese: n =92). In fully adjusted models, higher BMI was associated with risk of progression to ESKD in study A (hazard ratio [HR (95% confidence interval)], 1.09 [1.03 to 1.15] per unit higher BMI) but not in study B (HR, 0.98 [0.96 to 1.00]). Obesity was associated with increased risk of ESKD (HR, 2.71 [1.22 to 6.02] versus normal weight) in study A only. Results were similar when considering death as a competing risk.

Conclusions

Higher BMI, particularly obesity, increased the risk of progression to ESKD in patients with early-stage ADPKD but not in those with late-stage ADPKD.

GLP-1 and glucagon receptor dual agonism ameliorates kidney allograft fibrosis by improving lipid metabolism

Introduction

Kidney allograft fibrosis accelerates the progression of chronic kidney disease (CKD), leads to allograft failure, and increases patient mortality. Emerging evidence suggests that metabolic syndrome in transplant recipients is associated with fibrosis development. However, it remains unclear whether targeting metabolic pathways can mitigate allograft fibrosis. This study aimed to explore the potential of targeting metabolic pathways using the GLP-1R/GCGR dual agonist TB001 for the treatment of kidney allograft fibrosis.

Methods

Kidney allograft fibrosis was induced in rat kidney transplant models. Histological analysis, transcriptome sequencing, and in vitro experiments were performed to investigate the efficacy of TB001 and its underlying mechanisms.

Results

Compared with the control group, TB001-treated recipients had significantly improved kidney allograft function, as evidenced by lower creatinine and 24-hour urine protein levels. Moreover, TB001 treatment decreased the body weight and serum total cholesterol, LDL-cholesterol, and TNF-α levels in transplant recipients, indicating metabolic improvements. Pathological analysis demonstrated that TB001 treatment reduced inflammatory cell infiltration and downregulated the expression of fibrosis markers, including TGF-β1, α-SMA, COL1A1, and Vimentin. Further transcriptome sequencing of kidney grafts revealed that TB001-treated group had a gene expression pattern similar to that of the syngeneic control group and showed significant enhancement of lipid metabolism-related pathways, particularly the PPAR pathway. In vivo and in vitro experiments further demonstrated that TB001 upregulated the expression of CPT1A, a key molecule involved in lipid metabolism, and inhibited TGF-β1/Smad2/3/Twist and PKC-α/PKC-β pathways.

Conclusion

Targeting metabolic pathways using the GLP-1R/GCGR dual agonist TB001 shows potential for managing kidney allograft fibrosis.

Association Between Life's Essential 8 and Diabetic Kidney Disease in Patients With Diabetes Mellitus: Evidence From National Health and Nutrition Examination Survey 2005-2018

BACKGROUND

Diabetic kidney disease (DKD) is often connected with an elevated cardiovascular disease risk. A novel index, the Life's Essential 8 (LE8), was developed with the American Heart Association to ascertain cardiovascular health. In people with diabetes mellitus, we aimed to estimate if LE8 possessed a connection with DKD risk.

METHODS

We implemented data from the National Health and Nutrition Examination Survey from 2005 to 2018. The correlation between LE8 and DKD was evaluated with weighted multivariate logistic regression models and restricted cubic spline models with covariate adjustments. In addition, we performed subgroup analyses and interaction tests.

RESULTS

After taking into account relevant confounding factors, the findings indicated that higher levels of LE8 was linked to a decreased probability of developing DKD (per 10-point increase in LE8, OR = 0.75, 95%CI = 0.68-0.84, P < .001). The subscales of the LE8 similarly demonstrated negative associations with DKD risk. After grouping the LE8 scores, it was found that individuals with high LE8 were significantly less likely to develop DKD compared to those with low LE8 (OR = 0.32, 95%CI = 0.15-0.70, P = .005). The association between LE8 and DKD was consistent across different subgroups.

CONCLUSION

LE8 scores were shown to have a significantly negative association with the risk of DKD in people with diabetes mellitus. By concentrating on the state of cardiovascular health, it may be possible to lessen the impact of DKD.

Electrolyte Imbalances and Metabolic Emergencies in Obesity: Mechanisms and Clinical Implications

Electrolyte imbalances are a frequently overlooked yet critical component of obesity-related metabolic dysfunction, contributing to an increased risk of cardiovascular disease, kidney impairment, and metabolic emergencies such as diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), and acute kidney injury (AKI). These disturbances arise from insulin resistance, chronic inflammation, hormonal dysregulation, and renal dysfunction, leading to sodium retention, potassium depletion, and deficiencies in calcium and magnesium homeostasis. Managing electrolyte imbalances is essential in obesity management, as imbalances exacerbate hypertension, metabolic acidosis, neuromuscular complications, and insulin resistance. This review explores the pathophysiology of electrolyte disturbances in obesity and their impact on fluid balance, acid-base status, and metabolic health. Effective management strategies include individualized electrolyte monitoring, dietary sodium restriction, potassium supplementation, vitamin D and magnesium correction, and pharmacologic interventions targeting renin-angiotensin-aldosterone system (RAAS) activity and insulin resistance. Additionally, lifestyle interventions, including dietary modification, weight loss strategies, and hydration optimization, play a key role in preventing metabolic complications. Future research should investigate the long-term impact of electrolyte imbalances in obesity, the role of emerging therapies, and how lifestyle interventions can optimize electrolyte homeostasis and metabolic outcomes. A personalized, multidisciplinary approach integrating endocrinology, nephrology, and clinical nutrition is essential to improving the prevention and management of electrolyte imbalances in obese individuals.

Diabetes and Glucose Management in People on Hemodialysis

Diabetes is a major cause of end-stage kidney disease (ESKD). Glycemic management is challenging in this population, and A1C, commonly used for monitoring glycemic control, is unreliable. Continuous glucose monitoring indices can be used for glycemic monitoring in people with ESKD. Dipeptidyl peptidase 4 inhibitors, incretin mimetic agents (glucagon-like peptide 1 and glucose-dependent insulinotropic peptide receptor agonists), and insulin using an automated insulin delivery system are preferred to manage diabetes in people with ESKD on hemodialysis.

Metabolic/bariatric surgery optimization: a position statement by Arabic association for the study of diabetes and metabolism (AASD)

For patients considering bariatric surgery, it is essential to have clear answers to common questions to ensure the success of the procedure. Patients should understand that surgery is not a quick fix but a tool that must be complemented by lifestyle changes, including dietary adjustments and regular physical activity. The procedure carries potential risks that should be weighed against the potential benefits. Health authorities play a critical role in ensuring that bariatric surgery is performed under the highest standards of care. Recommendations are provided to determine who is an appropriate candidate for surgery, what preoperative evaluations are necessary, and how to monitor patients postoperatively to maximize outcomes and minimize risks. Additionally, authorities are responsible for ensuring access to follow-up care, including nutritional support and psychological counseling, which are vital for the long-term success of bariatric surgery.Understanding these aspects by both patients and decision-makers is critical before proceeding with bariatric surgery. The following questions guide patients and healthcare professionals in making informed decisions about the procedure and managing the expectations and outcomes associated with bariatric surgery.

Obesity-Related Chronic Kidney Disease: From Diagnosis to Treatment

Obesity has emerged as a global epidemic with far-reaching health complications, including its role as an independent risk factor for chronic kidney disease (CKD). Increasing evidence suggests that obesity contributes to CKD through multiple mechanisms, including chronic inflammation, hemodynamic alterations, insulin resistance, and lipid accumulation. These processes can culminate in histopathological changes collectively referred to as obesity-related glomerulopathy (ORG). This review aims to provide a comprehensive overview of the current knowledge regarding the prevalence, clinical manifestations, and pathophysiology of ORG. Furthermore, we emphasize the importance of identifying key biomarkers that facilitate the early detection of ORG. Finally, we explore emerging therapeutic strategies that offer promise in mitigating this growing global health crisis.

The role of M1/M2 macrophage polarization in the pathogenesis of obesity-related kidney disease and related pathologies

Obesity is a rapidly growing health problem worldwide, affecting both adults and children and increasing the risk of chronic diseases such as type 2 diabetes, hypertension and cardiovascular disease (CVD). In addition, obesity is closely linked to chronic kidney disease (CKD) by either exacerbating diabetic complications or directly causing kidney damage. Obesity-related CKD is characterized by proteinuria, lipid accumulation, fibrosis and glomerulosclerosis, which can gradually impair kidney function. Among the immune cells of the innate and adaptive immune response involved in the pathogenesis of obesity-related diseases, macrophages play a crucial role in the inflammation associated with CKD. In obese individuals, macrophages enter a pro-inflammatory state known as M1 polarization, which contributes to chronic inflammation. This polarization promotes tissue damage, inflammation and fibrosis, leading to progressive loss of kidney function. In addition, macrophage-induced oxidative stress is a key feature of CKD as it also promotes cell damage and inflammation. Macrophages also contribute to insulin resistance in type 2 diabetes by releasing inflammatory molecules that impair glucose metabolism, complicating the management of diabetes in obese patients. Hypertension and atherosclerosis, which are often associated with obesity, also contribute to the progression of CKD via immune and inflammatory pathways. Macrophages influence blood pressure regulation and contribute to vascular inflammation, particularly via the renin-angiotensin system. In atherosclerosis, macrophages accumulate in arterial plaques, leading to chronic inflammation and plaque instability, which may increase the risk of CVD in CKD patients. This review focuses on the involvement of macrophages in CKD and highlights their role as a critical link between CKD and other pathologies. Targeting macrophage polarization and the ensuing macrophage-induced inflammation could be an effective therapeutic strategy for CKD and related diseases and improve outcomes for patients with obesity-related kidney disease.

The relationship between kidney function and cardiometabolic risk factors, anthropometric indices, and dietary inflammatory index in the Iranian general population: a cross-sectional study

BACKGROUND

The prevalence of chronic kidney disease (CKD) is estimated to be about 13.4% worldwide. Studies have shown that CKD accounts for up to 2% of the health cost burden. Various factors, such as genetic polymorphisms, metabolic disorders, and unhealthy lifestyles, can contribute to the occurrence of CKD. Therefore, the present study aimed to investigate the relationship between renal function and cardiometabolic risk factors, anthropometric characteristics, and the dietary inflammatory index (DII) in an Iranian population.

METHODS

This study was conducted on 2472 male and female employees of Shiraz University of Medical Sciences (SUMS), selected through census between 2018 and 2019. In this cross-sectional study, renal function was evaluated using serum creatinine (sCr), blood urea nitrogen (BUN), and estimated glomerular filtration rate (eGFR). Biochemical indices including sCr, BUN, fasting blood sugar (FBS), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglyceride (TG) were measured using standard laboratory methods. eGFR was calculated using the Modification of Diet in Renal Disease formula. Systolic (SBP) and diastolic (DBP) blood pressure as well as anthropometric indices such as height (Ht), weight (Wt), hip circumference (HC), waist circumference (WC), body mass index (BMI), conicity index (C-Index), visceral adiposity index (VAI), abdominal volume index (AVI), body adiposity index (BAI), and body shape index (ABSI) were measured and calculated using standard methods and formulas. Diet was evaluated through a 113-item food frequency questionnaire, and the DII was calculated according to its specific instructions. To predict the factors influencing renal function and to remove the impact of confounders, multivariable linear regression was employed using the backward elimination method.

RESULTS

There was a significant direct relationship between sCr and FBS, TG, HDL, DBP, Wt, and BAI as well as between BUN and age, TG, HDL, and BAI. In addition, there was a significant inverse relationship between eGFR and SBP, Wt, BAI, and VAI. In women compared to men, sCr and BUN values were significantly lower, while eGFR levels were significantly higher.

CONCLUSIONS

It seems that age, gender, lipid profile, glycemic status, BP, BAI, VAI, and Wt can be considered factors associated with renal function.

Evaluation of the Soda Tax on Obesity and Diabetes in California: A Cost-Effectiveness Analysis

Introduction. Consumption of sugar-sweetened beverages (SSBs) contributes to weight gain, obesity, and diabetes. Soda tax has been proposed to reduce consumption of SSBs. What remains unclear is whether the soda tax has an effect on health and health care costs. We evaluated the cost-effectiveness of a 1-cent-per-ounce soda tax on obesity and diabetes in California. Methods. A microsimulation state-transition model was used to evaluate the cost-effectiveness of the soda tax. Health outcomes were measured in quality-adjusted life-years (QALYs). Health care costs were projected from 2015 to 2035. Results. In a simulated cohort of Californian adults, the soda tax policy prevented 2.28 million cases of overweight (95% confidence interval [CI] -0.06 to 6.63) and 0.49 million cases of obesity (95% CI -0.19 to 1.18). From the health care perspective, the incremental cost-effectiveness ratio of the soda tax was $124,839 dollars per QALY (95% CI -1,151,983 to 557,660). From the health care perspective, the soda tax policy was cost-effective 80% of the time in the probabilistic sensitivity analysis using a willingness-to-pay threshold of $100,000 per QALY. Conclusions. The 1-cent-per-ounce soda tax reduced the number of obesity cases, diabetes cases, and related complications. In addition, the soda tax policy implemented in California was cost-effective most of the time.

Highlights

Question: What remains unclear is whether the soda tax has an effect on health and health care costs.Findings: The 1-cent-per-ounce soda tax reduced the number of obesity cases, diabetes, and related complications. In addition, the soda tax policy brought large amounts of revenue.Meaning: This study provides additional evidence regarding the health care costs and cost-effectiveness related to the implementation of a soda tax.

The Kidney in Obesity: Current Evidence, Perspectives and Controversies

PURPOSE OF REVIEW

As obesity and chronic kidney disease (CKD) remain a public health issue, we aim to elaborate on their complex relationship regarding pathogenetic mechanisms and therapeutic potential as well. The purpose of this review is to enhance our understanding of the interplay between obesity and CKD in order to timely diagnose and treat obesity-related CKD.

RECENT FINDINGS

Obesity and CKD pose significant intertwined challenges to global health, affecting a substantial portion of the population worldwide. Obesity is recognized as an independent risk factor, intricately contributing to CKD pathogenesis through mechanisms such as lipotoxicity, chronic inflammation, and insulin resistance. Recent evidence highlights additional factors including hemodynamic changes and intestinal dysbiosis that exacerbate kidney dysfunction in obese individuals, leading to histologic alterations known as obesity-related glomerulopathy (ORG). This narrative review synthesizes current knowledge on the prevalence, pathophysiology, clinical manifestations, and diagnostic strategies of obesity-related kidney disease. Furthermore, it explores mechanistic insights to delineate current therapeutic approaches, future directions for managing this condition and controversies. By elucidating the multifaceted interactions between obesity and kidney health, this review aims to inform clinical practice and stimulate further research to address this global health epidemic effectively.

Approaches to patients with obesity and CKD: focus on nutrition and surgery

Obesity is recognized as a public health challenge. During the last three decades, the global age-standardized prevalence increased from 8.8% to 18.5% in women and from 4.8% to 14.0% in men, with an absolute current number of 878 million obese subjects. Obesity significantly increases per se the risk of developing disability and chronic diseases, including chronic kidney disease (CKD). Specifically, obesity acts as a major, modifiable cause of CKD onset and progression toward kidney failure; as such, it is considered by the International Society of Nephrology a major health priority. This review analyses the effectiveness, safety and practicability of non-pharmacological anti-obesity interventions in CKD as the different patient phenotypes that may take advantage of personalized approaches.

Association of weight-adjusted waist index (WWI) and a body shape index (ABSI) with serum neurofilament light chain levels in a national study of U.S. adults

OBJECTIVE

This study explored how the weight-adjusted waist index (WWI) and a body shape index (ABSI) are related to serum neurofilament light chain (sNfL) levels among U.S. adults. We aimed to evaluate sNfL, which plays key roles in neuronal injury in neurological diseases, given its understudied connection to obesity.

METHODS

We used cross-sectional data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) of people with complete information on the weight-adjusted waist index (WWI), a body shape index (ABSI), and serum neurofilament light chain (sNfL). Multiple linear regression analysis allowed us to investigate the separate connections among the WWI, ABSI, and sNfL. Moreover, interaction testing and subgroup analysis were performed to improve the general validity of our results. To assess any nonlinear correlations, we also performed threshold effect analysis and smoothed curve fitting.

RESULTS

WWI and ABSI were positively linked with sNfL (WWI: β = 0.05, 95% CI 0.01-0.09; ABSI: β = 1.65, 95% CI 3.53-13.72). There was no clear reliance on this association according to subgroup analysis and interaction tests. Smoothed curve fitting and saturation effects also demonstrated nonlinear associations between WWI and ABSI and sNfL, with inflection points of 10.38 and 0.38, respectively.

CONCLUSION

In the adult American population, while the WWI and ABSI are linearly positively correlated with serum neurofilament light protein (sNfL), the effect size is greater for the ABSI. This correlation provides fresh evidence connecting obesity to neurological conditions, deepening our comprehension of the extensive health impacts associated with obesity. Level of Evidence Level I, experimental studies.

Protective Effects of the Food Supplement Flexovital in a Model of Cardiovascular-Kidney-Metabolic Syndrome in Mice

Background/Objectives: The prevalence of cardiovascular-kidney-metabolic (CKM) syndrome is increasing rapidly, and cardiovascular complications pose significant risks in individuals with kidney disease and metabolic dysfunction. Understanding the mechanisms of CKM disorders is crucial, as is the discovery of novel preventive treatments. This study aimed to examine the therapeutic effects of a specially formulated nitric oxide-enhancing food additive in a mouse model of CKM syndrome induced by unilateral nephrectomy (UNX) in combination with chronic Western diet (WD) feeding. Methods: C57BL/6J mice underwent UNX and were fed a WD high in salt, sugar, and fat for 12 weeks, compared to sham-operated mice on standard chow. One group of UNX+WD mice received Flexovital (FLX), a food additive containing extracts of Rhodiola rosea and beetroot, and the amino acids L-arginine and L-citrulline. CKM parameters were assessed both in vivo and ex vivo alongside histological and biochemical analyses. Results: The UNX+WD mice showed an increase in body fat mass, the fat/lean mass ratio, and adipocyte area, of which most were significantly reduced by FLX. Elevated fasting glucose levels were also reduced by FLX, which tended towards improving glucose clearance. Elevated arterial blood pressure and endothelial dysfunction in UNX+WD mice were significantly reduced by FLX. FLX improved GFR and reduced glomerular and tubular injuries in UNX+WD mice. Additionally, FLX increased the P/O ratios of oxidative phosphorylation in the isolated renal mitochondria of UNX+WD mice. Conclusions: In this model of CKM syndrome, FLX effectively prevented the onset and progression of CKM dysfunctions induced by UNX+WD, as well as the associated organ injuries. These promising results highlight the need for validation in upcoming human trials.

Kidney Damage in Pediatric Obesity: Insights from an Emerging Perspective

The role of obesity as a risk factor for chronic kidney disease (CKD) in adulthood has been well established. Over the last years, kidney damage (KD) has emerged as a significant consequence of obesity since childhood. Indeed, a complex interplay of metabolic factors, including insulin resistance (IR), hypertension, oxidative stress, adipose tissue dysfunction, and systemic inflammation, might affect renal hemodynamics, contributing to CKD development over time in at-risk young patients. As the prevalence of pediatric obesity continues to rise globally, understanding the implications for kidney health in terms of early intervention is of paramount importance. Careful monitoring of kidney function within a multidisciplinary approach in children with obesity is crucial for detecting early KD, allowing for timely lifestyle modifications and treatment. In this framework, continued research is essential to further elucidate mechanisms linking obesity and KD and to explore not only effective preventive strategies but also the long-term impact of obesity on kidney health in children with obesity. Given the intimate link of KD with the metabolic milieu in children with obesity, we aimed to provide a comprehensive and insightful overview on KD and its implications in pediatric obesity by reviewing the most recent literature in the field.

Analysing premature cardiovascular disease mortality in the United States by obesity status and educational attainment

BACKGROUND

In the United States (US), premature cardiovascular disease (CVD) mortality rates (35-74 years) have exhibited increases in recent years, particularly in younger adults, and large differentials by educational attainment. This trend has occurred concurrently with high and increasing obesity prevalence, which also show significant differences by education. This study aims to jointly model premature CVD mortality trends in the US according to obesity status and educational attainment.

METHODS

We used multiple cause of death data from the National Center for Health Statistics, obesity prevalence data from the National Health and Nutrition Examination Survey (NHANES), and educational attainment data from the American Community Survey and NHANES. We applied Bayes' theorem to these data to calculate the conditional probability of premature CVD mortality given obesity status and educational attainment for 2003-2019. We then projected this conditional probability for 2020-2029 using the Lee-Carter model.

RESULTS

The probability of premature CVD mortality was greatest for obesity and low education (not graduated high school) and was substantially higher (females 6.7 times higher, males 5.9) compared with non-obesity and high education (Bachelor's degree or higher) in 2019. There was a widening of the gap in premature CVD mortality from 2003 to 2019 between the obese and non-obese populations, which occurred at each education level and was projected to continue in 2020-2029, especially for males. The conditional probability of premature CVD death for obesity and middle education (finished high school but no Bachelor's degree) increased substantially and was projected to surpass the level for non-obesity and low education in coming years for males and in younger age groups. At high education, the conditional probability of premature CVD death for the obese population was projected to increase to 2029, while for non-obesity it was projected to remain steady for females and fall for males; this projected widening is greatest at older age groups.

CONCLUSIONS

The findings demonstrate the public health challenge to reduce premature US CVD mortality posed by continued high obesity prevalence, especially for younger ages, lower education groups and males. The relative importance of obesity in influencing premature CVD mortality trends has risen partly due to the decline in CVD mortality attributable to other risk factors.

The risk of kidney dysfunction in metabolically healthy/unhealthy population with normal weight or overweight/obesity: a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) is a major global health concern with increasing prevalence and associated complications. Obesity and obesity-related metabolic disorders have been linked to chronic kidney disease (CKD), although the evidence is still inconsistent. To investigate the relationship between different obesity phenotypes and the risk of CKD, we conducted a systematic review and meta-analysis.

METHOD

We conducted a comprehensive search of databases for all relevant studies up to February 2024, without imposing a specific start date, for observational studies assessing the relationship between obesity phenotypes and incident kidney dysfunction. We used fixed and random effects models for the meta-analysis, subgroup analyses were carried out to explore heterogeneity, and Egger's and Begg's tests were used to assess publication bias.

RESULT

This meta-analysis included 13 eligible observational studies with 492,829 participants. Pooling the studies regardless of the effect measure showed that individuals with metabolically unhealthy normal weight (MUNW) (ES = 1.58, 95% CI = 1.43-1.76), metabolically healthy obese (MHO) (ES = 1.20, 95% CI = 1.06-1.34), and metabolically unhealthy obese (MUO) (ES = 1.90, 95% CI = 1.63-2.20) phenotypes had a significantly increased risk for kidney dysfunction (KD) events. On the other hand, MUOW individuals did not significantly correlate with risk of CKD (ES = 1.63, 95% CI = 0.97-2.23) compared to the MHNW phenotype.

CONCLUSION

Healthy overweight and obese individuals had higher risk for the incident KD events; refuting the notion that metabolically healthy overweight and obese phenotypes are benign conditions.

LEVEL OF EVIDENCE

III Evidence obtained from well-designed cohort or cross-sectional studies.

Analysis of the impact of obesity on the prognosis of IgA nephropathy according to renal function and sex

BACKGROUND

Few studies have observed the direct effect of obesity on renal prognoses in immunoglobulin A nephropathy (IgAN) or separately evaluated its effects according to sex. We aimed to evaluate the direct and indirect effects of obesity on the renal outcomes of IgAN and observe these effects separately according to renal function and sex.

METHODS

We extracted patients with body mass index (BMI) descriptions from a multicenter retrospective cohort analysis in Japan, and excluded those with < 30 days of follow-up, diabetes mellitus, and steroid treatment. Patients were divided into normal (n = 720; 18.5 ≤ BMI < 25) and obese (n = 212; BMI ≥ 25) groups, which were then compared. The endpoints were a 1.5-fold increase in serum creatinine levels and the initiation of renal replacement therapy.

RESULTS

The obese group was older, included more males, and was more likely have hypertension, dyslipidemia, proteinuria, tubular atrophy, and lower renal function than the normal group. Patients with an eGFR < 60 mL/min/1.73 m2 had well-matched characteristics between the groups; however, hypertension, low high-density lipoprotein cholesterol, and hypertriglyceridemia were more common in the obese group. Obesity contributed to tubular atrophy, even when adjusted for renal function. In addition, it contributed to proteinuria only in females. However, obesity itself was not a significant prognostic factor.

CONCLUSIONS

Although no independent effect on renal prognosis was observed during the study period, the obese group had more risk factors for IgAN progression and obesity contributed to tubular atrophy and female proteinuria. Our results suggest that separately analyzing the prognostic effect of obesity according to sex is important.

Exploring Adiposity and Chronic Kidney Disease: Clinical Implications, Management Strategies, Prognostic Considerations

Obesity poses a significant and growing risk factor for chronic kidney disease (CKD), requiring comprehensive evaluation and management strategies. This review explores the intricate relationship between obesity and CKD, emphasizing the diverse phenotypes of obesity, including sarcopenic obesity and metabolically healthy versus unhealthy obesity, and their differential impact on kidney function. We discuss the epidemiological evidence linking elevated body mass index (BMI) with CKD risk while also addressing the paradoxical survival benefits observed in obese CKD patients. Various measures of obesity, such as BMI, waist circumference, and visceral fat assessment, are evaluated in the context of CKD progression and outcomes. Mechanistic insights into how obesity promotes renal dysfunction through lipid metabolism, inflammation, and altered renal hemodynamics are elucidated, underscoring the role of adipokines and the renin-angiotensin-aldosterone system. Furthermore, the review examines current strategies for assessing kidney function in obese individuals, including the strengths and limitations of filtration markers and predictive equations. The management of obesity and associated comorbidities like arterial hypertension, type 2 diabetes mellitus, and non-alcoholic fatty liver disease in CKD patients is discussed. Finally, gaps in the current literature and future research directions aimed at optimizing the management of obesity-related CKD are highlighted, emphasizing the need for personalized therapeutic approaches to mitigate the growing burden of this intertwined epidemic.

Renal fat deposition measured on dixon-based MRI is significantly associated with early kidney damage in obesity

PURPOSE

To investigate the renal fat deposition on Dixon-based magnetic resonance imaging (MRI) and to explore the predictive value of renal fat biomarkers of magnetic resonance (MR-RFBs) for early kidney damage in obesity.

METHODS

This prospective study included 56 obese volunteers and 47 non-obese healthy volunteers. All volunteers underwent renal magnetic resonance examinations. The differences in MR-RFBs [including renal proton density fat fraction (PDFF), renal sinus fat volume (RSFV), and perirenal fat thickness (PRFT)] measured on Dixon-based MRI between the obese and non-obese volunteers were analyzed using a general linear model, taking sex, age, diabetes, and hypertension as covariates. The relationship between estimated glomerular filtration rate (eGFR) and demographic, laboratory, and imaging parameters in obese volunteers was examined by correlation analysis.

RESULTS

Obese volunteers had higher MR-RFBs than non-obese volunteers after controlling for confounders (all p < 0.001). Renal PDFF (r = - 0.383; p = 0.004), RSFV (r = - 0.368; p = 0.005), and PRFT (r = - 0.451; p < 0.001) were significantly negatively correlated with eGFR in obesity. After adjusting for age, sex, body mass index, diabetes, hypertension, visceral adipose tissue, subcutaneous adipose tissue, renal PDFF, and RSFV, PRFT remained independently negatively associated with eGFR (β = - 0.587; p = 0.003).

CONCLUSIONS

All MR-RFBs are negatively correlated with eGFR in obesity. The MR-RFBs, especially PRFT, may have predictive value for early kidney damage in obesity.

One anastomosis gastric bypass ameliorates diabetic nephropathy via regulating the GLP-1-mediated Sirt1/AMPK/PGC1α pathway

BACKGROUND

Diabetic nephropathy (DN), a complication of diabetes, is the most leading cause of end-stage renal disease. Bariatric surgery functions on the remission of diabetes and diabetes-related complications. One anastomosis gastric bypass (OAGB), one of popular bariatric surgery, can improve diabetes and its complications by regulating the glucagon-like peptide-1 (GLP-1) level. Meanwhile, GLP-1 can alleviate renal damage in high-fat-diet-induced obese rats. However, the effect of OAGB on renal injury remains uncertain in DN.

METHODS

A diabetes model was elicited in rats via HFD feeding and STZ injection. The role and mechanism of OAGB were addressed in DN rats by the body and kidney weight and blood glucose supervision, oral glucose tolerance test (OGTT), enzyme-linked immunosorbent assay (ELISA), biochemistry detection, histopathological analysis, and western blot assays.

RESULTS

OAGB surgery reversed the increase in body weight and glucose tolerance indicators in diabetes rats. Also, OAGB operation neutralized the DN-induced average kidney weight, kidney weight/body weight, and renal injury indexes accompanied with reduced glomerular hypertrophy, alleviated mesangial dilation and decreased tubular and periglomerular collagen deposition. In addition, OAGB introduction reduced the DN-induced renal triglyceride and renal cholesterol with the regulation of fatty acids-related proteins expression. Mechanically, OAGB administration rescued the DN-induced expression of Sirt1/AMPK/PGC1α pathway mediated by GLP-1. Pharmacological block of GLP-1 receptor inverted the effect of OAGB operation on body weight, glucose tolerance, renal tissue damage, and fibrosis and lipids accumulation in DN rats.

CONCLUSION

OAGB improved renal damage and fibrosis and lipids accumulation in DN rats by GLP-1-mediated Sirt1/AMPK/PGC1α pathway.

Does the Composition of Gut Microbiota Affect Chronic Kidney Disease? Molecular Mechanisms Contributed to Decreasing Glomerular Filtration Rate

Chronic kidney disease (CKD) is a very prevalent and insidious disease, particularly with initially poorly manifested symptoms that progressively culminate in the manifestation of an advanced stage of the condition. The gradual impairment of kidney function, particularly decreased filtration capacity, results in the retention of uremic toxins and affects numerous molecular mechanisms within the body. The dysbiotic intestinal microbiome plays a crucial role in the accumulation of protein-bound uremic toxins such as p-cresol (pC), indoxyl sulfate (IS), and p-cresyl sulfate (p-CS) through the ongoing fermentation process. The described phenomenon leads to an elevated level of oxidative stress and inflammation, subsequently resulting in tissue damage and complications, particularly an increase in cardiovascular risk, representing the predominant cause of mortality in chronic kidney disease (CKD). Therefore, exploring methods to reduce uremic toxins is currently a pivotal therapeutic strategy aimed at reducing the risk of organ damage in patients with chronic kidney disease (CKD). This review aims to summarize recent discoveries on modifying the composition of the intestinal microbiota through the introduction of special probiotic and synbiotic supplements for CKD therapy. The potential to connect the gut microbiota with CKD opens the possibility for further extensive research in this area, which could lead to the incorporation of synbiotics and probiotics into the fundamental treatment and prevention of CKD.

Association of obesity severity and duration with incidence of chronic kidney disease

INTRODUCTION

Obesity is a known risk factor for chronic kidney disease (CKD), but the impact of obesity severity and duration on CKD incidence is unclear.

METHODS

Cumulative Excess Weight (CEW) and Cumulative Excess Waist Circumference (CEWC) scores were calculated, which represent the accumulation of deviations from expected body mass index and waist circumference values over time until the development of CKD or the end of the follow-up period. Time-dependent Cox models were used to investigate the sex-stratified association of CEW and CEWC with CKD incidence while controlling for confounding variables.

RESULTS

Out of the 8697 participants who were evaluated in this study, 56% (4865) were women and the mean age was 40 ± 14. During the 15-year follow-up period, 41.7% (3629) of the participants developed CKD. Among the CKD patients, 65.4% (829) of men and 77.9% (1839) of women had a BMI higher than 25, and high WC was found to be 73.7% (934) and 55.3% (1306) for men and women, respectively. We found a significant association between one standard deviation change of CEW and the development of CKD in both sexes (fully adjusted hazard ratios and 95% CI of CEW in men and women were 1.155 [1.081-1.232) and 1.105 (1.047-1.167)]. However, the association between CEWC and CKD development was only significant among men participants [HR = 1.074 (1.006-1.147)].

CONCLUSION

Over a 15-year follow-up, the accumulation of general and central obesity was associated with an increased incidence of CKD development.

The Influence of Non-Pharmacological and Pharmacological Interventions on the Course of Autosomal Dominant Polycystic Kidney Disease

Polycystic kidney disease (PKD) includes autosomal dominant (ADPKD) and autosomal recessive (ARPKD) forms, both of which are primary genetic causes of kidney disease in adults and children. ADPKD is the most common hereditary kidney disease, with a prevalence of 329 cases per million in Europe. This condition accounts for 5-15% of end-stage chronic kidney disease (ESKD) cases, and in developed countries such as Poland, 8-10% of all dialysis patients have ESKD due to ADPKD. The disease is caused by mutations in the PKD1 and PKD2 genes, with PKD1 mutations responsible for 85% of cases, leading to a more aggressive disease course. Recent research suggests that ADPKD involves a metabolic defect contributing to cystic epithelial proliferation and cyst growth. Aim: This review explores the interplay between metabolism, obesity, and ADPKD, discussing dietary and pharmacological strategies that target these metabolic abnormalities to slow disease progression. Conclusion: Metabolic reprogramming therapies, including GLP-1 analogs and dual agonists of GIP/GLP-1 or glucagon/GLP-1 receptors, show promise, though further research is needed to understand their potential in ADPKD treatment fully.

Exploring the nexus: The place of kidney diseases within the cardiovascular-kidney-metabolic syndrome spectrum

Cardiovascular-kidney-metabolic (CKM) syndrome and chronic kidney disease (CKD) are two significant comorbidities affecting a large proportion of the general population with considerable crosstalk. In addition to substantial co-incidence of CKD and CKM syndrome in epidemiological studies, clinical and pre-clinical studies have identified similar pathophysiological pathways leading to both entities. Patients with CKM syndrome are more prone to develop acute kidney injury and CKD, while therapeutic alternatives and their success rates are considerably lower in such patient groups. Nevertheless, the association between CKM syndrome and CKD or ESKD is bidirectional rather than being a cause-effect relationship as patients with CKD are also prone to develop peripheral insulin resistance, high blood pressure, and dyslipidemia. Furthermore, such patients are less likely to receive kidney transplantation in addition to the higher allograft dysfunction risk. We hereby aim to evaluate the association in-between kidney diseases and CKM syndrome, including epidemiological data, pre-clinical studies with pathophysiological pathways, and potential therapeutic perspectives.

Kidney function evaluation in children and adolescents with obesity: a not-negligible need

The role of obesity as risk factor for chronic kidney disease (CKD) has been well-recognized. As previously demonstrated in adults, emerging data highlighted the relevant impact of obesity on renal function since childhood. As a matter of fact, obesity also affects renal health through a complex pathogenic mechanism in which insulin resistance (IR) plays a pivotal role. Worthy of note, the vicious interplay among obesity, IR, and renal hemodynamics clinically translates into a plethora of kidney function impairments potentially leading to CKD development. Therefore, renal injury needs to be added to the well-known spectrum of cardiometabolic obesity comorbidities (e.g., type 2 diabetes, IR, metabolic syndrome, cardiovascular disease).

CONCLUSION

Taking this into account, a careful and timely monitoring of kidney function should not be neglected in the global assessment of children with obesity. We aimed to provide a comprehensive overview on the relevance of kidney evaluation in children with obesity by shedding lights on the intriguing relationship of obesity with renal health in this at-risk population.

WHAT IS KNOWN

• Obesity has been found to be a risk factor for chronic kidney disease. • Unlike adults, pediatric data supporting the association between obesity and renal function are still limited.

WHAT IS NEW

• As observed in adults, obesity might affect renal function since childhood. • Kidney function should be carefully evaluated in children with obesity.

Obesity-related glomerulopathy is associated with elevated WT1 expression in podocytes

BACKGROUND

The prevalence of obesity is increasing worldwide at an alarming rate. In addition to the increased incidence of cardiovascular and metabolic diseases, obesity is the most potent risk factor for developing chronic kidney disease (CKD). Although systemic events such as hemodynamic factors, metabolic effects, and lipotoxicity were implicated in the pathophysiology of obesity-related glomerulopathy (ORG) and kidney dysfunction, the precise mechanisms underlying the association between obesity and CKD remain unexplored.

METHODS

In this study, we employed spontaneous WNIN/Ob rats to investigate the molecular events that promote ORG. Further, we fed a high-fat diet to mice and analyzed the incidence of ORG. Kidney functional parameters, micro-anatomical manifestations, and podocyte morphology were investigated in both experimental animal models. Gene expression analysis in the rodents was compared with human subjects by data mining using Nephroseq and Kidney Precision Medicine Project database.

RESULTS

WNIN/Ob rats were presented with proteinuria and several glomerular deformities, such as adaptive glomerulosclerosis, decreased expression of podocyte-specific markers, and effacement of podocyte foot process. Similarly, high-fat-fed mice also showed glomerular injury and proteinuria. Both experimental animal models showed increased expression of podocyte-specific transcription factor WT1. The altered expression of putative targets of WT1 such as E-cadherin, podocin (reduced), and α-SMA (increased) suggests elevated expression of WT1 in podocytes elicits mesenchymal phenotype. Curated data from CKD patients revealed increased expression of WT1 in the podocytes and its precursors, parietal epithelial cells.

CONCLUSION

WT1 is crucial during nephron development and has minimal expression in adult podocytes. Our study discovered elevated expression of WT1 in podocytes in obesity settings. Our analysis suggests a novel function for WT1 in the pathogenesis of ORG; however, the precise mechanism of WT1 induction and its involvement in podocyte pathobiology needs further investigation.

Prevalence and associated factors of impaired kidney functions among children and adolescents in India: insights from the Comprehensive National Nutrition Survey (CNNS) 2016-18

BACKGROUND

Chronic kidney disease (CKD) is a significant public health problem. The burden of CKD in children and adolescents in India is not well described. We used data from the recent Comprehensive National Nutrition Survey (CNNS) to estimate the prevalence of impaired kidney function (IKF) and its determinants in children and adolescents between the ages of 5 and 19.

METHODS

CNNS 2016-18 adopted a multi-stage sampling design using probability proportional to size sampling procedure after geographical stratification of urban and rural areas. Serum creatinine was tested once in 24,690 children and adolescents aged 5-19 years. The estimated glomerular filtration rate (eGFR) was derived using the revised Schwartz equation. The eGFR value below 60 ml/min/1.73 m2 is defined as IKF. Bivariate analysis was done to depict the weighted prevalence, and multivariable logistic regression examined the predictors of IKF.

RESULTS

The mean eGFR in the study population was 113.3 + 41.4 mL/min/1.73 m2. The overall prevalence of IKF was 4.9%. The prevalence in the 5-9, 10-14, and 15-19 year age groups was 5.6%, 3.4% and 5.2%, respectively. Regression analysis showed age, rural residence, non-reserved social caste, less educated mothers, Islam religion, children with severe stunting or being overweight/obese, and residence in Southern India to be predictors of IKF.

CONCLUSIONS

The prevalence of IKF among children and adolescents in India is high compared to available global estimates. In the absence of repeated eGFR-based estimates, these nationally representative estimates are intriguing and call for further assessment of socio-demographic disparities, genetics, and risk behaviours to have better clinical insights and public health preparedness.

MASLD and MASH at the crossroads of hepatology trials and cardiorenal metabolic trials

Steatotic liver disease (SLD) is a worldwide public health problem, causing considerable morbidity and mortality. Patients with SLD are at increased risk for major adverse cardiovascular (CV) events, type 2 diabetes mellitus and chronic kidney disease. Conversely, patients with cardiometabolic conditions have a high prevalence of SLD. In addition to epidemiological evidence linking many of these conditions, there is evidence of shared pathophysiological processes. In December 2022, a unique multi-stakeholder, multi-specialty meeting, called MOSAIC (Metabolic multi Organ Science Accelerating Innovation in Clinical Trials) was convened to foster collaboration across metabolic, hepatology, nephrology and CV disorders. One of the goals of the meeting was to consider approaches to drug development that would speed regulatory approval of treatments for multiple disorders by combining liver and cardiorenal endpoints within a single study. Non-invasive tests, including biomarkers and imaging, are needed in hepatic and cardiorenal trials. They can be used as trial endpoints, to enrich trial populations, to diagnose and risk stratify patients and to assess treatment efficacy and safety. Although they are used in proof of concept and phase 2 trials, they are often not acceptable for regulatory approval of therapies. The challenge is defining the optimal combination of biomarkers, imaging and morbidity/mortality outcomes and ensuring that they are included in future trials while minimizing the burden on patients, trialists and trial sponsors. This paper provides an overview of some of the wide array of CV, liver and kidney measurements that were discussed at the MOSAIC meeting.

Loss-of-function G6PD variant moderated high-fat diet-induced obesity, adipocyte hypertrophy, and fatty liver in male rats

Obesity is a major risk factor for liver and cardiovascular diseases. However, obesity-driven mechanisms that contribute to the pathogenesis of multiple organ diseases are still obscure and treatment is inadequate. We hypothesized that increased , glucose-6-phosphate dehydrogenase (G6PD), the key rate-limiting enzyme in the pentose shunt, is critical in evoking metabolic reprogramming in multiple organs and is a significant contributor to the pathogenesis of liver and cardiovascular diseases. G6PD is induced by a carbohydrate-rich diet and insulin. Long-term (8 months) high-fat diet (HFD) feeding increased body weight and elicited metabolic reprogramming in visceral fat, liver, and aorta, of the wild-type rats. In addition, HFD increased inflammatory chemokines in visceral fat. Interestingly, CRISPR-edited loss-of-function Mediterranean G6PD variant (G6PDS188F) rats, which mimic human polymorphism, moderated HFD-induced weight gain and metabolic reprogramming in visceral fat, liver, and aorta. The G6PDS188F variant prevented HFD-induced CCL7 and adipocyte hypertrophy. Furthermore, the G6PDS188F variant increased Magel2 - a gene encoding circadian clock-related protein that suppresses obesity associated with Prader-Willi syndrome - and reduced HFD-induced non-alcoholic fatty liver. Additionally, the G6PDS188F variant reduced aging-induced aortic stiffening. Our findings suggest G6PD is a regulator of HFD-induced obesity, adipocyte hypertrophy, and fatty liver.

Changes in tubular biomarkers with dietary intervention and metformin in patients with autosomal dominant polycystic kidney disease: a post-hoc analysis of two clinical trials

BACKGROUND

Tubular biomarkers, which reflect tubular dysfunction or injury, are associated with incident chronic kidney disease and kidney function decline. Several tubular biomarkers have also been implicated in the progression of autosomal dominant polycystic kidney disease (ADPKD). We evaluated changes in multiple tubular biomarkers in four groups of patients with ADPKD who participated in one of two clinical trials (metformin therapy and diet-induced weight loss), based on evidence suggesting that such interventions could reduce tubule injury.

METHODS

66 participants (26 M/40 F) with ADPKD and an estimated glomerular filtration rate (eGFR) ≥ 30 ml/min/1.73m2 who participated in either a metformin clinical trial (n = 22 metformin; n = 23 placebo) or dietary weight loss study (n = 10 daily caloric restriction [DCR]; n = 11 intermittent fasting [IMF]) were included in assessments of urinary tubular biomarkers (kidney injury molecule-1 [KIM-1], fatty-acid binding protein [FABP], interleukin-18 [IL-18], monocyte chemoattractant protein-1 [MCP-1], neutrophil gelatinase-associated lipocalin [NGAL], clusterin, and human cartilage glycoprotein-40 [YKL-40]; normalized to urine creatinine), at baseline and 12 months. The association of baseline tubular biomarkers with both baseline and change in height-adjusted total kidney volume (HtTKV; percent change from baseline to 12 months) and estimated glomerular filtration rate (eGFR; absolute change at 12 months vs. baseline), with covariate adjustment, was also assessed using multiple linear regression.

RESULTS

Mean ± s.d. age was 48 ± 8 years, eGFR was 71 ± 16 ml/min/1.73m2, and baseline BMI was 30.5 ± 5.9 kg/m2. None of the tubular biomarkers changed with any intervention as compared to placebo. Additionally, baseline tubular biomarkers were not associated with either baseline or change in eGFR or HtTKV over 12 months, after adjustments for demographics, group assignment, and clinical characteristics.

CONCLUSIONS

Tubular biomarkers did not change with dietary-induced weight loss or metformin, nor did they associate with kidney disease progression, in this cohort of patients with ADPKD.

Clinical characteristics and treatment compounds of obesity-related kidney injury

Disorders in energy homeostasis can lead to various metabolic diseases, particularly obesity. The obesity epidemic has led to an increased incidence of obesity-related nephropathy (ORN), a distinct entity characterized by proteinuria, glomerulomegaly, progressive glomerulosclerosis, and renal function decline. Obesity and its associated renal damage are common in clinical practice, and their incidence is increasing and attracting great attention. There is a great need to identify safe and effective therapeutic modalities, and therapeutics using chemical compounds and natural products are receiving increasing attention. However, the summary is lacking about the specific effects and mechanisms of action of compounds in the treatment of ORN. In this review, we summarize the important clinical features and compound treatment strategies for obesity and obesity-induced kidney injury. We also summarize the pathologic and clinical features of ORN as well as its pathogenesis and potential therapeutics targeting renal inflammation, oxidative stress, insulin resistance, fibrosis, kidney lipid accumulation, and dysregulated autophagy. In addition, detailed information on natural and synthetic compounds used for the treatment of obesity-related kidney disease is summarized. The synthesis of detailed information aims to contribute to a deeper understanding of the clinical treatment modalities for obesity-related kidney diseases, fostering the anticipation of novel insights in this domain.

Metabolic syndrome as a risk factor for the development of kidney dysfunction: a meta-analysis of observational cohort studies

Background

Chronic kidney disease (CKD) is a major global health concern with increasing prevalence and associated complications. Metabolic syndrome (MetS) has been linked to CKD, but the evidence remains inconsistent. We conducted a systematic review and meta-analysis to investigate the association between MetS and kidney dysfunction.

Method

We conducted a comprehensive search of databases until December 2022 for cohort studies assessing the association between MetS and incident kidney dysfunction. Meta-analysis was performed using fixed and random effects models. Subgroup analyses were conducted to explore heterogeneity. Publication bias was assessed using Egger's and Begg's tests.

Result

A total of 24 eligible studies, involving 6,573,911 participants, were included in this meta-analysis. MetS was significantly associated with an increased risk of developing CKD (OR, 1.42; 95% CI, 1.28, 1.57), albuminuria or proteinuria (OR, 1.43; 95% CI, 1.10, 1.86), and rapid decline in kidney function (OR, 1.25; 95% CI, 1.07, 1.47). Subgroup analyses showed a stronger association as the number of MetS components increased. However, gender-specific subgroups demonstrated varying associations.

Conclusion

Metabolic syndrome is a significant risk factor for kidney dysfunction, requiring close renal monitoring. Lifestyle changes and targeted interventions may help reduce CKD burden. Further research is needed to understand the connection fully and assess intervention efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01348-5.

Polycystic Kidney Disease Diet: What is Known and What is Safe

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by kidney cyst formation and progressive kidney function loss. Dietary interventions such as caloric restriction, intermittent fasting, and ketogenic diet have recently emerged as potential strategies to induce metabolic reprogramming and slow ADPKD progression. We review the available evidence supporting the efficacy and safety of these interventions in ADPKD. Dietary interventions show promise in managing ADPKD by improving metabolic health and reducing oxidative stress. However, while preclinical studies have shown favorable outcomes, limited clinical evidence supports their effectiveness. In addition, the long-term consequences of these dietary interventions, including their effect on adverse events in patients with ADPKD, remain uncertain. To optimize ADPKD management, patients are advised to follow a dietary regimen that aims to achieve or maintain an ideal body weight and includes high fluid intake, low sodium, and limited concentrated sweets. Caloric restriction seems particularly beneficial for patients with overweight or obesity because it promotes weight loss and improves metabolic parameters. Supplementation with curcumin, ginkgolide B, saponins, vitamin E, niacinamide, or triptolide has demonstrated uncertain clinical benefit in patients with ADPKD. Notably, β -hydroxybutyrate supplements have shown promise in animal models; however, their safety and efficacy in ADPKD require further evaluation through well-designed clinical trials. Therefore, the use of these supplements is not currently recommended for patients with ADPKD. In summary, dietary interventions such as caloric restriction, intermittent fasting, and ketogenic diet hold promise in ADPKD management by enhancing metabolic health. However, extensive clinical research is necessary to establish their effectiveness and long-term effects. Adhering to personalized dietary guidelines, including weight management and specific nutritional restrictions, can contribute to optimal ADPKD management. Future research should prioritize well-designed clinical trials to determine the benefits and safety of dietary interventions and supplementation in ADPKD.

Metabolic health's central role in chronic kidney disease progression: a 20-year study of obesity-metabolic phenotype transitions

This study investigates the risk of chronic kidney disease (CKD) across four metabolic phenotypes: Metabolically Healthy-No Obesity (MH-NO), Metabolically Unhealthy-No obesity (MU-NO), Metabolically Healthy-Obesity (MH-O), and Metabolically Unhealthy-Obesity (MU-O). Data from the Tehran Lipid and Glucose Study, collected from 1999 to 2020, were used to categorize participants based on a BMI ≥ 30 kg/m2 and metabolic health status, defined by the presence of three or four of the following components: high blood pressure, elevated triglycerides, low high-density lipoprotein, and high fasting blood sugar. CKD, characterized by a glomerular filtration rate < 60 ml/min/1.72 m2. The hazard ratio (HR) of CKD risk was evaluated using Cox proportional hazard models. The study included 8731 participants, with an average age of 39.93 years, and identified 734 incidents of CKD. After adjusting for covariates, the MU-O group demonstrated the highest risk of CKD progression (HR 1.42-1.87), followed by the MU-NO group (HR 1.33-1.67), and the MH-O group (HR 1.18-1.54). Persistent MU-NO and MU-O posed the highest CKD risk compared to transitional states, highlighting the significance of exposure during early adulthood. These findings emphasize the independent contributions of excess weight and metabolic health, along with its components, to CKD risk. Therefore, preventive strategies should prioritize interventions during early-adulthood.

Exercise for patients with chronic kidney disease: from cells to systems to function

Chronic kidney disease (CKD) is among the leading causes of death and disability, affecting an estimated 800 million adults globally. The underlying pathophysiology of CKD is complex creating challenges to its management. Primary risk factors for the development and progression of CKD include diabetes mellitus, hypertension, age, obesity, diet, inflammation, and physical inactivity. The high prevalence of diabetes and hypertension in patients with CKD increases the risk for secondary consequences such as cardiovascular disease and peripheral neuropathy. Moreover, the increased prevalence of obesity and chronic levels of systemic inflammation in CKD have downstream effects on critical cellular functions regulating homeostasis. The combination of these factors results in the deterioration of health and functional capacity in those living with CKD. Exercise offers protective benefits for the maintenance of health and function with age, even in the presence of CKD. Despite accumulating data supporting the implementation of exercise for the promotion of health and function in patients with CKD, a thorough description of the responses and adaptations to exercise at the cellular, system, and whole body levels is currently lacking. Therefore, the purpose of this review is to provide an up-to-date comprehensive review of the effects of exercise training on vascular endothelial progenitor cells at the cellular level; cardiovascular, musculoskeletal, and neural factors at the system level; and physical function, frailty, and fatigability at the whole body level in patients with CKD.

Long-Term Effects of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease: Predictors of Treatment Response and Safety over 6 Years of Continuous Therapy

Tolvaptan, an oral vasopressin V2 receptor antagonist, reduces renal volume expansion and loss of renal function in patients with autosomal dominant polycystic kidney disease (ADPKD). Data for predictive factors indicating patients more likely to benefit from long-term tolvaptan are lacking. Data were retrospectively collected from 55 patients on tolvaptan for 6 years. Changes in renal function, progression of renal dysfunction (estimated glomerular filtration rate [eGFR], 1-year change in eGFR [ΔeGFR/year]), and renal volume (total kidney volume [TKV], percentage 1-year change in TKV [ΔTKV%/year]) were evaluated at 3-years pre-tolvaptan, at baseline, and at 6 years. In 76.4% of patients, ΔeGFR/year improved at 6 years. The average 6-year ΔeGFR/year (range) minus baseline ΔeGFR/year: 3.024 (-8.77-20.58 mL/min/1.73 m2). The increase in TKV was reduced for the first 3 years. A higher BMI was associated with less of an improvement in ΔeGFR (p = 0.027), and family history was associated with more of an improvement in ΔeGFR (p = 0.044). Hypernatremia was generally mild; 3 patients had moderate-to-severe hyponatremia due to prolonged, excessive water intake in response to water diuresis-a side effect of tolvaptan. Family history of ADPKD and baseline BMI were contributing factors for ΔeGFR/year improvement on tolvaptan. Hyponatremia should be monitored with long-term tolvaptan administration.

Weight change in chronic kidney disease: Association with mortality and kidney function

Background

Excess body weight is a risk factor for the progression of chronic kidney disease (CKD), but weight loss in CKD has been associated with higher mortality. Consequently, blanket weight loss recommendations in this population are controversial. Little data is available on the patterns of weight-change in CKD. The authors aimed to describe weight-changes in moderate/severe CKD and explore associations with mortality and renal endpoints in patients with overweight and obesity.

Methods

Non-dialysis Canberra Hospital patients with estimated glomerular filtration (eGFR) < 60 mL/min/1.73 m2 and body mass index (BMI) ≥25 kg/m2 were followed for up to 5.5 years. Weight-change ≥5% was considered clinically significant. The renal endpoint was defined as the commencement of dialysis or transplant or a ≥40% fall in eGFR. Relationships between weight-change in the first year of follow-up and mortality or the renal endpoint were assessed using Cox-regression.

Results

Three hundred ten patients (median age 75, median BMI 31 kg/m2) were identified. 68% had Stage-4 CKD at baseline. Over 4.4-years median follow-up, 128 died and 140 had significant weight-change. During the first year of follow-up, 42 patients lost and 23 gained ≥5% body weight, of whom only 3 had intentionally lost weight. On multivariate regression, significant weight loss/gain at 1-year was associated with 2.74 (p < 0.0005) and 2.67 (p = 0.003) hazard of subsequent death and with 2.51 (p = 0.004) and 2.20 (p = 0.05) hazard of the renal endpoint respectively. There was no association between baseline eGFR and subsequent weight change.

Conclusions

Patients with moderate/severe CKD experience significant weight-change, but this has no relationship to baseline kidney function. Significant weight-change is associated with higher subsequent mortality and loss of kidney function, but this association is likely significantly affected by confounding.

Novel subgroups of obesity and their association with outcomes: a data-driven cluster analysis

BACKGROUND

Obesity is associated with various complications and decreased life expectancy, and substantial heterogeneity in complications and outcomes has been observed. However, the subgroups of obesity have not yet been clearly defined. This study aimed to identify the subgroups of obesity especially those for target of interventions by cluster analysis.

METHODS

In this study, an unsupervised, data-driven cluster analysis of 9,494 individuals with obesity (body mass index ≥ 35 kg/m2) was performed using the data of ICD-10, drug, and medical procedure from the healthcare claims database. The prevalence and clinical characteristics of the complications such as diabetes in each cluster were evaluated using the prescription records. Additionally, renal and life prognoses were compared among the clusters.

RESULTS

We identified seven clusters characterised by different combinations of complications and several complications were observed exclusively in each cluster. Notably, the poorest prognosis was observed in individuals who rarely visited a hospital after being diagnosed with obesity, followed by those with cardiovascular complications and diabetes.

CONCLUSIONS

In this study, we identified seven subgroups of individuals with obesity using population-based data-driven cluster analysis. We clearly demonstrated important target subgroups for intervention as well as a metabolically healthy obesity group.