Body-mass index and risk of advanced chronic kidney disease: Prospective analyses from a primary care cohort of 1.4 million adults in England

Development of risk models for early detection and prediction of chronic kidney disease in clinical settings

Chronic kidney disease (CKD) imposes a high burden with high mortality and morbidity rates. Early detection of CKD is imperative in preventing the adverse outcomes attributed to the later stages. Therefore, this study aims to utilize machine learning techniques to predict CKD at early stages. This study uses data obtained from a large longitudinal cohort study. The features include patients' sociodemographic, anthropometric, and laboratory tests that are mostly associated with CKD based on national and international studies. Missing data and outliers were deleted using listwise and interquartile range techniques, respectively. Data initially remained imbalanced to investigate the ability of models to work on imbalanced datasets. Stratified K-folds cross-validation, a robust approach that performs well on imbalanced data, was further performed to enhance the splitting. Interestingly, an interaction was found between age and gender where contrasting data was generated, therefore, to avoid this interaction gender-specific algorithms were developed. Four main algorithms and four algorithms using the stratified K-folds cross-validation technique, consisting of gender-specific Random Forest and feedforward Neural Networks were developed using the preprocessed data of 6855 participants. The RF model in women exhibited the highest AUC of 0.90 followed closely by 0.89 in their NN model. Both models constructed for men yielded an AUC of 0.88. Sensitivity scores were higher in men compared to women. Models demonstrated subpar results regarding specificity, however, the high precision and F1 scores, make the models extremely valuable in a clinical setting to accurately identify CKD cases while minimizing false positive diagnoses. Moreover, the results from stratified K-fold cross-validation indicated that the NN models were more sensitive to the imbalanced dataset and demonstrated a marked increase in performance, particularly specificity, after this approach. These data offer valuable insights for the development of future risk stratification models for CKD.

GLP-1 receptor agonists in patients with chronic kidney disease and either overweight or obesity

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have emerged as game-changers across the cardiovascular-kidney-metabolic (CKM) spectrum: overweight/obesity, type 2 diabetes mellitus (T2DM) and associated chronic kidney disease (CKD) and cardiovascular disease (CVD). Liraglutide, semaglutide and tirzepatide are European Medicines Agency approved to improve metabolic control in T2DM and to decrease weight in persons with obesity [body mass index (BMI) ≥30 kg/m2] or with overweight (BMI ≥27 kg/m2) associated with weight-related comorbidities such as hypertension, dyslipidaemia, CVD and others. Additionally, liraglutide and semaglutide are approved to reduce CVD risk in patients with CVD and T2DM. Semaglutide is also approved to reduce CVD risk in patients with CVD and either obesity or overweight and in phase 3 clinical trials showed kidney and cardiovascular protection in patients with T2DM and albuminuric CKD (FLOW trial) as well as in persons without diabetes that had CVD and overweight/obesity (SELECT trial). Thus, nephrologists should consider prescribing GLP-1 RAs to improve metabolic control, reduce CVD risk or improve kidney outcomes in three scenarios: patients with overweight and a related comorbid condition such as hypertension, dyslipidaemia or CVD, patients with obesity and patients with T2DM. This review addresses the promising landscape of GLP-1 RAs to treat persons with overweight or obesity, with or without T2DM, within the context of CKD, assessing their safety and impact on weight, metabolic control, blood pressure and kidney and cardiovascular outcomes, as part of a holistic patient-centred approach to preserve CKM health.

Sex and the Relationship Between Cardiometabolic Risk Factors and Estimated GFR Decline: A Population-Based Cohort Study

RATIONALE & OBJECTIVE

Females have a higher prevalence of chronic kidney disease (CKD) than males but are less likely to be treated with kidney replacement therapy (KRT). We studied the interaction between sex and the association of cardiometabolic risk factors for the decline in kidney function over time.

STUDY DESIGN

A population-based cohort study.

SETTING & PARTICIPANTS

1,127,731 adults living in Wales, United Kingdom, within the Secure Anonymised Information Linkage Databank.

EXPOSURE

Sex and risk factors including age, estimated glomerular filtration rate (eGFR), cardiometabolic conditions, smoking, and socioeconomic deprivation. These risk factors were defined using primary care records.

OUTCOME

The yearly declines in eGFR and the risk of incident kidney failure defined as long-term KRT and/or sustained eGFR<15mL/min/1.73m2.

ANALYTICAL APPROACH

Linear mixed effects models and Cox proportional hazards analysis.

RESULTS

The average decline in eGFR at age≤73 years was equal in males and females. After age 73 years, eGFR decline was faster in males than females, particularly for males with heart failure (males-1.22mL/min/1.73m2 per year [95% CI, -1.25 to-1.20] vs females-0.87mL/min/1.73m2 per year [95% CI, -0.89 to-0.85]) and current smokers (males-1.58mL/min/1.73m2 per year [95% CI, -1.60 to-1.55] vs females-1.27mL/min/1.73m2 per year [95% CI, -1.29 to-1.25]). Socioeconomic deprivation was one of the most impactful risk factors on eGFR decline among females aged>73 years, whereas cardiometabolic risk factors were more important among males. Older females at baseline were less likely to develop incident kidney failure than older males (P for age<0.001).

LIMITATIONS

Study of people who were almost exclusively White and who had blood laboratory test data. Reliance on creatinine-based eGFR. Albuminuria and body mass index data were incomplete.

CONCLUSIONS

The eGFR decline was faster in males than in females, especially in the setting of heart failure and smoking. Socioeconomic deprivation was an important risk factor associated with eGFR decline, particularly for females. further work is required to explore less well-recognized risk factors, but these findings may inform clinical management strategies of CKD overall and within sex-specific groups.

PLAIN-LANGUAGE SUMMARY

Kidney function is known to decline at a faster rate among males than females. This study incorporated blood laboratory test results from the routine care of 1.1 million adults living in the United Kingdom and found that the decline in kidney function associated with risk factors varied by sex. Before and at the age of 73 years, the decline in kidney function was similar between males and females. After age 73, cardiometabolic risk factors were associated with faster decline in kidney function among males than females, specifically heart failure and smoking. Socioeconomic deprivation was also associated with the decline in kidney function for both sexes, but it was a stronger risk factor among females. These findings may inform the management of kidney disease overall and within sex-specific groups.

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.

Impact of Metabolic Syndrome Traits on Kidney Disease Risk in Individuals with MASLD: A UK Biobank Study

BACKGROUND AND AIMS

The impact of metabolic syndrome (MetS) traits on chronic kidney disease (CKD) risk in metabolic dysfunction-associated steatotic liver disease (MASLD) is unknown. We investigated the impact of type and number of MetS traits and liver fibrosis on prevalent CKD and incident end-stage renal disease (ESRD) risk in SLD.

METHODS

234 488 UK Biobank participants' were analysed. Hepatic steatosis index (> 36 for SLD, < 30 for no SLD) and MRI-proton density fat fraction (≥ 5.56%) were used to identify SLD. MetS traits were identified using MASLD criteria. Advanced fibrosis (FIB-4 score > 2.67) was determined using FIB-4 scores. eGFR < 60 mL/min/1.73 m2 or albuminuria > 3 mg/mmol identified prevalent CKD. A validated algorithm identified incident ESRD. Binary logistic and Cox regressions were used to test associations with prevalent CKD ([adjusted odds ratios (ORs)]) and incident ESRD (adjusted hazard ratios [HRs]) respectively.

RESULTS

102 410 participants (41.2%) had SLD. 64.4% had MetS. 1.3% had FIB-4 score > 2.67. With SLD and only one MetS trait, hypertension (OR 1.35, 95% CI 1.35-1.72) or type 2 diabetes (T2D) (OR 1.89, 95% CI 1.06-3.38) increased risk of prevalent CKD. MetS (≥ 3 traits) increased prevalent CKD risk (OR 1.94, 95% CI 1.75-2.15), which was further increased by advanced liver fibrosis (OR 4.29, 95% CI 3.36-5.47). CKD prevalence increased with increasing MetS traits. Over 13.6 years (median follow-up), MetS was associated with increased risk of developing ESRD (HR 1.70, 95% CI 1.19-2.43).

CONCLUSIONS

In MASLD, hypertension, and T2D, number of MetS traits and liver fibrosis increased risk of prevalent CKD and presence of MetS increased the risk of incident ESRD.

Prevalence, Characteristics, and Outcomes of People With A High Body Mass Index Across the Kidney Disease Spectrum: A Population-Based Cohort Study

Background

Obesity has a major impact on health and health care, particularly in those with chronic kidney disease (CKD).

Objective

The objective was to describe the prevalence, characteristics, and outcomes of people living with CKD and obesity (defined by a body mass index [BMI] ≥30 kg/m2) in Canada.

Design

Population-based cohort study using linked administrative health data (ICES).

Patients

Adults aged 18 year and older with CKD G1-5D who had a height and weight recorded during a visit to an academic hospital in London Ontario Canada, between January 2010 and December 2019.

Measures

CKD as defined by CKD 3A or higher. BMI as defined by weight kg/m2.

Methods

As a primary interest, we described the percentage of patients with CKD across different BMI categories (<25 kg/m2, BMI 25-29.9 kg/m2, and BMI ≥30 kg/m2), as well as their demographic and clinical profiles. As secondary interests, we followed patients until January 1, 2022 to summarize: (1) the percentage with CKD G3 who had kidney disease progression (50% decline from baseline estimated glomerular filtration rate [eGFR]) by BMI category, (2) the percentage with CKD G3-4 who developed kidney failure (initiation of maintenance dialysis or an eGFR of <15 mL/min/1.73 m2) by BMI category, (3) the percentage with CKD G4-G5D who received a kidney transplant by BMI category, and (4) post-transplant outcomes in those transplanted over the study period, by BMI category. We performed similar analyses across CKD risk categories.

Results

Of the 198 151 patients included, the percentage with obesity defined by a BMI ≥30 kg/m2 increased from CKD G1 to CKD G4 (ie, 37% of those with CKD G1 had a BMI ≥30 kg/m2 vs 40.9% of CKD G4). In CKD G5D and CKD T, the prevalence of high BMI appeared to drop (only ~38% had a BMI ≥30 kg/m2 across groups). Across CKD categories, those with a BMI ≥30 kg/m2 appeared to have more comorbidities, use more health care resources, and have more socioeconomic disparities than those with lower BMIs. Although secondary outcome events were limited, those with G3-4 with a BMI ≥30 kg/m2 appeared to have a higher risk of CKD progression and those with CKD G5D with BMI ≥30 kg/m2 were less likely to receive transplant over the study period. Interestingly those transplanted with a BMI ≥30 kg/m2 appeared to have fewer post-transplant complications. We also observed an "obesity-paradox" in the risk of mortality, with high BMI appearing protective, particularly in the end stages of kidney disease.

Limitations

We used BMI to capture obesity in this study but recognize its limitations as a measure of body composition. Secondary outcomes were descriptive and unadjusted due to small sample size and may have been subject to selection bias and confounding.

Conclusions

Obesity defined by high BMI is highly prevalent in people with CKD, and patients have health, health care, and social disparity. Future studies to understand the impact of BMI on patients with CKD and how to individualize and manage BMI and obesity across the spectrum of CKD remain important.

Ten tips on how to manage obesity in the presence of CKD

Patients with chronic kidney disease are frequently facing the challenge of weight reduction. Finding a weight loss strategy is on the one hand essential to reduce the co-morbidity risks in CKD but remains complex due to the metabolic abnormalities with declining renal function. Here, we provide ten tips to support our CKD patients on their journey, focussing on dietary and behavioural habits and health professional supportive therapies.

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.

Exploring the link between kidney dimensions and anthropometric measurements: insights from a Saudi population study

Introduction

Ultrasound (US) measurements of kidney dimensions are essential for correlating with height, weight, and body mass index (BMI), establishing kidney size baselines, and assessing renal health. The global rise in obesity has increased interest in the links between BMI and chronic kidney disease (CKD). This study investigates the relationship between renal dimensions (length, width, and thickness) and anthropometric measures (height, weight, and BMI) in a Saudi population.

Material and methods

A cross-sectional study was conducted at two ultrasound clinics in Riyadh, Saudi Arabia, with 129 participants (73 males and 56 females) aged 18-60 years. Kidney dimensions were measured using ultrasound machines. Spearman correlation assessed relationships between kidney dimensions and age, height, weight, and BMI, while the Mann-Whitney U test investigated sex differences.

Results

Significant correlations were identified between kidney dimensions and anthropometric measures. Age negatively correlated with kidney thickness for both kidneys (right: r = -0.502, p < 0.0001; left: r = -0.542, p < 0.0001) and left kidney width (r = -0.204, p = 0.020). Height positively correlated with all kidney dimensions. Weight also positively correlated with kidney dimensions. BMI showed positive correlations with right kidney length (r = 0.219, p = 0.013) and width (r = 0.319, p < 0.0001), and left kidney length (r = 0.209, p = 0.018). Males had greater kidney thickness and left kidney width compared to females.

Conclusions

This study establishes significant correlations between renal dimensions and anthropometric measures in a Saudi population, highlighting the importance of considering individual characteristics in renal assessments. These findings support the development of personalized clinical guidelines for improved renal condition management.

Association of life's essential 8 with chronic cardiovascular-kidney disorder: a prospective cohort study

BACKGROUND

The coexistence of cardiovascular disease and chronic kidney disease, termed chronic cardiovascular-kidney disorder (CCV-KD), is increasingly prevalent. However, limited studies have assessed the association between cardiovascular health (CVH), assessed by the American Heart Association's Life's Essential 8 (LE8), and CCV-KD.

METHODS

We conducted a prospective cohort study using data from UK Biobank. Participants without cardiovascular disease and chronic kidney disease at baseline and having complete data on metrics of LE8 were included (N = 125,986). LE8 included eight metrics, and the aggregate score was categorized as low (< 50 points), intermediate (50 to < 80 points), and high (≥ 80 points), with a higher score indicating better CVH health. Adjusted Cox proportional hazard models were conducted to explore the association of CVH with the risk of CCV-KD. The adjusted proportion of population attributable risk (PAR%) was used to calculate the population-level risk caused by low or intermediate CVH.

RESULTS

During a median follow-up of 12.5 years, 1,054 participants (0.8%) had incident CCV-KD. Participants with intermediate and high CVH had 54% (HR = 0.46, 95% CI: 0.40-0.54, P < 0.001) and 75% (HR = 0.25, 95% CI: 0.18-0.34, P < 0.001) lower risks of incident CCV-KD compared with those in low CVH group. There was an approximately dose-response linear relationship between the overall LE8 score and incident CCV-KD. The risk of incident CCV-KD decreased by 30% (HR = 0.70, 95% CI: 0.67-0.74, P < 0.001) for a 10-point increment of LE8 score. The adjusted PAR% of lower overall CVH was 47.4% (95% CI: 31.6%-59.8%).

CONCLUSIONS

Better CVH, assessed by using LE8 score, was strongly associated with decreased risk of incident CCV-KD. These findings imply optimizing CVH may be a preventive strategy to reduce the burden of CCV-KD.

Effects of additional physical exercise on the nutritional status and disease progression during the low-protein diet in Chronic Kidney Disease Patients: a systematic review and meta-analysis

Low-protein diet (LPD) is the core of dietary and nutritional therapy for non-dialysis chronic kidney disease (CKD) patients. In addition, physical exercise could prevent and treat various illnesses and chronic diseases. The objective of the study was to search for and appraise evidence on the effect of additional physical exercise on patients' nutritional status and indicators of disease progression when compared with the LPD alone. PubMed Central, Embase, Cochrane, and Web of Knowledge for randomized controlled trials (published between January 1, 1956 and May 17, 2023) were searched. A total of 8698 identified studies, 9 were eligible and were included in our analysis (N = 250 participants). Compared with the LPD alone, additional physical exercise reduced serum creatinine by a mean of -0.21 mg/dL (95% CI -0.39 to -0.03) in CKD patients. Similarly, blood pressure decreased after physical exercise, with systolic blood pressure decreasing by -7.05 mm Hg (95% CI -13.13 to -0.96) and diastolic blood pressure decreasing by -5.31 mm Hg (95% CI -7.99 to -2.62). Subgroup analyses revealed that resistance exercise (RE) was effective in decreasing estimated glomerular filtration rate (eGFR) of -1.71 mL/min per 1.73 m² (95% CI -3.29 to -0.14). In addition, the VO2peak increasing by 2.41 mL/kg/min (95% CI 0.13 to 4.70) when physical exercise was continued for 24 weeks. The above results suggest that the LPD with additional physical exercise care is more beneficial for patients with CKD.

Low-, moderate-, and high-risk obesity in association with cost drivers, costs over the lifecycle, and life expectancy

BACKGROUND

The prevalence of low-, moderate-, and high-risk obesity has been increasing globally. Our aim was to estimate the societal burden of these three obesity classes in the Austrian population by taking a societal-annual perspective and an individual-life-cycle perspective. Secondly, we sought to identify the respective cost drivers and the effects on life expectancy.

METHODS

We used population-weighted survey data on the distribution of body mass index (BMI) and data on relative risks regarding 83 diseases. Using fractional polynomial regressions, we estimated relative risks per BMI unit for about 30 cost-intensive diseases up to BMI values of 50. The approach for the cost analysis was based on the use of population-attributable fractions applied to direct medical and indirect cost data. Macro-disease-specific data regarding cost factors came from cost-of-illness statistics and administrative sources.

RESULTS

About 8.2% of deaths and 4.6% of health expenditure are attributable to obesity in Austria in 2019, causing 0.61% of GDP loss. A third of annual direct and indirect costs came from class 2 and class 3 obesity. From an individual perspective, life-cycle costs of class 2 and class 3 obesity were 1.9 and 3.6 times the costs of class 1 obesity, respectively. At the age of 45, people with high-risk obesity are about to lose approximately 4.9 life years and 9.7 quality-adjusted life years.

CONCLUSIONS

We have extended the method of population-attributable fractions, allowing us to estimate differences in the life-cycle direct medical and indirect costs between low-, moderate-, and high-risk obesity. We found that the lifetime costs of obesity are strikingly different between obesity classes, which has been veiled in the societal-annual perspective. Our findings provide a foundation for evaluating public health interventions aimed at combating obesity in order to mitigate the escalating individual and societal burden resulting from obesity prevalence and complications in the future.

Nutritional status and its relationship with COVID-19 prognosis in hemodialysis patients

Introduction

Introduction: among the groups more affected by the COVID-19 pandemic were patients undergoing chronic hemodialysis (HD) treatment due to their comorbidities, advanced age, impaired innate and adaptive immune function, and increased nutritional risk due to their underlying inflammatory state. All of these factors contribute to a higher risk of severe complications and worse outcomes compared to the general population when infected with SARS-CoV-2. Objective: the objective of this study was to describe the nutritional characteristics of and their potential association with the prognosis of COVID-19 in patients undergoing chronic HD treatment. Method: a descriptive, retrospective, observational design. All cases of COVID-19 in patients undergoing chronic treatment at the Hemodialysis Unit of Hospital de Manises, Valencia, Spain, from the start of the pandemic to before vaccination were included. Results: for that, 189 patients were studied, who received chronic HD treatment in the hospital unit, 22 patients were diagnosed with COVID-19 (12 %) in that period. The mean age was 71 years, 10 were women, the Charlson index was 6.59 points, diabetes mellitus 10, vintage HD 51.6 months, 2 patients had previously received a currently non-functioning kidney transplant, 16 had arteriovenous fistula as vascular access, and 6 had central vascular access. The mean dialysis session time was 220.14 minutes and the initial value of the single dose of the Kt/V pool was 1.7. 16 patients had body composition measurement, a strong association (p < 0.05) was identified between mortality and BMI, as well as mortality and FTI. Furthermore, the differences between deceased and surviving groups in the serum levels of various variables related to nutritional status were analyzed, finding significant differences with p < 0.05 in the value of triglycerides and ferritin. Conclusions: higher body mass index and higher body fat content, along with lower baseline levels of triglycerides and ferritin, were significantly associated with higher COVID-19 mortality in patients on chronic hemodialysis. These findings suggest that the initial nutritional status of these patients can significantly influence the prognosis of SARS-CoV-2 infection.

The New Challenge of Obesity - Obesity-Associated Nephropathy

In recent years, obesity has become one of the major diseases that affect human health and consume human health resources, especially when it causes comorbidities such as hypertension, diabetes, cardiovascular disease and kidney disease. Many studies have demonstrated that obesity is associated with the development of chronic kidney disease and can exacerbate the progression of end-stage renal disease. This review described the mechanisms associated with the development of obesity-associated nephropathy and the current relevant therapeutic modalities, with the aim of finding new therapeutic targets for obesity-associated nephropathy. The mechanisms of obesity-induced renal injury include, in addition to the traditional alterations in renal hemodynamics, the involvement of various mechanisms such as macrophage infiltration in adipose tissue, alterations in adipokines (leptin and adiponectin), and ectopic deposition of lipids. At present, there is no "point-to-point" treatment for obesity-induced kidney injury. The renin-angiotensin-aldosterone system (RAAS) inhibitors, sodium-dependent glucose transporter 2 (SGLT-2) inhibitors and bariatric surgery described in this review can reduce urinary protein to varying degrees and delay the progression of kidney disease. In addition, recent studies on the therapeutic effects of intestinal flora on obesity may reduce the incidence of obesity-related kidney disease from the perspective of primary prevention. Both of these interventions have their own advantages and disadvantages, so the continuous search for the mechanism of obesity-induced related kidney disease will be extremely helpful for the future treatment of obesity-related kidney disease.

Bayesian modeling of quantiles of body mass index among under-five children in Ethiopia

BACKGROUND

Body Mass Index (BMI) is a measurement of nutritional status, which is a vital pre-condition for good health. The prevalence of childhood malnutrition and the potential long-term health risks associated with obesity in Ethiopia have recently increased globally. The main objective of this study was to investigate the factors associated with the quantiles of under-five children's BMI in Ethiopia.

METHODS

Data on 5,323 children, aged between 0-59 months from March 21, 2019, to June 28, 2019, were obtained from the Ethiopian Mini Demographic Health Survey (EMDHS, 2019), based on the standards set by the World Health Organization. The study used a Bayesian quantile regression model to investigate the association of factors with the quantiles of under-five children's body mass index. Markov Chain Monte Carlo (MCMC) with Gibbs sampling was used to estimate the country-specific marginal posterior distribution estimates of model parameters, using the Brq R package.

RESULTS

Out of a total of 5323 children included in this study, 5.09% were underweight (less than 12.92 BMI), 10.05% were overweight (BMI: 17.06 - 18.27), and 5.02% were obese (greater than or equal to 18.27 BMI) children's. The result of the Bayesian quantile regression model, including marginal posterior credible intervals (CIs), showed that for the prediction of the 0.05 quantile of BMI, the current age of children [ β = -0.007, 95% CI :(-0.01, -0.004)], the region Afar [ β = - 0.32, 95% CI: (-0.57, -0.08)] and Somalia[ β = -0.72, 95% CI: (-0.96, -0.49)] were negatively associated with body mass index while maternal age [ β = 0.01, 95% CI: (0.005, 0.02)], mothers primary education [ β = 0.19, 95% CI: (0.08, 0.29)], secondary and above [ β = 0.44, 95% CI: (0.29, 0.58)], and family follows protestant [ β = 0.22, 95% CI: (0.07, 0.37)] were positively associated with body mass index. In the prediction of the 0.95 (or 0.85?) quantile of BMI, in the upper quantile, still breastfeeding [ β = -0.25, 95% CI: (-0.41, -0.10)], being female [ β = -0.13, 95% CI: (-0.23, -0.03)] were negatively related while wealth index [ β = 0.436, 95% CI: (0.25, 0.62)] was positively associated with under-five children's BMI.

CONCLUSIONS

In conclusion, the research findings indicate that the percentage of lower and higher BMI for under-five children in Ethiopia is high. Factors such as the current age of children, sex of children, maternal age, religion of the family, region and wealth index were found to have a significant impact on the BMI of under-five children both at lower and upper quantile levels. Thus, these findings highlight the need for administrators and policymakers to devise and implement strategies aimed at enhancing the normal or healthy weight status among under-five children in Ethiopia.

Utility of serum β2-microglobulin for prediction of kidney outcome among patients with biopsy-proven diabetic nephropathy

AIM

To examine whether serum β2-microglobulin (β2-MG) could improve the prediction performance for kidney failure with replacement therapy (KFRT) among patients with diabetic nephropathy (DN).

METHODS

Patients with biopsy-proven DN at Nara Medical University Hospital were included. The exposure of interest was log-transformed serum β2-MG levels measured at kidney biopsy. The outcome variable was KFRT. Multivariable Cox regression models and competing-risk regression models, with all-cause mortality as a competing event, were performed. Model fit by adding serum β2-MG levels was calculated using the Akaike information criterion (AIC). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indexes were used to evaluate the improvement of predictive performance for 5-year cumulative incidence of KFRT by serum β2-MG levels.

RESULTS

Among 408 patients, 99 developed KFRT during a median follow-up period of 6.7 years. A higher serum β2-MG level (1-unit increase in log-transformed serum β2-MG level) was associated with a higher incidence of KFRT, even after adjustments for previously known clinical and histological risk factors (hazard ratio [95% confidence interval {CI}]: 3.30 [1.57-6.94] and subdistribution hazard ratio [95% CI]: 3.07 [1.55-6.06]). The addition of log-transformed serum β2-MG level reduced AIC and improved the prediction of KFRT (NRI and IDI: 0.32 [0.09-0.54] and 0.03 [0.01-0.56], respectively).

CONCLUSIONS

Among patients with biopsy-proven DN, serum β2-MG was an independent predictor of KFRT and improved prediction performance. In addition to serum creatinine, serum β2-MG should probably be measured for DN.

Impact of Ring Finger Protein 20 and Its Downstream Regulation on Renal Tubular Injury in a Unilateral Nephrectomy Mouse Model Fed a High-Fat Diet

Abnormal lipid metabolism increases the relative risk of kidney disease in patients with a single kidney. Using transcriptome analysis, we investigated whether a high-fat diet leads to abnormalities in lipid metabolism and induces kidney cell-specific damage in unilateral nephrectomy mice. Mice with unilateral nephrectomy fed a high-fat diet for 12 weeks exhibited progressive renal dysfunction in proximal tubules, including lipid accumulation, vacuolization, and cell damage. Ring finger protein 20 (RNF20) is a ligase of nuclear receptor corepressor of peroxisome proliferator-activated receptors (PPARs). The transcriptome analysis revealed the involvement of RNF20-related transcriptome changes in PPAR signaling, lipid metabolism, and water transmembrane transporter under a high-fat diet and unilateral nephrectomy. In vitro treatment of proximal tubular cells with palmitic acid induced lipotoxicity by altering RNF20, PPARα, and ATP-binding cassette subfamily A member 1 (ABCA1) expression. PPARγ and aquaporin 2 (AQP2) expression decreased in collecting duct cells, regulating genetic changes in the water reabsorption process. In conclusion, a high-fat diet induces lipid accumulation under unilateral nephrectomy via altering RNF20-mediated regulation and causing functional damage to cells as a result of abnormal lipid metabolism, thereby leading to structural and functional kidney deterioration.

Obesity, Hyperfiltration, and Early Kidney Damage: A New Formula for the Estimation of Creatinine Clearance

CONTEXT

Glomerular hyperfiltration may represent a direct pathogenetic link between obesity and kidney disease. The most widely used methods to estimate creatine clearance such as Cockroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) have not been validated in subjects with obesity.

OBJECTIVE

The performance of prediction formulas was compared with measured creatinine clearance (mCrCl) in subjects with obesity.

METHODS

The study population included 342 patients with obesity (mean BMI 47.6 kg/m2) without primary kidney disease. A urine collection was performed over 24 hours for measurement of CrCl.

RESULTS

mCrCl increased with body weight. The CG formula showed an overestimation at high CrCl, whereas an underestimation resulted from CKD-EPI and MDRD. To improve the accuracy of estimated CrCl (eCrCl), a new CG-based formula was developed:53+0.7×(140-Age)×Weight/(96xSCr)×(0.85iffemale)A cut-off point for BMI of 32 kg/m2 was identified, at which the new formula may be applied to improve eCrCl.

CONCLUSION

In patients with obesity the glomerular filtration rate increases with body weight, and it is associated with the presence of albuminuria, suggesting an early kidney injury. We propose a novel formula that improves the accuracy of eCrCl to avoid missed diagnoses of hyperfiltration in patients with obesity.

Lithium and the living kidney donor: Science or stigma?

Nearly 10 000 people are removed from the kidney transplant waiting list each year either due to becoming too ill for transplant or due to death. Live donor kidney transplant (LDKT) provides superior outcomes and survival benefit relative to deceased donor transplant, but the number of LDKT has decreased over the past few years. Therefore, it is of paramount importance that transplant centers employ evaluation processes that safely maximize LDKT. Decisions about donor candidacy should be based on the best available data, rather than on processes prone to bias. Here, we examine the common practice of declining potential donors based solely on treatment with lithium. We conclude that the risk of end-stage renal disease related to lithium treatment is comparable to other generally accepted risks in LDKT. We present this viewpoint to specifically challenge the carte blanche exclusion of individuals taking lithium and highlight the importance of using the best available data relevant to any risk factor, rather than relying on biases, when evaluating potential living kidney donors.

Estimated 24-h urinary sodium excretion and risk of end-stage kidney disease

The association between sodium intake and long-term kidney disease endpoints is debated and yet to be proven. We aimed to investigate the associations of estimated 24-h urinary sodium excretion, reflecting daily sodium intake, with the incidence of end-stage kidney disease (ESKD). In this prospective cohort study including 444,375 UK Biobank participant, 865 (0.2%) ESKD events occurred after median follow-up of 12.7 years. For every 1 g increment in estimated 24-h urinary sodium excretion, multivariable-adjusted hazard ratio for incident ESKD was 1.09 (95% confidence interval 0.94-1.26). Nonlinear associations were not detected with restricted cubic splines. The null findings were confirmed by a series of sensitivity analyses, which attenuated potential bias from measurement errors of the exposure, regression dilution, reverse causality, and competing risks. In conclusion, there is insufficient evidence that estimated 24-h urinary sodium excretion is associated with the incidence of ESKD.

The impact of non-alcoholic fatty liver disease and liver fibrosis on adverse clinical outcomes and mortality in patients with chronic kidney disease: a prospective cohort study using the UK Biobank

BACKGROUND

Chronic kidney disease (CKD) and non-alcoholic fatty liver disease (NAFLD) frequently co-exist. We assess the impact of having NAFLD on adverse clinical outcomes and all-cause mortality for people with CKD.

METHODS

A total of 18,073 UK Biobank participants identified to have CKD (eGFR < 60 ml/min/1.73 m² or albuminuria > 3 mg/mmol) were prospectively followed up by electronic linkage to hospital and death records. Cox-regression estimated the hazard ratios (HR) associated with having NAFLD (elevated hepatic steatosis index or ICD-code) and NAFLD fibrosis (elevated fibrosis-4 (FIB-4) score or NAFLD fibrosis score (NFS)) on cardiovascular events (CVE), progression to end-stage renal disease (ESRD) and all-cause mortality.

RESULTS

56.2% of individuals with CKD had NAFLD at baseline, and 3.0% and 7.7% had NAFLD fibrosis according to a FIB-4 > 2.67 and NFS ≥ 0.676, respectively. The median follow-up was 13 years. In univariate analysis, NAFLD was associated with an increased risk of CVE (HR 1.49 [1.38-1.60]), all-cause mortality (HR 1.22 [1.14-1.31]) and ESRD (HR 1.26 [1.02-1.54]). Following multivariable adjustment, NAFLD remained an independent risk factor for CVE overall (HR 1.20 [1.11-1.30], p < 0.0001), but not ACM or ESRD. In univariate analysis, elevated NFS and FIB-4 scores were associated with increased risk of CVE (HR 2.42 [2.09-2.80] and 1.64 [1.30-2.08]) and all-cause mortality (HR 2.82 [2.48-3.21] and 1.82 [1.47-2.24]); the NFS score was also associated with ESRD (HR 5.15 [3.52-7.52]). Following full adjustment, the NFS remained associated with an increased incidence of CVE (HR 1.19 [1.01-1.40]) and all-cause mortality (HR 1.31 [1.13-1.52]).

CONCLUSIONS

In people with CKD, NAFLD is associated with an increased risk of CVE, and the NAFLD fibrosis score is associated with an elevated risk of CVE and worse survival.

Novel Asian-Specific Visceral Adiposity Indices Are Associated with Chronic Kidney Disease in Korean Adults

BACKGROUND

The Chinese visceral adiposity index (CVAI) and new visceral adiposity index (NVAI) are novel indices of visceral adiposity used to predict metabolic and cardiovascular diseases in Asian populations. However, the relationships of CVAI and NVAI with chronic kidney disease (CKD) have not been investigated. We aimed to characterize the relationships of CVAI and NVAI with the prevalence of CKD in Korean adults.

METHODS

A total of 14,068 participants in the 7th Korea National Health and Nutrition Examination Survey (6,182 men and 7,886 women) were included. Receiver operating characteristic (ROC) analyses were employed to compare the associations between indices of adiposity and CKD, and a logistic regression model was used to characterize the relationships of CVAI and NVAI with CKD prevalence.

RESULTS

The areas under the ROC curves for CVAI and NVAI were significantly larger than for the other indices, including the visceral adiposity index and lipid accumulation product, in both men and women (all P<0.001). In addition, high CVAI or NVAI was significantly associated with a high CKD prevalence in both men (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.31 to 3.48 in CVAI and OR, 6.47; 95% CI, 2.91 to 14.38 in NVAI, P<0.05) and women (OR, 4.87; 95% CI, 1.85 to 12.79 in CVAI and OR, 3.03; 95% CI, 1.35 to 6.82 in NVAI, P<0.05); this association remained significant after adjustment for multiple confounding factors in men and women.

CONCLUSION

CVAI and NVAI are positively associated with CKD prevalence in a Korean population. CVAI and NVAI may be useful for the identification of CKD in Asian populations, including in Korea.

Nontraditional Risk Factors for Progression Through Chronic Kidney Disease Risk Categories: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

There may be nontraditional pathways of chronic kidney disease (CKD) progression that are complementary to classical pathways. Therefore, we aimed to examine nontraditional risk factors for incident CKD and its progression.

METHODS

We used the generally healthy population (n = 4382) starting at age 27-41 years in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which is an observational longitudinal study. Nontraditional risk factors included forced vital capacity, inflammation, serum urate, and serum carotenoids. CKD risk category was classified using the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) measured in 1995-1996 and repeated every 5 years for 20 years: No CKD, low risk, moderate risk, high risk, and very high risk.

RESULTS

At baseline, 84.8% had no CKD (eGFR ≥60 mL/min/1.73 m2 and UACR <10 mg/g), 10.3% were in the low risk (eGFR ≥60 and UACR 10-29), and 4.9% had CKD (eGFR <60 and/or UACR ≥ 30). Nontraditional risk factors were significantly associated with the progression of CKD to higher categories. Hazard ratios per standard deviation of the predictor for incident CKD and its progression from the No CKD and low and moderate risk into CKD were inverse for forced vital capacity and serum carotenoids and positive for serum urate, GlycA, and C-reactive protein, the first 3 even after adjustment for conventional risk factors.

CONCLUSION

Several nontraditional markers were significantly associated with an increased risk of progression to higher CKD categories in generally healthy young to middle-aged adults.

Inflammatory profiles, gut microbiome, and kidney function are impacted after high-fidelity firefighter training

BACKGROUND

Firefighters are frequently exposed to high temperatures, environmental toxicants, and strenuous physical demands. The health impacts of these occupational exposures on processes including inflammation and kidney function as well as on the gut microbiota are poorly understood. A firefighter training course may provide a controlled environment to assess these health risks.

METHODS

Basic health measures, stool, and blood samples were obtained from 24 firefighters participating in a one-week, heat-intensive training course. Indicators of inflammation, gut permeability, kidney health, and stool microbiota composition were measured before and after the training course in 18 participants. Urine specific gravity was measured before and after a heat-intensive training day to evaluate dehydration.

RESULTS

The majority of firefighters in this cohort were categorized as hypertensive and experienced multiple heat-related illness symptoms during the training week and dehydration after the heat-intensive training day. While plasma IL-1β, CXCL8, and NGAL decreased over the training week, other indicators of inflammation and acute kidney injury increased, and estimated kidney function declined. Microbiota composition shifted over the course of the training week, with changes in Peptostreptococcus anaerobius and Streptococcus.

CONCLUSIONS

This pilot study conducted in a controlled field setting suggests that the occupational environment of firefighters may increase their risk for systemic inflammation and kidney disease.

Management of obesity across women's life course: FIGO Best Practice Advice

Obesity is a chronic, progressive, relapsing, and treatable multifactorial, neurobehavioral disease. According to the World Health Organization, obesity affects 15% of women and has long-term effects on women's health. The focus of care in patients with obesity should be on optimizing health outcomes rather than on weight loss. Appropriate and common language, considering cultural sensitivity and trauma-informed care, is needed to discuss obesity. Pregnancy is a time of significant physiological change. Pre-, ante-, and postpartum clinical encounters provide opportunities for health optimization for parents with obesity in terms of, but not limited to, fertility and breastfeeding. Pre-existing conditions may also be identified and managed. Beyond pregnancy, women with obesity are at an increased risk for gastrointestinal and liver diseases, impaired kidney function, obstructive sleep apnea, and venous thromboembolism. Gynecological and reproductive health of women living with obesity cannot be dismissed, with accommodations needed for preventive health screenings and consideration of increased risk for gynecologic malignancies. Mental wellness, specifically depression, should be screened and managed appropriately. Obesity is a complex condition and is increasing in prevalence with failure of public health interventions to achieve significant decrease. Future research efforts should focus on interprofessional care and discovering effective interventions for health optimization.

Individualized prediction of chronic kidney disease for the elderly in longevity areas in China: Machine learning approaches

Background

Chronic kidney disease (CKD) has become a major public health problem worldwide and has caused a huge social and economic burden, especially in developing countries. No previous study has used machine learning (ML) methods combined with longitudinal data to predict the risk of CKD development in 2 years amongst the elderly in China.

Methods

This study was based on the panel data of 925 elderly individuals in the 2012 baseline survey and 2014 follow-up survey of the Healthy Aging and Biomarkers Cohort Study (HABCS) database. Six ML models, logistic regression (LR), lasso regression, random forests (RF), gradient-boosted decision tree (GBDT), support vector machine (SVM), and deep neural network (DNN), were developed to predict the probability of CKD amongst the elderly in 2 years (the year of 2014). The decision curve analysis (DCA) provided a range of threshold probability of the outcome and the net benefit of each ML model.

Results

Amongst the 925 elderly in the HABCS 2014 survey, 289 (18.8%) had CKD. Compared with the other models, LR, lasso regression, RF, GBDT, and DNN had no statistical significance of the area under the receiver operating curve (AUC) value (>0.7), and SVM exhibited the lowest predictive performance (AUC = 0.633, p-value = 0.057). DNN had the highest positive predictive value (PPV) (0.328), whereas LR had the lowest (0.287). DCA results indicated that within the threshold ranges of ~0-0.03 and 0.37-0.40, the net benefit of GBDT was the largest. Within the threshold ranges of ~0.03-0.10 and 0.26-0.30, the net benefit of RF was the largest. Age was the most important predictor variable in the RF and GBDT models. Blood urea nitrogen, serum albumin, uric acid, body mass index (BMI), marital status, activities of daily living (ADL)/instrumental activities of daily living (IADL) and gender were crucial in predicting CKD in the elderly.

Conclusion

The ML model could successfully capture the linear and nonlinear relationships of risk factors for CKD in the elderly. The decision support system based on the predictive model in this research can help medical staff detect and intervene in the health of the elderly early.

Association of renal function with muscle strength in Korean adults: A population-based study using the Korea National Health and Nutrition Examination Surveys (KNHANES) from 2014 to 2018

Hand grip strength (HGS), a simple measure of upper limb muscle function, can be used to assess overall muscular strength, and reduced HGS in patients with poor renal functions has been observed. This study examined the associations between renal function and HGS, a surrogate marker of muscular strength, among a stratified sample of Korean adults. This study obtained data from the Korea National Health and Nutrition Examination Survey from 2014 to 2018, a cross-sectional and nationally representative survey conducted by the Korea Centers for Diseases Control and Prevention. In men, low muscle strength (LMS) and normal muscle strength (NMS) were defined as HGS < 28.9 kg and HGS ≥ 28.9 kg, respectively. In women, LMS and NMS were considered as HGS < 16.8 kg and HGS ≥ 16.8 kg, respectively. Of the 25,746 subjects in this study, there were 3603 (14.0%) and 22,143 (86.0%) subjects who displayed LMS and NMS, respectively. Subjects with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 had a higher risk of developing LMS than those with eGFR ≥ 60 mL/min/1.73 m2 after adjusting for age (odds ratio, 1.772; 95% CI, 1.498-2.096); the significant differences remained after adjusting for other factors including age. Similar tendencies were shown in men and women when analyzed according to gender; however, the risk of developing LMS was higher in men than in women. Results showed that decreased renal function was likely to contribute to an increased prevalence of LMS based on HGS. This association may assist in developing better strategies to estimate renal function in clinical or public health practice.

Elevated triglycerides and reduced high-density lipoprotein cholesterol are independently associated with the onset of advanced chronic kidney disease: a cohort study of 911,360 individuals from the United Kingdom

Background

Increased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and decreased high-density lipoprotein cholesterol (HDL-C) concentrations, are established risk factors for cardiovascular morbidity and mortality; but their impact on the risk of advanced chronic kidney disease (CKD) is unclear. This study evaluates the association between the different lipid profiles and the onset of advanced CKD using a general population sample.

Methods

This observational study used records of 911,360 individuals from the English Clinical Practice Research Datalink (from 2000 to 2014), linked to coded hospital discharges and mortality registrations. Cox models were used to examine the independent association between the equal quarters of TC, TG, LDL-C, and HDL-C and the risk of advanced CKD, after adjustment for sex and age, and potential effect mediators.

Results

During a median follow-up of 7.5 years, 11,825 individuals developed CKD stages 4–5. After adjustment for sex and age, the hazard ratios (HRs) and confidence intervals (CIs) for CKD stages 4–5 comparing the 4th vs. 1st quarters of TG and 1st vs. 4th quarters of HDL-C were 2.69 (95% CI, 2.49–2.90) and 2.61 (95% CI, 2.42–2.80), respectively. Additional adjustment for potential effect mediators reduced the HRs to 1.28 (95% CI, 1.15–1.43), and 1.27 (95% CI, 1.14–1.41), respectively. There was no evidence of fully adjusted associations with CKD stages 4–5 for levels of either TC or LDL-C.

Conclusions

Elevated TG and reduced HDL-C levels are independently associated with the onset of advanced CKD. Future studies, such as in basic science and randomized trials, are needed to understand whether associations between TG and HDL-C and the development of CKD are causal.

High Rates of Multimorbidity Reported Among People of Color Despite Healthy Weight

Purpose:

Methods:

Results:

Conclusion:

The Association of Excess Body Weight with Risk of ESKD Is Mediated Through Insulin Resistance, Hypertension, and Hyperuricemia

BACKGROUND

Insulin resistance, hypertension, hyperuricemia, and hypercholesterolemia are hypothesized to be important intermediates in the relationship between excess body weight and CKD risk. However, the magnitude of the total effect of excess body weight on ESKD mediated through these four pathways remains to be quantified.

METHODS

We applied a model for analysis of correlated mediators to population-based data from 100,269 Austrian individuals (mean age 46.4 years). Association of body mass index (BMI) was coalesced with ESKD risk into direct association. Indirect associations were mediated through the triglyceride-glucose (TyG) index (as an indicator of insulin resistance), mean arterial pressure (MAP), uric acid (UA), and total cholesterol (TC).

RESULTS

Mean follow-up was 23.1 years with 463 (0.5%) incident ESKD cases. An unhealthy metabolic profile (prevalence 32.4%) was associated with a markedly increased ESKD risk (multivariably adjusted hazard ratio (aHR), 3.57; 95% CI, 2.89 to 4.40), independent of BMI. A 5-kg/m2 higher BMI was associated with a 57% increased ESKD risk (aHRtotal association, 1.57; 1.38 to 1.77). Of this association, 99% (76% to 140%) arose from all mediators jointly; 33% (22% to 49%) through TyG index; 34% (24% to 50%) through MAP; 30% (21% to 45%) through UA; and 2% (-1% to 4%) through TC. The remaining direct association was nonsignificant (aHRdirect association, 1.01; 0.88 to 1.14).

CONCLUSIONS

TyG index, MAP, and UA, but not TC, mediate the association of BMI with ESKD in middle-aged adults. Our findings highlight that in addition to weight reduction, the control of metabolic risk factors might be essential in mitigating the adverse effects of BMI on kidney function.

Obesity and Kidney Function: A Two-Sample Mendelian Randomization Study

BACKGROUND

Obesity and type 2 diabetes (T2D) are correlated risk factors for chronic kidney disease (CKD).

METHODS

Using summary data from GIANT (Genetic Investigation of Anthropometric Traits), DIAGRAM (DIAbetes Genetics Replication And Meta-analysis), and CKDGen (CKD Genetics), we examined causality and directionality of the association between obesity and kidney function. Bidirectional 2-sample Mendelian randomization (MR) estimated the total causal effects of body mass index (BMI) and waist-to-hip ratio (WHR) on kidney function, and vice versa. Effects of adverse obesity and T2D were examined by stratifying BMI variants by their association with WHR and T2D. Multivariable MR estimated the direct causal effects of BMI and WHR on kidney function. The inverse variance weighted random-effects MR for Europeans was the main analysis, accompanied by several sensitivity MR analyses.

RESULTS

One standard deviation (SD ≈ 4.8 kg/m2) genetically higher BMI was associated with decreased estimated glomerular filtration rate (eGFR) [β=-0.032 (95% confidence intervals: -0.036, -0.027) log[eGFR], P = 1 × 10-43], increased blood urea nitrogen (BUN) [β = 0.010 (0.005, 0.015) log[BUN], P = 3 × 10-6], increased urinary albumin-to-creatinine ratio [β = 0.199 (0.067, 0.332) log[urinary albumin-to-creatinine ratio (UACR)], P = 0.003] in individuals with diabetes, and increased risk of microalbuminuria [odds ratios (OR) = 1.15 [1.04-1.28], P = 0.009] and CKD [1.13 (1.07-1.19), P = 3 × 10-6]. Corresponding estimates for WHR and for trans-ethnic populations were overall similar. The associations were driven by adverse obesity, and for microalbuminuria additionally by T2D. While genetically high BMI, unlike WHR, was directly associated with eGFR, BUN, and CKD, the pathway to albuminuria was likely through T2D. Genetically predicted kidney function was not associated with BMI or WHR.

CONCLUSIONS

Genetically high BMI is associated with impaired kidney function, driven by adverse obesity, and for albuminuria additionally by T2D.

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.

The Effect of ß-Glucan Prebiotic on Kidney Function, Uremic Toxins and Gut Microbiome in Stage 3 to 5 Chronic Kidney Disease (CKD) Predialysis Participants: A Randomized Controlled Trial

There is growing evidence that gut dysbiosis contributes to the progression of chronic kidney disease (CKD) owing to several mechanisms, including microbiota-derived uremic toxins, diet and immune-mediated factors. The aim of this study was to investigate the effect of a ß-glucan prebiotic on kidney function, uremic toxins and the gut microbiome in stage 3 to 5 CKD participants. Fifty-nine participants were randomized to either the ß-glucan prebiotic intervention group (n = 30) or the control group (n = 29). The primary outcomes were to assess kidney function (urea, creatinine and glomerular filtration rate), plasma levels of total and free levels of uremic toxins (p-cresyl sulfate (pCS), indoxyl-sulfate (IxS), p-cresyl glucuronide (pCG) and indoxyl 3-acetic acid (IAA) and gut microbiota using 16S rRNA sequencing at baseline, week 8 and week 14. The intervention group (age 40.6 ± 11.4 y) and the control group (age 41.3 ± 12.0 y) did not differ in age or any other socio-demographic variables at baseline. There were no significant changes in kidney function over 14 weeks. There was a significant reduction in uremic toxin levels at different time points, in free IxS at 8 weeks (p = 0.003) and 14 weeks (p < 0.001), free pCS (p = 0.006) at 14 weeks and total and free pCG (p < 0.001, p < 0.001, respectively) and at 14 weeks. There were no differences in relative abundances of genera between groups. Enterotyping revealed that the population consisted of only two of the four enterotypes: Bacteroides 2 and Prevotella. The redundancy analysis showed a few factors significantly affected the gut microbiome: these included triglyceride levels (p < 0.001), body mass index (p = 0.002), high- density lipoprotein (p < 0.001) and the prebiotic intervention (p = 0.002). The ß-glucan prebiotic significantly altered uremic toxin levels of intestinal origin and favorably affected the gut microbiome.

Ileal conduit versus neobladder: A propensity score-matched analysis of the effect on renal function

OBJECTIVES

To analyze the long-term effects of continent (neobladder) compared with incontinent (ileal conduit) urinary diversion.

METHODS

We carried out a retrospective review of our departmental database. Estimated glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Neobladder and ileal conduit patients were matched in a 1:2 ratio and a propensity score-matched analysis was carried out. Data were summarized using descriptive analysis. Trend plots were generated using baseline and follow-up creatinine values to compare estimated glomerular filtration rate at 3 months, then annually for 5 years. Variables associated with estimated glomerular filtration rate were assessed using multivariate linear analysis.

RESULTS

Our cohort consisted of 137 patients (neobladder n = 50 and ileal conduit n = 87) with a median follow-up time of 3 years (interquartile range 1-7 years). The ileal conduit group had shorter operative times (352 vs 444 min, P < 0.01), intracorporeal diversions were more common (66% vs 44%, P = 0.01), had prior abdominal surgery (66% vs 38%, P < 0.01) and had radiation (9% vs 0%, P = 0.03). The neobladder group more commonly had recurrent urinary tract infections (22% vs 3%, P < 0.01) and a steeper decrease in estimated glomerular filtration rate in the first year. On multivariate linear analysis, age/year (-0.59), body mass index per kg/m2 (-0.52), preoperative estimated glomerular filtration rate per unit (0.51), recurrent urinary tract infections (-14.03) and time versus day 90 (year 1, -7.52; year 2, -9.06; year 3, -10.78) were significantly associated with estimated glomerular filtration rate.

CONCLUSION

Ileal conduits and neobladders showed a similar effect on the estimated glomerular filtration rate up to 5 years after robot-assisted radical cystectomy. Recurrent urinary tract infections were associated with a worse estimated glomerular filtration rate.

APOL1 renal risk variants are associated with obesity and body composition in African ancestry adults: An observational genotype-phenotype association study

ABSTRACT

While increased obesity prevalence among persons of African ancestry (AAs) compared to persons of European ancestry (EAs) is linked to social, environmental and behavioral factors, there are no gene variants that are common and significantly associated with obesity in AA populations. We sought to explore the association between ancestry specific renal risk variants in the apolipoprotein L1 (APOL1) gene with obesity related traits in AAs.We conducted a genotype-phenotype association study from 3 electronic medical record linked cohorts (BioMe Biobank, BioVU, nuGENE); randomized controlled trials (genetic testing to understand and address renal disease disparities) and prospective cohort study (Jackson Heart Study). We analyzed association of APOL1 renal risk variants with cross-sectional measures of obesity (average body mass index (BMI), and proportion of overweight and obesity) and with measures of body composition (in Jackson Heart Study).We had data on 11,930 self-reported AA adults. Across cohorts, mean age was from 42 to 49 years and percentage female from 58% to 75.3%. Individuals who have 2 APOL1 risk alleles (14% of AAs) have 30% higher obesity odds compared to others (recessive model adjusted odds ratio 1.30; 95% confidence interval 1.16-1.41; P = 2.75 × 10-6). An additive model better fit the association, in which each allele (47% of AAs) increases obesity odds by 1.13-fold (adjusted odds ratio 1.13; 95% confidence interval 1.07-1.19; P = 3.07 × 10-6) and increases BMI by 0.36 kg/m2 (∼1 kg, for 1.7 m height; P = 2 × 10-4). APOL1 alleles are not associated with refined body composition traits overall but are significantly associated with fat free mass index in women [0.30 kg/m2 increment per allele; P = .03].Thus, renal risk variants in the APOL1 gene, found in nearly half of AAs, are associated with BMI and obesity in an additive manner. These variants could, either on their own or interacting with environmental factors, explain a proportion of ethnic disparities in obesity.

Relation of glomerular filtration to insulin resistance and related risk factors in obese children

BACKGROUND AND OBJECTIVE

Childhood obesity is associated with later development of significant renal morbidity. We evaluated the impact of the degree of insulin sensitivity on estimated glomerular filtration rate (eGFR) and determined the factors associated with eGFR in obese children. We further tested the relation of eGFR to clinical outcomes such as blood pressure and microalbuminuria.

MATERIALS AND METHODS

We evaluated the relation of whole body insulin sensitivity and estimated glomerular filtration rate (eGFR) across the spectrum of obesity in children and adolescents. eGFR was calculated using the iCARE formula, which has been validated in obese children with varying glucose tolerance.

RESULTS

1080 children and adolescents with overweight and obesity (701 females and 379 males) participated. Insulin sensitivity was a strongly negatively associated with (B = -2.72, p < 0.001) eGFR), even after adjustment for potential confounders. Male sex emerged to be significantly associated with eGFR with boys having greater values than girls (B = 18.82, p < 0.001). Age was a positively associated (B = 2.86, p < 0.001) with eGFR. Whole body and hepatic insulin sensitivity decreased across eGFR quartiles. Adjusted eGFR was tightly positively associated with systolic blood pressure (B = 0.09, p = 0.003) and negatively associated with the presence of microalbuminuria (B = -2.18, p = 0.04).

CONCLUSIONS

eGFR tends to increase with greater degrees of insulin resistance in children and adolescents representing hyperfiltration and is associated with cardiovascular risk factors. Longitudinal studies are needed to determine the natural history of childhood insulin resistance related hyperfiltration in regards to future kidney disease.

Perioperative Risks of Sleeve Gastrectomy Versus Roux-en-Y Gastric Bypass Among Patients With Chronic Kidney Disease: A Review of the MBSAQIP Database

OBJECTIVE

To determine whether patients with CKD experience higher rates of perioperative complications after RYGB compared to sleeve gastrectomy.

SUMMARY OF BACKGROUND DATA

For obese CKD patients who qualify for bariatric surgery, sleeve gastrectomy is often preferred to RYGB based on perceptions of prohibitively-high perioperative risks surrounding RYGB. However, some patients with CKD are not candidates for sleeve gastrectomy and the incremental increased-risk from RYGB has never been rigorously tested in this population.

METHODS

CKD patients who underwent RYGB or sleeve gastrectomy between 2015 and 2017 were identified from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program Participant Use File. RYGB patients were 1:1 propensity-score matched with sleeve gastrectomy patients based on preoperative factors that influence operative choice. Primary outcomes included 30-day readmissions, surgical complications, medical complications, and death. Secondary outcomes included the individual complications used to create the composite surgical/medical complications. Univariate logistic regression was used to compare outcomes. E-value statistic was used to test the strength of outcome point estimates against possible unmeasured confounding.

RESULTS

Demographics were similar between RYGB (n = 673) and sleeve gastrectomy (n = 673) cohorts. There were no statistically significant differences in primary outcomes. Among secondary outcomes, only acute kidney injury was statistically-significantly higher among RYGB patients (4.9% vs 2.7%, P = 0.035, E-value 1.27).

CONCLUSIONS

Among well-matched cohorts of RYGB and sleeve gastrectomy patients, incidence of primary outcomes were similar. Among secondary outcomes, only acute kidney injury was statistically-significantly higher among RYGB patients; however, the E-value for this difference was small and relatively weak confounder(s) could abrogate the statistical difference. The perception that RYGB has prohibitively-high perioperative risks among CKD patients is disputable and operative selection should be weighed on patient candidacy and anticipated long-term benefit.

Changes in GFR and Albuminuria in Routine Clinical Practice and the Risk of Kidney Disease Progression

RATIONALE & OBJECTIVE

Changes in urinary albumin-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) have been used separately as alternative kidney disease outcomes in randomized trials. We tested the hypothesis that combined changes in UACR and eGFR predict advanced kidney disease better than either alone.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

91,319 primary care patients assembled from the Clinical Practice Research Datalink in the United Kingdom between 2000 and 2015.

EXPOSURES

Changes in UACR and eGFR (categorized as ≥30% increase, stable, or ≥30% decrease), alone and in combination, over a 3-year period.

OUTCOMES

The primary outcome was advanced CKD (sustained eGFR <30 mL/min/1.73 m2); secondary outcomes included kidney failure, cardiovascular disease, and all-cause mortality.

ANALYTICAL APPROACH

Multivariable Cox regression with bias from missing values assessed using multiple imputation; discrimination statistics compared across exposure groups.

RESULTS

91,319 individuals were studied, with a mean eGFR of 72.6 mL/min/1.73 m2 and median UACR of 9.7 mg/g; 70,957 (77.7%) had diabetes. During a median follow-up of 2.9 years, 2,541 people progressed to advanced CKD. Compared with stable values, hazard ratios for a ≥30% increase in UACR and ≥30% decrease in eGFR were 1.78 (95% CI, 1.59-1.98) and 7.53 (95% CI, 6.70-8.45), respectively, for the outcome of advanced CKD. Compared with stable values of both, the hazard ratio for the combination of an increase in UACR and a decrease in eGFR was 15.15 (95% CI, 12.43-18.46) for the outcome of advanced CKD. The combination of changes in UACR and eGFR predicted kidney outcomes better than either alone.

LIMITATIONS

Selection bias, relatively small proportion of individuals without diabetes, and very few kidney failure events.

CONCLUSIONS

In a large-scale general population, the combination of an increase in UACR and a decrease in eGFR was strongly associated with the risk of advanced CKD. Further assessment of combined changes in UACR and eGFR as an alternative outcome for kidney failure in trials of CKD progression is warranted.

Obesity-related indices are associated with albuminuria and advanced kidney disease in type 2 diabetes mellitus

Obesity is an important risk factor for the development of diseases including diabetes, hypertension, and cardiovascular disease. However, few reports have investigated the relationships between these obesity-related indices and diabetic nephropathy. The aim of this study was to evaluate associations between obesity-related markers with albuminuria and advanced kidney disease in patients with type 2 diabetes mellitus (DM). Obesity-related indices including body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body roundness index (BRI), conicity index (CI), lipid accumulation product (LAP), visceral adiposity index (VAI), body adiposity index (BAI), abdominal volume index (AVI), body shape index (BSI), and triglyceride glucose (TyG) index were measured. Albuminuria was defined as a urine albumin/creatinine ratio of ≥30 mg/g. Advanced kidney disease was defined as an estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m². A total of 1872 patients with type 2 DM (mean age 64.0 ± 11.3 years, 809 males and 1063 females) were enrolled. In multivariable analysis, 11 high obesity-related indices (BMI, WHR, WHtR, LAP, BRI, CI, VAI, BAI, AVI, ABSI, and TyG index) were significantly associated with albuminuria. In addition, high BMI, WHR, WHtR, LAP, BRI, CI, VAI, and AVI were significantly associated with eGFR <30 ml/min/1.73 m². The results of this study showed that various obesity-related indices were significantly associated with albuminuria and advanced kidney disease in patients with type 2 DM. Screening may be considered in public health programs to recognize and take appropriate steps to prevent subsequent complications.

Chronic kidney disease

Chronic kidney disease is a progressive disease with no cure and high morbidity and mortality that occurs commonly in the general adult population, especially in people with diabetes and hypertension. Preservation of kidney function can improve outcomes and can be achieved through non-pharmacological strategies (eg, dietary and lifestyle adjustments) and chronic kidney disease-targeted and kidney disease-specific pharmacological interventions. A plant-dominant, low-protein, and low-salt diet might help to mitigate glomerular hyperfiltration and preserve renal function for longer, possibly while also leading to favourable alterations in acid-base homoeostasis and in the gut microbiome. Pharmacotherapies that alter intrarenal haemodynamics (eg, renin-angiotensin-aldosterone pathway modulators and SGLT2 [SLC5A2] inhibitors) can preserve kidney function by reducing intraglomerular pressure independently of blood pressure and glucose control, whereas other novel agents (eg, non-steroidal mineralocorticoid receptor antagonists) might protect the kidney through anti-inflammatory or antifibrotic mechanisms. Some glomerular and cystic kidney diseases might benefit from disease-specific therapies. Managing chronic kidney disease-associated cardiovascular risk, minimising the risk of infection, and preventing acute kidney injury are crucial interventions for these patients, given the high burden of complications, associated morbidity and mortality, and the role of non-conventional risk factors in chronic kidney disease. When renal replacement therapy becomes inevitable, an incremental transition to dialysis can be considered and has been proposed to possibly preserve residual kidney function longer. There are similarities and distinctions between kidney-preserving care and supportive care. Additional studies of dietary and pharmacological interventions and development of innovative strategies are necessary to ensure optimal kidney-preserving care and to achieve greater longevity and better health-related quality of life for these patients.

Obesity Without Metabolic Abnormality and Incident CKD: A Population-Based British Cohort Study

RATIONALE & OBJECTIVE

Metabolically healthy obesity (obesity without any metabolic abnormality) is not considered to be associated with increased risk of morbidity and mortality. We examined and quantified the association between metabolically healthy overweight/obesity and the risk of incident chronic kidney disease (CKD) in a British primary care population.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING & PARTICIPANTS

4,447,955 of the 5,182,908 adults in The Health Improvement Network (THIN) database (United Kingdom, 1995-2015) with a recorded body mass index (BMI) at the time of registration date who were free of CKD and cardiovascular disease.

EXPOSURE

11 body size phenotypes were created, defined by BMI categories (underweight, normal weight, overweight, and obesity) and 3 metabolic abnormalities (diabetes, hypertension, and dyslipidemia).

OUTCOME

Incident CKD defined as a recorded code for kidney replacement therapy, a recorded diagnosis of CKD, or by an estimated glomerular filtration rate of<60mL/min/1.73m² for≥90 days, or a urinary albumin-creatinine ratio>3mg/mmol for≥90 days.

RESULTS

Of the 4.5 million individuals, 1,040,921 (23.4%) and 588,909 (13.2%) had metabolically healthy overweight and metabolically healthy obesity, respectively. During a mean follow-up interval of 5.4±4.3 (SD) years, compared with individuals with a metabolically healthy normal weight (n=1,656,231), there was a higher risk of incident CKD among those who had metabolically healthy overweight (adjusted HR, 1.30 [95% CI, 1.28-1.33]) and metabolically healthy obesity (adjusted HR, 1.66 [95% CI, 1.62-1.70]). The association was stronger in those younger than 65 years of age. In all BMI categories, there was greater risk of incident CKD with a greater number of metabolic abnormalities in a graded manner.

LIMITATIONS

Potential misclassification of metabolic status due to delayed diagnosis and residual confounding due to unmeasured factors.

CONCLUSIONS

Overweight and obesity without metabolic abnormality are associated with a higher risk of incident CKD compared with those with normal body weight and no metabolic abnormality.

Renal Function Impairment and Associated Factors Among Adult HIV-Positive Patients Attending Antiretroviral Therapy Clinic in Mettu Karl Referral Hospital: Cross-Sectional Study

BACKGROUND

Human immunodeficiency virus (HIV) affects every organ system in the body through impairment or by rendering the patient vulnerable to opportunistic infections. The kidney is the vital organ in the excretion of waste products and toxins (urea, creatinine and uric acid), and regulation of extracellular fluid volume, serum osmolality and electrolyte concentrations. The risk of kidney disease is greater in HIV-infected individuals than in the general population. This study aimed to assess the magnitude of renal function impairment and its associated factors among adult HIV-positive patients attending an ART clinic in Mettu Karl Referral Hospital, Mettu town, south-west Ethiopia.

METHODS

The institution-based, cross-sectional quantitative study was conducted from March 8 to May 30, 2020. A total of 352 clients participated and a systematic sampling technique was used to allocate study participants. Data were entered into Epi data and exported to SPSS version 22 for analysis. Bivariate analysis was conducted to identify candidate variables for multivariate analysis at P <0.25. Multivariable logistic regression analysis was conducted to determine the predictors of renal function impairment with ART. P value < 0.05 was considered to indicate statistical significance.

RESULTS

A total of 352 HIV-infected patients participated in this study with a response rate of 98.1%. Out of 352 HIV patients on ART, 73 (20.7%) were found to have renal function impairment. Cigarette smoking [AOR = 9.60, 95% CI: 4.73-19.48], diabetes mellitus [AOR = 6.16, 95% CI: 2.79-13.59], hypertension [AOR = 4.71, 95% CI: 1.98-11.17] and low CD4 count [AOR = 6.47, 95% CI: 3.31-12.64] were found to be independent predictors of renal function impairment among adult HIV positive patients.

CONCLUSION

The prevalence of renal function impairment among HIV patients on ART is high. Hypertension, diabetes, cigarette smoking and low CD4 count were associated factors of renal function impairment. HIV patients on ART should be regularly screened for early diagnosis and management of renal function impairment.

Association of sarcopenia with mortality and end-stage renal disease in those with chronic kidney disease: a UK Biobank study

BACKGROUND

Sarcopenia, a degenerative and generalized skeletal muscle disorder involving the loss of muscle function and mass, is an under-recognized problem in clinical practice, particularly in chronic kidney disease (CKD). We aimed to investigate the prevalence of sarcopenia in individuals with CKD, its risk factors, and its association with all-cause mortality and progression to end-stage renal disease (ESRD).

METHODS

UK Biobank participants were grouped according to the presence of CKD (defined as an estimated glomerular filtration rate <60 mL/min/1.73 m² ) and as having probable (low handgrip strength), confirmed (plus low muscle mass), and severe sarcopenia (plus poor physical performance) based on the 2019 European Working Group of Sarcopenia in Older People and Foundation for the National Institutes of Health criteria. Risk factors were explored using logistic regression analysis. Survival models were applied to estimate risk of mortality and ESRD.

RESULTS

A total of 428 320 participants, of which 8767 individuals with CKD (46% male, aged 62.8 (standard deviation 6.8) years, median estimated glomerular filtration rate 54.5 (interquartile range 49.0-57.7) mL/min/1.72 m² ) were included. Probable sarcopenia was present in 9.7% of individuals with CKD compared with 5.0% in those without (P < 0.001). Sarcopenia was associated with being older; inflammation; poorer renal function; and lower serum albumin, total testosterone, and haemoglobin. The largest risk factors for sarcopenia were having three or more comorbidities (odds ratio: 2.30; 95% confidence interval: 1.62 to 3.29; P < 0.001) and physical inactivity: participants in the highest quartile of weekly activity were 43% less likely to have sarcopenia compared to the lowest quartile (odds ratio: 0.57; 0.42 to 0.76; P < 0.001). Participants with CKD and sarcopenia had a 33% (7% to 66%; P = 0.011) higher hazard of mortality compared with individuals without. Sarcopenic CKD individuals had a 10 year survival probability of 0.85 (0.82 to 0.88) compared with 0.89 (0.88 to 0.30) in those without sarcopenia, an absolute difference of 4%. Those with sarcopenia were twice as likely to develop ESRD (hazard ratio: 1.98; 1.45 to 2.70; P < 0.001).

CONCLUSIONS

Participants with reduced kidney function are at an increased risk of premature mortality. The presence of sarcopenia increases the risk of mortality and ESRD. Appropriate measurement of sarcopenia should be used to identify at-risk individuals. Interventions such as physical activity should be encouraged to mitigate sarcopenia.

Severity and Duration of Acute Kidney Injury and Chronic Kidney Disease after Cardiac Surgery

We aimed to evaluate whether the duration and stage of acute kidney injury (AKI) are associated with the occurrence of chronic kidney disease (CKD) in patients undergoing cardiac or thoracic aortic surgery. A total of 2009 cases were reviewed. The patients with postoperative AKI stage 1 and higher stage were divided into transient (serum creatinine elevation ≤48 h) or persistent (>48 h) AKI, respectively. Estimated glomerular filtration rate (eGFR) values during three years after surgery were collected. Occurrence of new-onset CKD stage 3 or higher or all-cause mortality was determined as the primary outcome. Multivariable Cox regression and Kaplan-Meier survival analysis were performed. The Median follow-up of renal function after surgery was 32 months. The cumulative incidences of our primary outcome at one, two, and three years after surgery were 19.8, 23.7, and 26.1%. There was a graded significant association of AKI with new-onset CKD during three years after surgery, except for transient stage 1 AKI (persistent stage 1: HR 3.11, 95% CI 2.62-4.91; transient higher stage: HR 4.07, 95% CI 2.98-6.11; persistent higher stage: HR 13.36, 95% CI 8.22-18.72). There was a significant difference in survival between transient and persistent AKI at the same stage. During three years after cardiac surgery, there was a significant and graded association between AKI stages and the development of new-onset CKD, except for transient stage 1 AKI. This association was stronger when AKI lasted more than 48 h at the same stage. Both duration and severity of AKI provide prognostic value to predict the development of CKD.

Interventions for weight loss in people with chronic kidney disease who are overweight or obese

BACKGROUND

Obesity and chronic kidney disease (CKD) are highly prevalent worldwide and result in substantial health care costs. Obesity is a predictor of incident CKD and progression to kidney failure. Whether weight loss interventions are safe and effective to impact on disease progression and clinical outcomes, such as death remains unclear.

OBJECTIVES

This review aimed to evaluate the safety and efficacy of intentional weight loss interventions in overweight and obese adults with CKD; including those with end-stage kidney disease (ESKD) being treated with dialysis, kidney transplantation, or supportive care.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 14 December 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of more than four weeks duration, reporting on intentional weight loss interventions, in individuals with any stage of CKD, designed to promote weight loss as one of their primary stated goals, in any health care setting.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility and extracted data. We applied the Cochrane 'Risk of Bias' tool and used the GRADE process to assess the certainty of evidence. We estimated treatment effects using random-effects meta-analysis. Results were expressed as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) or standardised mean difference (SMD) for continuous outcomes or in descriptive format when meta-analysis was not possible.

MAIN RESULTS

We included 17 RCTs enrolling 988 overweight or obese adults with CKD. The weight loss interventions and comparators across studies varied. We categorised comparisons into three groups: any weight loss intervention versus usual care or control; any weight loss intervention versus dietary intervention; and surgical intervention versus non-surgical intervention. Methodological quality was varied, with many studies providing insufficient information to accurately judge the risk of bias. Death (any cause), cardiovascular events, successful kidney transplantation, nutritional status, cost effectiveness and economic analysis were not measured in any of the included studies. Across all 17 studies many clinical parameters, patient-centred outcomes, and adverse events were not measured limiting comparisons for these outcomes. In studies comparing any weight loss intervention to usual care or control, weight loss interventions may lead to weight loss or reduction in body weight post intervention (6 studies, 180 participants: MD -3.69 kg, 95% CI -5.82 to -1.57; follow-up: 5 weeks to 12 months, very low-certainty evidence). In very low certainty evidence any weight loss intervention had uncertain effects on body mass index (BMI) (4 studies, 100 participants: MD -2.18 kg/m², 95% CI -4.90 to 0.54), waist circumference (2 studies, 53 participants: MD 0.68 cm, 95% CI -7.6 to 6.24), proteinuria (4 studies, 84 participants: 0.29 g/day, 95% CI -0.76 to 0.18), systolic (4 studies, 139 participants: -3.45 mmHg, 95% CI -9.99 to 3.09) and diastolic blood pressure (4 studies, 139 participants: -2.02 mmHg, 95% CI -3.79 to 0.24). Any weight loss intervention made little or no difference to total cholesterol, high density lipoprotein cholesterol, and inflammation, but may lower low density lipoprotein cholesterol. There was little or no difference between any weight loss interventions (lifestyle or pharmacological) compared to dietary-only weight loss interventions for weight loss, BMI, waist circumference, proteinuria, and systolic blood pressure, however diastolic blood pressure was probably reduced. Furthermore, studies comparing the efficacy of different types of dietary interventions failed to find a specific dietary intervention to be superior for weight loss or a reduction in BMI. Surgical interventions probably reduced body weight (1 study, 11 participants: MD -29.50 kg, 95% CI -36.4 to -23.35), BMI (2 studies, 17 participants: MD -10.43 kg/m², 95% CI -13.58 to -7.29), and waist circumference (MD -30.00 cm, 95% CI -39.93 to -20.07) when compared to non-surgical weight loss interventions after 12 months of follow-up. Proteinuria and blood pressure were not reported. All results across all comparators should be interpreted with caution due to the small number of studies, very low quality of evidence and heterogeneity across interventions and comparators.

AUTHORS' CONCLUSIONS

All types of weight loss interventions had uncertain effects on death and cardiovascular events among overweight and obese adults with CKD as no studies reported these outcome measures. Non-surgical weight loss interventions (predominately lifestyle) appear to be an effective treatment to reduce body weight, and LDL cholesterol. Surgical interventions probably reduce body weight, waist circumference, and fat mass. The current evidence is limited by the small number of included studies, as well as the significant heterogeneity and a high risk of bias in most studies.

Association Between Midlife Obesity and Kidney Function Trajectories: The Atherosclerosis Risk in Communities (ARIC) Study

RATIONALE & OBJECTIVE

Obesity has been related to risk for chronic kidney disease. However, the associations of different measures of midlife obesity with long-term kidney function trajectories and whether they differ by sex and race are unknown.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

13,496 participants from the Atherosclerosis Risk in Communities (ARIC) Study.

PREDICTORS

Midlife obesity status as measured by body mass index (BMI), waist-to-hip ratio, and predicted percent fat at baseline.

OUTCOMES

Estimated glomerular filtration rate (eGFR) calculated using serum creatinine level measured at 5 study visits, and incident kidney failure with replacement therapy (KFRT).

ANALYTICAL APPROACH

Mixed models with random intercepts and random slopes for eGFR. Cox proportional hazards models for KFRT.

RESULTS

Baseline mean age was 54 years, median eGFR was 103mL/min/1.73m2, and median BMI was 27kg/m2. Over 30 years of follow-up, midlife obesity measures were associated with eGFR decline in White and Black women but not consistently in men. Adjusted for age, center, smoking, and coronary heart disease, the differences in eGFR slope per 1-SD higher BMI, waist-to-hip ratio, and predicted percent fat were 0.09 (95% CI, -0.18 to 0.36), -0.25 (95% CI, -0.50 to 0.01), and-0.14 (95% CI, -0.41 to 0.13) mL/min/1.73m2 per decade for White men; -0.91 (95% CI, -1.15 to-0.67), -0.82 (95% CI, -1.06 to-0.58), and-1.02 (95% CI, -1.26 to-0.78) mL/min/1.73m2 per decade for White women; -0.70 (95% CI, -1.54 to 0.14), -1.60 (95% CI, -2.42 to-0.78), and-1.24 (95% CI, -2.08 to-0.40) mL/min/1.73m2 per decade for Black men; and-1.24 (95% CI, -2.08 to-0.40), -1.50 (95% CI, -2.05 to-0.95), and-1.43 (95% CI, -2.00 to-0.86) mL/min/1.73m2 per decade for Black women. Obesity indicators were independently associated with risk for KFRT for all sex-race groups except White men.

LIMITATIONS

Loss to follow-up during 3 decades of follow-up with 5 eGFR assessments.

CONCLUSIONS

Obesity status is a risk factor for future decline in kidney function and development of KFRT in Black and White women, with less consistent associations among men.

Obesity as a predictive factor for chronic kidney disease in adults: systematic review and meta-analysis

Chronic kidney disease (CKD) is one of the main chronic diseases affecting the world population due to its high prevalence and increasing morbidity. Similarly, obesity gained the interest of the scientific community as it directly or indirectly increases mortality from cardiovascular causes, and its prevalence characterizes a pandemic. The objective of this study was to investigate obesity measured by body mass index as a predictor for end-stage renal disease in the general adult population. A systematic review and meta-analysis was carried out by searching 10 databases for prospective or retrospective cohort studies, with no restrictions on the language of publication, including adults with obesity without previous renal disease and who evolved to CKD (diagnosed by estimated glomerular filtration rate below 60 mL&mac_middot;min^-1&mac_middot;(1.73 m²)^-1 over the follow-up period. The R software and Meta package were used for data analysis. After removing duplicates, 5431 studies were submitted to the steps of the systematic review, and 21 articles were included in the data analysis. In total, 3,504,303 patients, 521,216 with obesity, and an average follow-up time of 9.86 years were included. The relative risk of obese people for developing CKD in the random effects model was 1.81 (95%CI: 1.52-2.16). The evidence found in this meta-analysis confirmed that obese people are at higher risk of developing CKD that the non-obese population (1.81 times higher), with obesity being a priority risk factor in preventive actions.

Association between Adiposity Indexes and Kidney Disease: Findings from the Longitudinal Study of Adult Health (Elsa-Brazil)

INTRODUCTION

Chronic kidney disease (CKD) is a public health problem and it is associated with a high risk of mortality. Overweight and obesity are known as independent risk factors for CKD.

OBJECTIVE

To investigate the association between adiposity indexes and kidney disease.

METHODS

This study included 14,636 adults from ELSA-Brazil. Outcome variables: altered glomerular filtration rate (GFR), categorized as yes (GFR <60 mL/min/1.73 m²) and no (GFR ≥60 mL/min/1.73 m²), albuminuria, estimated by albumin-creatinine ratio and categorized as yes (≥30 mg/g) and no (<30 mg/g), and presence of chronic kidney disease (CKD) (altered GFR and/or albuminuria). Exposure variables: obesity and overweight (body mass index (BMI)≥30 and ≥25 kg/m², respectively), high waist circumference (WC) (≥102 cm in men and ≥88 cm in women), high waist-to-hip ratio (WHR) (≥0.90 in men and ≥0.85 in women), and high waist-to-height ratio (WHtR) (≥0.5). To estimate the association between main exposures and outcomes, logistic regression analyses were performed using models adjusted for sociodemographic variables (age, gender, race/skin color, education), behavioral (smoking, physical activity, alcohol consumption), components of the metabolic syndrome (HDL cholesterol, triglycerides, hypertension, diabetes mellitus) and history of cardiovascular disease (myocardial infarction, angina or heart failure).

RESULTS

Individuals with obesity, high WC, WHR and WHtR were more prone to albuminuria when compared to individuals with normal values for these measures. It was also observed that these altered measures were positively associated with the presence of CKD.

CONCLUSION

Adiposity indexes have a direct and significant association with albuminuria and CKD.