Elevated body mass index as a risk factor for chronic kidney disease: current perspectives

Relación entre sobrepeso y obesidad con la progresión de la enfermedad renal crónica en pacientes del Centro Médico Naval en México

Introducción: La progresión de la enfermedad renal crónica podría estar asociada directa o indirectamente al sobrepeso y la obesidad; sin embargo, hasta el momento no hay evidencias suficientes para constatar esta relación. Objetivo: Determinar si el sobrepeso y obesidad son factores que contribuyen a una progresión más acelerada de la enfermedad renal crónica en una muestra de pacientes del Centro Médico Naval. Material y Método: A través de un estudio cuantitativo y observacional, de tipo comparativo, longitudinal y retrospectivo, se determinaron los cambios en el normopeso, sobrepeso y obesidad en 44 pacientes. La progresión de la enfermedad renal crónica se determinó con base en la tasa de filtración glomerular y niveles de albuminuria que presentaron estos pacientes. Los datos se recabaron con un instrumento de registro de diseño propio, durante un seguimiento de 3 años que se llevó a cabo de enero de 2019 a diciembre de 2021. Resultados: Los resultados muestran una tendencia al aumento en la progresión de la enfermedad renal crónica. Conclusiones: A pesar de que se encontró una tendencia al aumento, no se pudo probar una asociación estadísticamente significativa entre la obesidad y el sobrepeso con la progresión de esta enfermedad.

Relación entre sobrepeso y obesidad con la progresión de la enfermedad renal crónica en pacientes del Centro Médico Naval en México

Introducción: La progresión de la enfermedad renal crónica podría estar asociada directa o indirectamente al sobrepeso y la obesidad; sin embargo, hasta el momento no hay evidencias suficientes para constatar esta relación. Objetivo: Determinar si el sobrepeso y obesidad son factores que contribuyen a una progresión más acelerada de la enfermedad renal crónica en una muestra de pacientes del Centro Médico Naval. Material y Método: A través de un estudio cuantitativo y observacional, de tipo comparativo, longitudinal y retrospectivo, se determinaron los cambios en el normopeso, sobrepeso y obesidad en 44 pacientes. La progresión de la enfermedad renal crónica se determinó con base en la tasa de filtración glomerular y niveles de albuminuria que presentaron estos pacientes. Los datos se recabaron con un instrumento de registro de diseño propio, durante un seguimiento de 3 años que se llevó a cabo de enero de 2019 a diciembre de 2021. Resultados: Los resultados muestran una tendencia al aumento en la progresión de la enfermedad renal crónica. Conclusiones: A pesar de que se encontró una tendencia al aumento, no se pudo probar una asociación estadísticamente significativa entre la obesidad y el sobrepeso con la progresión de esta enfermedad.

Kidney dysfunction: prevalence and associated risk factors in a community-based study from the North West Province of South Africa

BACKGROUND

Globally, the World Health Organization ranks chronic kidney disease (CKD) as one of the top 10 causes of mortality. In South Africa, where noncommunicable diseases have become leading causes of mortality, the true population prevalence of CKD is unknown and associated risk factors remain understudied. This study aimed to describe the prevalence of kidney dysfunction and associated risk factors in a community from the North West province of South Africa.

METHODS

This cross-sectional study included 1999 participants older than 30 years. Kidney dysfunction was defined as (i) estimated glomerular filtration rate (eGFR) < 90 ml/min/1.73m², or (ii) urine albuminuria-to-creatinine ratio (uACR) ≥ 3.0 mg/mmol, or a combination (i and ii). Risk factors included age, sex, urban/rural locality, body mass index (BMI), blood pressure (BP), lipid profile, haemoglobin A1c (HbA1C), C-reactive protein (CRP), gamma-glutamyl transferase (GGT), tobacco use, and HIV status.

RESULTS

Mean age of participants was 48 (42;56) years, and 655/1999 (33%) had eGFR < 90 ml/min/1.73m² and/or uACR ≥ 3.0 mg/mmol. Compared to those with normal kidney function, participants with eGFR < 90 ml/min/1.73m² and/or uACR ≥ 3.0 mg/mmol were older, female, had higher measures of adiposity, systolic, diastolic, and mean arterial blood pressure, serum lipids and C-reactive protein (CRP) (all p ≤ 0.024). In multiple regression analyses eGFR was associated with systolic BP (β = 0.11) and HIV infection (β = -0.09), and albuminuria was associated with elevated CRP (β = 0.12) and HIV infection (β = 0.11) (all p < 0.026). In both groups (individuals with and without kidney dysfunction respectively), eGFR was associated with age (β = -0.29, β = -0.49), male sex (β = 0.35, β = 0.28), BMI (β = -0.12, β = -0.09), low-density/high-density lipoprotein cholesterol ratio (β = -0.17, β = -0.09) and CRP (β = 0.10, β = 0.09) (all p < 0.005); and uACR was associated with female sex (β = 0.10, β = -0.14), urban locality (β = -0.11, β = -0.08), BMI (β = -0.11, β-0.11), and systolic BP (β = 0.27, β = 0.14) (all p < 0.017).

CONCLUSION

In this study from the North West province, South Africa, eGFR < 90 ml/min/1.73m² and/or uACR ≥ 3.0 mg/mmol was prevalent and associated with modifiable risk factors. The findings may inform screening strategies for kidney disease prevention, focusing on women, obesity, blood pressure control, dyslipidaemia, identifying and treating inflammation, and HIV diagnosis and treatment.

Pathogenesis, Murine Models, and Clinical Implications of Metabolically Healthy Obesity

Although obesity is commonly associated with numerous cardiometabolic pathologies, some people with obesity are resistant to detrimental effects of excess body fat, which constitutes a condition called “metabolically healthy obesity” (MHO). Metabolic features of MHO that distinguish it from metabolically unhealthy obesity (MUO) include differences in the fat distribution, adipokine types, and levels of chronic inflammation. Murine models are available that mimic the phenotype of human MHO, with increased adiposity but preserved insulin sensitivity. Clinically, there is no established definition of MHO yet. Despite the lack of a uniform definition, most studies describe MHO as a particular case of obesity with no or only one metabolic syndrome components and lower levels of insulin resistance or inflammatory markers. Another clinical viewpoint is the dynamic and changing nature of MHO, which substantially impacts the clinical outcome. In this review, we explore the pathophysiology and some murine models of MHO. The definition, variability, and clinical implications of the MHO phenotype are also discussed. Understanding the characteristics that differentiate people with MHO from those with MUO can lead to new insights into the mechanisms behind obesity-related metabolic derangements and diseases.

Association between urinary sodium excretion and hard outcomes in non-dialysis chronic kidney disease patients

Background

Restriction of sodium intake is routinely recommended for patients with chronic kidney disease (CKD). Whether or not sodium intake is associated with the progression of CKD and mortality remains uncertain. We evaluated the association between urinary sodium excretion (as a surrogate for sodium intake) with the occurrence of renal failure and mortality in patients with non-dialytic CKD.

Methods

We conducted a retrospective study of patients followed at a CKD clinic care hospital from October 2006 to March 2017. Adult patients with non-dialytic CKD were included. Using a time-to-event analysis, we examined the association of urinary sodium excretion as a categorical variable (categorized as quintiles: 1st quintile: 0.54–2.51 g; 2nd quintile: 2.52–3.11 g, 3rd quintile: 3.12–3.97 g, 4th quintile: 3.98–5.24 g and 5th quintile: 5.26–13.80 g) and the outcomes of interest. The primary outcome was defined as progression to end-stage renal disease requiring any type of renal replacement therapy. The secondary outcome was mortality.

Results

Two hundred five patients were included in the study (mean follow up of 2.6 years) with a mean eGFR of 26 (19–41) ml/min/1.73m2. 37 patients (18%) required renal replacement therapy and 52 (25,3%) died. There was association between urinary sodium excretion and need for renal replacement therapy (adjusted HR 0.245; 95%CI 0.660–0.912). There was no association between urinary sodium excretion and mortality in adjusted models.

Conclusion

Moderate sodium intake was associated with a lower risk of renal failure.

Association between metabolic phenotype and urinary albumin-creatinine ratio in Chinese community adults: A cross-sectional study

BACKGROUND

Urinary albumin-creatinine ratio (UACR) is a sensitive marker of kidney injury. This study analyzed the prevalence of different metabolic phenotypes and investigated their relationship with UACR in Chinese community adults.

METHODS

This study involved 33 303 participants over 40 years old from seven centers across China. They were stratified into six groups according to their body mass index (BMI) and metabolic status: metabolically healthy normal weight (MHNW), metabolically healthy overweight (MHOW), metabolically healthy obesity (MHO), metabolically unhealthy normal weight (MUNW), metabolically unhealthy overweight (MUOW), and metabolically unhealthy obesity (MUO). Increased albuminuria was defined as a UACR ≥30 mg/g.

RESULTS

The percentages of MHNW, MHOW, MHO, MUNW, MUOW, and MUO were 27.6%, 15.9%, 4.1%, 19.8%, 22.5%, and 9.6%, respectively. Multiple logistic regression analysis showed that the MHO group (odds ratio [OR] 1.205; 95% CI, 1.081-1.343), MUNW group (OR 1.232; 95% CI, 1.021-1.486), MUOW group (OR 1.447; 95% CI, 1.303-1.607), and MUO group (OR 1.912; 95% CI, 1.680-2.176) were at higher risk of increased albuminuria compared to the MHNW group. Subgroup analysis indicated that the risk of increased albuminuria was further elevated among regular smokers in men aged 40 to 55 years old with abdominal obesity.

CONCLUSIONS

Among Chinese community adults, increased albuminuria was associated with increased BMI whether metabolism was normal or not, and those with abnormal metabolism were at greater risk of increased albuminuria than those with normal metabolism. These findings suggest that overweight or obesity or metabolic abnormalities are risk factors for chronic kidney disease.

Renal Function Following Bariatric Surgery: a Literature Review of Potential Mechanisms

Obesity is a major and independent risk factor for onset and progression of many renal diseases. Bariatric surgery (BS) improves renal function by improving obesity-related metabolic disorders. However, the procedure is also accompanied by renal risks, including acute kidney injury (AKI) and oxalate nephropathy. Here, we briefly review the history and principle of frequently applied technique for BS and summarize the comprehensive BS effect on kidney function. Importantly, we highlight the possible molecular mechanisms associated with the recovery of renal function to provide novel ideas for future studies and clinical applications.

The association between a body shape index and elevated urinary albumin-creatinine ratio in Chinese community adults

BACKGROUND

Obesity, especially visceral obesity, seems to be one of the most decisive risk factors for chronic kidney disease. A Body Shape Index (ABSI) is an emerging body size measurement marker of visceral obesity. This study aimed to explore whether ABSI is associated with albuminuria in Chinese community adults.

METHODS

This cross-sectional study enrolled 40,726 participants aged 40 or older from seven provinces across China through a cluster random sampling method. ABSI was calculated by body mass index, waist circumference, and height. Increased albuminuria was defined as urinary albumin-creatinine ratio (UACR) ≥ 30 mg/g, indicating kidney injury. For ABSI, we divided it by quartile cutoff points and tried to determine the association between ABSI levels and UACR by multiple regression analysis. DAG (Directed Acyclic Graph) was plotted using literature and expert consensus to identify potential confounding factors.

RESULTS

The average age of subjects with elevated UACR was 61.43 ± 10.07, and 26% were men. The average age of subjects with normal UACR was 57.70 ± 9.02, and 30.5% were men. Multiple logistic regression analysis was conducted and demonstrated that the ABSI quartiles were related to elevated UACR positively (OR [95% CI] Q2 vs. Q1: 1.094 [1.004, 1.197]; OR [95% CI] Q3 vs. Q1: 1.126 [1.030, 1.231]; OR [95% CI] Q4 vs. Q1: 1.183 [1.080, 1.295], p for trend < 0.001) after adjustments for confounding factors. The stratified analysis further showed that with the mounting for ABSI levels, elevated UACR more easily occurred in the people characterized by the elderly, men, and hypertension.

CONCLUSIONS

In Chinese community adults, people with higher ABSI levels can be deemed as high-risk individuals with UACR elevation, and it will be beneficial for them to lose weight and significantly reduce visceral fat.

A low serum iron level is a potential predictor of poor renal function in patients following laparoscopic sleeve gastrectomy: a retrospective study

This study aimed to assess the association of serum iron level (Iron) with the estimated glomerular filtration rate (eGFR) after bariatric surgery (BS). We reviewed 210 patients with mean age of 39.1 ± 10.6 years (body mass index, 41.4 ± 5.5 kg/m²) undergoing BS. The primary outcome was the relationship between Iron and eGFR at 12-month after surgery. Multiple linear regression analyses were performed using postoperative eGFR as dependent variables and using Iron and other variables (i.e., age) as independent variables. At 12-month follow-up, 94 patients were analyzed. BMI significantly decreased, whereas serum iron level significantly increased. Although the percentage of patients with eGFR of < 90 mL/min/1.73 m² increased during the study period, no significant difference was found in postoperative 12-month eGFR. No correlations were noted between Iron and eGFR at baseline and postoperative 1 and 6 months, whereas a significant relationship was observed between Iron and postoperative 12-month eGFR. Multiple linear regression analyses revealed that Iron and presence of diabetes were the independent predictors of postoperative 12-month eGFR. This pilot study showed a positive association of postoperative serum iron level with renal function in this patient population. Further large-scale trials are needed to confirm the findings.

Bariatric Surgery Improves Renal Function in Patients With Obesity

Background

Obesity affects 93.3 million adults in the United States and is a predisposing factor for the development and progression of chronic kidney disease (CKD). The objective of this study is to examine the association between weight loss and renal function in participants undergoing bariatric surgery following a 12-week multidisciplinary, community-based weight loss program.

Methodology

This is a retrospective chart review of participants who voluntarily enrolled in a 12-week multidisciplinary weight loss program prior to bariatric surgery from 2009 to 2018. The primary outcome was to assess the association between weight loss and renal function in participants undergoing bariatric surgery. Secondary outcomes included changes in hemoglobin A1c, lipids, fasting glucose, and blood pressure.

Results

Among the 55 participants, baseline glomerular filtration rate (GFR) was 49 mL/min/m², 80% were female, and the average baseline weight was 131 kg. At one-year post-intervention, 69% of patients improved in the CKD stage, with 45% of the participants improving from stage 3A to stage 2. GFR improved to 15 mL/min/1.73m² (p = 0.025), and there was a negative correlation (r_s = -0.3556) between weight and GFR (p = 0.013). Participants with hyperlipidemia had a 12 mL/min/1.73m² rise in GFR, while participants without the diagnosis at one year had a 24 mL/min/1.73m² rise in GFR (p = 0.007).

Conclusions

This study demonstrated improved renal function and reduced progression of CKD following a combined lifestyle and surgical intervention, indicating the importance of a comprehensive approach for the management of the chronic disease.

Warm ischemia time length during on-clamp partial nephrectomy: dose it really matter?

BACKGROUND

The impact of warm ischemia time (WIT) on renal functional recovery remains controversial. We examined the length of WIT >30 min. on the long-term renal function following on-clamp partial nephrectomy (PN).

METHODS

Data from 23 centers for patients undergoing on-clamp PN between 2000 and 2018 were analyzed. We included patients with two kidneys, single tumor, cT1, minimum 1-year followup, and preoperative eGFR ≥60 ml/min/1.73m2. Patients were divided into two groups according to WIT length: group Ⅰ "WIT ≤30 min." and group Ⅱ "WIT >30 min.". A propensity-score matched analysis (1:1 match) was performed to eliminate potential confounding factors between groups. We compared eGFR values, eGFR (%) preservation, eGFR decline, events of chronic kidney disease (CKD) upgrading, and CKD-free progression rates between both groups. Cox regression analysis evaluated WIT impact on upgrading of CKD stages.

RESULTS

The primary cohort consisted of 3526 patients: group Ⅰ (n=2868) and group Ⅱ (n=658). After matching the final cohort consisted of 344 patients in each group. At last followup, there were no significant differences in median eGFR values at 1, 3, 5, and 10 years (P>0.05) between the matched groups. In addition, the median eGFR (%) preservation and absolute eGFR change were similar (89% in group Ⅰ vs. 87% in group Ⅱ, p=0.638) and (-10 in group Ⅰ vs. -11 in group Ⅱ, p=0.577), respectively. The 5 years new-onset CKD-free progression rates were comparable in the non-matched groups (79% in group Ⅰ vs. 81% in group Ⅱ, log-rank, p=0.763) and the matched groups (78.8% in group Ⅰ vs. 76.3% in group Ⅱ, log-rank, p=0.905). Univariable Cox regression analysis showed that WIT >30 min. was not a predictor of overall CKD upgrading (HR:0.953, 95%CI 0.829-1.094, p=0.764) nor upgrading into CKD stage ≥Ⅲ (HR:0.972, 95%CI 0.805-1.173, p=0.764). Retrospective design is a limitation of our study.

CONCLUSIONS

Our analysis based on a large multicenter international cohort study suggests that WIT length during PN has no effect on the long-term renal function outcomes in patients having two kidneys and preoperative eGFR ≥60 ml/min/1.73m2.

Serum and urinary soluble α-Klotho levels in patients with chronic kidney disease

Background: Chronic kidney disease is an epidemic global health problem that leads to death. To prevent any disease progression and treatment, the diagnosis must be made in the early stage by studying renal damage. Klotho is a protein found in many organs of the human body, but it is mainly abundant in the kidney. Objectives: This study is aimed to evaluate klotho’s clinical significance as an additional biomarker for diagnosing chronic kidney disease in its early stages. Methods: One hundred subjects were included in this study to measure their serum and urinary klotho. Forty patients with chronic kidney disease (pre-dialysis) and sixty normal subjects were enrolled in this study. Serum and urinary klotho were determined using the ELISA technique in addition to other renal function tests. Results: Serum and urinary alpha klotho were decreased in CKD patients when compared with control subjects. A positive correlation was found between serum creatinine and urinary alpha klotho in the patients’ group. Conclusion: Serum and urinary alpha klotho levels were decreased significantly in patients with chronic kidney disease compared with healthy controls.

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.

Serum symmetric dimethylarginine shows a relatively consistent long-term concentration in healthy dogs with a significant effect of increased body fat percentage

Symmetric dimethylarginine (SDMA) is a promising renal marker that correlates well with the glomerular filtration rate and could allow earlier detection of impaired renal function. The main objectives of this study were to assess the long-term variability of SDMA in healthy dogs and examine the influence of an increased body fat percentage on the level of SDMA. Sixteen lean Beagles were randomly assigned to the control group or weight-change group in age- and gender-matched pairs. The energy intake of the control group (n = 8) was strictly regulated to maintain an ideal body weight for 83 weeks, while the weight-change group (n = 8) was fed to induce weight gain (week 0–47), to maintain stable excessive body weight (week 47–56) and to lose weight (week 56–83), consecutively. At 8 specified time points, the body condition score, body composition, glomerular filtration rate, serum concentration of SDMA and creatinine were analyzed. In the control group, the within-subject coefficient of variation, between-subject coefficient of variation, reference change value (type I error = 5%) and index of individuality were 0.16, 0.22, 0.43 and 0.73, respectively. The control group and weight-change group did not differ significantly in SDMA concentration. SDMA showed a significant negative association (coefficient = -0.07) with body fat percentage (p<0.01) in the weight-change group and a significant positive association (coefficient = 7.79) with serum creatinine (p<0.01) in the entire study population. In conclusion, SDMA concentration has high long-term stability in healthy adult dogs. For the evaluation of SDMA concentrations, subject-specific reference values are preferred over a population-based reference value seen their higher sensitivity. Moreover, an increased body fat percentage does seem to affect the serum SDMA concentration of otherwise healthy dogs, but its clinical relevance has to be clarified in further research.

Association between obesity and urinary albumin-creatinine ratio in the middle-aged and elderly population of Southern and Northern China: a cross-sectional study

OBJECTIVE

The relationship between obesity and albuminuria has not been clarified. This study aimed to investigate the correlation between obesity and the urinary albumin-creatinine ratio (UACR) in Southern and Northern China.

DESIGN

A descriptive, cross-sectional study.

SETTING

Eight regional centres in REACTION (China's Risk Evaluation of cAncers in Chinese diabeTic Individuals, a lONgitudinal study), including Dalian, Lanzhou, Zhengzhou, Guangzhou, Guangxi, Luzhou, Shanghai and Wuhan.

PARTICIPANTS

A total of 41 085 patients who were not diagnosed with chronic kidney disease (CKD) and had good compliance were selected according to the inclusion criteria. Patients who were diagnosed with CKD, who had other kidney diseases that could lead to increased urinary protein excretion, who were using angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers and whose important data were missing were excluded.

RESULTS

Participants with both, central and peripheral obesity, had a higher risk of elevated UACR, even after adjusting for multiple factors (OR: 1.14, 95% CI: 1.07 to 1.12, p<0.001), and the risk of high UACR in the South was more prominent than that in the North (OR _South: 1.22, 95% CI: 1.11 to 1.34; OR _North: 1.13, 95% CI: 1.04 to 1.22, p<0.001). The risk was also elevated in the male population, hypertensive individuals, glycosylated haemoglobin (HbA1c)≥6.5% and age ≥60 years in the South. Besides the above groups, diabetes was also a risk factor for the Northern population.

CONCLUSIONS

In China, people with both central and peripheral obesity are prone to a high UACR, and the southern population has a higher risk than northern population. Factors such as male sex, hypertension, HbA1c≥6.5% and an age ≥60 years are also risk factors for CKD.

[Correlation of type 2 diabetes and impaired glucose regulation with chronic kidney disease in middle-aged and elderly individuals]

OBJECTIVE

To explore the correlation of different glucose metabolism statues with chronic kidney disease (CKD) in middle-aged and elderly individuals in Lanzhou.

METHODS

Based on the baseline data of REACTION Study in Lanzhou area, we randomly sampled 10 038 residents aged 40-75 years in 3 communities in Lanzhou, who were classified into normal glucose tolerance (NGT), impaired glucose regulation (IGR) and diabetes groups. The estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (ACR) were used to assess the renal function and albuminuria, respectively. Binary logistic regression was performed to analyze the contribution of the risk factors to CKD. Polynominal regression was used to determine the trends of eGFR with the increment of ACR.

RESULTS

Among all the participants, the prevalences of albuminuria, CKD and renal insufficiency (RI) were 26.2%, 27.4% and 2.5%, respectively. The prevalence of albuminuria, CKD and RI were significantly higher in the diabetes group than in IGR and NGT groups (P < 0.05). In IGR group, age, hypertension, and hypertriglyceridemia were positively correlated with the risk of RI (OR: 1.113, 1.904, and 2.608, respectively; P < 0.05). In diabetes group, age, coronary heart disease, obesity, hypertriglyceridemia, and elevated LDL-C level were positively correlated with the risk of RI (OR: 1.069, 2.535, 3.359, 1.827, and 2.690, respectively; P < 0.05). Logistic regression analysis showed that diabetes mellitus significantly increased the risk of albuminuria (OR: 1.543, P=0.000) and RI (OR: 1.446, P=0.005). Logistic regression analysis and multivariate regression analysis showed that although the deterioration trends of eGFR were similar in diabetes group and IGR group, IGR was not a significant risk factor for albuminuria or RI (OR:1.057, P=0.355; OR: 0.918, P=0.614).

CONCLUSIONS

Diabetes mellitus is a significant risk factor for albuminuria and RI, while IGR is not. Screening for albuminuria and eGFR is highly recommended for individuals with diabetes, hypertension, and obesity, especially in women and the elderly population.

Transtubular potassium gradient predicts kidney function impairment after adrenalectomy in primary aldosteronism

Background:

In primary aldosteronism (PA), kidney function impairment could be concealed by relative hyperfiltration and emerge after adrenalectomy. We hypothesized transtubular gradient potassium gradient (TTKG), a kidney aldosterone bioactivity indicator, could correlate to end organ damage and forecast kidney function impairment after adrenalectomy.

Methods:

In the present prospective study, we enrolled lateralized PA patients who underwent adrenalectomy and were followed up 12 months after operation in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry from 2010 to 2018. The clinical outcome was kidney function impairment, defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² at 12 months after adrenalectomy. End organ damage is determined by microalbuminuria and left ventricular mass.

Results:

In total, 323 patients [mean, 50.8 ± 10.9 years old; female 178 (55.1%)] were enrolled. Comparing pre-operation and post-operation data, systolic blood pressure, serum aldosterone, urinary albumin to creatinine ratio and eGFR decreased. TTKG ⩾ 4.9 correlated with pre-operative urinary albumin to creatinine ratio >50 mg/g [odds ratio (OR) = 2.42; p = 0.034] and left ventricular mass (B = 20.10; p = 0.018). Multivariate logistic regression analysis demonstrated that TTKG ⩾ 4.9 could predict concealed chronic kidney disease (OR = 5.42; p = 0.011) and clinical success (OR = 2.90, p = 0.017) at 12 months after adrenalectomy.

Conclusions:

TTKG could predict concealed kidney function impairment and cure of hypertension in PA patients after adrenalectomy. TTKG more than 4.9 as an adverse surrogate of aldosterone and hypokalaemia correlated with pre-operative end organ damage in terms of high proteinuria and cardiac hypertrophy.

The Short-Term Renal Effects of Bariatric Surgery: A Comparative Study Between Sleeve Gastrectomy and One Anastomosis Gastric Bypass Operations Among Egyptian Patients With Severe Obesity

PURPOSE

Obesity is a major health problem with many renal sequelae. Bariatric surgery (BS) has become the treatment of choice for severe obesity. This study was conducted to assess the short-term renal effects of BS and to compare such effects between two distinct forms of BS.

MATERIALS AND METHODS

A single-center non-randomized prospective observational study was conducted on 57 patients with severe obesity. Two distinct forms of BS have been performed; laparoscopic sleeve gastrectomy (LSG) and laparoscopic one anastomosis gastric bypass (OAGB). Anthropometric measurements, 24-h urinary creatinine clearance (CL_Cr), protein and oxalate excretion, and abdominal fat tissue analysis by computerized tomography were performed prior to surgery and 6 months later.

RESULTS

LSG and OAGB were performed in 47 and 10 participants, respectively. BS resulted in pronounced reduction of body mass index (- 27.1% ± 7.11), with no substantial weight loss discrepancy between LSG and OAGB. The median percent change in 24-h urinary CL_Cr and protein and oxalate excretion were - 35.7, - 42.2, and - 5.8, respectively. The median (IQR) percent change of urinary oxalate excretion was - 11.1 (- 22.6, - 1.4) and 113.08 (82.5, 179.7) for LSG and OAGB, respectively (p < 0.001). The subcutaneous abdominal fat surface area has been found to be the significant predictor of the persistence of glomerular hyperfiltration after BS.

CONCLUSION

Both LSG and OAGB can alleviate many of the obesity-related pathological renal changes. However, postoperative hyperoxaluria remains a serious issue particularly in OAGB. Detailed radiological abdominal fat tissue analysis by CT may aid in predicting the renal outcome following BS.

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

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

Impact of a Community-Based Weight Loss Program on Renal Function

Introduction Obesity is associated with increased morbidity and mortality and is an independent risk factor for the development and progression of chronic kidney disease (CKD). This study investigated the effect of a community-based, lifestyle-focused, weight-loss intervention on renal function among participants at baseline following 12 weeks of therapy.  Methods A retrospective analysis of adults enrolled in a weight management program from 2009 to 2014 was conducted. Participants consumed at least 800 kilocalories per day in meal replacements, attended weekly behavioral education classes, and expended approximately 300 kilocalories per day in physical activity. The primary outcome was the association of weight loss and changes in glomerular filtration rate (GFR). Secondary outcomes included changes in blood sugar levels, lipid parameters, blood pressure, and the use of medication for hypertension and diabetes mellitus.  Results Of the 71 participants, 63.4% were female, the average weight was 289 pounds, the average body mass index (BMI) of 53, and baseline GFR 47 ml/min/1.73m². Following 12 weeks of the intervention, 76.1% of participants improved in CKD stage, 22.4% remained within the same stage, and 1.5% progressed to a higher stage (3A to 3B). Analysis revealed a correlation between weight loss and improved GFR (p=0.0006). Improvements were noted in blood sugar levels, blood pressure, and lipids (p<0.05). Medications were reduced in 61.8% of participants for hypertension and 83.3% for diabetes. Conclusions A significant correlation was observed between weight loss and improved renal function, with most participants improving in CKD stage. Participants also improved in markers of chronic disease and required fewer medications. When controlling for both diabetes and hypertension, the effect of improved renal function persisted.

Impact of Transition in Metabolic Health and Obesity on the Incident Chronic Kidney Disease: A Nationwide Cohort Study

CONTEXT

Metabolically healthy obesity (MHO) is a dynamic condition.

OBJECTIVE

To evaluate the risk of chronic kidney disease (CKD) among people with MHO according to its longitudinal change.

DESIGN

Observational study.

SETTING

A nationwide population-based cohort.

PARTICIPANTS

A total of 514 866 people from the Korean National Health Insurance Service-National Sample Cohort.

INTERVENTION

The initial presence and changes of obesity (using body mass index [BMI] and waist circumference [WC]) and metabolic health status.

MAIN OUTCOME MEASURE

Incident CKD from 2011 to 2015.

RESULTS

Of the people classified as MHO at baseline (BMI criteria), 47.6% remained as MHO in 2011 and 2012, whereas 12.1%, 5.5%, and 34.8% were classified as metabolically healthy, non-obese (MHNO), metabolically unhealthy, non-obese, and metabolically unhealthy, obese, respectively. The risk of incident CKD in the baseline MHO group was higher than that in the MHNO group (hazard ratio, 1.23; 95% confidence interval, 1.12-1.36). However, when transition was taken into account, people who converted to MHNO were not at increased risk (hazard ratio, 0.98; 95% confidence interval, 0.72-1.32), whereas the stable MHO group and the groups that evolved to metabolically unhealthy status had a higher risk of incident CKD than the stable MHNO group. When the risk was analyzed using WC criteria, it showed a similar pattern to BMI criteria except for the stable MHO group.

CONCLUSIONS

MHO was a dynamic condition, and people with MHO constituted a heterogeneous group. Although the MHO phenotype was generally associated with incident CKD, maintenance of metabolic health and weight reduction might alleviate the risk of CKD.

Association between metabolic body composition status and risk for impaired renal function: A cross-sectional study

BACKGROUND

The risk for obesity-related disorders is proportional to the visceral region and had been observed to be highly related with impaired renal function. In the current study, we aimed to evaluate renal function impairment, according to sex, age, and different status of metabolic body composition.

METHODS

We retrospectively collected from the medical records the basic information and metabolic titers of Chinese adults (13,373 men and 10,175 women) who underwent health checkup from 2013 to 2016. The population was divided into four groups, according to metabolic body composition, including metabolic healthy norms-weight (MHNW), metabolic healthy obesity (MHO), metabolic unhealthy norms-weight (MUNW), and metabolic unhealthy obesity (MUO). The categorical data were compared among the groups and logistic regression analyses were conducted to investigate the association between metabolic body composition status and risk for renal function impairment.

RESULTS

Across all ages in both sexes, the odds ratios (OR) for renal function impairment were higher in the MHO, MUNW, and MUO groups than in the MHNW group, except for women <45 years old in the MUNW group. However, after adjustment, the trend was no longer significant in all groups under 45 years old. For individuals >45 years old, the relatively high risk for renal function impairment remained significantly associated with the MUNW group (OR 2.95, 95% CI 2.02-4.30 in men and OR 1.95, 95% CI 1.35-2.82 in women) and MUO group (OR 2.33, 95% CI 1.82-3.00 in men and OR 2.67, 95% CI 2.04-3.48 in women).

CONCLUSION

Impaired renal function was independently associated with the status of metabolic obesity. However, the trend was only observed in individuals >45 years old, with significant sex difference.

Visfatin and chemerin levels correspond with inflammation and might reflect the bridge between metabolism, inflammation and fibrosis in patients with systemic sclerosis

Introduction

Adipokines are regulatory molecules which act as mediators of the inflammatory, fibrotic and metabolic processes by interacting with the immune system.

Aim

We hypothesized that chemerin and visfatin by pro-inflammatory properties play a significant role in inflammation in systemic sclerosis. To address this hypothesis, we determined serum chemerin and visfatin levels in SSc patients, compared with the control group and defined the correlations with clinical and laboratory parameters in SSc patients.

Material and methods

The study included 48 Caucasian female patients with SSc and 38 healthy subjects of the control group. Serum concentrations of selected adipokines were measured using commercially available ELISA Kits.

Results

Patients with SSc had higher chemerin levels (209.38 ±55.35 ng/ml) than the control group (182.71 ±33.94 ng/ml) and the difference was statistically significant (Z = 2.14, p = 0.032). The highest chemerin levels were found in dcSSc patients (242.46 ±95.82 ng/ml). We indicated a positive correlation of chemerin and visfatin with levels of inflammatory markers: CRP (r = 0.35, p = 0.013 for chemerin; r = 0.41, p = 0.003 for visfatin) and ESR (r = 0.31, p = 0.03 for chemerin; r = 0.30, p = 0.03 for visfatin). What is more, chemerin manifested a statistically significant positive correlation with the concentration of complement component C3 (r = 0.47, p = 0.001) and C4 (r = 0.29, p = 0.049), whereas visfatin correlated with C4 levels (r = 0.32, p = 0.029).

Conclusions

The results of our study indicate that chemerin and visfatin as pro-inflammatory cytokines might represent new markers corresponding with inflammation in systemic sclerosis and might reflect the bridge between metabolism, inflammation and potentially, chemerin may also link inflammation with skin and lung fibrosis.

Long-Term Impact of Bariatric Surgery on Renal Outcomes at a Community-Based Publicly Funded Bariatric Program: The Regina Bariatric Study

Background:

Obesity is recognized as an independent risk factor for chronic kidney disease through multiple direct and indirect biological pathways. Bariatric surgery is a proven, effective method for sustained weight loss. However, there is a relative paucity of data on the impact of bariatric surgery on renal outcomes.

Objective:

The primary objective was to evaluate the change in urine albumin/creatinine ratio (ACR) in patients undergoing bariatric surgery, at 12 months after the procedure. Secondary objectives were to determine the changes in ACR at (6 and 24 months), estimated glomerular filtration rate (eGFR; 6, 12, and 24 months), and hemoglobin A1c (HbA1c); 12 and 24 months) after the procedure.

Design:

This observational retrospective cohort study included consecutive obese patients who underwent bariatric surgery.

Setting:

Provincial Bariatric Surgery Clinic at the Regina General Hospital, Saskatchewan.

Patients:

This study includes 471 consecutive obese adult patients who underwent bariatric surgery between 2008 and 2015.

Measurements:

We studied the impact of bariatric surgery on body mass index (BMI), renal outcomes (urine ACR and eGFR) and metabolic outcomes (fasting glucose, total cholesterol, low-density lipoprotein, triglycerides, and HbA1c) in 471 patients.

Methods:

Patients were followed for 2 years postsurgery in the bariatric clinic. Mixed linear models that accounted for the repeated nature of the data were used to access changes in outcomes over time.

Results:

Patients were predominantly female (81%) with a mean age (±SD) of 46 ± 10 years. Most patients (87%) had a BMI > 40 kg/m² and 81% of the patients underwent Roux-en-Y gastric bypass. The mean BMI decreased from 47.7 ± 7.8 kg/m² at baseline to 37.1 ± 7.9 kg/m² at 6 months and 34.8 ± 8.8 kg/m² at 12 months. In a subcohort of patients with microalbuminuria, ACR showed an improvement from a median [interquartile] value of 5.1 [3.7-7.5] mg/mmol at baseline to 2.3 [1.2-3.6] mg/mmol at 6 months (P = .007), to 1.4 [0.9-3.7] mg/mmol at 2-year follow-up (P < .001). Similarly, eGFR increased in patients with microalbuminuria from 109 ± 10 mL/min/1.73 m² at baseline to 120 ± 36 mL/min/1.73 m² at 2-year follow-up (P = .013). There were statistically significant reductions in triglycerides, fasting glucose, and HbA1c.

Limitations:

This was a retrospective chart review, with the lack of a control group. Patients with eGFR less than 60 mL/min/1.73 m² were not considered for surgery, and we had to measure renal outcomes predominantly on the presence of proteinuria.

Conclusions:

Our results suggest bariatric surgery significantly decreased weight and consequently improved renal and metabolic outcomes (eGFR, ACR, fasting glucose, cholesterol, and triglycerides) in patients with elevated BMI.

The Effects of Bariatric Surgery on Renal Outcomes: a Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVE

Although promising, data regarding the renal impact and safety of bariatric surgery (BS) are insufficient. We aimed at investigating the benefits and harms of BS for weight loss on kidney function.

METHODS

A systematic review and meta-analysis of observational studies reporting data about the impact of BS (any techniques) on serum/plasma creatinine, creatinine clearance, glomerular filtration rate (GFR), proteinuria, nephrolithiasis, and need for renal replacement therapy (RRT)) was performed. Obese adults (non-chronic kidney disease (CKD), CKD or transplanted patients) that underwent BS for weight loss were included. After searching MEDLINE (inception to August 2017), the Cochrane Library (Issue 10-12, October 2017), and the websiteclinicaltrials.gov (August 2017), data were extracted and summarized using a random-effects model.

RESULTS

The final analysis included 23 cohort studies, comprising 3015 participants. Compared with renal function before treatment, BS significantly decreased serum creatinine level (mean difference (MD), - 0.08 mg dl^-1; 95% confidence interval (CI), - 0.10 to - 0.06); p < 0.001) and proteinuria (MD, - 0.04 g 24 h^-1; 95% CI, - 0.06 to - 0.02; p < 0.001) in the overall group. GFR significantly improved 6 months or more after BS both in the hyperfiltration and CKD subgroups. Renal function also tended to improve in renal transplant patients. Data on nephrolithiasis and the need for RRT were scarce or not reported.

CONCLUSIONS

BS apparently has positive effects on kidney function and tends to normalize GFR across different categories of renal impairment (hyperfiltration and CKD patients).

Metabolic phenotypes of obese, overweight, and normal weight individuals and risk of chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE

Chronic kidney disease (CKD) risk is inconsistent in the normal-weight, overweight, and obese individuals due to the heterogeneity of metabolic status. This meta-analysis aimed to examine the combined effects of body mass index (BMI) and metabolic status on CKD risk.

MATERIALS AND METHODS

The MEDLINE, EMBASE, and Web of Knowledge databases were systematically searched up to March 2019 to identify all eligible studies investigating the CKD risk (defined as GFR < 60 mL/min per 1.73 m2 and/or microalbuminuria or proteinuria) associated with the body size phenotypes which are known as metabolically unhealthy normal-weight (MUNW), metabolically healthy overweight (MHOW), metabolically unhealthy overweight, metabolically healthy obese (MHO) and metabolically unhealthy obese (MUHO). The classification of subjects in included studies as metabolically unhealthy was based on the presence of three components of metabolic syndrome. BMI categorization was based on the criteria of included studies. The risk estimates and 95% confidence intervals (CIs) were extracted and pooled using random effects analysis.

RESULTS

A total of 9 prospective cohort studies with 128773 participants and 4797 incident cases were included in the meta-analysis. Compared with healthy normal-weight individuals as reference, MUNW and MHO subjects showed an increased risk for CKD events with a pooled RR of 1.58 (95% CI = 1.28-1.96) in MUNW and 1.55 (95% CI = 1.34-1.79) in MHO persons. Also, MHOW was at increased risk for CKD (RR = 1.34, 95% CI = 1.20-1.51). MUHO individuals were at the highest risk for the development of CKD (RR = 2.13, 95% CI = 1.66-2.72).

CONCLUSIONS

Individuals with metabolic abnormality, although at normal-weight, have an increased risk for CKD. Healthy overweight and obese individuals had higher risk; refuting the notion that metabolically healthy overweight and obese phenotypes are benign conditions.

Clinical and metabolomic risk factors associated with rapid renal function decline in sickle cell disease

Sickle cell disease (SCD) nephropathy and lower estimated glomerular filtration rate (eGFR) are risk factors for early mortality. Furthermore, rate of eGFR decline predicts progression to end-stage renal disease in many clinical settings. However, factors predicting renal function decline in SCD are poorly documented. Using clinical, laboratory, genetic, and metabolomic data, we evaluated predictors of renal function decline in a longitudinal cohort of 288 adults (mean age 33.0 years). In 193 subjects with 5-year follow-up data, mean rate of eGFR decline was 2.35 mL/min/1.73 m² /year, nearly twice that of African American adults overall. Hyperfiltration was prevalent at baseline (61.1%), and 36.8% of subjects experienced rapid eGFR decline (≥3 mL/min/1.73 m² /year). Severe Hb genotype; proteinuria; higher platelet and reticulocyte counts, and systolic BP; and lower Hb level and BMI were associated with rapid decline. A risk scoring system was created using these 7 variables and was highly predictive of rapid eGFR decline, with odds of rapid decline increasing 1.635-fold for every point increment (P < 0.0001). Rapid eGFR decline was also associated with higher organ system severity score and peak creatinine. Additionally, two metabolites (asymmetric dimethylarginine and quinolinic acid) were associated with rapid decline. Further investigation into longitudinal SCD nephropathy (SCDN) trajectory, early markers of SCDN, and tools for risk stratification should inform interventional studies targeted to slowing GFR decline and improving SCD outcomes.

Incidence and predictors of chronic kidney diseases among type 2 diabetes mellitus patients at St. Paul's Hospital, Addis Ababa, Ethiopia

OBJECTIVE

This study aimed to estimate the incidence of chronic kidney disease and its predictors among newly diagnosed type 2 diabetes patients attending St. Paul's Hospital, Addis Ababa, Ethiopia.

RESULTS

The overall incidence of chronic kidney disease was a major public health issue among type 2 diabetes mellitus patients with 2178 (95% CI 12,801, 21,286) cases per 10,000 patient-months. Moreover, 62(14.25%) patients in the sample experienced chronic kidney disease. Old age [adjusted hazard ratio (AHR) = 1.06, 95%CI 1.03, 1.09], no diabetic retinopathy [AHR = 0.13, 95%CI 0.07-0.24], high density lipoprotein cholesterol ≥ 40 mg/dl [AHR = 0.55, 95%CI 0.31, 0.97] and high body mass index [AHR = 1.17, 95%CI 1.1, 1.25] were common factors for chronic kidney diseases.

Predictive metabolomic signatures of end-stage renal disease: A multivariate analysis of population-based data

The variability of molecular signatures and predictive low molecular weight markers of chronic kidney disease (CKD) in different populations are poorly understood. Thus, in a large sample with 4763 people we compare the molecular signatures and metabolites with diagnostic relevance in plasma and urine of CKD patients of different geographical origins. From an integrated model based on dynamic networks and multivariate statistics, metabolites with predictive value obtained from targeted and untargeted molecular analysis, interactions between metabolic pathways affected by CKD, and the methodological quality of metabolomic studies were analyzed. The metabolites 3-methylhistidine, citrulline, kynurenine, p-cresol sulfate, urea, and citrate presented consistent expression in all population groups. Only increased kynurenine and p-cresol sulfate in plasma samples obtained acceptable scores as CKD biomarkers, independent of geographic origin. Metabolites such as leucine, alanine, isoleucine, serine, histidine, and citrate were nodal points, indicating that protein metabolism pathways are similarly impaired in Asian, European and North American patients. Based on our integrated model, we show that the metabolome of CKD patients exhibits a strong geographic influence, leading to unique metabolic signatures. Contrary to the likelihood of molecular similarities between geographically distinct populations, metabolic convergences in protein metabolism pathways and the molecules kynurenine and p-cresol sulfate were relevant as general predictors of CKD. In general, the quality assessment indicated that the current evidence is based on research models with variable methodological quality, whose limitations described in this study should be considered in the refinement of molecular approaches.

Prevalence and Risk Factors for CKD: A Comparison Between the Adult Populations in China and the United States

Introduction

Chronic kidney disease (CKD) is an important noncommunicable disease globally. Overall prevalence of CKD and distribution of its stages differ between countries. We postulate that these differences may not only be due to variation in prevalence of risk factors but also their differential impact in different populations or settings.

Methods

We used nationally representative data on the adult populations from both the United States (US; National Health and Nutrition Examination Survey [NHANES], 2009 to 2010, N = 5557) and China (China National Survey of CKD, 2009 to 2010, N = 46,949). Age, sex, central obesity, cardiovascular disease, diabetes, hypertension, and hyperuricemia were explored as candidate risk factors for CKD. The prevalence of CKD was calculated using survey weights.

Results

The prevalence of decreased estimated glomerular filtration rate (eGFR), defined as eGFR < 60 ml/min per 1.73 m², was 6.5% in the US versus 2.7% in China, whereas the prevalence of albuminuria (defined as urine albumin to creatinine ratio of ≥30 mg/g) was 8.1% in the US versus 9.5% in China. The distribution of eGFR categories differed between the countries (P < 0.001). Stronger associations of diabetes with both indicators were seen in the US participants, whereas stronger associations of male sex with both indicators and of hypertension with albuminuria were observed in the Chinese participants (P < 0.05). After multivariable adjustment, a 65% change in prevalence difference for decreased eGFR was seen between China and the US.

Conclusion

People in China and the US share many common risk factors for CKD, but differences in prevalence and the potential impact of these risk factors for CKD were observed.

Obesity, hyperhomocysteinaemia and risk of chronic kidney disease: a population-based study

BACKGROUND

Obesity is associated with increased risk of cardiovascular disease and chronic kidney disease (CKD). Hyperhomocysteinaemia refers to increased oxidative stress and has been associated with the risk of CKD.

OBJECTIVES

We investigated the association among body mass index (BMI), homocysteine level and impaired renal function in a Taiwanese adult population.

METHODS

This was a retrospective cross-sectional study involving 24826 subjects who underwent a health check-up from January 2013 to December 2015. A multivariate linear regression model was developed to analyse the relationship among BMI, serum homocysteine and estimated glomerular filtration rate (eGFR). A multivariate logistic regression model was used to assess the relationship among weight categories, hyperhomocysteinaemia and CKD.

RESULTS

The prevalence of CKD in the quartile groups of homocysteine were 2.5%, 2.7%, 3.4% and 5.2% (P < 0.01). For every one-unit increase in BMI (kg/m2), the eGFR decreased by 0.50 ml/min/1.73 m2. Overweight/obese subjects with high homocysteine levels had a higher odds ratio (OR) for CKD, as compared with normal weight subjects (1.84 versus 1.38, respectively; P < 0.01 versus P = 0.02, respectively). Overweight/obese female subjects with hyperhomocysteinaemia had an OR of 3.40 [P < 0.01; 95% confidence interval (CI): 2.06-5.61] for CKD; in males, the OR was 1.66 (P < 0.01; 95% CI: 1.38-1.99).

CONCLUSIONS

Patients who are overweight/obese with higher homocysteine levels have an increased risk of CKD, especially females. Additional studies exploring whether the effect of weight loss or homocysteine-lowering therapies such as folic acid, vitamin B12 supplements that may prevent or slow the progression of declining renal function, is warranted.

Metabolic syndrome and its components are associated with increased chronic kidney disease risk: Evidence from a meta-analysis on 11 109 003 participants from 66 studies

BACKGROUND & AIMS

Observational studies examining the relationship between metabolic syndrome and the risk of chronic kidney disease (CKD) have reported inconclusive results. This meta-analysis was performed to resolve these controversies.

METHODS

The MEDLINE, EMBASE, and PubMed databases were systematically searched from their inception until March 2016 to identify all relevant studies. Risk estimates and their corresponding 95% confidence intervals (CIs) for the associations of MetS and its components with CKD risk were extracted and pooled using a random-effects model.

RESULTS

A total of 66 studies, including 18 prospective cohorts and 48 cross-sectional studies, with 699 065 CKD patients and 11 109 003 participants were included in the meta-analysis. When all definitions were pooled, the presence of MetS was associated with a significant 50% increase of CKD risk (OR = 1.50, 95% CI = 1.43-1.56), with evidence of moderate heterogeneity (I2  = 72.3%, P < .001). The risk of CKD associated with MetS was higher in studies using the American Heart Association/National Heart, Lung, and Blood Institute criteria (OR = 1.68, 95% CI = 1.25-2.10) compared with those using the Adult Treatment Panel III (OR = 1.49, 95% CI = 1.42-1.56) and the International Diabetes Federation (OR = 1.32, 95% CI = 1.22-1.41) definitions. This relationship was independent of diabetes status. Moreover, all individual components of the MetS were significantly associated with CKD, and their coexistence resulted in an escalating dose-response relationship. The sensitivity and subgroup analyses established the stability of the findings.

CONCLUSIONS

This meta-analysis strongly suggests that the metabolic syndrome and its components are independently associated with the increased risk of CKD.

Associations between socioeconomic status and chronic kidney disease: a meta-analysis

BACKGROUND

Socioeconomic status (SES) has long been conjectured to be associated with the incidence and progression of chronic kidney disease (CKD), but few studies have examined this quantitatively. This meta-analysis aims to fill this gap.

METHODS

A systematic literature review was performed using Medline and EMBASE to identify observational studies on associations between SES and incidence and progression of CKD, published between 1974 and March 2017. Individual results were meta-analysed using a random effects model, in line with Meta-analysis of Observational Studies in Epidemiology guidelines.

RESULTS

In total, 43 articles met our inclusion criteria. CKD prevalence was associated with several indicators of SES, particularly lower income (OR 1.34, 95% CI (1.18 to 1.53), P<0.001; I²=73.0%, P=0.05); lower education (OR 1.21, 95% CI (1.11 to 1.32), P<0.001; I²=45.20%, P=0.034); and lower combined SES (OR 2.18, 95% CI (1.64 to 2.89), P<0.001; I²=0.0%, P=0.326). Lower levels of income, occupation and combined SES were also significantly associated with progression to end-stage renal disease (risk ratio (RR) 1.24, 95% CI (1.12 to 1.37), P<0.001; I²=66.6%, P=0.006; RR 1.05, 95% CI (1.01 to 1.09), P=0.012; I²=0.0%, P=0.796; and RR 1.39, 95% CI (1.09 to 1.79), P=0.009; I²=74.2%, P=0.009). Subgroup analyses generally confirmed these results, except in a few cases, such as an inverse association related to particular socioeconomic backgrounds and where results were adjusted by more disease-related risk factors.

CONCLUSION

Lower income was most closely associated with prevalence and progression of CKD, and lower education was significantly associated with its prevalence. Evidence for other indicators was inconclusive.

Serum chemerin levels are inversely associated with renal function in a general population

OBJECTIVE

Chemerin has been found to be highly expressed in the kidneys of rodents and has been suggested to affect metabolic syndrome (MetS)-related phenotypes which are in turn related to kidney damage. Only few clinical studies have addressed the relation between circulating chemerin and renal function in humans, and no population-based analyses have yet been performed. The potential influence of MetS-related phenotypes on the assumed association has been largely neglected. We aimed to investigate the association of serum chemerin with renal function in a general population with special regard to possible interactions between chemerin and metabolic phenotypes.

DESIGN, PATIENTS AND MEASUREMENTS

Linear and logistic regression models were applied to analyse data from 4082 subjects of the German Study of Health in Pomerania. Main outcomes included estimated glomerular filtration rate (eGFR), serum creatinine and cystatin C and chronic kidney disease.

RESULTS

Inverse associations of chemerin with eGFR were observed. The components of the MetS emerged as modulating factors in this relation and enhanced the association. Logistic regression models confirmed the relation between chemerin and eGFR and revealed that each increase in chemerin per 25 ng/mL was associated with an about threefold higher odds of chronic kidney disease [odds ratio 2.72 (95% confidence interval 2.26-3.29)].

CONCLUSIONS

Our results demonstrate a strong inverse association between serum chemerin levels and renal function. This association might be explained by MetS-related phenotypes, which lead to renal damage and are associated with increased chemerin levels and/or an impaired renal elimination of chemerin by diseased kidneys.

Association Between Body Mass Index Combined with Albumin: creatinine Ratio and All-cause Mortality in Chinese Population

The association between body mass index (BMI) combined with albumin: creatinine ratio (ACR) and all-cause mortality in the general population has not been established. To address this, we examined a representative sample from the general population of China. The study included 46,854 participants with a follow-up of 4.6 years. Compared to the normal weight with ACR <10 mg/g group (the reference group), the crude hazard ratios (HRs) for all-cause mortality for the underweight with ACR >10 mg/g, normal weight with ACR >10 mg/g, overweight with ACR >10 mg/g, and obese with ACR >10 mg/g groups, were 2.22 (95% CI, 1.41 to 3.49), 1.70 (95% CI, 1.42 to 2.04), 1.52 (95% CI, 1.22 to 1.89), and 2.05 (95% CI, 1.45 to 2.89), respectively. After multivariable adjustments for age, race, comorbidities, and baseline eGFR, the HRs for the underweight with ACR >10 mg/g and normal weight with ACR >10 mg/g groups were 1.85 (95% CI, 1.17 to 2.91) and 1.36 (95% CI, 1.13 to 1.63), respectively. The results indicate that BMI combined with ACR can better predict all-cause mortality than BMI alone in the general Chinese population. Underweight and normal weight people with elevated ACR are at a higher risk of all-cause mortality than those in the same BMI category with ACR <10 mg/g.

Increased body mass index is a risk factor for end-stage renal disease in the Chinese Singapore population

The relationship between body mass index (BMI) and end-stage renal disease (ESRD) is confounded by co-morbidities associated with both conditions. Furthermore, the association at low range BMI is controversial. We studied this association in the Singapore Chinese Health Study, a population-based prospective cohort that recruited Singaporean Chinese men and women 45-74 years of age from 1993 to 1998. Self-reported weight, height, lifestyle factors, usual diet, and medical history were collected via an interviewer-administered questionnaire. Incident ESRD cases were identified via record linkage with the nationwide ESRD registry. The computed Cox proportional hazard regression was adjusted for potential risk factors. After an average follow-up of 15.5 years, 827 incident ESRD cases were identified. Compared with a normal BMI of 18.5 to under 23 kg/m², the hazard ratios and (95% confidence intervals) of ESRD risk for BMIs under 18.5, 23 to under 27.5, and 27.5 kg/m² or more were 0.54 (0.37-0.79), 1.40 (1.20-1.64) and 2.13 (1.74-2.59), respectively. This significantly trended, linear, dose-dependent association was only present among those with no history of diabetes, hypertension, coronary heart disease, and stroke at baseline, but not significantly among those with any of these co-morbidities. Thus, BMI itself is a risk factor for ESRD in the general population and this association is present in those without pre-existing diabetes, hypertension, coronary heart disease, and stroke.

On the occasion of world kidney day 2017; obesity and its relationship with chronic kidney disease

Context:

Numerous studies have reported the impact of obesity in the incidence of chronic kidney disease (CKD). Some studies have suggested the direct role of obesity in the incidence of CKD, while some other studies suggest an indirect effect caused by the effects of obesity on blood pressure and diabetes.

Evidence Acquisition:

PubMed, EBSCO, Web of Science, directory of open access journals (DOAJ), EMBASE, and Google Scholar have been searched.

Results:

Recent studies have presented more strong evidences on the role of obesity on the incidence of CKD. The double role of obesity in the incidence of CKD has also been mentioned in some studies.

Conclusions:

Such an additional effect arises from the impact of obesity on the incidence of some conditions and diseases such as cardiovascular disease, hypertension, and diabetes, which in turn are involved in the incidence of CKD and are considered as its risk factors.

The association of chronic kidney disease and waist circumference and waist-to-height ratio in Chinese urban adults

This study aims to investigate the association of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) with chronic kidney disease (CKD).A cross-sectional survey was conducted in a nationally representative sample of 123,629 Chinese urban adults who participated in health examinations between 2008 and 2009. BMI, WC, and WHtR were measured, as well as serum and urine biochemical tests. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m or urine protein positivity (proteinuria)≥1+ with dipstick testing.WHtR had the largest areas under ROC curve for CKD in men and women, followed by WC and BMI. Higher levels of BMI, WC, and WHtR were each associated with an increased odds for CKD among men. For per unit size change, the multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of CKD were 1.19 (95% CI, 1.13-1.25) for BMI, 1.12 (95% CI, 1.08-1.16) for WC, and 1.13 (95% CI, 1.10-1.17) for WHtR. The corresponding values were significant in multivariable models among women aged 40 years and above. Using Chinese-recommended cutoffs for BMI (≥24 kg/m), WC (≥85 cm for men, and ≥80 cm for women), and WHtR (≥0.05), WHtR was superior in the association with CKD than BMI for men, whereas WC was superior for women.Increased obesity indices were positively associated with the odds of CKD. Central obesity, defined by WC and WHtR, may be more closely correlated with CKD for Chinese urban adults.

On the rationale of population screening for chronic kidney disease: a public health perspective

Unlike opportunistic screening, population screening is accompanied by stringent quality control measures and careful programme monitoring. Sufficient evidence for benefit together with acceptable harms and costs to society are needed before launching a programme. A screening programme is a complex process organized at the population level involving multiple actors of the health care system that should ideally be supervised by public health authorities and evaluated by an independent and trustful body. Chronic kidney disease is defined by reduced glomerular filtration rate and/or presence of kidney damage for at least three months. Chronic kidney disease is divided into 5 stages with stages 1 to 3 being usually asymptomatic. Chronic kidney disease affects one in ten adults worldwide and its prevalence sharply increases with age. Kidney function is measured using serum creatinine-based, and/or cystatin C-based, equations. Markers of renal function show high intra-individual and inter-laboratory variabilities, highlighting the need for standardized procedures. There is also large inter-individual variability in age-related kidney function decline. Despite these limitations, chronic kidney disease, as currently defined, has been consistently associated with high cardiovascular morbidity and mortality and high risk of end-stage renal disease. Major modifiable risk factors for chronic kidney disease are diabetes, hypertension, obesity and cardiovascular disease. Several treatment options, ranging from antihypertensive and lipid-lowering treatments to dietary measures, reduce all-cause mortality and/or end-stage renal disease in patients with stages 1-3 chronic kidney disease. So far, no randomized controlled trial comparing outcomes with and without population screening for stages 1-3 chronic kidney disease has been published. Population screening for stages 1-3 chronic kidney disease is currently not recommended because of insufficient evidence for benefit. Given the current and future burden attributable to chronic kidney disease, randomized controlled trials exploring benefits and harms of population screening are clearly needed to prioritize resource allocations.

Influence of the PNPLA3 rs738409 Polymorphism on Non-Alcoholic Fatty Liver Disease and Renal Function among Normal Weight Subjects

In normal weight subjects (body mass index < 25 kg/m2), non-alcoholic fatty liver disease (NAFLD) is likely to coexist with metabolic diseases. The patatin-like phospholipase 3 (PNPLA3) polymorphism rs738409 (c.444C>G) is associated with the risk of NAFLD and/or renal dysfunction; however, the influence of the weight status on the associations remains unknown. We aimed to clarify the associations of the PNPLA3 polymorphism with the risk of NAFLD and/or renal dysfunction, while also paying careful attention to the weight status of the subjects. Cross-sectional and retrospective longitudinal studies with 5.5 ± 1.1 years of follow-up were conducted in 740 and 393 Japanese participants (61.2 ± 10.5 and 67.5 ± 6.0 years), respectively, during a health screening program. Among 591 subjects who did not have a habitual alcohol intake and/or hepatitis B or C virus infections, the PNPLA3 G/G genotype was associated with the risk for NAFLD in normal weight subjects [odds ratio (95% CI): 3.06 (1.11-8.43), P < 0.05]. Among all subjects, carriers of the PNPLA3 G/G genotype with a normal weight had a lower eGFR than those of the C/C genotype [partial regression coefficient (SE): -3.26 (1.48), P < 0.05]. These associations were replicated in the longitudinal analyses. Among the overweight subjects, none of the genotypes were significantly associated in the cross-sectional and longitudinal analyses; however, the power of the analyses was small, especially in the analyses among overweight subjects. The findings of this study suggest that carriers of the PNPLA3 G/G genotype with a normal weight status should nevertheless be carefully monitored for the presence of NAFLD and/or renal dysfunction.

Health-Risk Factors and the Prevalence of Chronic Kidney Disease: Cross-Sectional Findings from a National Cohort of 87,143 Thai Open University Students

BACKGROUND

Chronic kidney disease (CKD) is becoming a major health challenge worldwide as its aetiology has transferred from predominantly infectious disease to emerging chronic diseases, especially diabetes and hypertension. A rapid health-risk transition driven by economic development is transforming Thailand which is now becoming an ageing country where chronic diseases are a major health burden.

METHODS

This study used the 2005 baseline cross-sectional dataset of 87,143 Thai Cohort Study members to investigate risk factors associated with CKD. Using multivariate logistic regression, we looked into the relationship between CKD and demographic and socioeconomic factors, personal health status and various health-related behaviours.

RESULTS

The prevalence of CKD in men was lower than that in women (2.5% vs 2.7%). In both sexes, CKD is associated with ageing, cigarette smoking and drinking alcohol, having diabetes, high lipids and hypertension. In men, CKD was associated with living in rural areas, having a low income, a higher BMI, short sleeping and having Western fast food. In women, marriage is associated with a higher risk of CKD.

CONCLUSIONS

CKD is strongly associated with ageing, underlying diseases, smoking and drinking. Hypertension, elevated lipids, or diabetes are all risk factors that could be prevented or detected and treated. The Ministry of Public Health should encourage Thai people to consume healthy food, maintain a normal weight, stop smoking and drink alcohol in moderation, all of which will help prevent CKD.