Mid-arm muscle circumference and quality of life and survival in maintenance hemodialysis patients

Survival in patients on hemodialysis: Effect of gender according to body mass index and creatinine

Background

The association of a higher body mass index (BMI) with better survival is a well-known “obesity paradox” in patients on hemodialysis (HD). However, men and women have different body compositions, which could impact the effect of BMI on mortality. We investigated the effect of gender on the obesity-mortality relationship in Korean patients on HD.

Methods

This study included 2,833 maintenance patients on HD from a multicenter prospective cohort study in Korea (NCT00931970). The relationship between categorized BMI and gender-specific mortality was evaluated by an adjusted Cox proportional hazard model with restricted cubic spline analyses and the Competing risk analysis. We also investigated the effect of changes in BMI over 12 months and serum creatinine level on survival in male and female patients on HD.

Results

The mean BMI was 22.6 ± 3.3 kg/m² and the mean follow up duration was 24.2 ± 3.4 months. The patients with the highest quintile of BMI (≥25.1 kg/m²) showed lower mortality (subdistributional hazard ratio [SHR] = 0.63, 95% confidence interval [CI] = 0.43–0.93, P = 0.019) compared with those with the reference BMI quintile. When analyzed by gender, male patients with a BMI over 25.1 kg/m² had lower mortality risk (HR = 0.43, 95% CI = 0.25–0.75, P = 0.003); however, no significant difference was found in female patients. Increased BMI after 12 months and high serum creatinine were associated with better survival only in male patients on HD.

Conclusions

BMI could be used as a risk factor for mortality in male patients on HD. However, the mortality of female patients on HD was not related with baseline and follow-up BMI. This suggests that BMI is a good surrogate marker of lean body composition, especially in male patients on HD.

Association of lean body mass with nutritional parameters and mortality in hemodialysis patients: A long-term follow-up clinical study

Objective:

This study aimed to evaluate the correlation between lean body mass (LBM) and nutritional status in hemodialysis (HD) patients to better predict their long-term prognosis.

Methods:

Anthropometric body measurements and biochemical parameters were recorded from 222 patients on maintenance hemodialysis (MHD) at the Shanghai Pudong Hospital Hemodialysis Center. LBM was calculated using the serum creatinine index (LBM-SCR), mid-arm muscle circumference (LBM-MAMC), and dominant-arm hand-grip strength (LBM-HGS). Patient mortality and hospitalization were observed after 24 months.

Results:

LBMs measured from LBM-SCR and LBM-MAMC were associated with sex, body mass index (BMI), serum albumin, and serum creatinine (SCR) ( p < 0.05). Through three methods of LBM evaluation, low LBM was shown to be associated with a higher mortality in patients undergoing HD ( p < 0.05). In addition, the rate of hospitalization among these patients was significantly increased ( p < 0.05). Performing multivariate regression analysis using mortality and hospitalization as the dependent variable, we found LBM-SCR and LBM-HGS are strongly associated with hospitalization and mortality in HD patients, indicating LBM is an important factor in prediction of outcomes in those patients.

Conclusion:

LBM is associated with nutritional parameters in HD patients, and LBM-SCR, HGS, and MAMC are simple approaches for accurately predicting the patient’s risk of hospitalization and/or death.

Muscle mass assessment by computed tomography in chronic kidney disease patients: agreement with surrogate methods

BACKGROUND/OBJECTIVES

Patients with chronic kidney disease (CKD) are subjected to muscle wasting. Therefore, it is important to investigate surrogate methods that enable the assessment of muscle mass loss in the clinical setting. We aimed to analyze the agreement between computed tomography (CT) and surrogate methods for the assessment of muscle mass in non-dialysis CKD patients.

SUBJECTS/METHODS

Cross-sectional study including 233 non-dialysis patients on CKD stages 3 to 5 (61 ± 11 years; 64% men; glomerular filtration rate 22 (14-33) mL/min/1.73 m²). The muscle mass was evaluated by CT and bioelectrical impedance, skinfold thicknesses, midarm muscle circumference (MAMC), the predictive equations of Janssen and Baumgartner and the physical examination of muscle atrophy from the subjective global assessment.

RESULTS

In males, the MAMC showed the best agreement with CT as indicated by the kappa test (k = 0.57, P < 0.01), sensitivity (S = 68%), specificity (S = 89%) and accuracy (area under the curve-AUC = 0.78), followed by the Baumgartner equation (kappa = 0.46, P < 0.01; sensitivity = 60%; specificity = 87% and AUC = 0.73). In female, the Baumgartner equation showed the best agreement with CT (kappa = 0.43, P < 0.01; sensitivity = 57%; specificity = 86% and AUC = 0.71).

CONCLUSIONS

The MAMC and Baumgartner equation showed the best agreement with CT for the assessment of muscle mass in non-dialysis CKD patients.

Sarcopenia, Relative Sarcopenia and Excess Adiposity in Chronic Kidney Disease

Background: Conventional definitions of sarcopenia based on lean mass fail to capture low lean mass relative to fat mass, i.e., relative sarcopenia. Unlike percent body fat (%BF) and Quételet’s (body mass) index (BMI, kg/m2), definitions of obesity based on fat mass index (FMI, kg/m2) are not confounded by lean mass.  The objective is to determine the prevalence of sarcopenia, relative sarcopenia, and obesity in CKD, and determine if CKD is associated with relative sarcopenia and obesity, independent of demographics and comorbidities. Methods:  DXA-derived appendicular lean mass index (ALMI, kg/m2) and FMI were assessed in 13,980 NHANES participants. ALMI, FMI, and ALMI relative to FMI (ALMI FMI) were expressed as sex- and race/ethnicity-specific standard deviation scores compared with young adults (T-scores) and by age (Z-scores). Sarcopenia was defined as ALMI T-score < -2, relative sarcopenia as ALMI FMI T-score < -2, and low lean mass relative to fat mass for age as ALMI FMI Z-score < -1.  Obesity was defined using conventional BMI and %BF cutpoints and as sex- and race/ethnicity-specific FMI cutpoints. Glomerular filtration rate (GFR) was estimated using creatinine- (eGFR Cr) and cystatin C- (eGFR Cys).Results: The prevalence of relative sarcopenia was higher than the prevalence of sarcopenia, especially in CKD stages 3b and 4 using eGFR Cr; these CKD stages were associated with the highest FMI. CKD stage was independently associated with low ALMI FMI for age using eGFR Cys. BMI underestimated and %BF overestimated the prevalence of obesity compared with FMI. CKD was not independently associated with obesity by FMI.Conclusions: In CKD, conventional definitions of sarcopenia underestimate muscle deficits and %BF overestimates the prevalence of obesity. CKD is independently associated with relative sarcopenia, but not excess adiposity.

Mid-arm muscle circumference as a substantial factor against mortality among people with elevated gamma gaps

Gamma gap is the difference in total serum proteins and albumin and an elevated gamma gap is related to infections, malignancy, and rheumatic diseases. An elevated gamma gap is also associated with higher mortality due to the correlation with inflammatory status. The study aimed to utilize mid-arm muscle circumference (MAMC) to assist in predicting all-cause mortality, cancer mortality, and cardiovascular mortality in people with elevated gamma gaps. Data were obtained from the third U.S. National Health and Nutrition Examination Survey (1988–1994), which contained 14,011 adults aged 20 to 90 years during up to 14.3 years of follow-up. The Primary analysis examined MAMC in tertiles and revealed the demographic and characteristics of the study population. Receiver operating characteristic curve analysis was used and the most suitable cut-off point of gamma gap was 3.65 g/dl. The secondary analysis employed Cox proportional hazards models stratified by age, gender and body mass index to evaluate the hazard ratios for all-cause mortality, cancer mortality, and cardiovascular mortality associated with the MAMC. As the MAMC tertiles increased in group with gamma gap ≥ 3.65 g/dl, individuals with elder age (60–90 years), normal range of body mass index (19–24.9 kg/m²), and male gender tended to have lower hazard ratios for all-cause mortality, cancer mortality, and cardiovascular mortality. These substantial findings indicate that higher MAMC may be a protective factor of all cause-mortality, cancer mortality, and cardiovascular mortality among older male with normal body mass index and elevated gamma gaps.

Mid-arm muscle circumference as a surrogate in predicting insulin resistance in non-obese elderly individuals

The homeostatic model assessment of insulin resistance (HOMA-IR) was used to measure the degree of insulin resistance (IR). Previous literature revealed that mid-arm muscle circumference (MAMC) is one of the anthropometric indicators for nutritional status and the relationship between MAMC and HOMA-IR remains uncertain in the obese and non-obese elderly individuals. The present study included 5,607 participants aged between 60 to 84 years old, using data from the 1999 to 2006 National Health and Nutrition Examination Survey (NHANES). To further explore the association between HOMA-IR and MAMC in the obese and non-obese elderly population using multivariate Cox regression analyses, we divided the participants into obese (BMI ≥ 30 kg/m²) group and non-obese (19 ≤ BMI < 30 kg/m²) group in this study; each group was then divided into quartiles based on their MAMC levels. A positive association was noted between the MAMC and HOMA-IR in all of the designed models initially. After adjusting for multiple covariates, a higher level of the MAMC was significantly associated with elevated HOMA-IR (P < 0.05) in the non-obesity group, which was not the case in the obesity group. Additionally, subjects in the higher quartiles of MAMC tended to have higher HOMA-IR with a significant association (P for trend = 0.003 in model 1; P for trend < 0.001 in model 2, 3, and 4). These results demonstrated that the MAMC can be an auxiliary indicator of HOMA-IR in non-obese elderly individuals and may have substantial additional value in screening for IR if well extrapolated.

Associations of Body Mass Index and Body Fat With Markers of Inflammation and Nutrition Among Patients Receiving Hemodialysis

BACKGROUND

Understanding the extent to which visceral and subcutaneous body fat are associated with markers of nutrition and inflammation in patients on dialysis therapy could shed light on the obesity paradox and the biology of subcutaneous fat.

STUDY DESIGN

Cross-sectional.

SETTING & PARTICIPANTS

609 adults receiving hemodialysis who participated in the ACTIVE/ADIPOSE Study.

PREDICTORS

Body mass index (BMI), waist circumference, and bioelectrical impedance spectroscopy-derived estimates of percent body fat.

OUTCOMES

C-Reactive protein (CRP), interleukin 6 (IL-6), prealbumin, albumin, leptin, and adiponectin concentrations.

MEASUREMENTS

We performed linear regression analyses to examine the extent to which proxies of visceral and subcutaneous fat were associated with inflammation, nutrition, and adiposity-related hormones.

RESULTS

BMI was directly associated with markers of inflammation (standardized estimate for ln[CRP in mg/L]: 0.30 [95% CI, 0.22-0.38] per 10kg/m²; for ln[IL-6 in pg/mL]: 0.10 [95% CI, 0.02-0.18] per 10kg/m²), but was not associated with markers of nutrition. BMI was also inversely associated with adiponectin and directly associated with leptin. With waist circumference and percent body fat (as a proxy of visceral and subcutaneous fat, respectively) modeled together, waist circumference was associated with markers of inflammation (standardized estimate for ln[CRP in mg/L]: 0.21 [95% CI, 0.09-0.34] per 10cm; for ln[IL-6 in pg/mL]: 0.18 [95% CI, 0.07-0.29] per 10cm), whereas percent body fat was not associated with CRP (standardized estimate for ln[CRP in mg/L]: 0.03 [95% CI, -0.10 to 0.15] per 1%) and was inversely associated with IL-6 (standardized estimate for ln[IL-6 in pg/mL]: -0.15 [95% CI, -0.27 to -0.02] per 1%). In addition, waist circumference was inversely associated with prealbumin and albumin (standardized estimates of -0.12 [95% CI, -0.23 to -0.02] mg/dL per 10cm and -0.17 [95% CI, -0.28 to -0.06] g/dL per 10cm, respectively), and percent body fat was directly associated with prealbumin and albumin (0.20 [95% CI, 0.07-0.32] mg/dL and 0.15 [95% CI, 0.02-0.28] g/dL per 1%, respectively). Higher waist circumference was associated indirectly with adiponectin and directly with leptin concentrations.

LIMITATIONS

Although the observed associations implicate visceral fat as the cause of inflammation, it cannot be determined in this cross-sectional study.

CONCLUSIONS

Proxies of visceral and subcutaneous fat appear to have opposing associations with biomarkers of inflammation and nutrition. Subcutaneous fat may be an indicator of nutritional status, and visceral fat, an indicator of inflammation.

Obesity and kidney disease: Hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long-term. The incidence of obesity-related glomerulopathy has increased tenfold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle, and health policy measures that makes preventive behaviors an affordable option.

Thyroid Status and Mortality in a Prospective Hemodialysis Cohort

CONTEXT AND OBJECTIVE

Compared with the general population, hemodialysis patients have a substantially higher risk of hypothyroidism, as defined by an elevated serum thyrotropin (TSH) level, and cardiovascular mortality. Whereas an elevated TSH is associated with cardiovascular disease and death in the general population, associations among dialysis patients have been inconsistent.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

We examined 541 hemodialysis patients from 17 southern California dialysis centers in the prospective Hypothyroidism, Cardiovascular Health, and Survival study who underwent protocolized measurement of repeated serum TSH levels every 6 months from 2013 to 2015. Associations between TSH tertiles (<1.28, 1.28 to <2.14, and 2.14 to 86.7 mIU/L) and mortality were estimated using time-dependent Cox models with four adjustment levels. In sensitivity analyses, we excluded patients receiving thyroid hormone supplementation.

RESULTS

Compared with the lowest TSH tertile, the highest TSH tertile was associated with a 2.2- to 2.5-fold higher mortality risk in unadjusted, case-mix, expanded case-mix+laboratory, and expanded case-mix+laboratory+medication models [hazard ratios (95% confidence interval), 2.54 (1.32 to 4.89), 2.53 (1.30 to 4.93), 2.19 (1.11 to 4.32), and 2.28 (1.45 to 3.58), respectively]. We observed a consistent trend between higher TSH tertiles and numerically higher mortality risk across all models. Similar findings were observed in analyses excluding patients receiving thyroid hormone supplementation.

CONCLUSION

In time-dependent analyses, TSH levels in the high-normal to high range were independently associated with higher death risk in hemodialysis patients. Further studies are indicated to determine whether normalization of TSH levels with thyroid hormone supplementation improves survival in this population.

Obesity and listing for renal transplantation: weighing the evidence for a growing problem

A 56-year-old female patient was referred to the transplant assessment clinic in July 2016. She started haemodialysis in 2012 for renal failure due to urinary tract infections. She is doing very well on dialysis and has an excellent exercise tolerance without shortness of breath or angina. She has had no infections since starting dialysis and no other comorbidity, except well-controlled hypertension and hyperparathyroidism requiring treatment with cinacalcet. Clinical examination is essentially normal except for truncal obesity with height 167 cm and weight 121 kg, giving her a body mass index of 43.4. Can she be listed for a renal transplant? If not, which target weight should be given to the patient before she can be transplant listed? Which interventions, if any, should be recommended to achieve weight loss?

Associations of Dietary Protein and Energy Intakes With Protein-Energy Wasting Syndrome in Hemodialysis Patients

Introduction

The associations of dietary protein and/or energy intakes with protein or energy wasting in patients on maintenance hemodialysis are controversial. We examined these in the Hemodialysis (HEMO) Study.

Methods

In 1487 participants in the HEMO Study, baseline dietary protein intake (grams per kilogram per day) and dietary energy intake (kilocalories per kilograms per day) were related to the presence of the protein-energy wasting (PEW) syndrome at month 12 (defined as the presence of at least 1 criteria in 2 of the 3 categories of low serum chemistry, low body mass, and low muscle mass) in logistic regression models. In additional separate models, protein intake estimated from equilibrated normalized protein catabolic rate (enPCR) was also related to the PEW syndrome.

Results

Compared with the lowest quartile, the highest quartile of baseline dietary protein intake was paradoxically associated with increased risk of the PEW syndrome at month 12 (odds ratio [OR]: 4.11; 95% confidence interval [CI]: 2.79-6.05). This relationship was completely attenuated (OR: 1.35; 95% CI: 0.88-2.06) with adjustment for baseline body weight, which suggested mathematical coupling. Results were similar for dietary energy intake. Compared with the lowest quartile of baseline enPCR, the highest quartile was not associated with the PEW syndrome at 12 months (OR: 0.78; 95% CI: 0.54-1.12).

Discussion

These data do not support the use of dietary protein intake or dietary energy intake criteria in the definition of the PEW syndrome in patients on maintenance hemodialysis.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long-term. The incidence of obesity-related glomerulopathy has increased ten-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day will promote education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Sarcopenia and its individual criteria are associated, in part, with mortality among patients on hemodialysis

The relative importance of sarcopenia and its individual components as independent predictors of mortality in the dialysis population has not been determined. We estimated whole-body muscle mass using pre-dialysis bioimpedance spectroscopy measurements in 645 ACTIVE/ADIPOSE-enrolled prevalent hemodialysis patients from San Francisco and Atlanta. Low muscle mass was defined as two standard deviations below sex-specific means for young adults from NHANES and indexed to height², body weight, body surface area, or body mass index. We evaluated the association of sarcopenia (low muscle mass) by four indexing methods, weak hand grip strength, and slow gait speed with mortality. Seventy-eight deaths were observed during a mean follow-up of 1.9 years. Sarcopenia was not significantly associated with mortality after adjusting for covariates. No muscle mass criteria were associated with death, regardless of indexing metrics. In contrast, having weak grip strength or slow walking speed was associated with mortality in the adjusted model. Only gait slowness significantly improved the predictive accuracy for death with an increase in C-statistic from 0.63 to 0.68. However, both gait slowness and hand grip weakness significantly improved the net reclassification index compared to models without performance measures (50.5% for slowness and 33.7% for weakness), whereas models with muscle size did not. Neither sarcopenia nor low muscle mass by itself was a better predictor of mortality than functional limitation alone in patients receiving hemodialysis. Thus, physical performance measures, including slow gait speed and weak hand grip strength, were associated with mortality even after adjustment for muscle size and other confounders.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

The Obesity Paradox in Kidney Disease: How to Reconcile it with Obesity Management

Obesity, a risk factor for de novo chronic kidney disease (CKD), confers survival advantages in advanced CKD. This so-called obesity paradox is the archetype of the reverse epidemiology of cardiovascular risks, in addition to the lipid, blood pressure, adiponectin, homocysteine, and uric acid paradoxes. These paradoxical phenomena are in sharp contradistinction to the known epidemiology of cardiovascular risks in the general population. In addition to advanced CKD, the obesity paradox has also been observed in heart failure, chronic obstructive lung disease, liver cirrhosis, and metastatic cancer, as well as in the elderly. These are populations in whom protein-energy wasting and inflammation are strong predictors of early death. Both larger muscle mass and higher body fat provide longevity in these patients, whereas thinner body habitus and weight loss are associated with higher mortality. Muscle mass appears to be superior to body fat in conferring an even greater survival. The obesity paradox may be the result of a time discrepancy between competing risk factors, i.e., overnutrition as the long-term killer versus undernutrition as the short-term killer. Hemodynamic stability of obesity, lipoprotein defense against circulating endotoxins, protective cytokine profiles, toxin sequestration of fat mass, and antioxidation of muscle may play important roles. Despite claims that obesity paradox is a statistical fallacy and a result of residual confounding, the consistency of data and other causality clues suggest a high biologic plausibility. Examining the causes and consequences of the obesity paradox may help discover important pathophysiologic mechanisms leading to improved outcomes in patients with CKD.

Mid-arm muscle circumference as a significant predictor of all-cause mortality in male individuals

BACKGROUND

Emerging evidences indicate that mid-arm muscle circumference (MAMC) is one of the anthropometric indicators that reflect health and nutritional status, but its correlative effectiveness in all-cause mortality prediction of United States individuals remains uncertain.

METHODS AND FINDINGS DESIGN

We investigated the joint association between MAMC and all-cause mortality in the US general population. A population-based longitudinal study of 6,769 participants aged 40 to 90 years in the third National Health and Nutrition Examination Survey (NHANES III) conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. All participants were divided into two groups based on the gender: male and female group; each group was then divided into three subgroups depending on their MAMC level. The tertiles were as follows: T1 (18<27.3), T2 (27.3<29.6), T3 (29.6≤40.0) cm in the male group and T1 (15<22.3), T2 (22.3<24.6), T3 (24.6≤44.0) cm in the female group. Multivariable Cox regression analyses and Kaplan-Meier survival probabilities were utilized to jointly relate all-cause mortality risk to different MAMC level. For all-cause mortality in male participants, multivariable adjusted hazard ratios (HRs) were 0.83 (95% confidence interval (CI): 0.69-0.98; p = 0.033) for MAMC of 27.3-29.6 cm compared with 18-27.3 cm, and 0.76 (95% CI: 0.61-0.95; p = 0.018) for MAMC of 29.6-40 cm compared with 18-27.3 cm. For all-cause mortality in female participants, multivariable adjusted hazard ratios (HRs) were 0.84 (95% confidence interval (CI): 0.69-1.02; p = 0.075) for MAMC of 22.3-24.6 cm compared with 15-22.3 cm, and 0.94 (95% CI: 0.75-1.17; p = 0.583) for MAMC of 24.6-44 cm compared with 15-22.3 cm.

CONCLUSION

Results support a lower MAMC is associated with a higher mortality risk in male individuals.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease. A high body mass index is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease. A high body mass index is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Abdominal lean muscle is associated with lower mortality among kidney waitlist candidates

Morphometric assessments, such as muscle density and body fat distribution, have emerged as strong predictors of cardiovascular risk and postoperative morbidity and mortality. To date, no study has examined morphometric mortality risk prediction among kidney transplant (KT) candidates. KT candidates, waitlisted 2008-2009, were identified (n=96) and followed to the earliest of transplant, death, or administrative end of study. Morphometric measures, including abdominal adipose tissue, paraspinous and psoas muscle composition, and aortic calcification, were measured from CTs. Risk of waitlist mortality was examined using Cox proportional hazard regression. On adjusted analyses, radiologic measures remained independently and significantly associated with lower waitlist mortality; the addition of radiologic measures significantly improved model predictive ability over models containing traditional risk factors alone (net reclassification index: 0.56, 95% CI: 0.31-0.75). Higher psoas muscle attenuation (indicative of leaner muscle) was associated with decreased risk of death (aHR: 0.93, 95% CI: 0.91-0.96, P<.001), and for each unit increase in lean paraspinous volume, there was an associated 2% decreased risk for death (aHR: 0.98, 95% CI: 0.96-0.99, P=.03). Radiologic measures of lean muscle mass, such as psoas muscle attenuation and paraspinous lean volume, may improve waitlist mortality risk prediction and candidate selection.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease. A high BMI is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased tenfold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease. A high body mass index is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyles and health policy measures that make preventive behaviors an affordable option.

Concurrence of Serum Creatinine and Albumin With Lower Risk for Death in Twice-Weekly Hemodialysis Patients

OBJECTIVE

Markers of better nutritional status including both higher levels of serum albumin (as a measure of visceral proteins) and creatinine (as a measure of the muscle mass) are associated with lower mortality in conventional (thrice weekly) hemodialysis patients. However, data for these associations in twice-weekly hemodialysis patients, in whom less frequent hemodialysis may confound nutritional predictors, are lacking.

DESIGN AND SUBJECTS

We identified 1,113 twice-weekly and matched 4,448 thrice-weekly hemodialysis patients from a large national dialysis cohort of incident hemodialysis patients over 5 years (2007-2011). Mortality risk, adjusted for potential confounders, was examined across two-by-two combinations of serum creatinine (<6 vs. ≥6 mg/dL) and albumin (<3.5 g/dL vs. ≥3.5 g/dL) for each treatment frequency yielding a total of 8 groups.

RESULTS

Patients were aged 70 ± 14 years and included 48% women and 55% diabetics. Using the thrice-weekly hemodialysis patients with creatinine ≥ 6 mg/dL and albumin ≥ 3.5 g/dL as reference, patients with creatinine <6 mg/dL and albumin <3.5 g/dL had a 1.8-fold higher risk of mortality (hazard ratio: 1.75, 95% confidence interval: 1.33-2.30) in twice-weekly and 2.2-fold increased risk of mortality (hazard ratio: 2.21, 95% confidence interval: 1.81-2.70) in thrice-weekly hemodialysis patients, respectively in fully adjusted models adjusted for demographics, comorbidities, and markers of malnutrition and inflammation. A test for interaction showed that there was no significant difference in albumin creatinine mortality associations between twice-weekly and thrice-weekly hemodialysis patients (P-for-interaction = .7667).

CONCLUSIONS

Surrogate markers of higher visceral protein and muscle mass combined may confer greatest survival in both twice-weekly and thrice-weekly hemodialysis patients.

Prevalence and predictors of low muscle mass in HIV/viral hepatitis coinfection

OBJECTIVE

Low muscle mass is associated with reduced survival in HIV, possibly mediated by systemic inflammation. Viral hepatitis coinfection can induce additional inflammation and hepatic dysfunction that may exacerbate low muscle mass. We determined the prevalence of and risk factors for low muscle mass in HIV/viral hepatitis coinfection.

DESIGN AND METHODS

A cross-sectional study of participants in the Multicenter AIDS Cohort Study and Women's Interagency HIV Study with anthropometry performed after 1 January 2000. Viral hepatitis defined by positive hepatitis B virus surface antigen and/or hepatitis C virus RNA. Low muscle mass defined as less than 10th percentile of age-matched and sex-matched reference values for mid-upper arm circumference. Using multivariable logistic regression, we determined adjusted odds ratios with 95% confidence intervals (CIs) of the association of HIV/viral hepatitis coinfection with low muscle mass and factors associated with low muscle mass in coinfected persons. Analyses adjusted for age, race, BMI, alcohol use, and IDU (also, nadir CD4 cell count and HIV RNA where appropriate).

RESULTS

Among 3518 participants (164 HIV/viral hepatitis, 223 viral hepatitis alone, 1070 HIV alone, and 2061 uninfected), HIV/viral hepatitis-coinfected persons had a 3.50-fold (95% CI, 1.51-8.09), 1.93-fold (1.17-3.20), and 2.65-fold (1.62-4.35) higher odds of low muscle mass than viral hepatitis-monoinfected, HIV-monoinfected, and uninfected persons, respectively. Lack of HIV RNA suppression [odds ratio, 2.26 (95% CI, 1.10-4.63)] was the only factor associated with low muscle mass in coinfected persons.

CONCLUSION

HIV/viral hepatitis-coinfected persons have a higher likelihood of low muscle mass than those with viral hepatitis monoinfection, HIV monoinfection, or neither infection. HIV viremia is an important risk factor for low muscle mass among coinfected persons.

From chronic kidney disease to kidney transplantation: The impact of obesity and its treatment modalities

Obesity is associated with worse short-term outcomes after kidney transplantation but the effect on long-term outcomes is unknown. Although some studies have reported worse outcomes for obese recipients when compared to recipients with a BMI in the normal range, obese recipients who receive a transplant have better outcomes than those who remain wait-listed. Whether transplant candidates should be advised to lose weight before or after transplant has been debated and this is mainly due to the gap in the literature linking pre-transplant weight loss with better outcomes post-transplantation. The issue is further complicated by the use of BMI as a metric of body fat, the obesity paradox in dialysis patients and the different ethical viewpoints of utility versus equity. Measures used to reduce weight loss, including orlistat and bariatric surgery (in particular those with a malabsorptive component), have been associated with enteric hyperoxaluria with consequent risk of nephrolithiasis and oxalate nephropathy. In this review, we discuss the evidence regarding the use of weight loss measures in the kidney transplant candidate and recipient with a view to recommending whether weight loss should be pursued before or after kidney transplantation.

Screening for muscle wasting and dysfunction in patients with chronic kidney disease

Skeletal muscle mass and muscle function are negatively affected by a variety of conditions inherent to chronic kidney disease (CKD) and to dialysis treatment. Skeletal muscle mass and function serve as indicators of the nutritional and clinical state of CKD patients, and low values or derangements over time are strong predictors of poor patient outcomes. However, muscle size and function can be affected by different factors, may decline at different rates, and may have different patient implications. Therefore, operational definitions of frailty and sarcopenia have emerged to encompass these 2 dimensions of muscle health, i.e., size and functionality. The aim of this review is to appraise available methods for assessment of muscle mass and functionality, with an emphasis on their accuracy in the setting of CKD patients. We then discuss the selection of reference cutoffs for defining conditions of muscle wasting and dysfunction. Finally, we review definitions applied in studies addressing sarcopenia and frailty in CKD patients and discuss their applicability for diagnosis and monitoring.

Handgrip strength is an independent predictor of all-cause mortality in maintenance dialysis patients

BACKGROUND & AIMS

Muscle wasting is associated with mortality in dialysis patients. The measurement of muscle mass has some limitations, while muscle strength assessment is simple, safe and allows the recognition of patients at risk of progressing to poor outcomes related to malnutrition. The aim of this study is verify if handgrip strength (HGS) is associated with all-cause mortality in patients in maintenance haemodialysis (HD) and peritoneal dialysis (PD).

METHODS

This was an observational retrospective cohort study which included all patients in maintenance HD and PD from July 2012 to October 2014. Patients were followed-up until June 2015.

RESULTS

Two-hundred sixty five patients were enrolled (218 HD and 47 PD) and they were followed for 13.4 ± 7.9 months. During the follow-up period, 53 patients (20%) have died, 36 patients (13.6%) have undergone renal transplantation, 13 patients (4.9%) have switched off dialysis method and 5 patients (1.9%) have transferred to another facility. The cut-off of HGS able to predict mortality was 22.5 kg for men and 7 kg for women. Using this cut-off to fit the Kaplan-Meier survival curve, the association of HGS with all-cause mortality for both genders was confirmed. Finally, in the multivariate analysis adjusted for demographic, clinical and nutritional variables, HGS remained significant predictor of mortality, independent of dialysis modality.

CONCLUSIONS

HGS cut-offs that predict mortality were 22.5 kg for men and 7 kg for women. HGS was associated with mortality independent of dialysis modality.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease. A high body mass index is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=458481.

Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis

BACKGROUND

The inverse association between body mass index (BMI) and mortality observed in patients treated with maintenance hemodialysis (MHD), also known as the obesity paradox, may be a result of residual confounding. Marginal structural model (MSM) analysis, a technique that accounts for time-varying confounders, may be more appropriate to investigate this association. We hypothesize that after applying MSM, the inverse association between BMI and mortality in MHD patients is attenuated.

METHODS

We examined the associations between BMI and all-cause mortality among 123 624 adult MHD patients treated during 2001-6. We examined baseline and time-varying BMI using Cox proportional hazards models and MSM while considering baseline and time-varying covariates, including demographics, comorbidities and markers of malnutrition and inflammation.

RESULTS

The patients included 45% women and 32% African Americans with a mean age of 61(SD 15) years. In all models, BMI showed a linear incremental inverse association with mortality. Compared with the reference (BMI 25 to <27.5 kg/m(2)), a BMI of <18 kg/m(2) was associated with a 3.2-fold higher death risk [hazard ratio (HR) 3.17 (95% CI 3.05-3.29)], and mortality risks declined with increasing BMI with the greatest survival advantage of 31% lower risk [HR 0.69 (95% CI 0.64-0.75)] observed with a BMI of 40 to <45 kg/m(2).

CONCLUSIONS

The linear inverse relationship between BMI and mortality is robust across models including MSM analyses that more completely account for time-varying confounders and biases.

Inflammation Modifies the Paradoxical Association between Body Mass Index and Mortality in Hemodialysis Patients

High body mass index (BMI) is paradoxically associated with better outcome in hemodialysis (HD) patients. Persistent inflammation commonly features in clinical conditions where the obesity paradox is described. We examined the relationship between BMI and mortality in HD patients, accounting for inflammation, in a historic cohort study of 5904 incident HD patients enrolled in 2007-2009 (312 facilities; 15 European countries) with ≥3 months of follow-up. Patients were classified by presence (n=3231) or absence (n=2673) of inflammation (C-reactive protein ≥10 mg/l and/or albumin ≤35 g/l). Patients were divided into quintiles by BMI (Q1-Q5: <21.5, 21.5-24.0, >24.0-26.4, >26.4-29.8, and >29.8 kg/m(2), respectively). Noninflamed patients in BMI Q5 formed the reference group. During a median follow-up period of 36.7 months, 1929 deaths occurred (822 cardiovascular), with 655 patients censored for renal transplantation and 1183 for loss to follow-up. Greater mortality was observed in inflamed patients (P<0.001). In fully adjusted time-dependent analyses, the all-cause mortality risk in noninflamed patients was higher only in the lowest BMI quintile (hazard ratio [HR, 1.80; 95% confidence interval [95% CI], 1.26 to 2.56). No protective effect was associated with higher BMI quintiles in noninflamed patients. Conversely, higher BMI associated with lower all-cause mortality risk in inflamed patients (HR [95% CI] for Q1: 5.63 [4.25 to 7.46]; Q2: 3.88 [2.91 to 5.17]; Q3: 2.89 [2.16 to 3.89]; Q4: 2.14 [1.59 to 2.90]; and Q5: 1.77 [1.30 to 2.40]). Thus, whereas a protective effect of high BMI was observed in inflamed patients, this effect was mitigated in noninflamed patients.

The Associations Between Body Cell Mass and Nutritional and Inflammatory Markers in Patients With Chronic Kidney Disease and in Subjects Without Kidney Disease

OBJECTIVES

Body cell mass (BCM), a component of lean tissue mass (LTM), is a metabolically active part of the body. Lean tissue loss is one of the diagnostic criteria of protein energy wasting. In patients with chronic kidney disease (CKD), a decrease of lean tissue, including BCM, may be replaced by an increase of extracellular water. Bioimpedance spectroscopy (BIS) enables the assessment of the amount of BCM, LTM, and fluid overload. The aim of our study was to assess the relationship between BCM measured by BIS and anthropometric measurements, biochemical markers of nutrition and also inflammatory markers.

METHODS

Forty-eight patients treated with hemodialysis (HD; 32 males and 16 females) with a mean age 59.8 ± 15.5 (HD group), 61 patients with CKD Stage 4 to 5 (35 males and 26 females) with a mean age of 60.1 ± 17.7 (predialysis group) and 33 individuals with normal renal function (18 males and 15 women) with a mean age 58.7 ± 17.0 (control group) were included. Body mass index, handgrip strength (HGS), body composition measured by BIS, and biochemical analyses were performed on all of them.

RESULTS

Positive correlations were observed between BCM and LTM, HGS, serum creatinine and insulin-like growth factor 1 concentrations in all groups. Serum prealbumin concentration correlated positively with BCM only in the predialysis group (r = 0.406; P = .001). The amount of lymphocytes also correlated passively with BCM in predialysis group (r = 0.314; P = .024). Negative correlations were noted between BCM and fat mass in all groups and between BCM and interleukin 6 concentrations only in the HD group. In this study, BCM neither correlated with body mass index and serum albumin nor with C-reactive protein.

CONCLUSIONS

BCM is strongly associated with biochemical determinants of muscle mass (serum creatinine, insulin-like growth factor 1) and muscle function (HGS) in patients treated with HD, with CKD Stage 4 to 5 and in individuals without kidney disease. Its significance requires further investigation.

Lean Body Mass and Survival in Hemodialysis Patients and the Roles of Race and Ethnicity

BACKGROUND

Lean body mass (LBM) represents the "fat-free" muscle mass in hemodialysis (HD) patients and is an important nutritional measure. Previous studies have found that both higher LBM and body mass index (BMI) were related to greater survival in HD patients. Additional studies have shown differences in survival across racial-ethnic groups of HD patients. However, the association of LBM and mortality across racial-ethnic subgroups has not been examined.

OBJECTIVE

We hypothesize that racial differences in LBM affect the mortality in HD patients.

SETTING AND SUBJECTS

Chronic HD patients from a large dialysis organization in the United States.

PREDICTORS

Estimated LBM (eLBM), self-identified racial subgroups.

MAIN OUTCOME MEASURE

5-year survival.

STUDY DESIGN

We examined the association between baseline eLBM and survival using Cox proportional hazard models adjusted for demographics, comorbidities, and laboratory measures. Associations were examined across subgroups of race-ethnicity (non-Hispanic white, African American, and Hispanic) and BMI.

RESULTS

The final cohort included 117,683 HD patients, who were 62 ± 15 (mean ± standard deviation) years old, 43% women and 59% with diabetes mellitus. Higher eLBM was linearly associated with lower mortality. Compared with the reference group (48.4-<50.5 kg), patients with the lowest eLBM (<41.3 kg) had a 1.4-fold higher risk of mortality (hazard ratio: 1.37; 95% confidence interval: 1.30-1.44) in the fully adjusted model. A similar linear association was seen among patients with BMI < 35 kg/m(2) and in non-Hispanic whites and African American subgroups. However, higher eLBM was not associated with improved survival in Hispanic patients or patients with BMI ≥ 35 kg/m(2).

LIMITATION

Potential residual confounding.

CONCLUSIONS

Higher eLBM is associated with a lower mortality risk in HD patients, especially among non-Hispanic white and African American groups. Hispanic patients do not demonstrate a similar inverse relationship. The association between LBM and mortality among different racial groups of HD patients deserves additional study.