Body fat mass and lean mass as predictors of survival in hemodialysis patients

Fat tissue quantity, waist circumference or waist-to-hip ratio in patients with chronic kidney disease: A systematic review and meta-analysis

The BMI predicts mortality and cardiovascular disease (CVD) in the general population, while in patients with end-stage chronic kidney disease (CKD) a high BMI is associated with improved survival, a phenomenon referred to as the "obesity paradox". While BMI is easy to determine and helps to categorize patients, it does not differentiate between fat tissue, lean tissue and bone mass. As the BMI may be altered in CKD, e.g. by muscle wasting, we determined in this meta-analysis (i) the association of mortality with fat tissue quantity in CKD and (ii) the association of mortality with abdominal obesity (as measured by waist circumference (WC) or waist-to-hip ratio (WHR)) in CKD. We systematically reviewed databases for prospective or retrospective cohort studies. In eleven studies with 23,523 patients the association between mortality and high fat tissue quantity in CKD was calculated. The pooled hazard ratio (HR) for this association in the CKD group in the dialysis group 0.91 (CI 0.84- 0.98, p = 0.01) which is comparable to the HR for the association with BMI. The HR in patients without dialysis was 0.7 (95% CI 0.53- 0.93, p = 0.01), suggesting a better risk prediction of high fat tissue content with mortality as compared to higher BMI with mortality in patients with CKD without dialysis. Importantly, both BMI and fat tissue quantity in CKD are described by the "obesity paradox": the higher the fat tissue content or BMI, the lower the mortality risk. In thirteen studies with 55,175 patients the association between mortality and high WC or WHR in CKD (with or without dialysis) was calculated. We observed, that the HR in the WHR group was 1.31 (CI 1.08-1.58, p = 0.007), whereas the overall hazard ratio of both groups was 1.09 (CI 1.01-1.18, p = 0.03), indicating that a higher abdominal obesity as measured by WHR is associated with higher mortality in CKD. Our analysis suggests gender-specific differences, which need larger study numbers for validation. This meta-analysis confirms the obesity paradox in CKD using fat tissue quantity as measure and further shows that using abdominal obesity measurements in the routine in obese CKD patients might allow better risk assessment than using BMI or fat tissue quantity. Comparable to the overall population, here, the higher the WHR, the higher the mortality risk.

Klotho and lean mass as novel cardiovascular risk factors in hemodialysis patients

Background

Patients with chronic kidney disease (CKD) present a higher risk of cardiovascular (CV) morbidity and mortality compared with the general population. While there are several well-established traditional CV risk factors, few studies have addressed novel potential risk factors such as α-Klotho, asymmetric dimethylarginine (ADMA) and lean mass.

Methods

This was an observational, prospective, single-center, cohort study that included prevalent hemodialysis (online hemodiafiltration) adult patients. By univariate logistic regression models, univariate and multivariate Cox proportional hazards models, and Kaplan-Meier analysis, we evaluated the association between the levels of α-Klotho, ADMA and lean mass, with the risk of peripheral vascular disease (PVD), CV events and all-cause mortality in these patients.

Results

A total of 200 HD patients was included. We found that increased levels of log-α-Klotho were significantly associated with decreased odds of both PVD [odds ratio (OR) 0.521, 95% confidence interval (CI) 0.270-0.954, P = .034] and CV events (OR 0.415, 95% CI 0.203-0.790, P = .01), whereas increased levels of log-ADMA were only significantly associated with increased odds of PVD (OR 13.482, 95% CI 5.055-41.606, P < .001). We also found that the levels of log-α-Klotho (HR 0.357, 95% CI 0.140-0.906, P < .05) and lean mass (HR 0.187, 95% CI 0.042-0.829, P < .05), but not log-ADMA, were significantly associated with the risk of all-cause mortality, even after adjusting for possible confounding variables.

Conclusions

Novel long-term clinical associations were generated that support α-Klotho and lean mass as novel CV risk factors in hemodialysis patients.

Obesity and Kidney Transplantation-How to Evaluate, What to Do, and Outcomes

Obesity is a growing issue that is spreading worldwide; its prevalence is ever increasing in patients with end-stage renal disease and represents a potential barrier to transplantation. The lack of unanimous guidelines exacerbates the current disparity in treatment, which can affect outcomes, leading to a significantly longer time on the waiting list. Multidisciplinary and multimodal management (encompassing several healthcare professionals such as nephrologists, transplant physicians and surgeons, primary care providers, and nurses) is of paramount importance for the optimal management of this patient population in a continuum from waitlisting to transplantation. Development of this guideline followed a standardized protocol for evidence review. In this review, we report on our clinical experience in transplantation of obese patients; strategies to manage this condition, including bariatric surgery, suitable timing for transplantation among this patient population, and clinical experience in robotic sleeve gastrectomy; and simultaneous robotic kidney transplantation to achieve optimal outcomes.

Sarcopenic Obesity Versus Nonobese Sarcopenia in Hemodialysis Patients: Differences in Nutritional Status, Quality of Life, and Clinical Outcomes

OBJECTIVE

Sarcopenia and sarcopenic obesity (SO) are linked to unfavorable prognosis in maintenance hemodialysis (MHD) populations. We tested whether nonobese sarcopenia and SO, as different stages of extreme protein-energy wasting, have different prognoses.

METHODS

In this prospective observational study, 261 MHD patients were recruited from October 2010 to April 2012 and followed until October 2020. Two definitions were used to diagnose sarcopenia: the European Working Group on Sarcopenia in Older People consensus and the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium criteria. Obesity was determined as the percentage of total body fat, ≥27% for men and ≥38% for women. Data for all-cause and cardiovascular morbidity and mortality, baseline nutrition markers, inflammation and oxidative stress, adipokines, body composition parameters, handgrip strength, and quality of life (QoL) scores were measured.

RESULTS

According to European Working Group on Sarcopenia in Older People, 115 (44.1%) patients were sarcopenic and 120 (46.0%) according to FNIH definitions. Of them, 28.4% and 34.5% were SO, respectively. Higher levels of albumin, creatinine, uric acid, leptin, phase angle, better nutritional scores, and lower adiponectin levels characterized SO patients compared with nonobese sarcopenic patients regardless of indexing method. Better QoL scores were noted in SO compared with nonobese sarcopenic patients using the FNIH sarcopenia criteria. The hazard of all-cause death, cardiovascular death, and first cardiovascular event for patients with SO was lower compared with the nonobese patients after multivariate adjustments. Statistical significance of these associations disappeared after including fat mass in multivariate models.

CONCLUSIONS

MHD patients with SO have better nutritional status and prognosis for cardiovascular events, all-cause and cardiovascular disease mortality, and possibly better QoL compared with nonobese sarcopenic MHD patients. The better prognosis appears to be entirely due to the excess fat, which is protective in sarcopenic MHD patients similar to that described in the entire MHD population.

Long-term weight loss as a predictor of mortality in haemodialysis patients

BACKGROUND

Serial weight decrease can be a prognostic predictor in chronic haemodialysis (HD) patients. We investigated the impact of long-term post-HD body weight (BW) changes on all-cause mortality among HD patients.

METHODS

This longitudinal cohort study and post-hoc analysis evaluated participants of a previous randomised controlled trial conducted between 2006 and 2011 who were followed up until 2018. Weight change slopes were generated with repeated measurements every 6 months during the trial for patients having ≥5 BW measurements. Participants were categorised into four groups based on quartiles of weight change slopes; the median weight changes per 6 months were -1.02 kg, -0.25 kg, +0.26 kg, and +0.86 kg. Cox proportional hazard regression was used to evaluate differences in subsequent survival among the four groups. BW trajectories were plotted with a backward time-scale and multilevel regression analysis to visualise the difference in BW trajectories between survivors and non-survivors.

RESULTS

Among the 461 patients, 404 were evaluated, and 168 (41.6%) died within a median follow-up period of 10.2 years. The Cox proportional hazard regression adjusted for covariates and baseline BW showed that a higher rate of weight loss was associated with higher mortality. The hazard ratios were 2.02 (1.28-3.20), 1.77 (1.10-2.85), 1.00 (reference), and 1.11 (0.67-1.83) for the first, second, third (reference), and fourth quartiles, respectively. BW trajectories revealed a significant decrease in BW in non-survivors.

CONCLUSIONS

Weight loss elucidated by serial BW measurements every 6 months is significantly associated with higher mortality among HD patients.

Comparison of appendicular lean mass indices for predicting physical performance in Korean hemodialysis patients: A cross-sectional study

ABSTRACT

Few studies have examined the optimal adjustment indices for predicting low muscle strength or physical performance in hemodialysis (HD) patients. Thus, the present study aimed to identify optimal adjustment indices for predicting strength and/or physical performance in HD patients.Our study was performed at an HD center (n = 84). Appendicular lean mass (ALM; kg) was calculated using dual-energy X-ray absorptiometry. ALM were adjusted to body weight, height2 (Ht2), body surface area, or body mass index. Physical performance tests (sit-to-stand test performed 5 times test, sit-to-stand for 30 second test, 6-minute walk test, timed up and go test, gait speed, hand grip strength, average steps per day (AST), and short physical performance battery) were also evaluated. Participants with a below median value for each physical performance test were defined as the low group.The mean participant age was 55.6 ± 12.8 years; 44 (52.4%) were men. The univariate analysis revealed a significant difference in ALM/Ht2 values between the low and normal physical performance group in all physical performance tests except short physical performance battery. The multivariate analysis revealed a significant difference in ALM/Ht2 between the low and normal physical performance groups in hand grip strength, 5 times sit-to-stand test, sit-to-stand for 30-second test, and AST. In women on HD, most indices were not associated with physical performance or strength.We demonstrated that, in men on HD, ALM/Ht2 may be the most valuable among various variables adjusted for ALM for predicting physical performance or strength.

A case of autosomal dominant polycystic kidney disease with amelioration of refractory cyst infections following prolonged hemodialysis time

Renal cyst infection is a frequent and serious problem in patients with autosomal dominant polycystic kidney disease (ADPKD). Cyst infection is often a refractory complication of treatment that leads to sepsis and death in patients with ADPKD. It was previously reported that a higher dose of dialysis demonstrated clearly better survival than shorten-time dialysis. The relationship between the frequency of cyst infection episodes in hemodialysis (HD) patients with ADPKD and the dialysis dose has not yet been fully elucidated. In this report, we describe a case of an HD patient with ADPKD that was provided elongation of HD time from 4-h twice weekly HD to 8-h thrice weekly nocturnal HD. As a result, the frequency of cyst infection episodes decreased from 10.0 to 1.5 days a month. Our findings suggest that prolonged HD time might contribute to amelioration of refractory cyst infections in patients with ADPKD.

Significance of Adipose Tissue Maintenance in Patients Undergoing Hemodialysis

In the general population, obesity is known to be associated with adverse outcomes, including mortality. In contrast, high body mass index (BMI) may provide a survival advantage for hemodialysis patients, which is known as the obesity paradox. Although BMI is the most commonly used measure for the assessment of obesity, it does not distinguish between fat and lean mass. Fat mass is considered to serve as an energy reserve against a catabolic condition, while the capacity to survive starvation is also thought to be dependent on its amount. Thus, fat mass is used as a nutritional marker. For example, improvement of nutritional status by nutritional intervention or initiation of hemodialysis is associated with an increase in fat mass. Several studies have shown that higher levels of fat mass were associated with better survival in hemodialysis patients. Based on body distribution, fat mass is classified into subcutaneous and visceral fat. Visceral fat is metabolically more active and associated with metabolic abnormalities and inflammation, and it is thus considered to be a risk factor for cardiovascular disease and mortality. On the other hand, subcutaneous fat has not been consistently linked to adverse phenomena and may reflect nutritional status as a type of energy storage. Visceral and subcutaneous adipose tissues have different metabolic and inflammatory characteristics and may have opposing influences on various outcomes, including mortality. Results showing an association between increased subcutaneous fat and better survival, along with other conditions, such as cancer or cirrhosis, in hemodialysis patients have been reported. This evidence suggests that fat mass distribution (i.e., visceral fat and subcutaneous fat) plays a more important role for these beneficial effects in hemodialysis patients.

Sex Difference in the Association between Physical Activity and All-Cause Mortality in Ambulatory Patients with Chronic Kidney Disease

(1) Background: The purpose of this article was to investigate the association between self-reported physical activity (PA) and all-cause mortality in ambulatory patients with chronic kidney disease (CKD), stage 4–5 including maintenance dialysis. (2) Methods: Ambulatory patients with CKD (eGFR < 30 mL/min/1.73 m²) with conservative treatment or chronic dialysis were included. PA was assessed using the Saltin–Grimby Physical Activity Level Scale. A Cox proportional hazards regression model––adjusted for age, sex, plasma–albumin, body mass index, socioeconomic status, and treatment––was applied. (3) Results: Participants (n = 374) were followed 39 ± 15 months from entry to death or censoring. Throughout the study period of 39 months, 156 deaths (42%) were registered. Regarding physical activity, 128 (34%) of the participants were inactive, 212 (57%) were moderately active, and 34 (9%) were highly or vigorously active. Moderate PA was associated with a decreased mortality risk in women (n = 150) compared to inactivity (HR 0.27 (0.15; 0.51), p < 0.001), whereas a high/vigorous level of PA was not significantly associated with mortality risk compared to inactivity. In men (n = 224), the associations between PA levels and mortality risk were not significant. (4) Conclusions: Moderate PA was associated with reduced all-cause mortality in ambulatory women with stage 4–5 CKD with or without maintenance dialysis treatment. Physical activity was not significantly associated with mortality in men.

Positive and Negative Aspects of Sodium Intake in Dialysis and Non-Dialysis CKD Patients

Sodium intake theoretically has dual effects on both non-dialysis chronic kidney disease (CKD) patients and dialysis patients. One negatively affects mortality by increasing proteinuria and blood pressure. The other positively affects mortality by ameliorating nutritional status through appetite induced by salt intake and the amount of food itself, which is proportional to the amount of salt under the same salty taste. Sodium restriction with enough water intake easily causes hyponatremia in CKD and dialysis patients. Moreover, the balance of these dual effects in dialysis patients is likely different from their balance in non-dialysis CKD patients because dialysis patients lose kidney function. Sodium intake is strongly related to water intake via the thirst center. Therefore, sodium intake is strongly related to extracellular fluid volume, blood pressure, appetite, nutritional status, and mortality. To decrease mortality in both non-dialysis and dialysis CKD patients, sodium restriction is an essential and important factor that can be changed by the patients themselves. However, under sodium restriction, it is important to maintain the balance of negative and positive effects from sodium intake not only in dialysis and non-dialysis CKD patients but also in the general population.

Body Composition Analysis as a Predictor of Prognosis for Patients With Acute Kidney Injury Requiring Kidney Replacement Therapy

OBJECTIVES

The aim of this study is to investigate the association between body composition, measured by bioelectrical impedance analysis, and outcomes in patients with acute kidney injury (AKI) receiving kidney replacement therapy (KRT).

METHODS

Patients with severe AKI treated with KRT in our hospital between September 2016 and August 2018 were enrolled. These patients were assessed by body composition analysis before KRT, and on the 3rd day and the 7th day after initiation of KRT. The predictors included lean tissue index (LTI), fat tissue index, and body cell mass index (BCMI). The association between all-cause mortality and predictors was analyzed using Cox regression.

RESULTS

A total of 152 patients were included in this study, with a 28-day mortality of 46.7% and 1-year mortality of 60.5%. LTI (adjusted hazard ratio per standard deviation: 0.37; 95% confidence interval = 0.21-0.66, P < .001) and BCMI (adjusted hazard ratio per standard deviation: 0.37; 95% confidence interval = 0.21-0.67, P < .001) on day 7 after initiation of KRT, rather than before KRT, were associated with mortality during follow-up. LTI and BCMI before KRT were associated with 28-day mortality rather than 1-year mortality.

CONCLUSIONS

LTI and BCMI before KRT were associated with short-term prognosis, and those on day 7 after KRT initiation were associated with intermediate mortality in patients with AKI requiring KRT.

The effect of different measurement modalities in the association of lean mass with mortality: A systematic review and meta-analysis

OBJECTIVES

Lean mass is commonly measured by 3 modalities, dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and computerized tomography (CT). CT is considered the most accurate, while lean mass measured by DXA and BIA often consists of non-muscle compartment, and hence considered less accurate when compared with CT. It remains unclear if the association of lean mass with mortality would differ using different measurement modalities.

METHODS

A systematic review and meta-analysis of lean mass and mortality was conducted. The analysis was stratified by different measurement modalities and health conditions. Pooled hazard ratios were estimated using a random effects model.

RESULTS

This meta-analysis included 188 studies with 98 468 participants. Reduced lean mass measured by BIA, DXA, and CT, was associated with increased risk of mortality with a hazard ratio (HR) of 1.35 (95% CI, 1.21-1.49), 1.18 (95% CI, 1.06-1.30), and 1.44 (95% CI, 1.32-1.57), respectively. Similarly, low lean mass defined by BIA-, DXA-, and CT-measurement was associated with increased risk of mortality, with an HR of 1.81 (95% CI, 1.56-2.10), 1.44 (95% CI, 1.29-1.60), and 1.78 (95% CI, 1.64-1.93).

CONCLUSIONS

Reduced and low lean mass were robustly associated with increased mortality in studies using different measurement modalities.

Systematic review and meta-analysis of lean mass and mortality: Rationale and study description

Objectives

Muscle mass is one of the key components in defining sarcopenia and is known to be important for locomotion and body homeostasis. Lean mass is commonly used as a surrogate of muscle mass and has been shown to be associated with increased mortality. However, the relationship of lean mass with mortality may be affected by different clinical conditions, modalities used, cut-off point to define low or normal lean mass, and even types of cancer among cancer patients. Thus, we aim to perform a comprehensive meta-analysis of lean mass with mortality by considering all these factors.

Methods

Systematic search was done in PubMed, Cochrane Library and Embase for articles related to lean mass and mortality. Lean mass measured by dual X-ray absorptiometry, bioelectrical impedance analysis, and computerized tomography were included.

Results

The number of relevant studies has increased continuously since 2002. A total of 188 studies with 98 468 people were included in the meta-analysis. The association of lean mass with mortality was most studied in cancer patients, followed by people with renal diseases, liver diseases, elderly, people with cardiovascular disease, lung diseases, and other diseases. The meta-analysis can be further conducted in subgroups based on measurement modalities, site of measurements, definition of low lean mass adopted, and types of cancer for studies conducted in cancer patients.

Conclusions

This series of meta-analysis provided insight and evidence on the relationship between lean mass and mortality in all directions, which may be useful for further study and guideline development.

Comparison of Body Composition Monitor and InBody 720 Bioimpedance Devices for Body Composition Estimation in Hemodialysis Patients and Healthy Controls

Bioelectric impedance devices have become a standard of care not only for peritoneal dialysis but also for hemodialysis patients. We compared the most important body composition variables (extracellular water, intracellular water, total body water and fat mass) measured with the multifrequency bioelectric impedance device InBody 720 (MF-BIA) and bioimpedance spectroscopy body composition monitor Fresenius (BIS BCM) in hemodialysis patients (n = 51, 175.1 + 7.8 cm, 82.2 + 15.2 kg) and healthy controls (n = 51, 175.1 + 7.6 cm, 82.3 + 15.3 kg). The MF-BIA InBody 720 device compared to the BIS BCM device showed significantly larger total body water and intracellular water estimates and significantly smaller extracellular water and body fat estimates in hemodialysis patients (p < 0.001). These differences (p < 0.001) were similar in the cohort of healthy controls; moreover, we observed high correlations in all variables between the hemodialysis patients and the healthy controls (0.80–0.95, p < 0.001). The mean relative differences in the order of 8% were lower for extracellular water and total body fat, but the limits of agreement were still wide enough to be clinically significant. We conclude that the results of the measurements with InBody 720 and BCM Fresenius cannot be used interchangeably. Physicians and nutritionists involved in the care of hemodialysis patients should be aware of this discrepancy between the two devices and should try to use the same device to track the body in their hemodialysis population in a longitudinal direction.

Effect of high bicarbonate hemodialysis solution on biochemical parameters and anthropometric indices

INTRODUCTION

Protein energy wasting is an adverse consequence of renal failure, which is correlated with increased mortality and morbidity. Metabolic acidosis has a major role in the development of protein energy wasting in hemodialysis patients. Every effort that could ameliorate this catabolic state would be beneficial to stabilize body composition. The aim of this study was to investigate the possible beneficial effects of high bicarbonate dialysis on anthropometric indices and biochemical parameters of nutrition.

METHODS

Fifty-six hemodialysis patients were randomly enrolled in two groups: an intervention group that underwent hemodialysis for 6 months with high bicarbonate dialysate concentration (36 mmol/L, N = 26) and a control group that underwent hemodialysis using a bicarbonate dialysate concentration of 30 mmol/L (N = 30). Biochemical parameters of nutrition and weight, body mass index (BMI), total body water, percent body fat, and other anthropometric indices were measured at the beginning and the end of the trial.

FINDINGS

At the end of the 6 month evaluation period, plasma levels of albumin, phosphorus, K, calcium, and bicarbonate showed no significant changes. Body weight and BMI increased significantly in high bicarbonate arm but did not change significantly in the control group. Percent body fat in the arms and legs did not change in intervention arm, but decreased significantly in the controls.

DISCUSSION

The results suggest that higher bicarbonate dialysis can have beneficial effects on nutritional status and might protect against loss of fat mass.

Comparison of Body Mass Index, Skinfold Thickness, and Bioelectrical Impedance Analysis With Dual-Energy X-Ray Absorptiometry in Hemodialysis Patients

BACKGROUND

Malnutrition is a consistent finding in hemodialysis (HD) patients and is associated with high mortality. The aim was to compare nutrition status indicators using dual-energy x-ray absorptiometry (DXA) as reference in HD patients.

METHODS

Observational cross-sectional study with 42 patients, 55.8 years (±14.6) old, 60% male, HD 2-3 times per week for ≥3 months. HD ranged from 3 months to 28 years (median, 17.3; interquartile range, 8.73-39.0). We used body mass index (BMI) and fat mass (FM) by skinfold thickness (SFT), bioelectrical impedance analysis (BIA), and DXA. Statistical analyses used Bland-Altman plots, Lin's concordance correlation coefficient, the paired t-test, and Pearson or Spearman correlation. P < .05 was significant.

RESULTS

SFT and DXA presented the lowest prevalence of malnutrition (2.4%) and BMI the highest (28.6%). BMI, BIA FM, and SFT FM presented strong positive correlations with DXA FM (r = 0.915; r = 0.976; r = 0.910, P < .001, respectively). BIA FM and fat-free mass (FFM) demonstrated substantial agreement with DXA values (ρ = 0.974 and 0.960, P < .001). Thus, the measurement procedures used, SFT and BIA, underestimated %FM (-4.65% and -2.13%) and overestimated FFM (3.12 kg and 1.0 kg) according to DXA. No differences were found between mean values of BIA FM and DXA (P = .178).

CONCLUSIONS

Compared with DXA, BIA was the most appropriate nutrition indicator for measuring body composition.

The Fate of Older Diabetic Patients on Peritoneal Dialysis: Myths and Mysteries and Suggestions for Further Research

The outcome of older and especially of female diabetic patients appears to be worse on peritoneal dialysis (PD) than on hemodialysis (HD). This opinion is based mostly on data coming from the USA, whereas data from other regions seem to give a more balanced picture. The questions arise whether indeed outcome is worse in this patient group, and what might be the underlying reasons for this; further research to unravel this phenomenon is warranted. This review proposes several suggestions for further exploration. The observed differences in outcome might be attributable to differences in treatment practices and experience with PD versus HD. As cardiovascular mortality is a major killer in end-stage renal disease patients, differences in fluid homeostasis and how it is achieved are potential explanations. Fluid balance is potentially more difficult to obtain in PD patients, especially as in the past it was spuriously suggested that fluid restriction was less important in PD patients. PD and HD might also have different impacts on factors related to inflammation, insulin resistance, and hormone balance. The adipocytokine network is of special interest in this respect. It is also possible that bias introduced by the way we measure body composition might have a more negative impact on PD than on HD patients. Finally, it still is not fully established that if diabetic patients are treated appropriately, their outcome on PD is worse than that on HD; further observational trials in this respect are needed. All these topics require further clarification and investigation.

Obesity in kidney transplantation

The prevalence of obesity among patients with chronic kidney disease continues to increase as a reflection of the trend observed in the general population. Factors affecting the access to the waiting list and the transplantability of this specific population will be analysed. From observational studies, kidney transplantation in obese patients carries an increased risk of surgical complications compared to the nonobese population; therefore, many centres have been reluctant to proceed with transplantation, despite this treatment modality confers a survival advantage over dialysis. As a consequence, obese patients continue to face decreased access to the waiting list, with a lower likelihood of being transplanted and higher waiting times when compared to the nonobese candidates. In this review will be described the current strategies for treatment of obesity in different settings (pretransplant, at transplant and post-transplant). Obesity represents a risk factor for surgical complications but not a contraindication for kidney transplantation; outcomes could be greatly improved with its multidisciplinary and multimodal treatment. The modern technology with minimally invasive techniques, mainly using robotic platform, allows a reduction in the surgical complications rate, with graft and patient survival rates comparable to the nonobese counterpart.

A North American Expert Opinion Statement on Sarcopenia in Liver Transplantation

Loss of muscle mass and function, or sarcopenia, is a common feature of cirrhosis and contributes significantly to morbidity and mortality in this population. Sarcopenia is a main indicator of adverse outcomes in this population, including poor quality of life, hepatic decompensation, mortality in patients with cirrhosis evaluated for liver transplantation (LT), longer hospital and intensive care unit stay, higher incidence of infection following LT, and higher overall health care cost. Although it is clear that muscle mass is an important predictor of LT outcomes, many questions remain, including the best modality for assessing muscle mass, the optimal cut-off values for sarcopenia, the ideal timing and frequency of muscle mass assessment, and how to best incorporate the concept of sarcopenia into clinical decision making. For these reasons, we assembled a group of experts to form the North American Working Group on Sarcopenia in Liver Transplantation to use evidence from the medical literature to address these outstanding questions regarding sarcopenia in LT. We believe sarcopenia assessment should be considered in all patients with cirrhosis evaluated for liver transplantation. Skeletal muscle index (SMI) assessed by computed tomography constitutes the best-studied technique for assessing sarcopenia in patients with cirrhosis. Cut-off values for sarcopenia, defined as SMI < 50 cm² /m² in male and < 39 cm² /m² in female patients, constitute the validated definition for sarcopenia in patients with cirrhosis. Conclusion: The management of sarcopenia requires a multipronged approach including nutrition, exercise, and additional pharmacological therapy as deemed necessary. Future studies should evaluate whether recovery of sarcopenia with nutritional management in combination with an exercise program is sustainable as well as how improvement in muscle mass might be associated with improvement in clinical outcomes.

Relative sarcopenia and mortality and the modifying effects of chronic kidney disease and adiposity

BACKGROUND

Conventional definitions of sarcopenia based on lean mass may fail to capture low lean mass relative to higher fat mass, that is, relative sarcopenia. The objective of this study is to determine the associations of sarcopenia and relative sarcopenia with mortality independent of co-morbidities, and whether chronic kidney disease (CKD) and adiposity alter these associations.

METHODS

Dual energy X-ray absorptiometry-derived appendicular lean mass index (ALMI, kg/m2 ) and fat mass index (FMI, kg/m2 ) were assessed in 14 850 National Health and Nutrition Examination Survey participants from 1999 to 2006 and were linked to death certificate data in the National Death Index with follow-up through 2011. Sarcopenia was defined using sex-specific and race/ethnicity-specific standard deviation scores compared with young adults (T-scores) as an ALMI T-score < -2 and relative sarcopenia as fat-adjusted ALMI (ALMIFMI ) T-score < -2. Glomerular filtration rate (GFR) was estimated using creatinine-based (eGFRCr ) and cystatin C-based (eGFRCys ) regression equations.

RESULTS

Three (3.0) per cent of National Health and Nutrition Examination Survey participants met criteria for sarcopenia and 8.7% met criteria for relative sarcopenia. Sarcopenia and relative sarcopenia were independently associated with mortality (HR sarcopenia 2.20, 95% CI 1.69 to 2.86; HR relative sarcopenia 1.60, 95% CI 1.31 to 1.96). The corresponding population attributable risks were 5.2% (95% CI 3.4% to 6.4%) and 8.4% (95% CI 4.8% to 11.2%), respectively. Relative sarcopenia remained significantly associated with mortality (HR 1.32, 95% CI 1.08 to 1.61) when limited to the subset who did not meet the criteria for sarcopenia. The risk of mortality associated with relative sarcopenia was attenuated among persons with higher FMI (P for interaction <0.01) and was not affected by CKD status for either sarcopenia or relative sarcopenia.

CONCLUSIONS

Sarcopenia and relative sarcopenia are significantly associated with mortality regardless of CKD status. Relative sarcopenia is nearly three-fold more prevalent amplifying its associated mortality risk at the population level. The association between relative sarcopenia and mortality is attenuated in persons with higher FMI.

Altered uric acid metabolism in isolated colonic Crohn's disease but not ulcerative colitis

BACKGROUND AND AIM

Patients with inflammatory bowel disease (IBD) have higher incidence of developing nephrolithiasis. Increased uric acid production induced by Saccharomyces cerevisiae exacerbates colitis in mice. We aimed to evaluate the association between serum uric acid level and disease activity in IBD population.

METHODS

Four hundred and thirty-five patients enrolled in Jinling Hospital from January 1, 2015 to August 31, 2017 were included in the retrospective study. Clinical parameters were collected and compared with non-IBD matched controls (n = 51). Serum uric acid to creatinine ratio (UA/Cr) was used as a biomarker for uric acid metabolism. Sixty-five active IBD patients were longitudinally studied to investigate the UA/Cr before and after therapy. Linear mixed models were estimated for Crohn's disease (CD) group to explore the relationship between UA/Cr and other parameters.

RESULTS

Uric acid to creatinine ratio was significantly correlated with Crohn's disease activity index (ρ = 0.184, P = 0.002) and Harvey Bradshaw index (ρ = 0.154, P = 0.010) and C-reactive protein (ρ = 0.591, P < 0.001) in CD group. Colonic CD and anti-Saccharomyces cerevisiae antibody (ASCA) positive CD had an increased UA/Cr compared with L1, L3, and ASCA negative CD (P = 0.027, P = 0.0013, and P = 0.043, respectively). A significant decrease in UA/Cr was observed after induction therapy in active CD (P = 0.0002) but not in ulcerative colitis (P = 0.076).

CONCLUSION

Uric acid to creatinine ratio correlated with disease activity in CD. Colonic CD and ASCA positive CD had an increased UA/Cr. Effective treatment for CD patients lowered UA/Cr. Uric acid metabolism might be a novel aspect to investigate disease activity of IBD.

Body composition is associated with clinical outcomes in patients with non-dialysis-dependent chronic kidney disease

An inverse relationship between body mass index (BMI) and mortality (the obesity paradox) has been found in patients with non-dialysis-dependent chronic kidney disease (CKD). However, it is unclear whether increased muscle mass or body fat confers the survival advantage. To resolve this we investigated the impact of body makeup on a composite outcome of death or cardiovascular events in a prospective cohort of 326 patients with stage 3-5 CKD not yet on dialysis. Lean mass and body fat were determined using the Body Composition Monitor, a multifrequency bioimpedance spectroscopy device, and were expressed as the lean tissue or fat tissue index, respectively. Patients were stratified as High (above median) or Low (below median) BMI, High or Low lean tissue index, or as High or Low fat tissue index. During a median follow-up of 4.6 years, there were 40 deaths and 68 cardiovascular events. In Cox proportional hazards models, a High lean tissue index, but not High BMI or High fat tissue index, predicted a lower risk of both the composite or its component outcomes (reference: below median). When patients were further stratified into four distinct body composition groups based on both the lean and fat tissue index, only the High lean/fat tissue index group had a significantly lower risk of the composite outcome (hazard ratio 0.36, 95% confidence interval 0.14-0.87; reference: Low lean/fat tissue index group). Thus, the lean tissue index can provide better risk prediction than the BMI alone in non-dialysis-dependent patients with CKD. The High lean/fat tissue index appears to be associated with best outcomes. An optimal body composition for improving the prognosis of CKD needs to be determined.

Paradoxical positive association of serum adiponectin with all-cause mortality based on body composition in Japanese haemodialysis patients

We have previously reported a paradoxical association of serum adiponectin with aortic calcification in haemodialysis patients. Because serum adiponectin is a nutritional marker, we examined the association between serum adiponectin and all-cause mortality based on body composition in haemodialysis patients. The trunk and total body fat were determined. The patients were divided into two groups based on serum adiponectin levels. In Kaplan–Meier analysis, the higher adiponectin group showed higher mortality than the lower adiponectin group. Serum adiponectin showed an inverse correlation with the percentage of truncal fat, suggesting serum adiponectin as an inverse marker for adiposity in haemodialysis patients. However, even after adjustment for other factors, multivariate Cox proportional hazards analysis identified higher serum adiponectin as an independent factor positively associated with higher mortality in haemodialysis patients. This association held true even when the total fat mass was replaced with the percentage of truncal fat, and when total fat mass and percentage of truncal fat were simultaneously included. Thus, we found a paradoxical association of higher serum adiponectin with higher all-cause mortality in Japanese haemodialysis patients, independent of adiposity.

Low lean tissue mass can be a predictor of one-year survival in hemodialysis patients

Purpose: Nutritional status has a significant impact on the outcomes in the dialysis population. The aim of this study was to evaluate the association between body composition and a one-year survival of hemodialysis patients.

Methods: Forty-eight patients with chronic kidney disease stage V treated with hemodialysis for more than three months were included. Body composition was assessed by bioimpedance spectroscopy (Body Composition Monitor, Fresenius Medical Care). Blood samples for serum creatinine, serum albumin, serum prealbumin, high sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6), insulin-like growth factor 1(IGF-1) concentrations were taken before the midweek dialysis session.

Results: Over the course of a one-year observation, seven patients died. We observed a significantly lower lean tissue index (LTI) (p = .013) and higher IL-6 (p = .032) and hsCRP levels (p = .011) among the patients who died. The remaining biochemical markers did not differ between these two groups. Kapplan–Meier analysis revealed a worse survival rate in patients with sarcopenia (lower than the 10th percentile for their age and gender) in comparison with those with normal LTI. However, it was not of statistical significance (p = .055). LTI inversely correlated with age and IL-6 and positively with IGF-1.

Conclusions: Sarcopenia defined as decreased LTI, is a relatively common condition among patients undergoing maintenance hemodialysis, it can also be associated with a lower one-year survival rate. Decreased lean tissue mass can be associated with old age, lower IGF-1 levels and higher IL-6 levels. Body composition assessment may provide prognostic data for hemodialysis patients.

Association between obesity with low muscle mass and dialysis mortality

BACKGROUND/AIM

To examine the association between body composition and dialysis mortality.

METHODS

Adult patients who underwent haemodialysis in Taoyuan General Hospital from 2012 to 2016 were enrolled. We reviewed their baseline characteristics and followed up their treatment over 5 years after dialysis. Patients with body mass index >25 kg/m² were defined as obese. High or low muscle mass were classified by skeletal muscle mass index (SMMI) based on consensus from Chinese population. All age-matched subjects were classified into four groups: (A) optimal; (B) obesity; (C) low muscle mass; and (D) obesity with low muscle mass. Adjusted hazard ratios for mortality and cumulative survival curves were evaluated by Cox proportional hazard model and Kaplan-Meier method. The discriminative power of SMMI was calculated according to the area under the curve and the receiver operating characteristic curve.

RESULTS

From a total of 176 age-matched patients, the incidence rates of mortality for different groups were 3.7, 7.8, 10.3 and 16.5 per 1000 person-months. After adjusting for continuous variables, SMMI was independently associated with mortality. The difference between groups A and D was more significant in women than in men after multivariate adjustment (adjusted hazard ratios: 7.465 vs 1.682) (P = 0.035 and 0.553). The discriminative power of SMMI to predict 5-year mortality was 0.700 for men and 0.750 for women, and the best cut-off values were 11.1 and 8.4 kg/m² CONCLUSIONS: Low muscle mass was associated with dialysis mortality. Obesity with low muscle mass was a predictor for dialysis mortality in women.

Body fat mass is correlated with serum transthyretin levels in maintenance hemodialysis patients

Serum transthyretin (TTR), also known as prealbumin, is a reliable nutritional indicator and an independent prognostic factor for maintenance hemodialysis patients. However, we recently reported that serum TTR levels did not affect protein-energy wasting (PEW). In this study, we investigated factors affecting serum TTR levels in 60 maintenance hemodialysis patients. The patients were divided into High-TTR and Low-TTR groups according to the median serum TTR level. Albumin levels were significantly higher and C-reactive protein (CRP) levels were significantly lower in the High-TTR group than in the Low-TTR group. Although body fat mass was significantly higher in the High-TTR group than in the Low-TTR group, no significant difference in body fat ratio were observed. These findings suggest that body fat mass is related to serum TTR levels, apart from factors such as albumin and CRP levels, which showed correlations with serum TTR levels. Because body fat mass is related to better survival in maintenance hemodialysis patients, it may contribute to the prognostic value of serum TTR levels. In addition, in such patients, it may be important to evaluate body fat mass rather than body fat ratio and to maintain the minimum necessary body fat mass. J. Med. Invest. 64: 222-227, August, 2017.

Diagnosis and prevalence of protein-energy wasting and its association with mortality in Japanese haemodialysis patients

AIM

The International Society of Renal Nutrition and Metabolism (ISRNM) has proposed the diagnostic criteria for protein-energy wasting (PEW). We studied Japanese haemodialysis (HD) patients to verify the diagnostic method, especially with respect to the body mass index (BMI) criterion, as well as the prevalence of PEW and its association with mortality.

METHODS

Japanese patients receiving maintenance HD at three outpatient clinics in Tokyo (n = 210) were enrolled, and prospectively followed-up for 3 years. PEW was diagnosed at baseline, according to the four categories (serum chemistry, body mass, muscle mass and dietary intake) recommended by the ISRNM. For the category of body mass, we select a body mass index (BMI) and set up three thresholds, <18.5, <20.0 and <23.0 kg/m² , as the diagnostic criterion. The patients who satisfied at least three out of the four categories were diagnosed as PEW.

RESULTS

Protein-energy wasting, when the threshold of a BMI among the diagnostic criteria was defined as <18.5 kg/m² , was recognized as an independent risk factor for mortality. However, PEW was not recognized as a risk factor when the BMI diagnostic criterion was set at <20.0 or <23.0 kg/m² . Overall, 14.8% of the patients had PEW. The survival rate of PEW patients was significantly lower than that of non-PEW patients (log rank, P < 0.001).

CONCLUSIONS

The diagnosis algorithm of PEW proposed by an expert panel of the ISRNM strongly associates with mortality. However, given differences in body size in Japan, we suggest to revise the BMI criterion from <23.0 kg/m² to <18.5 kg/m² .

Relationship between body mass index and renal function deterioration among the Taiwanese chronic kidney disease population

This study investigated the characteristics of patients with different chronic kidney disease (CKD) stages according to various body mass index (BMI) categories and determined the influence of BMI in renal function deterioration. We conducted a multicenter, longitudinal cohort study based on the Epidemiology and Risk Factors Surveillance of CKD project (2008–2013) and National Health Insurance Research Database (2001–2013). A total of 7357 patients with CKD aged 20–85 years from 14 hospitals were included in the study. A higher male sex, diabetes mellitus (DM) and hypertension were noted among overweight and obese CKD patients, while more cancer prevalence was noted among underweight CKD patients. Charlson comorbidity index was significantly higher and correlated with BMI among late CKD patients. Patients with BMI < 18.5 kg/m² exhibited non-significantly higher events of eGFR decline events in both early and late CKD stages than other BMI groups. BMI alone is not a determinant of CKD progression among our Taiwanese CKD patients. Obesity should be re-defined and body weight manipulation should be individualized in CKD patients.

Depressive symptoms but not chronic pain have an impact on the survival of patients undergoing maintenance hemodialysis

INTRODUCTION

More than 1/3 of patients with end-stage renal disease who are in a chronic dialysis program suffer from chronic pain and depression/anxiety. The aim of the study was to determine the impacts of symptoms of depression/anxiety, chronic pain and quality of life (QoL) on 6-year patient survival.

MATERIAL AND METHODS

Observational study of end-stage renal disease patients on maintenance hemodialysis (n = 205) who met the inclusion criteria. Patients from three dialysis centers in Lower Silesia were asked to complete a battery of validated questionnaires: the Hospital Anxiety and Depression Scale (HADS), the 36-item Short Form Health Survey Questionnaire, the Verbal Rating Scale (VRS) and the Visual Analog Scale (VAS). Clinical and biochemical data (dialysis adequacy) were recorded.

RESULTS

One hundred thirty from 205 enrolled hemodialysis patients (63.4%) suffered from chronic pain. Patients with pain were on maintenance dialysis for longer times and had higher levels of parathyroid hormone, more depressive symptoms and a lower QoL than those without pain. In the 6-year period, 96 (46.8%) patients died. The most common cause of death was cardiovascular disease in 44 (45.8%) patients. Highly depressed patients (HADS depression score > 8) exhibited higher mortality (< 8 vs. > 8 points; p = 0.016) independent of age, diabetes, cardiovascular disease, C-reactive protein or albumin level.

CONCLUSIONS

Chronic pain, although common among hemodialysis patients, did not lower survival. Depressive symptoms are an important predictor for all-cause mortality in hemodialysis patients, with the relationship independent of nutritional or inflammatory status.

Prognostic factors for mortality in middle-aged and older hemodialysis patients: a 5-year observational study

Clinical guidelines for hemodialysis therapy have been described in an evidence-based manner with most evidence from randomized control trials or retrospective studies in which all generations of the hemodialysis patients were enrolled. Therefore, the question still remains whether these guidelines can be applied to increasing older patients. This study is an observational study, including 735 patients who received maintenance hemodialysis in April 2006. At baseline, the participants' age was 62.1 ± 12.8 years (mean ± SD). Hemodialysis duration was 103.7 ± 89.3 months. In a 5-year observation period (actual follow-up period: 1551 ± 499 days), 175 patients died. Prognostic factors were investigated by multivariate analysis with Cox proportional hazard model. Next, we stratified the patients according to their age. 363 patients were included in the middle-aged patient's category between 40 and 64 years, and 314 were involved in the older patient's category between 65 and 84 years old. As a subanalysis, significant predictors of 5-year survival were examined in the age-stratified cohort. Then, Kt/V, serum β₂-microglobulin and calcium concentration were significant predictors in our entire cohort, as well as body mass index, neutrophil count, and serum sodium concentration even after adjustment for age, gender, diabetic status and hemodialysis duration. However, Kt/V, serum β₂-microglobulin and calcium concentration controlled by hemodialysis prescriptions were independent risk factors especially in older patients, not in middle-aged patients. In conclusion, hemodialysis prescriptions for lowering uremic toxins and managing mineral-bone disorder are important to decrease the risk of death even in older hemodialysis patients.

The association of serum adiponectin with abdominal aortic calcification in Japanese male hemodialysis patients: a cross-sectional observational study

The negative relation of serum adiponectin to atherosclerosis becomes a positive association in patients with chronic kidney disease (CKD). We conducted a small-scale cross-sectional observational study, in 101 Japanese male hemodialysis patients, to examine the relationship of serum adiponectin and leptin to abdominal aortic calcification (AAC). The presence of AAC was evaluated from simple X-ray radiographs of the left lateral abdomen. Serum adiponectin was significantly higher in AAC-positive patients [18.8 (13.0-28.1) μg/mL] than in AAC-negative patients [15.4 (8.9-22.8) μg/mL] (p = 0.03), whereas serum leptin did not differ significantly between the two groups. Multiple logistic regression analysis showed that log adiponectin, but not log leptin, was independently and significantly associated in a positive manner with AAC (odds ratio: 16.31, 95% confidence interval: 1.70-156.41, p = 0.02), after adjustment for age, body weight, percentage body fat, hemodialysis duration, prevalence of diabetes mellitus, and other risk factors. In conclusion, we found a positive and independent association of serum adiponectin with AAC in male hemodialysis patients, indicating that the reversed association between serum adiponectin and atherosclerosis in patients with CKD dose not result from increased serum adiponectin due to the impaired urinary secretion.

Evaluating Muscle Mass by Using Markers of Kidney Function: Development of the Sarcopenia Index

OBJECTIVES

Sarcopenia is associated with a poor prognosis in the ICU. The purpose of this study was to describe a simple sarcopenia index using routinely available renal biomarkers and evaluate its association with muscle mass and patient outcomes.

DESIGN

A retrospective cohort study.

SETTING

A tertiary-care medical center.

PATIENTS

High-risk adult ICU patients from October 2008 to December 2010.

INTERVENTIONS

The gold standard for muscle mass was quantified with the paraspinal muscle surface area at the L4 vertebrae in the subset of individuals with an abdominal CT scan. Using Pearson's correlation coefficient, serum creatinine-to-serum cystatin C ratio was found to be the best performer in the estimation of muscle mass. The relationship between sarcopenia index and hospital and 90-day mortality, and the length of mechanical ventilation was evaluated.

MEASUREMENTS AND MAIN RESULTS

Out of 226 enrolled patients, 123 (54%) were female, and 198 (87%) were white. Median (interquartile range) age, body mass index, and body surface area were 68 (57-77) years, 28 (24-34) kg/m, and 1.9 (1.7-2.2) m, respectively. The mean (± SD) Acute Physiology and Chronic Health Evaluation III was 70 (± 22). ICU, hospital, and 90-day mortality rates were 5%, 12%, and 20%, respectively. The correlation (r) between sarcopenia index and muscle mass was 0.62 and coefficient of determination (r) was 0.27 (p < 0.0001). After adjustment for Acute Physiology and Chronic Health Evaluation III, body surface area, and age, sarcopenia index was independently predictive of both hospital (p = 0.001) and 90-day mortality (p < 0.0001). Among the 131 patients on mechanical ventilator, the duration of mechanical ventilation was significantly lower on those with higher sarcopenia index (-1 d for each 10 unit of sarcopenia index [95% CI, -1.4 to -0.2; p = 0.006]).

CONCLUSIONS

The sarcopenia index is a fair measure for muscle mass estimation among ICU patients and can modestly predict hospital and 90-day mortality among patients who do not have acute kidney injury at the time of measurement.

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.

Hypophosphatemia: nutritional status, body composition, and mortality in hemodialysis patients

PURPOSE

The aim of the present study was to investigate the relationship between serum phosphate levels, clinical parameters, body composition, and mortality.

METHODS

Multicenter longitudinal observational study of a cohort of 3552 patients in hemodialysis (HD) from 34 Nephrocare dialysis units in Portugal with 24 months of follow-up. Patients were divided into three groups depending on their serum phosphorus (<3.5; 3.5-5.5; >5.5 mg/dL). Statistical tests were performed with SPSS, version 20.0. A p < 0.05 was considered significant.

RESULTS

On the one hand, hypophosphatemia was significantly associated with better dialysis adequacy, higher age and overhydration. On the other hand, it was associated with lower albumin, protein intake, creatinine, hemoglobin, calcium, potassium, magnesium, body mass index (BMI), body cell mass index, fat tissue index and lean tissue index. These patients had lower survival rates compared with those with normo- and hyperphosphatemia. Hypophosphatemia was a predictor of death when adjusted for age, diabetes, HD vintage, gender, and Kt/V. Comparing the mortality predictors in hypo- and hyperphosphatemia, we found that low albumin, BMI, and high overhydration increased the mortality risk in the hypophosphatemic group, whereas in hyperphosphatemic patients data were not statistically significant.

CONCLUSION

Currently, a high prevalence of hypophosphatemia exists in Portuguese HD patients. This condition is associated with worst nutritional and body composition parameters. In the context of additional indices of malnutrition (low albumin, low BMI or severe overhydration), hypophosphatemic patients presented higher mortality risk.

Associations of Protein-Energy Wasting Syndrome Criteria With Body Composition and Mortality in the General and Moderate Chronic Kidney Disease Populations in the United States

Introduction

It is unknown whether the criteria used to define protein−energy wasting (PEW) syndrome in dialysis patients reflect protein or energy wasting in the general and moderate CKD populations.

Methods

In 11,834 participants in the 1999 to 2004 National Health and Nutrition Examination Survey, individual PEW syndrome criteria and the number of PEW syndrome categories were related to lean body and fat masses (measured by dual-energy absorptiometry) using linear regression in the entire cohort and CKD subpopulation.

Results

Serum chemistry, body mass, and muscle mass PEW criteria tended to be associated with lower lean body and fat masses, but the low dietary protein and energy intake criteria were associated with significantly higher protein and energy stores. When the number of PEW syndrome categories was defined by nondietary categories alone, there was a monotonic inverse relationship with lean body and fat masses and a strong positive relationship with mortality. In contrast, when dietary category alone was present, mean body mass index was in the obesity range; the additional presence of 2 nondietary categories was associated with lower body mass index and lower lean body and fat masses. Thus, the association of a dietary category plus 2 additional nondietary categories with lower protein or energy stores was driven by the presence of the 2 nondietary categories. Results were similar in CKD subgroup.

Discussion

Hence, a definition of PEW syndrome without dietary variables has face validity and reflects protein or energy wasting.

Ratio of C-Reactive Protein to Albumin Predicts Muscle Mass in Adult Patients Undergoing Hemodialysis

Recent studies have indicated that the ratio of C-reactive protein to albumin (CRP–Alb ratio) is associated with clinical outcomes in patients with disease. We examined the predictive value of this ratio in patients undergoing hemodialysis (HD). In this cross-sectional study, 91 eligible adult HD patients were analyzed, and the correlation between the CRP–Alb ratio and skeletal muscle mass normalized for body weight (SMM/wt; estimated using a bioelectrical impedance analyzer) was investigated. The mean age of the study participants was 54.9 ± 6.6 years (ranging from 27 to 64 years); 43 (47.2%) were men. The mean values for the SMM/wt were 39.1% ± 5.4%. The CRP–Alb ratio was found to be negatively correlated with SMM/wt (r = −0.33, P = 0.002) and creatinine (r = −0.20, P = 0.056). All the univariate significant and nonsignificant relevant covariates were selected for multivariable stepwise regression analysis. We determined that the homeostasis model assessment-estimated insulin resistance and CRP–Alb ratio were independent risk determinants for SMM/wt (β_HOMA-IR = −0.18 and β_{CRP–Alb ratio} = −3.84, adjusted R² = 0.32). This study indicated that the CRP–Alb ratio may help clinicians in predicting muscle mass in adult patients undergoing HD.

Lower thigh muscle mass is associated with all-cause and cardiovascular mortality in elderly hemodialysis patients

BACKGROUND/OBJECTIVES

Higher body mass index appears protective in hemodialysis patients, although it remains to be determined which component of muscle or fat mass is primarily associated with this survival advantage.

SUBJECTS/METHODS

Eighty-one hemodialysis patients in our institution were prospectively followed from July 2011 to August 2015. Muscle and fat mass were evaluated by measuring the cross-sectional areas of the thigh and abdomen using computed tomography. The relationship between muscle and fat mass, and all-cause and cardiovascular mortality was studied using the Kaplan-Meier analyses and multivariate Cox proportional hazard models.

RESULTS

During more than 4 years of follow-up, 26 patients (32%) died. In the Kaplan-Meier curve analyses, lower thigh muscle mass was significantly associated with all-cause and cardiovascular mortality (log-rank test, P<0.01 and P<0.001, respectively), but there was no such association with thigh fat, abdominal muscle and fat mass levels. In multivariate Cox proportional hazard models, each 0.1 cm²/kg increase in the thigh muscle area adjusted by dry weight was associated with an estimated 22% lower risk of all-cause mortality (95% confidence interval (95% CI), 0.64-0.95, P<0.05) and a 30% lower risk of cardiovascular mortality (95% CI, 0.54-0.90, P<0.01).

CONCLUSIONS

Lower thigh muscle mass is significantly associated with all-cause and cardiovascular mortality in hemodialysis patients. Our findings indicate the importance of focusing on the muscle mass of lower extremities to predict the clinical outcomes of hemodialysis patients.

Reappraisal of effects of serum chemerin and adiponectin levels and nutritional status on cardiovascular outcomes in prevalent hemodialysis patients

Although chemerin, an adipokine, increases the cardiovascular (CV) risk in obese people, it is associated with a survival advantage in incident hemodialysis (HD) patients. We explored the potential effects of chemerin on CV outcomes in prevalent HD patients. This prospective study included 343 prevalent HD patients. The composite outcome was the occurrence of CV events and death during follow-up. We used multivariate Cox regression analysis to test the predictive power of different chemerin and adiponectin levels and geriatric nutritional risk index (GNRI) for the outcomes. HD patients with higher chemerin levels (≥211.4 ng/mL) had a lower risk of CV events (adjusted hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.41-0.98) and composite CV outcome (adjusted HR, 0.67; 95% CI, 0.45-0.99) than those with lower chemerin levels (<211.4 ng/mL). When evaluating CV outcomes, we identified an interaction between chemerin levels and GNRI, but not between chemerin and adiponectin levels. The findings remained robust in the sensitivity analysis. Thus, in prevalent HD patients with negligible residual renal function, higher chemerin levels predict more favourable CV outcomes.

Validating Body Fat Assessment by Bioelectric Impedance Spectroscopy in Taiwanese Hemodialysis Patients

OBJECTIVE

Obesity is becoming increasingly common in hemodialysis (HD) patients and is associated with inflammation and increased mortality. The primary aim of the present study was to evaluate the accuracy and variability of the bioimpedance device in measuring body fat in Taiwanese dialysis patients.

DESIGN

Cross-sectional study.

SUBJECTS

One hundred twenty-two adult patients receiving HD in a single hospital in Taiwan.

SETTING

We compared the results of fat mass (FM) measured by dual-energy x-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy device (Body composition monitor, BCM).

MAIN OUTCOME MEASUREMENT

FM measured by BCM was calculated by subtracting fat-free mass (FFM) from body mass assuming fractional hydration of FFM of 0.73 or the proprietary prediction equations from the BCM model.

RESULTS

Assessment of whole-body composition showed that percentage FM measured using the 2 techniques was highly correlated when using the BCM model or estimating from total body water using constant (0.73) hydration (r = 0.87, P < .001). There was no evident difference in measurement between patients gender. The Bland-Altman plot also showed good agreement of percentage of FM (t = 3.82; P < .001). In female patients, it was found that BCM significantly underestimated mean FM as compared to DEXA. However, the mean differences of the estimates between the methods were small (0.35 ± 3.00 kg) and with Bland-Altman plot the limits of agreements were -5.5 to 6.2 kg (P = .40) for FM in female patients.

CONCLUSIONS

Using DEXA as the reference test, BCM is a valid tool for the assessment of total body fat in HD patients. Hence, it may provide a more accessible tool for early detection of changes in body composition in these high-risk patients.