Survival predictability of lean and fat mass in men and women undergoing maintenance hemodialysis

The Utility of the Cachexia Index and the Modified Glasgow Score in Young Patients With Breast Cancer

Background Breast cancer is the most common cancer in women. Body composition and inflammatory markers are increasingly important for predicting cancer prognosis. The Cancer Cachexia Index (CXI) and the modified Glasgow Prognostic Score (GPS) are two new markers evaluating prognosis in cancer. In this study, we evaluated the utility of the CXI and the modified GPS in young patients with breast cancer. Methods Eighty patients diagnosed between 2012 and 2023 were included in the study. The following information was recorded: patient features, pathological subtype, estrogen receptor and human epidermal growth factor receptor-2 (HER-2) status, disease stage, therapies, disease recurrence, and last control or death date. The CXI and the modified GPS were calculated using clinical data, including skeletal muscle index, albumin, C-reactive protein, and neutrophil-to-lymphocyte ratio. Results There were no differences in overall survival with respect to the CXI in the study population (p=0.96). Only stage 4 patients showed statistically significant survival differences according to the CXI (p=0.046). Although the median survival time was not reached for the modified GPS groups, there was a statistical overall survival difference favoring the negative group (p=0.017). No significant differences were observed in disease-free survival due to the CXI (p=0.128). In multivariate analysis, no factors, including the modified GPS and the CXI, influenced overall survival. There was a significant effect of the modified GPS and body mass index on recurrence (p=0.037; p=0.034). The CXI had a non-significant marginal p-value (p=0.074). Conclusion Our study showed that the modified GPS may be related to disease-free survival and overall survival, whereas the CXI has a more prominent prognostic effect on overall survival in advanced-stage breast cancers. In early-stage and young patients, optimization of risk scores is lacking.

Creatinine index: a retrospective cohort study in an urban Australian dialysis context

AIM

This study aimed to described the relationship between the CI and mortality in an Australian context.

INTRODUCTION

Maintenance haemodialysis is a catabolic state associated with a significant decrease in lean body mass (LBM) and protein energy wasting. LBM can be derived or estimated from creatinine kinetic modelling, specifically the creatinine index (CI). This has been demonstrated in cohort studies to predict mortality.

METHODS

One hundred seventy-nine patients undergoing haemodialysis in 2015 were included in this cohort. They were followed for 5 years with pertinent clinical data collected to calculate the CI as of December 2015. For analysis, patients were split into a high and low CI group based on the median (18.32 mg/kg/day). The primary outcome of interest was all-cause mortality, and secondary outcomes included myocardial infarction, stroke and transplantation.

RESULTS

During follow-up, 69 (76.7%) patients in the low CI group and 28 (31.5%) patients in the high CI group died (P < 0.001). The relative risk (RR) of mortality within the low compared with the high CI group was 2.43 (95% confidence interval, 1.75-3.38). Fully adjusted Cox proportional hazards modelling demonstrated a hazard ratio (HR) of 0.498 (95% CI, 0.292-0.848) for survival in the high CI group. Lower CI was associated with increased risk of stroke (RR, 5.43 [95% CI, 1.24-23.84]), whereas transplant was more likely in the high CI group (RR, 6.4 [95% confidence interval, 1.96-20.88]).

CONCLUSIONS

In a single-centre Australian haemodialysis cohort, the CI was strongly associated with mortality and stroke risk. The CI is an accurate and simple method to identify patients with low LBM at risk for significant morbidity and mortality.

Chronic kidney disease-related sarcopenia as a prognostic indicator in elderly haemodialysis patients

BACKGROUND

The mortality of dialysis patients greatly exceeds that of the general population and identifying predictive factors for mortality may provide opportunities for earlier intervention. This study assessed the influence of sarcopenia on mortality in patients on haemodialysis.

METHODS

This prospective, observational study enrolled 77 haemodialysis patients aged 60 years and over, of whom 33 (43%) were female, from two community dialysis centres. Baseline demographic and laboratory data were collected, and sarcopenia was diagnosed using grip strength, muscle mass by bioimpedance analysis (BIA) and muscle function by timed up-and-go according to European Working Group on Sarcopenia in Older People criteria. Nutritional status was assessed using a subjective nutritional assessment score, comprising functional changes in weight, appetite, gastrointestinal symptoms and energy.. A comorbidity score (maximum 7 points) was derived from the presence or absence of hypertension, ischaemic heart disease, vascular disease (cerebrovascular disease, peripheral vascular disease, and abdominal aortic aneurysm), diabetes mellitus, respiratory disease, a history of malignancy and psychiatric disease. Outcomes over six years were linked to the Australian and New Zealand Dialysis and Transplant Registry.

RESULTS

The median participant age was 71 years (range 60-87). Probable and confirmed sarcopenia was present in 55.9% and severe sarcopenia with reduced functional testing in 11.7%. Over 6 years, overall mortality was 50 of the 77 patients (65%), principally from cardiovascular events, dialysis withdrawal and infection. There were no significant survival differences between patients with no, probable, confirmed, or severe sarcopenia, or between tertiles of the nutritional assessment score. After adjustment for age, dialysis vintage, mean arterial pressure (MAP) and the total comorbidity score, no sarcopenia category predicted mortality. However, the total comorbidity score [Hazard Ratio (HR) 1.27, Confidence Intervals (CI) 1.02, 1.58, p = 0.03] and MAP (HR 0.96, CI 0.94, 0.99, P = < 0.01) predicted mortality.

CONCLUSION

Sarcopenia is highly prevalent in elderly haemodialysis patients but is not an independent predictor of mortality. Haemodialysis patients have multiple competing risks for mortality which, in this study, was predicted by a lower MAP and a higher total comorbidity score.

TRIAL REGISTRATION

Recruitment commenced December 2011. The study was registered 10.01.2012 with the Australian New Zealand Clinical Trials Registry (ACTRN12612000048886).

Cut points of the conicity index as an indicator of abdominal obesity in individuals undergoing hemodialysis: An analysis of latent classes

OBJECTIVES

Abdominal obesity favors the involvement of cardiometabolic complications in renal patients on hemodialysis. Thus, the aim of the study was to identify the cut-points of the conicity index in individuals undergoing hemodialysis.

METHODS

This was a cross-sectional study carried out with 953 individuals undergoing hemodialysis in clinics in a metropolitan region of southeastern Brazil. The conicity index was calculated using the following mathematical equation: waist circumference/0.109 × √weight/height. The receiver operating characteristic (ROC) curve was calculated from the analysis of latent classes by cross-validation through a latent variable of abdominal obesity. This latent variable was defined using the response pattern of the observed anthropometric variables considering the presence and absence of abdominal obesity: waist circumference, waist-to-height ratio, and body shape index. The cut-points identified were elucidated by the area under the curve (AUC), Youden index, sensitivity, and specificity.

RESULTS

The cut-points for the conicity index found for both sexes were similar, resulting in a cut-point for men of 1.275 (AUC, 0.921; Youden index, 0.666), with a sensitivity and specificity of 83% and 83.6%, and a cut-point for women of 1.285 (AUC, 0.921; Youden index, 0.679), with a sensitivity and specificity of 78.6% and 89.3%, respectively.

CONCLUSIONS

The conicity index showed high discriminatory power for the identification of abdominal obesity in hemodialysis patients, therefore it can be a simple and easily accessible tool to be incorporated into clinical practice in this population.

Ultrafiltration rate thresholds associated with increased mortality risk in hemodialysis, unscaled or scaled to body size

Introduction

One proposed threshold ultrafiltration rate (UFR) of concern in hemodialysis patients is 13 ml/h per kg. We evaluated associations among UFR, postdialysis weight, and mortality to determine whether exceeding such a threshold would result in similar levels of risk for patients of different body weights.

Methods

Data were analyzed in this retrospective cohort study for 1 year following dialysis initiation (baseline) and over 2 years of follow-up in incident patients receiving thrice-weekly in-center hemodialysis. Patient-level UFR was averaged over the baseline period. To investigate the joint effect of UFR and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions, adjusting for sex, race, age, diabetes, and predialysis serum albumin, phosphorus, and systolic blood pressure (BP). We constructed contour plots of mortality hazard ratios (MHRs) over the entire range of UFR values and postdialysis weights.

Results

In the studied 2542 patients, UFR not scaled to body weight was strongly associated with MHR, whereas postdialysis weight was inversely associated with MHR. MHR crossed 1.5 when unscaled UFR exceeded 1000 ml/h, and this relationship was largely independent of postdialysis weight in the range of 80 to 140 kg. A UFR warning level associated with a lower MHR of 1.3 would be 900 ml/h, whereas the UFR associated with an MHR of 1.0 was patient-size dependent. The MHR when exceeding a UFR threshold of 13 ml/h per kg was dependent on patient weight (MHR = 1.20, 1.45, and >2.0 for a 60, 80, and 100 kg patient, respectively).

Conclusion

UFR thresholds based on unscaled UFR give more uniform risk levels for patients of different sizes than thresholds based on UFR/kg.

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.

Longitudinal Assessment of Body Composition and Its Association With Survival Among Participants of the ACTIVE/ADIPOSE Study

OBJECTIVES

The importance of muscle wasting as a predictor of mortality in the hemodialysis population is not clear. Lack of association of muscle mass with survival in some studies could be related to reliance on single measures or to incorporation of excess extracellular water (ECW) into estimates of muscle mass. We examined changes in body composition over a 2-year period and the association of body composition with survival.

DESIGN AND METHODS

We analyzed data from 325 adults receiving hemodialysis in the Bay Area. We estimated ECW, intracellular water (ICW), and fat mass by whole-body bioimpedance spectroscopy (BIS) at 0, 12, and 24 months from enrollment. We used linear mixed modeling to examine changes in body mass index and BIS-derived estimates of body composition and Cox modeling with BIS-derived estimates as time-varying independent variables to examine associations between body composition and survival in multivariable analyses.

RESULTS

Body mass index declined over time. Considering individual components of body composition, ICW declined (-0.09 kg/m² per year, 95% confidence interval -0.14 to -0.04), but fat mass and ECW did not change significantly. There were 120 deaths over a median of 5.2 years. The relationship between ICW and mortality was not linear such that the association was steeper at low values of ICW, whereas higher ICW was associated with better survival that was relatively stable above 9 kg/m2. Higher ECW was associated with higher mortality, and fat mass was not associated with survival. These associations were independent of markers of inflammation and nutritional status.

CONCLUSIONS

ICW declined over 2 years in this cohort, whereas fat mass and ECW remained relatively stable. Higher ICW was associated with better survival, but higher fat mass was not. Higher ECW was associated with worse survival. These results suggest that muscle mass may predict survival among patients on hemodialysis.

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.

Agreement of Single-Frequency Electrical Bioimpedance in the Evaluation of Fat Free Mass and Fat Mass in Peritoneal Dialysis Patients

Background: Protein-energy wasting is related to impairment of quality of life and lower survival of end-stage kidney disease (ESKD) patients. The evaluation of body composition, especially fat free mass (FFM) and fat mass (FM), is important for the prediction of outcomes in these individuals. The aim of this study was to compare the FFM and FM measurements obtained by single-frequency bioimpedance (SF-BIA) and by a multiple frequency bioimpedance (MF-BIA) device, using dual energy X-ray absorptiometry (DXA) peritoneal dialysis (PD) patients. Methods: This was a cross-sectional study involving adult patients undergoing regular PD, in which we performed SF-BIA, MF-BIA, and DXA at the same visit. To compare the bioimpedance values with DXA, we used: Person correlation (r), intraclass correlation coefficient (ICC), and Bland-Altman concordance analysis. Results: The sample consisted of 50 patients in the PD, with mean age of 55.1 ± 16.3 years. Both bioimpedance methods showed a strong correlation (r > 0.7) and excellent reproducibility (ICC > 0.75) compared to DXA. According to the Bland-Altman diagram, SF-BIA showed agreement in body compartment measurements, with no proportionality bias (p > 0.05), without systematic bias for FFM (-0.5 ± 4.9, 95% CI -1.8 to 0.9, p = 0.506), and for FM (0.3 ± 4.6, p = 0.543). MF-BIA did not present a proportionality bias for the FFM, but it underestimated this body compartment by 2.5 ± 5.4 kg (p = 0.002). In addition, MF-BIA presented proportionality bias for FM. Conclusion: SF-BIA was a more accurate assessing method than MBIA for FFM and FM measurements in PD patients. Because it is a low-cost, non-evaluator-dependent measurement and has less systematic bias, it can also be recommended for fat mass and free-fat mass evaluation in PD patients.

Evolution of body composition and wasting indicators by time of day of haemodialysis

BACKGROUND

It has been a long-standing clinical concern that haemodialysis (HD) patients on afternoon shifts (ASs) are more prone to protein-energy wasting (PEW) than those on morning shifts (MSs), as their dialysis scheme and post-dialysis symptoms may interfere with meal intake. We evaluated the effect of time of day of HD on the evolution of body composition changes and PEW surrogates.

METHODS

We conducted a retrospective study among 9.963 incident HD patients treated in NephroCare centres (2011-16); data were routinely collected in the European Clinical Database. The course of multi-frequency bioimpedance determined lean and fat tissue indices (LTI and FTI) between patients in MSs/ASs over 2 years were compared with linear mixed models. Secondary PEW indicators were body mass index, albumin, creatinine index and normalized protein catabolic rate. Models included fixed (age, sex, vascular access and diabetes mellitus) and random effects (country and patient).

RESULTS

Mean baseline LTI and FTI were comparable between MSs (LTI: 12.5 ± 2.9 kg/m2 and FTI: 13.7 ± 6.0 kg/m2) and ASs (LTI: 12.4 ± 2.9 kg/m2 and FTI: 13.2 ± 6.1 kg/m2). During follow-up, LTI decreased and FTI increased similarly, with a mean absolute change (baseline to 24 months) of -0.3 kg/m2 for LTI and +1.0 kg/m2 for FTI. The course of these malnutrition indicators did not differ between dialysis shifts (P for interaction ≥0.10). We also did not observe differences between groups for secondary PEW indicators.

CONCLUSIONS

This study suggests that a dialysis shift in the morning or in the afternoon does not impact the long-term nutritional status of HD patients. Regardless of time of day of HD, patients progressively lose muscle mass and increase body fat.

Effects of age and sex on the relationship between body fat area and kidney events in patients with chronic kidney disease

We examined the effects of age and sex on the relationship between body fat area and kidney events. We included 367 chronic kidney disease patients between 2011 and 2017. Patients' median age was 73.0 years; 262 (71.4%) patients were male. The median estimated glomerular filtration rate was 20.2 mL/min/1.73 m² . During the observation period, 187 patients developed kidney events. In males aged <75 years, high subcutaneous fat area was a risk factor for kidney events (hazard ratio: 1.06, 95% CI: 1.02-1.11). In females aged <75 years, high visceral fat area reduced kidney events (hazard ratio: 0.83, 95% CI: 0.71-0.97). In males and females ≥75 years, visceral fat area and subcutaneous fat area were not associated with kidney events. Body fat area was not a risk factor for chronic kidney disease progression in elderly patients. Opposite effects, in sex-related body fat and kidney events, were shown in young patients.

Visceral Adipose Tissue Index and Hepatocellular Carcinoma Are Independent Predictors of Outcome in Patients with Cirrhosis Having Endoscopic Treatment for Esophageal Varices

BACKGROUND

The relationship between the amount of adipose tissue and advanced-stage liver cirrhosis with esophageal varices (EV) is unknown. We aimed to reveal the prognostic significance of adipose tissues in patients with liver cirrhosis.

METHODS

We enrolled 87 patients with EV who received initial endoscopic treatment and underwent scheduled treatments in our hospital. Computed tomography (CT) images were obtained of a 5-mm slice at the umbilical level. We evaluated the effect of mortality based on the visceral adipose tissue index (VATI), subcutaneous adipose tissue index (SATI), and visceral to subcutaneous adipose tissue ratio (VSR).

RESULTS

Cox hazard multivariate analysis showed that the presence of hepatocellular carcinoma (HCC; hazard ratio [HR]: 4.650, 95% confidence interval [CI]: 1.750-12.353, p = 0.002), γ-GTP (HR: 1.003, 95% CI: 1.001-1.006, p = 0.026), and VATI (HR: 1.057, 95% CI: 1.030-1.085, p < 0.001) significantly affected mortality. Cox hazard multivariate analysis for liver-related death was also significantly affected by HCC (HR: 1.057, 95% CI: 1.030-1.085, p < 0.001) and VATI (HR: 1.052, 95% CI: 1.019-1.086, p = 0.002). The difference between the Child-Pugh scores 12 months after treatment and that during initial treatment were significantly positively correlated with VATI (r = 0.326, p = 0.027). Patients with high VATI had a significantly higher frequency of HCC after EV treatment by Kaplan-Meier analysis (p = 0.044).

CONCLUSION

Our findings suggest that VATI measured by CT could significantly predict mortality in cirrhosis patients through decreasing liver function and increasing HCC frequency, and appropriately controlling VATI could improve their prognosis.

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.

Determining Malnutrition Assessment Criteria to Predict One-Year Mortality for Locally Advanced Head and Neck Cancer Patients Undergoing Concurrent Chemoradiotherapy

Study on the impact of pretreatment malnutrition on treatment outcomes in locally advanced head and neck cancer (LAHNC) patients is still lacking. We prospectively collected various malnutrition assessment methods including nutrition indexes, inflammatory biomarkers, and lean body mass index (LBMI) data before treatments. The one year mortality rate was assessed, and the factors associated with this outcome were investigated. Furthermore, the association between malnutrition assessment methods was examined. A total of 113 patients were enrolled. By prognostic stratification based on the prognostic nutritional index (PNI) and platelet-to-lymphocyte ratio (PLR) combination, the low PNI/high PLR group had highest and the high PNI/low PLR group had the lowest mortality rate. Furthermore, the PNI was positively correlated with the LBMI, and the PLR was inversely correlated with the LBMI. PNI and PLR were found to be independent prognostic factors of one year mortality and also associated with the loss of muscle.

Low body cell mass index in hemodialysis patients: Association with clinical parameters and survival

INTRODUCTION

Body cell mass (BCM) is a useful nutritional marker and is not affected by changes in the hydration status that commonly occur in hemodialysis (HD) patients. This study aimed to examine the association between body cell mass index (BCMI) and nutritional parameters, as well as its relationship with long-term survival in these patients.

METHODS

This longitudinal prospective multicenter study followed a cohort of patients in HD for 24 months. The clinical parameters of 2527 patients (mean age 70.3 ± 14.6 years, 55.8% male and mean HD vintage 58 (IQR:33-95) months) were measured and their body composition parameters were assessed by a body composition monitor before the HD session. BCM was converted to BCMI (BCM/height² ) and, taking into account the mean value (6.4 ± 2.1 kg/m² ), we split our study population into 2 groups: G1 (BCMI <6.4 kg/m² ; n = 1366) and G2 (BCMI ≥ 6.4 kg/m² ; n = 1161). All statistical tests were performed using SPSS 20.0 software. A P value lower than 0.05 was considered statistically significant.

FINDINGS

Patients with a BCMI <6.4 kg/m² displayed higher age (P < 0.001), dialysis adequacy (Kt/V) (P < 0.001), total cholesterol (TC) (P = 0.033), high-density lipoprotein cholesterol (HDL-C) (P < 0.001), relative overhydration (overhydration/extracellular water [OH/ECW]) (P < 0.001), CRP (P < 0.001), fat tissue index (FTI) (P < 0.001) and lower normalized protein equivalent of nitrogen appearance (nPNA) (P < 0.001), albumin (P < 0.001), serum creatinine (P < 0.001), creatinine index (P < 0.001), potassium (P < 0.001), phosphorus (P < 0.001), calcium/phosphorus product (Ca X P) (P < 0.001), lean tissue index (LTI) (P < 0.001) and body mass index (BMI) (P = 0.046). The Kaplan-Meier survival curve showed a significantly better survival in female and male patients with BCMI ≥6.4 kg/m² (P = 0.001 and P < 0.001, respectively). In the cox regression analysis, a significantly higher mortality risk was observed in G1 patients (P = 0.001).

DISCUSSION

Our study showed that a low BCMI was a mortality predictor and was associated with worse nutritional parameters in patients undergoing HD.

Impact of Percent Body Fat on All-Cause Mortality among Adequate Dialysis Patients with and without Insulin Resistance: A Multi-Center Prospective Cohort Study

The association between body fat and mortality in hemodialysis patients remains controversial. We examined the effect of percent body fat (PBF) on all-cause mortality among adequate hemodialysis patients with and without insulin resistance (IR). A prospective cohort study was conducted on 365 adequate hemodialysis patients (equilibrated Kt/V ≥ 1.2) from seven hospitals. Patients’ characteristics and clinical and biochemical parameters were assessed at baseline between September 2013 and April 2017. Patients were followed up for all-cause mortality until April 2018. The median value of homeostatic model assessment (HOMA-IR) was used to classify IR. Cox proportional hazard models were utilized to examine predictors of all-cause mortality. During 1.4 (1.0–3.2) years of follow-up, 46 patients died. In patients with IR (HOMA-IR ≥ 5.18), PBF was significantly higher in the survival group than in the death group (31.3 ± 9.0 vs. 25.4 ± 8.2, p = 0.005). After controlling for confounding factors, PBF was significantly associated with lower risk for all-cause mortality in patients with IR (hazard ratio, 0.94; 95% confidence interval, 0.89–1.00; p = 0.033). The association was not observed in patients without IR. In conclusion, percent body fat shows a protective effect on survival in hemodialysis patients with IR.

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.

Low subcutaneous adiposity associates with higher mortality in female patients with cirrhosis

BACKGROUND & AIMS

Two major body compartments, skeletal muscle and adipose tissue, exhibit independent functions. We aimed to explore the prognostic significance of skeletal muscle, visceral and subcutaneous adipose tissue, according to sex, in patients with cirrhosis assessed for liver transplantation (LT).

METHODS

CT images taken at the 3rd lumbar vertebra from 677 patients were quantified for three body composition indexes (cm²/m²), visceral adipose tissue index, subcutaneous adipose tissue index (SATI), and skeletal muscle index (SMI). Cox proportional and competing-risk analysis hazard models were conducted to assess associations between mortality and body composition.

RESULTS

The majority of patients were male (67%) with a mean age of 57 ± 7 years, model for end-stage liver disease (MELD) score of 14 ± 8 and mean body mass index of 27 ± 6 kg/m². Despite similar body mass index between the sexes, male patients had greater SMI (53 ± 12 vs. 45 ± 9 cm²/m²), whereas SATI (67 ± 52 vs. 48 ± 37 cm²/m²) was higher in females (p <0.001 for each). In sex stratified multivariate analyses after adjustment for MELD score and other confounding variables, SATI in females (hazard ratio [HR] 0.99; 95% CI 0.98-1.00; p = 0.01) and SMI in males (HR 0.98; 95% CI 0.96-1.00; p = 0.02) were significant predictors of mortality. Female patients with low SATI (<60 cm²/m²) had a higher risk of mortality (HR 2.06; 95% CI 1.08-3.91; p = 0.03). Using competitive risk analysis in female patients listed for LT, low SATI was also an independent predictor of mortality (subdistribution HR 2.80; 95% CI 1.28-6.12; p = 0.01) after adjusting for MELD, and other confounding factors.

CONCLUSIONS

A lower SATI is associated with higher mortality in female patients with cirrhosis. Subcutaneous adipose tissue has a favorable metabolic profile - low SATI may reflect depletion of this major energy reservoir, leading to poor clinical outcomes.

LAY SUMMARY

We looked at the importance of two of the main body compartments, skeletal muscle and adipose tissue (fat) on the prognosis of males and females with end-stage liver disease. Lower amounts of subcutaneous fat but not visceral fat (around internal organs), are associated with higher mortality in female patients with end-stage liver disease. However, low skeletal muscle predicts mortality in male patients with end-stage liver disease.

The Incidence and Pathophysiology of the Obesity Paradox: Should Peritoneal Dialysis and Kidney Transplant Be Offered to Patients with Obesity and End-Stage Renal Disease?

PURPOSE OF REVIEW

To educate nephrologists and primary-care physicians about the incidence, pathophysiology, and survival benefits of the obesity paradox in end-stage renal disease (ESRD). This review also discusses the future of kidney transplant and peritoneal dialysis in obese dialysis patients.

RECENT FINDINGS

Obesity paradox in ESRD was first reported three decades ago, and since then, there have been several epidemiological studies that confirmed the phenomenon. Regardless of the anthropometric indices used to define obesity in ESRD patients, these markers serve to predict the dialysis patient's survival. The pathophysiology of obesity paradox tends to be multifactorial. Recent cohort studies demonstrated a survival benefit in all race and ethnic groups, but Hispanics and blacks experienced increased survival rates when compared to non-Hispanic whites. Obese dialysis patients should be offered peritoneal dialysis, especially if they are new to dialysis and have an adequate renal residual function. Several studies have shown that the benefit of receiving kidney transplant in obese patients exceeds the risks. The robotic-assisted kidney transplant (RAKT) procedure is the latest innovation that could offer hope for obese dialysis patients who have been denied or are waiting for kidney transplant. The obesity paradox phenomenon in ESRD is a unique illustration of survival benefit in a population that has a high overall annual mortality. Peritoneal dialysis should be encouraged for obese patients who have preserved residual renal function. Kidney transplant centers should encourage RAKT utilization in obese dialysis patients instead of denying them a kidney transplant.

Obesity Paradox in Advanced Kidney Disease: From Bedside to the Bench

While obesity is associated with a variety of complications including diabetes, hypertension, cardiovascular disease and premature death, observational studies have also found that obesity and increasing body mass index (BMI) can be linked with improved survival in certain patient populations, including those with conditions marked by protein-energy wasting and dysmetabolism that ultimately lead to cachexia. The latter observations have been reported in various clinical settings including end-stage renal disease (ESRD) and have been described as the "obesity paradox" or "reverse epidemiology", engendering controversy. While some have attributed the obesity paradox to residual confounding in an effort to "debunk" these observations, recent experimental discoveries provide biologically plausible mechanisms in which higher BMI can be linked to longevity in certain groups of patients. In addition, sophisticated epidemiologic methods that extensively adjusted for confounding have found that the obesity paradox remains robust in ESRD. Furthermore, novel hypotheses suggest that weight loss and cachexia can be linked to adverse outcomes including cardiomyopathy, arrhythmias, sudden death and poor outcomes. Therefore, the survival benefit observed in obese ESRD patients can at least partly be derived from mechanisms that protect against inefficient energy utilization, cachexia and protein-energy wasting. Given that in ESRD patients, treatment of traditional risk factors has failed to alter outcomes, detailed translational studies of the obesity paradox may help identify innovative pathways that can be targeted to improve survival. We have reviewed recent clinical evidence detailing the association of BMI with outcomes in patients with chronic kidney disease, including ESRD, and discuss potential mechanisms underlying the obesity paradox with potential for clinical applicability.

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.

The obesity paradox in cancer: clinical insights and perspectives

A series of evidence demonstrated that obesity represents an established risk factor for an increase in the incidence of multiple cancer types and for poor cancer survival. Nevertheless, recent studies suggested that, in a series of cancers, patients with a normal body mass index (BMI) have worse outcomes than obese patients. This phenomenon, named 'obesity paradox' or 'reverse epidemiology' in cancer, is not well understood and presents controversial aspects. Therefore, this review aims to explore the available studies concerning the relationship between obesity and cancer incidence or survival and to highlight the hypothetical explanations and the methodological framework. In this regard, we underline the limits of BMI as a potential marker of adiposity and the relevance to assessing body composition, beyond the body size. Further studies are needed to define the impact of obesity in cancer patients, to tailor weight management after cancer diagnosis and to hopefully improve overall clinical outcome.

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.

Visceral adiposity increases risk for hepatocellular carcinoma in male patients with cirrhosis and recurrence after liver transplant

Visceral adipose tissue (VAT) is a metabolically active organ, associated with higher risk of malignancies. We evaluated whether VAT is associated with the risk of hepatocellular carcinoma (HCC) in patients presenting with cirrhosis as well as HCC recurrence after liver transplantation (LT). Patients with cirrhosis (n = 678; 457 male) who were assessed for LT (289 with HCC) were evaluated for body composition analysis. Patients who underwent LT (n = 247, 168 male) were subsequently evaluated for body composition, and 96 of these patients (78 male) had HCC. VAT, subcutaneous adipose tissues, and total adipose tissues were quantified by computed tomography at the level of the third lumbar vertebra and reported as indexes (cross-sectional area normalized for height [square centimeters per square meter]). At the time of LT assessment, the VAT index (VATI) was higher in male patients with HCC compared to non-HCC patients (75 ± 3 versus 60 ± 3 cm² /m² , P = 0.001). The VATI, subcutaneous adipose tissue index, and total adipose tissue index were higher in male patients with HCC compared to non-HCC patients. By multivariate analysis, male patients with VATI ≥65 cm² /m² had a higher risk of HCC (hazard ratio, 1.90; 95% confidence interval, 1.31-2.76; P = 0.001). In male patients with HCC who underwent LT, a VATI ≥65 cm² /m² adjusted for Milan criteria was independently associated with higher risk of HCC recurrence (hazard ratio, 5.34; 95% confidence interval, 1.19-23.97; P = 0.03).

CONCLUSION

High VATI is an independent risk factor for HCC in male patients with cirrhosis and for recurrence of HCC after LT. (Hepatology 2018;67:914-923).

Body Mass Index Change and Hospitalization Risk in Elderly Hemodialysis Patients: Results from Japanese Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Short-term weight gains and losses are associated with a lower and higher mortality risk, respectively, in patients undergoing hemodialysis (HD). However, little is known about their association with the risk of subsequent hospitalization.

METHODS

In a prospective cohort of 1,804 HD patients aged ≥65 years enrolled in the Japanese Dialysis Outcomes and Practice Patterns Study phases 3 (2005-2008) and 4 (2009-2011), we examined the associations between changes in body mass index (BMI) over a 4-month baseline period (<-3%, -3 to <-1%, -1 to <1% [reference], 1 to <3%, and ≥3%) and subsequent risk of all-cause, cardiovascular, and noncardiovascular hospitalization using Cox models with adjustment for potential confounders.

RESULTS

During a median follow-up of 1.2 years, we noted 1,028 incident hospitalizations for any cause, including 275 and 753 hospitalizations for cardiovascular and noncardiovascular causes, respectively. An L-shaped association was observed between BMI change and all-cause hospitalization. The multivariable-adjusted hazard ratios (HRs; 95% CI) of all-cause hospitalization associated with BMI changes of <-3%, -3 to <-1%, 1 to <3%, and ≥3% (vs. -1 to <1%) were 1.29 (1.01-1.65), 1.22 (0.98-1.51), 1.04 (0.83-1.29), and 1.10 (0.83-1.45), respectively. Qualitatively similar associations were present for cardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.58 [1.06-2.37], 1.09 [0.75-1.58], 0.99 [0.72-1.36], and 0.91 [0.51-1.64], respectively) but not for noncardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.19 [0.90-1.57], 1.26 [0.99-1.59], 1.06 [0.84-1.35], and 1.18 [0.86-1.63], respectively).

CONCLUSIONS

Decreases in BMI over a relatively short-term period were independently associated with higher risk of subsequent hospitalization, particularly cardiovascular-related hospitalization, among elderly HD patients.

Frailty and the Quality of Life in Hemodialysis Patients: The Importance of Waist Circumference

OBJECTIVE

Frailty among the end-stage renal disease (ESRD) population is highly prevalent and has been associated with mortality. Little is known about the relation of different aspects of body composition, a modifiable risk factor, with the risk of frailty in ESRD population.

DESIGN AND METHODS

One hundred and fifty-one patients including 85 men and 66 women, aged ≥18 years with ESRD who had been receiving conventional maintenance hemodialysis (HD) for at least 3 months were included. Body fat and muscle mass from both bioimpedance spectroscopy and skin-fold thickness and waist circumference as a surrogate of abdominal obesity were measured. Frailty was defined based on Fried's criteria. Health-related quality of life was collected using the RAND version of the Kidney Disease Quality of Life (KDQOL-36) Survey.

RESULTS

We performed single and multiple predictor logistic regression analyses to determine factors associated with frailty. After adjustment for age, sex, and comorbidities, fat mass (both by bioimpedance spectroscopy and anthropometry) and waist circumference, but not muscle mass remained the main predictors of frailty. The odds ratio of frailty in the third tertile compared with the first was 4.97 (1.70-14.55) and 3.84 (1.39-10.61) for fat mass and waist circumference, respectively (P for trends for both <.05). The scores of physical health and kidney disease effect component of quality of life were lower in frail compared with nonfrail patients (40.7 ± 9.2 vs. 33.7 ± 10.2, P < .01 and 66.8 ± 22.4 vs. 51.6 ± 25.7, P < .05 for physical health and effects of disease, respectively).

CONCLUSIONS

Frailty, which is associated with poor outcomes in chronic HD patients, is common and predicted by fat mass and waist circumference but not by body mass index and muscle mass. Interventions to modify abdominal obesity, reflected by waist circumference, could potentially lower the incidence of frailty and hence improve the quality of life in the HD population.

Time to redefine body mass index categories in chronic diseases? Spotlight on obesity paradox

Obesity is a complex condition classically characterised by excessive body fat accumulation and represents one of the most important public health problems worldwide. Although several epidemiological studies have shown that elevated BMI is associated with higher morbidity, and with increased rate of death from all causes and from cardiovascular disease, accumulating evidence suggests that being overweight or obese may be protective (the so-called obesity paradox), at least in chronic diseases. These observations, not only question the validity of the BMI system, but also raise the intriguing question of whether we should redefine what the normal range of BMI is in individuals suffering from a chronic disease. In the present article, we review the available information on the association between elevated BMI and increased morbidity and mortality including obesity-related paradoxes, explore key aspects of the role and limitations of BMI as a measure of increased adiposity and outline potential solutions to address the current controversies regarding the impact of obesity on human health.

Subcutaneous adiposity is an independent predictor of mortality in cancer patients

BACKGROUND

Prognostic significance of adiposity, at the time of cancer diagnosis, on survival is not clear. Body mass index (kg m^-2) does not provide an appropriate assessment of body composition; therefore, the concept of the 'obesity paradox' needs to be investigated based on the prognostic significance of fat and muscle. Independent prognostic significance of adipose tissue in predicting mortality, importance of visceral and subcutaneous adiposity in the presence and absence of sarcopenia on survival, was investigated.

METHODS

Adiposity markers including total adipose index (TATI), visceral adipose tissue index (VATI) and subcutaneous adipose tissue index (SATI) were estimated for 1473 gastrointestinal and respiratory cancer patients and 273 metastatic renal cell carcinoma patients using computed tomography. Univariate and multivariate analysis to determine mortality hazard ratios (HR) were conducted using cox proportional hazard models.

RESULTS

Low SATI (SATI <50.0 cm² m^-2 in males and <42.0 cm² m^-2 in females) independently associated with increased mortality (HR: 1.26; 95% CI: 1.11-1.43; P<0.001) and shorter survival (13.1 months; 95% CI, 11.4-14.7) compared to patients with high SATI (19.3 months; 95% CI, 17.6-21.0; P<0.001). In the presence of sarcopenia, the longest survival was observed in patients with high subcutaneous adiposity.

CONCLUSIONS

Subcutaneous adipose tissues appear to associate with reduction in mortality risk demonstrating the prognostic importance of fat distribution. The effect of sarcopenia on survival was more pronounced in patients with low subcutaneous adiposity.

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.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

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.

Potential Role of Vegetarianism on Nutritional and Cardiovascular Status in Taiwanese Dialysis Patients: A Case-Control Study

Background & Objectives

Cardiovascular disease remains the most common cause of death for patients on chronic dialysis. End stage renal disease patients undergoing dialysis imposed to reduce phosphorus intake, which likely contributes to development of vegetarian diet behaviors. Vegetarian diets are often lower in protein content, in contradiction to the recommendation that a high protein diet is followed by patients undergoing dialysis. The purpose of the study was to investigate the effects of a vegetarian diet on the nutritional and cardiovascular status of dialysis patients.

Design, Setting, Participants, Measurements

A study of 21 vegetarian dialysis patients and 42 age- and sex-matched non-vegetarian dialysis patients selected as controls was conducted in the Kaohsiung Veterans General Hospital. Brachial-ankle pulse wave velocity and biochemistry data including total homocysteine levels, serum lipid profiles, high-sensitivity C-reactive protein, vitamin D levels, albumin, and normalized protein catabolic rate were measured.

Results

Compared with the non-vegetarian control group, vegetarian subjects had lower body weight, body mass index, serum phosphate, blood urea nitrogen, serum creatinine, vitamin D, uric acid, albumin, and normalized protein catabolic rate (p < 0.05). The vegetarian group showed higher brachial-ankle pulse wave velocity than the non-vegetarian group (1926.95 ± 456.45 and 1684.82 ± 309.55 cm/sec, respectively, p < 0.05). After adjustment for age, albumin, pre-dialysis systolic blood pressure, and duration of dialysis, vegetarian diet remained an independent risk factor for brachial-ankle pulse wave velocity.

Conclusions

The present study revealed that patients on dialysis who follow vegetarian diets may experience subclinical protein malnutrition and vitamin D deficiency that could offset the beneficial cardiovascular effects of vegetarianism.

Hidden Obesity in Dialysis Patients: Clinical Implications

While body-mass index (BMI) is used to diagnose obesity in the general population, its application in the end-stage renal disease (ESRD) population is fraught with difficulty. A major limitation is its inability to distinguish muscle mass from fat mass, thereby leading to misclassification of individuals with poor muscle mass but excess adipose tissue as non-obese (i.e. BMI <30 kg/m(2) ). As muscle wasting is common among ESRD patients, this is an important problem. A substantial proportion of ESRD patients have levels of BMI in the normal range, yet excess adiposity based on other measures. The importance of this "hidden" obesity remains to be determined, but it must be recognized in order for obesity interventions to be appropriately targeted and tested in the ESRD population.

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.

Impact of protein energy wasting status on survival among Afro-Caribbean hemodialysis patients: a 3-year prospective study

Background

We assessed the prognostic value of protein-energy wasting (PEW) on mortality in Afro-Caribbean MHD patients and analysed how diabetes, cardiovascular disease (CVD) and inflammation modified the predictive power of a severe wasting state.

Method

A 3-year prospective study was conducted in 216 patients from December 2011. We used four criteria from the nomenclature for PEW proposed by the International Society of Renal Nutrition and Metabolism in 2008: serum albumin 38 g/L, body mass index (BMI) ≤23 kg/m², serum creatinine ≤818 µmol/L and protein intake assessed by nPCR ≤0.8 g/kg/day. PEW status was categorized according the number of criteria. Cox regression analyses were used.

Results

Forty deaths (18.5 %) occurred, 97.5 % with a CV cause. Deaths were distributed as follows: 7.4 % in normal nutritional status, 13.2 % in slight wasting (1 PEW criterion), 28 % in moderate wasting (2 criteria) and 50 % in severe wasting (3–4 criteria). Among the PEW markers, low serum albumin (HR 3.18; P = 0.001) and low BMI (HR 1.97; P = 0.034) were the most significant predictors of death. Among the PEW status categories, moderate wasting (HR 3.43; P = 0.021) and severe wasting (HR 6.59; P = 0.001) were significant predictors of death. Diabetes, CVD, and inflammation were all additives in predicting death in association with severe wasting with a strongest HR (7.76; P < 0.001) for diabetic patients.

Conclusions

The nomenclature for PEW predicts mortality in our Afro-Caribbean MHD patients and help to identify patients at risk of severe wasting to provide adequate nutritional support.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-015-1257-3) contains supplementary material, which is available to authorized users.

Novel Equations for Estimating Lean Body Mass in Peritoneal Dialysis Patients

♦

OBJECTIVES

To develop and validate equations for estimating lean body mass (LBM) in peritoneal dialysis (PD) patients. ♦

METHODS

Two equations for estimating LBM, one based on mid-arm muscle circumference (MAMC) and hand grip strength (HGS), i.e., LBM-M-H, and the other based on HGS, i.e., LBM-H, were developed and validated with LBM obtained by dual-energy X-ray absorptiometry (DEXA). The developed equations were compared to LBM estimated from creatinine kinetics (LBM-CK) and anthropometry (LBM-A) in terms of bias, precision, and accuracy. The prognostic values of LBM estimated from the equations in all-cause mortality risk were assessed. ♦

RESULTS

The developed equations incorporated gender, height, weight, and dialysis duration. Compared to LBM-DEXA, the bias of the developed equations was lower than that of LBM-CK and LBM-A. Additionally, LBM-M-H and LBM-H had better accuracy and precision. The prognostic values of LBM in all-cause mortality risk based on LBM-M-H, LBM-H, LBM-CK, and LBM-A were similar. ♦

CONCLUSIONS

Lean body mass estimated by the new equations based on MAMC and HGS was correlated with LBM obtained by DEXA and may serve as practical surrogate markers of LBM in PD patients.

Impact of BMI Variations on Survival in Elderly Hemodialysis Patients

OBJECTIVES

In elderly hemodialysis patients, protein-energy wasting is associated with poor outcome; however, the association between body mass index (BMI) changes over time, and survival has been seldom studied in this particularly frail population.

DESIGN AND METHODS

This prospective study recruited 502 hemodialysis patients aged ≥75 years from the French cohort ARNOS and followed them from 2005 to 2009. BMI changes over time were modeled by individual linear regression models. Survival analyses used frailty Cox models.

RESULTS

The population average age was 80.9 years. Forty-one percent of the patients died during follow-up. A 1 kg/m(2) lower baseline BMI was associated with a 4% increase in the risk of death over the study period (hazard ratio [HR] 1.04, 95% confidence interval [1.01-1.08], P = .02). A 5% BMI loss per year was associated with a 52% increase in the risk of death (HR 1.52, 95% confidence interval [1.32-1.75], P < .001). In patients who lost weight (>5% BMI loss per year), the lower was the baseline BMI, the higher was the HR for death. There was a similar trend in the patients with stable weight (5% BMI loss-5% BMI gain per year). In patients who gained weight, the HR was unexpectedly higher than in those with stable weight.

CONCLUSIONS

In elderly hemodialysis patients, the impact of the BMI percent change on survival was stronger than that of the baseline BMI. Patients with stable weight had longer survivals than patients who lost or gained weight. Thus, in this population, BMI changes should be regularly assessed. Further studies should assess the safety of weight gain strategies.

Dietary restrictions in dialysis patients: is there anything left to eat?

A significant number of dietary restrictions are imposed traditionally and uniformly on maintenance dialysis patients, whereas there is very little data to support their benefits. Recent studies indicate that dietary restrictions of phosphorus may lead to worse survival and poorer nutritional status. Restricting dietary potassium may deprive dialysis patients of heart-healthy diets and lead to intake of more atherogenic diets. There is little data about the survival benefits of dietary sodium restriction, and limiting fluid intake may inherently lead to lower protein and calorie consumption, when in fact dialysis patients often need higher protein intake to prevent and correct protein-energy wasting. Restricting dietary carbohydrates in diabetic dialysis patients may not be beneficial in those with burnt-out diabetes. Dietary fat including omega-3 fatty acids may be important caloric sources and should not be restricted. Data to justify other dietary restrictions related to calcium, vitamins, and trace elements are scarce and often contradictory. The restriction of eating during hemodialysis treatment is likely another incorrect practice that may worsen hemodialysis induced hypoglycemia and nutritional derangements. We suggest careful relaxation of most dietary restrictions and adoption of a more balanced and individualized approach, thereby easing some of these overzealous restrictions that have not been proven to offer major advantages to patients and their outcomes and which may in fact worsen patients' quality of life and satisfaction. This manuscript critically reviews the current paradigms and practices of recommended dietary regimens in dialysis patients including those related to dietary protein, carbohydrate, fat, phosphorus, potassium, sodium, and calcium, and discusses the feasibility and implications of adherence to ardent dietary restrictions and future research.

Nutritional Markers and Body Composition in Hemodialysis Patients

The aims of this study were to analyse body composition, to detect the presence of undernutrition, and to establish a relationship between undernutrition and the biological markers routinely used as indicators of nutritional status in hemodialysis (HD) patients (pts). We used a body composition monitor (BCM) that expresses body weight in terms of lean tissue mass (LTM) and fat tissue mass (FTM) independent of hydration status. From nine HD units, 934 pts were included. Undernutrition was defined as having a lean tissue index (LTI = LTM/height²) below the 10th percentile of a reference population. Biochemical markers and parameters delivered by BCM were used to compare low LTI and normal LTI groups. Undernutrition prevalence was 58.8% of the population studied. Low LTI pts were older, were significantly more frequently overhydrated, and had been on HD for a longer period of time than the normal LTI group. FTI (FTI = FTM/ height²) was significantly higher in low LTI pts and increased according to BMI. LTI was not influenced by different BMI levels. Albumin and C-reactive protein correlated inversely (r = −0.28). However neither of them was statistically different when considering undernourished and normal LTI pts. Our BCM study was able to show a high prevalence of undernutrition, as expressed by low LTI. In our study, BMI and other common markers, such as albumin, failed to predict malnutrition as determined by BCM.

Dietary restriction and exercise for diabetic patients with chronic kidney disease: a systematic review

BACKGROUND

Obesity and sedentary lifestyle are major health problems and key features to develop cardiovascular disease. Data on the effects of lifestyle interventions in diabetics with chronic kidney disease (CKD) have been conflicting.

STUDY DESIGN

Systematic review.

POPULATION

Diabetes patients with CKD stage 3 to 5. SEARCH STRATEGY AND SOURCES: Medline, Embase and Central were searched to identify papers.

INTERVENTION

Effect of a negative energy balance on hard outcomes in diabetics with CKD.

OUTCOMES

Death, cardiovascular events, glycaemic control, kidney function, metabolic parameters and body composition.

RESULTS

We retained 11 studies. There are insufficient data to evaluate the effect on mortality to promote negative energy balance. None of the studies reported a difference in incidence of Major Adverse Cardiovascular Events. Reduction of energy intake does not alter creatinine clearance but significantly reduces proteinuria (mean difference from -0.66 to -1.77 g/24 h). Interventions with combined exercise and diet resulted in a slower decline of eGFR (-9.2 vs. -20.7 mL/min over two year observation; p<0.001). Aerobic and resistance exercise reduced HbA1c (-0.51 (-0.87 to -0.14); p = 0.007 and -0.38 (-0.72 to -0.22); p = 0.038, respectively). Exercise interventions improve the overall functional status and quality of life in this subgroup. Aerobic exercise reduces BMI (-0.74% (-1.29 to -0.18); p = 0.009) and body weight (-2.2 kg (-3.9 to -0.6); p = 0.008). Resistance exercise reduces trunk fat mass (-0,7±0,1 vs. +0,8 kg ±0,1 kg; p = 0,001-0,005). In none of the studies did the intervention cause an increase in adverse events.

LIMITATIONS

All studies used a different intervention type and mixed patient groups.

CONCLUSIONS

There is insufficient evidence to evaluate the effect of negative energy balance interventions on mortality in diabetic patients with advanced CKD. Overall, these interventions have beneficial effects on glycaemic control, BMI and body composition, functional status and quality of life, and no harmful effects were observed.

Serum uric acid as a clinically useful nutritional marker and predictor of outcome in maintenance hemodialysis patients

OBJECTIVE

The importance of serum uric acid (SUA) for the maintenance of a hemodialysis (MHD) population has not been well established. The aim of this study was to determine if SUA levels are associated with nutritional risk and consequently with adverse clinical outcomes in MHD patients.

METHODS

This was a 2-y prospective observational study, performed on 261 MHD outpatients (38.7% women) with a mean age of 68.6 ± 13.6 y. We measured prospective all-cause and cardiovascular (CV) hospitalization and mortality, nutritional scores (malnutrition-inflammation score [MIS) and geriatric nutritional risk index (GNRI), handgrip strength (HGS), and short-form 36 (SF36) quality-of-life (QoL) scores.

RESULTS

SUA positively correlated with laboratory nutritional markers (albumin, creatinine), body composition parameters, HGS (r = 0.26; P < 0.001) and GNRI (r = 0.34; P < 0.001). SUA negatively correlated with MIS (r = -0.33; P < 0.001) and interleukin-6 (r = -0.13; P = 0.04). Patients in the highest SUA tertile had higher total SF-36 scores (P = 0.04), higher physical functioning (P = 0.003), and role-physical (P = 0.006) SF-36 scales. For each 1 mg/dL increase in baseline SUA levels, the first hospitalization hazard ratio (HR) was 0.79 (95% confidence interval [CI], 0.68-0.91) and first CV event HR was 0.60 (95% CI, 0.44-0.82); all-cause death HR was 0.55 (95% CI, 0.43-0.72) and CV death HR was 0.55 (95% CI, 0.35-0.80). Associations between SUA and mortality risk continued to be significant after adjustments for various confounders including MIS and interleukin-6. Cubic spline survival models confirmed the linear trends.

CONCLUSIONS

In MHD patients, SUA is a good nutritional marker and associates with body composition, muscle function, inflammation, and health-related QoL, upcoming hospitalizations, as well as independently predicting all-cause and CV death risk.

Obesity paradox in end-stage kidney disease patients

In the general population, obesity is associated with increased cardiovascular risk and decreased survival. In patients with end-stage renal disease (ESRD), however, an "obesity paradox" or "reverse epidemiology" (to include lipid and hypertension paradoxes) has been consistently reported, i.e. a higher body mass index (BMI) is paradoxically associated with better survival. This survival advantage of large body size is relatively consistent for hemodialysis patients across racial and regional differences, although published results are mixed for peritoneal dialysis patients. Recent data indicate that both higher skeletal muscle mass and increased total body fat are protective, although there are mixed data on visceral (intra-abdominal) fat. The obesity paradox in ESRD is unlikely to be due to residual confounding alone and has biologic plausibility. Possible causes of the obesity paradox include protein-energy wasting and inflammation, time discrepancy among competitive risk factors (undernutrition versus overnutrition), hemodynamic stability, alteration of circulatory cytokines, sequestration of uremic toxin in adipose tissue, and endotoxin-lipoprotein interaction. The obesity paradox may have significant clinical implications in the management of ESRD patients especially if obese dialysis patients are forced to lose weight upon transplant wait-listing. Well-designed studies exploring the causes and consequences of the reverse epidemiology of cardiovascular risk factors, including the obesity paradox, among ESRD patients could provide more information on mechanisms. These could include controlled trials of nutritional and pharmacologic interventions to examine whether gain in lean body mass or even body fat can improve survival and quality of life in these patients.

Serum creatinine level, a surrogate of muscle mass, predicts mortality in peritoneal dialysis patients

BACKGROUND

In hemodialysis patients, higher serum creatinine (Cr) concentration represents larger muscle mass and predicts greater survival. However, this association remains uncertain in peritoneal dialysis (PD) patients.

METHODS

In a cohort of 10 896 PD patients enrolled from 1 July 2001 to 30 June 2006, the association of baseline serum Cr level and change during the first 3 months after enrollment with all-cause mortality was examined.

RESULTS

The cohort mean ± SD age was 55 ± 15 years old and included 52% women, 24% African-Americans and 48% diabetics. Compared with patients with serum Cr levels of 8.0-9.9 mg/dL, patients with serum Cr levels of <4.0 mg/dL and 4.0-5.9 mg/dL had higher risks of death {HR 1.36 [95% confidence interval (95% CI) 1.19-1.55] and 1.19 (1.08-1.31), respectively} whereas patients with serum Cr levels of 10.0-11.9 mg/dL, 12.0-13.9 mg/dL and ≥14.0 mg/dL had lower risks of death (HR 0.88 [95% CI 0.79-0.97], 0.71 [0.62-0.81] and 0.64 [0.55-0.75], respectively) in the fully adjusted model. Decrease in serum Cr level over 1.0 mg/dL during the 3 months predicted an increased risk of death additionally. The serum Cr-mortality association was robust in patients with PD treatment duration of ≥12 months, but was not observed in those with PD duration of <3 months.

CONCLUSIONS

Muscle mass reflected in serum Cr level may be associated with survival even in PD patients. However, the serum Cr-mortality association is attenuated in the early period of PD treatment, suggesting competing effect of muscle mass versus residual renal function on mortality.

Optimal nutrition in hemodialysis patients

Protein-energy wasting (PEW) is highly prevalent in patients undergoing maintenance hemodialysis (MHD). It is important to note that there is a robust association between the extent of PEW and the risk of hospitalization and death in these patients, regardless of the nutritional marker used. The multiple etiologies of PEW in advanced kidney disease are still being elucidated. Apart from the multiple mechanisms that might lead to PEW, it appears that the common pathway for all of the derangements is related to exaggerated protein degradation along with decreased protein synthesis. The hemodialysis procedure per se is an important contributor to this process. Metabolic and hormonal derangements such as acidosis, inflammation, and resistance to anabolic properties of insulin resistance and growth hormone are all implicated for the development of PEW in MHD patients. Appropriate management of MHD patients at risk for PEW requires a comprehensive combination of strategies to diminish protein and energy depletion and to institute therapies that will avoid further losses. The mainstay of nutritional treatment in MHD patients is provision of an adequate amount of protein and energy, using oral supplementation as needed. Intradialytic parenteral nutrition should be attempted in patients who cannot efficiently use the gastrointestinal tract. Other anabolic strategies such as exercise, anabolic hormones, anti-inflammatory therapies, and appetite stimulants can be considered as complementary therapies in suitable patients.