Lean body mass predicts long-term survival in Chinese patients on peritoneal dialysis

Estimating Dietary Protein and Sodium Intake with Sodium Removal in Peritoneal Dialysis Patients

An increase in dietary protein intake (DPI) carries a risk with respect to increased sodium intake, which further leads to the development of cardiovascular morbidity in peritoneal dialysis (PD) patients. Dialytic (DSR) and urinary sodium removal (USR) are potential indicators of sodium intake. In this single-center cross-sectional study with 60 prevalent PD patients, we analyze the correlation of DPI with sodium intake and the association between residual renal function (RRF) and comorbidity grade, expressed as the Davies score with sodium removal and protein metabolism indices such as normalized protein catabolic rate (nPCR) and lean body mass (LBM). The value of RRF < 2 mL/min/1.73 m2 is significantly associated with lower USR (p = 0.000) and lower %LBM (p < 0.001). The greatest USR is detected in patients with low Davies comorbidity grade (p = 0.018). Compared to patients with DPI < 0.8 g/kg/day, patients with DPI > 0.8 g/kg/day have a greater sodium intake (3.69 ± 0.71 vs. 2.94 ± 0.86; p < 0.018) and a greater nPCR (p < 0.001). Protein intake is significantly correlated with sodium intake (p = 0.041), but not with total sodium removal (TSR). A strong correlation is observed between sodium intake and TSR (p = 0.000), although single TSR values are not the same as the corresponding sodium intake values. An increasing protein intake implies the necessity to determine both sodium intake and sodium removal. Preservation of RRF has a beneficial role not just in sodium removal, but also in the increase of LBM.

Quantification of Abdominal Muscle Mass and Diagnosis of Sarcopenia with Cross-Sectional Imaging in Patients with Polycystic Kidney Disease: Correlation with Total Kidney Volume

Background: Polycystic kidney disease (PKD) is an inherited disorder characterized by renal cysts that may mask lean body loss. This study quantified and compared muscle mass by using computed tomography (CT) and magnetic resonance imaging (MRI) images between the PKD and control groups and correlated muscle mass with total kidney volume (TKV). Methods: We retrospectively enrolled patients who had a new diagnosis of PKD from May 2015 to May 2016. The CT and MRI images at the third lumbar level were processed to measure the total abdominal muscle (TAM) area for the diagnosis of sarcopenia, and TKV was estimated using the ellipsoid formula. Results: We included 37 women and 25 men (mean age: 50.40 years) in the PKD group. There was no difference in body mass index and albumin levels, but significant differences in creatinine level (p < 0.001), TAM area (p = 0.047), and TKV (p < 0.001), were noted between the two groups. A significantly negative correlation was observed between TKV and TAM area after adjustment for body height (r = −0.217, p = 0.003). Conclusions: CT and MRI images can accurately diagnose sarcopenia, which may be masked by cysts in patients with PKD.

Computed tomography-based sarcopenia in patients receiving peritoneal dialysis: Correlation with lean soft tissue and survival

BACKGROUND/PURPOSE

We evaluated whether the results of the computed tomography (CT)-based sarcopenia assessment were correlated with edema-free lean soft tissue (LST) and were associated with the prognosis of patients receiving peritoneal dialysis (PD).

METHODS

We conducted a prospective cohort study and enrolled patients aged >20 years who started to undergo PD between February 2009 and February 2012. All patients underwent LST evaluation and non-contrast abdominal CT for assessing the total skeletal muscle (TSM) and psoas muscle (PM) indices at the level of the third lumbar vertebra. We analyzed the correlation between LST and CT assessment of muscle mass. Then we determined optimal sex-specific cutoff values for TSM-defined and PM-defined sarcopenia to predict mortality, aided by the maximally selected rank statistics.

RESULTS

A total of 158 patients were enrolled, of whom 41 (25.9%) and 65 (41.1%) had sarcopenia based on the TSM and PM indices, respectively. LST was significantly strong correlated with TSM and PM indices (r = 0.517, p < 0.001 and r = 0.688, p < 0.001, respectively). In univariate and multivariate analyses after adjusting clinical and PD-related parameters, only patients with PM-defined sarcopenia had poorer survival than did those without (hazard ratio [HR]: 2.386, 95% confidence interval [CI]: 1.315-4.330), but patients with TSM-defined sarcopenia did not show a poorer survival (HR: 1.608, 95% CI: 0.860-3.006).

CONCLUSION

Sarcopenia assessment based on CT was strongly correlated with LST and PM-defined sarcopenia indicated poor prognosis in patients receiving long-term PD.

Serum Sphingosine-1-phosphate level and peritonitis in peritoneal dialysis patients

BACKGROUND

Given the important role of Sphingosine-1-phosphate (S1P) in maintaining the hemostasis in intestinal barrier function and regulation of inflammation and immune, we hypothesize that S1P might be a biomarker to predict peritonitis in peritoneal dialysis (PD) patients.

METHODS

In this case-control study, 78 stable, continuous ambulatory peritoneal dialysis patients were enrolled and followed for the episode of PD associated peritonitis. Patients were divided into two groups by whether or not they had peritonitis during follow-up: non-peritonitis (n = 65) and peritonitis (n = 13) group. S1P was analyzed by enzyme-linked immunosorbent assay. Logistic regression analysis was used to assess factors associated with peritonitis. The variables identified by univariable regression models (p < 0.1) were further selected into the multivariable logistic regression model to determine whether they could independently affect peritonitis.

RESULTS

Patients with peritonitis had a lower level of S1P than that of patients without peritonitis (1.3 ng/mL IQ 0.8, 3.6 ng/mL vs. 2.8 ng/mL IQ 1.5, 5.4 ng/mL, p = 0.018). The peritonitis group had lower serum albumin, lower blood leukocyte, lower hemoglobin and lower platelet count as compared to the non-peritonitis group. Logistic regression analysis showed that S1P (OR = 0.381, 95% CI = 0.171-0.848, p = 0.018), blood leukocyte count (OR = 0.438, 95% CI = 0.207-0.925, p = 0.030), and serum albumin (OR = 0.732, 95% CI = 0.556-0.962, p = 0.025) were independent factors associated with peritonitis in the present PD population.

CONCLUSION

Our study showed that S1P was an independent determinant of subsequent peritonitis in PD patients. S1P might serve as a biomarker to predict peritonitis in PD 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.

Muscle-Bone Crosstalk in Chronic Kidney Disease: The Potential Modulatory Effects of Exercise

Chronic kidney disease (CKD) is a prevalent worldwide public burden that increasingly compromises overall health as the disease progresses. Two of the most negatively affected tissues are bone and skeletal muscle, with CKD negatively impacting their structure, function and activity, impairing the quality of life of these patients and contributing to morbidity and mortality. Whereas skeletal health in this population has conventionally been associated with bone and mineral disorders, sarcopenia has been observed to impact skeletal muscle health in CKD. Indeed, bone and muscle tissues are linked anatomically and physiologically, and together regulate functional and metabolic mechanisms. With the initial crosstalk between the skeleton and muscle proposed to explain bone formation through muscle contraction, it is now understood that this communication occurs through the interaction of myokines and osteokines, with the skeletal muscle secretome playing a pivotal role in the regulation of bone activity. Regular exercise has been reported to be beneficial to overall health. Also, the positive regulatory effect that exercise has been proposed to have on bone and muscle anatomical, functional, and metabolic activity has led to the proposal of regular physical exercise as a therapeutic strategy for muscle and bone-related disorders. The detection of bone- and muscle-derived cytokine secretion following physical exercise has strengthened the idea of a cross communication between these organs. Hence, this review presents an overview of the impact of CKD in bone and skeletal muscle, and narrates how these tissues intrinsically communicate with each other, with focus on the potential effect of exercise in the modulation of this intercommunication.

Predictive Value of Estimated Lean Body Mass for Neurological Outcomes after Out-of-Hospital Cardiac Arrest

Background: Postcardiac arrest patients with a return of spontaneous circulation (ROSC) are critically ill, and high body mass index (BMI) is ascertained to be associated with good prognosis in patients with a critically ill condition. However, the exact mechanism has been unknown. To assess the effectiveness of skeletal muscles in reducing neuronal injury after the initial damage owing to cardiac arrest, we investigated the relationship between estimated lean body mass (LBM) and the prognosis of postcardiac arrest patients. Methods: This retrospective cohort study included adult patients with ROSC after out-of-hospital cardiac arrest from January 2015 to March 2020. The enrolled patients were allocated into good- and poor-outcome groups (cerebral performance category (CPC) scores 1–2 and 3–5, respectively). Estimated LBM was categorized into quartiles. Multivariate regression models were used to evaluate the association between LBM and a good CPC score. The area under the receiver operating characteristic curve (AUROC) was assessed. Results: In total, 155 patients were analyzed (CPC score 1–2 vs. 3–5, n = 70 vs. n = 85). Patients’ age, first monitored rhythm, no-flow time, presumed cause of arrest, BMI, and LBM were different (p < 0.05). Fourth-quartile LBM (≥48.98 kg) was associated with good neurological outcome of postcardiac arrest patients (odds ratio = 4.81, 95% confidence interval (CI), 1.10–25.55, p = 0.04). Initial high LBM was also a predictor of good neurological outcomes (AUROC of multivariate regression model including LBM: 0.918). Conclusions: Initial LBM above 48.98kg is a feasible prognostic factor for good neurological outcomes in postcardiac arrest patients.

Technique Failure in Peritoneal Dialysis: Etiologies and Risk Assessment

Technique failure (TF) is a well-recognized challenge encountered in patients undergoing peritoneal dialysis (PD). Identification of patients at risk for this complication is of utmost importance. Early detection of patients at risk and development of preventative strategies can improve technique survival that may lead to an increased utilization of PD. It will also promote a safe and planned transfer to hemodialysis once a patient identified with TF. The aim of this review is to summarize risk factors and scenarios associated with TF focusing on prevention of remediable factors at their earliest stage. Furthermore, integration of this knowledge into quality improvement initiatives should be entertained in an effort to improve outcomes.

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.

How to Prevent Renal Cachexia? A Clinical Randomized Pilot Study Testing Oral Supplemental Nutrition in Hemodialysis Patients With and Without Human Immunodeficiency Virus Infection

OBJECTIVE

End-stage renal disease associates with catabolism and sarcopenia. Hypothetically, peroral supplemental nutrition over 6 months prevents catabolism in hemodialysis patients.

DESIGN

Prospective randomized pilot study (ClinicalTrials.gov Identifier: NCT00687050).

SUBJECTS

Twenty-three hemodialysis patients (15 males and 7 females) with or without human immunodeficiency virus (HIV) infection of 2 ambulatory hemodialysis centers.

INTERVENTION

HIV-positive hemodialysis patients (n = 7, Group 1) were started on supplemental nutrition drinks (250 kcal/day), HIV-negative hemodialysis patients (n = 16, Group 2) were randomized to supplemental nutrition drinks (250 kcal/day) or received none.

MAIN OUTCOME MEASURES

Body impedance analysis, anthropometric measures, magnetic resonance imaging results for mid-iliopsoas muscle cross-sectional area and laboratory parameters including albumin, cytokines at baseline, and at 6 months follow-up.

RESULTS

Seven patients in Group 1 (mean age: 50.6 ± 9.6 years) and 16 patients in Group 2 (mean age: 54.0 ± 13.3 years) were recruited. Serum creatinine (Group 1: 6.4 ± 3.0 mg/dL; Group 2: 10.7 ± 2.5 mg/dL; P < .01), Body impedance analysis-derived phase angle alpha (Group 1: 5.1 ± 1.2; Group 2: 6.9 ± 1.6; P < .01), mid-arm circumference (Group 1: 26.1 ± 1.3 cm; Group 2: 29.6 ± 2.4 cm; P < .01) were less in Group 1 versus Group 2 patients at baseline suggesting that HIV-positive hemodialysis patients had a poorer nutritional status at baseline. At 6-month follow-up, mortality was higher in Group 1 patients (29%) than in Group 2 patients (6%). There was no significant treatment effect on nutritional status in survivors of Group 1 or in the supplemental nutrition arm of Group 2 when compared with baseline or to untreated controls.

CONCLUSIONS

A new oral supplemental nutrition over 6 months had no treatment effect in surviving HIV-positive hemodialysis patients or in maintenance hemodialysis patients without HIV infection. The limitations of this study were small study size and unexpected high mortality among HIV-positive hemodialysis patients.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Reproducibility of serial creatinine excretion measurements in peritoneal dialysis

AIM

To test whether muscle mass evaluated by creatinine excretion (EX_Cr) is maintained in patients with end-stage kidney disease (ESKD) treated by peritoneal dialysis (PD), we evaluated repeated measurements of EX_Cr in a PD population.

METHODS

One hundred and sixty-six PD patients (94 male, 72 female) receiving the same PD dose for the duration of the study (up to approximately 2.5 years) had repeated determinations of total (in urine plus spent dialysate) 24-h EX_Cr (EX_Cr T) to assess the adequacy of PD by creatinine clearance. All 166 patients had two EX_Cr T determinations, 84 of the 166 patients had three EX_Cr T determinations and 44 of the 166 patients had four EX_Cr T measurements. EX_Cr T values were compared using the paired t test in the patients who had two studies and by repeated measures ANOVA in those who were studied three or four times.

RESULTS

In patients who were studied twice, with the first and second EX_Cr T measurements performed at 9.2 ± 15.2 mo and 17.4 ± 15.8 mo after onset of PD, respectively, EX_Cr T did not differ between the first and second study. In patients studied three times and whose final assessment occurred 24.7 ± 16.3 mo after initiating PD, EX_Cr T did not differ between the first and second study, but was significantly lower in the third study compared to the first study. In patients who were studied four times and whose fourth measurement was taken 31.9 ± 16.8 mo after onset of PD, EX_Cr T did not differ between any of the studies. The average EX_Cr T value did not change significantly, with the exception of the third study in the patients studied thrice. However, repeated determinations of EX_Cr T in individuals showed substantial variability, with approximately 50% of the repeated determinations being higher or lower than the first determination by 15% or more.

CONCLUSION

The average value of EX_Cr T remains relatively constant for up to 2.5 years of follow-up in PD patients who adhere to the same PD schedule. However, repeated individual EX_Cr T values vary considerably in a large proportion of the patients. Further studies are needed to evaluate the clinical significance of varying EX_Cr T values and the stability of EX_Cr T beyond 2.5 years of PD follow-up.

Low appendicular muscle mass is associated with mortality in peritoneal dialysis patients: a single-center cohort study

BACKGROUND/OBJECTIVES

There are few studies of the association between low appendicular muscle mass (LAM) and clinical outcomes in peritoneal dialysis (PD) patients. We aimed to determine the clinical association between LAM and clinical outcomes in PD patients.

SUBJECT/METHODS

We reviewed all PD patients who underwent PD between January 2001 and April 2014. Each patient's appendicular lean mass was estimated using dual-energy X-ray absorptiometry. The appendicular muscle mass index (AMI) was calculated using total appendicular lean mass (kg) over body mass index (kg/m²). The cut-off AMI value for LAM was <0.789 for men and <0.512 for women.

RESULTS

The number of patients in the Non-LAM and LAM groups was 328 and 303, respectively. The median follow-up durations in the Non-LAM and LAM groups were 47 and 49 months, respectively. The numbers of deaths in the Non-LAM and LAM groups were 96 (29.3%) and 160 (52.8%), respectively. In a comparison with the Non-LAM group, the hazard ratio in the LAM group was 1.74 (95% confidence interval (CI), 1.35-2.24) in univariate and 1.71 (95% CI, 1.28-2.26) in multivariate Cox regression analysis. In addition, the hazard ratio for a 0.1 increase in baseline AMI was 0.89 (95% CI, 0.84-0.95) in univariate analysis and 0.84 (95% CI, 0.76-0.91) in multivariate analysis. Analyses using the 1-year AMI showed trends similar to those for the initial AMI.

CONCLUSIONS

Our study showed the association of LAM with mortality in the incident PD patients.

The association between body mass index and mortality among Asian peritoneal dialysis patients: A meta-analysis

BACKGROUND

Previous studies have revealed that increased body mass index (BMI) is associated with decreased mortality among hemodialysis patients. However, few studies have dealt with the association between BMI and mortality among patients undergoing peritoneal dialysis (PD) and even fewer studies have focused on the Asian PD patients. The reported studies were often non-conclusive and some even yielded contradictory results. This paper, to our best knowledge, registers the first attempt to systematically review the current literature and summarize new results on the association between BMI and mortality among the Asian PD population.

METHOD

A systematic literature review was performed in Medline and EMBASE to identify relevant cohort studies on all-cause and cardiovascular disease (CVD) mortality stratified by BMI categories tailored to Asians among the Asian PD population. We meta-analyzed individual results based on a random effect model, strictly complying with Preferred Reporting Items for Systematic Reviews and Meta-analysis.

RESULTS

The paper reviews seven cohort studies with a total of 3,610 Asian PD patients. Obese group (BMI = 25-29.9 kg/m2) was associated with higher risk of all-cause mortality (HR = 1.46, 95%CI [1.07-1.98]; p = 0.02) and CVD mortality (HR = 2.01, 95%CI [1.14-3.54]; p = 0.02), compared to the normal group (BMI = 18.5-22.9 kg/m2). The underweight group (BMI<18.5kg/m2) was also associated with an elevated risk of all-cause mortality (HR = 2.11, 95%CI [1.46-3.07]; p<0.001). No significant associations between BMI with all-cause mortality were found among the overweight group (23-24.9 kg/m2) (HR = 1.00, 95%CI [0.76-1.32]; p = 0.9). The association between BMI and CVD mortality risk among the underweight and overweight groups was found nonsignificant (p = 0.5 and 0.6 respectively).

CONCLUSION

Obesity is associated with increased mortality in Asian PD patients. The study indicates a "V-shaped" trend in the association between BMI and mortality in these patients.

A Simpler Creatinine Index Can Predict Long-Term Survival in Chinese Hemodialysis Patients

Background

Low lean body mass (LBM) is an indicator of malnutrition inflammation syndrome, which is common in hemodialysis (HD) patients. The creatinine index (CI) has been validated as a reliable method to estimate LBM and evaluate the protein-energy status of HD patients. However, the traditional creatinine index formula was complex. We sought to investigate the impact of CI derived from a new simple formula on Chinese HD patient outcomes.

Methods

In this retrospective cohort study, we enrolled 1269 patients who initiated HD between February 1981 and February 2012 and followed them until the end of February 2013. CI was calculated using the simple creatinine kinetic model (CKM) formula. Multiple linear regression analysis and Cox regression proportional hazard analysis were used to define independent variables and compare survival between groups.

Results

The 1269 HD patients were categorized into 3 groups according to the tertiles of calculated CI between men and women. Each group consisted of 423 patients (50.6% men, 49.4% women). Patients in the highest sex-specific tertile of CI had longer overall survival (HR, 0.46; P 0.002). BMI did not significantly associate with survival after adjustment (HR,0.99; P 0.613).

Conclusions

CI derived from the simple CKM formula serves as a good parameter than BMI to predict the survival of HD patients. The formula could extend its convenient use in clinical practice for HD patients.

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.

[The specific nutritionnal care in peritoneal dialysis]

Protein energy wasting is a major complication in peritoneal dialysis. It is leading to a poor quality of life and increasing mortality. Diagnosis must be early, according to criteria defined by the International society of renal nutrition and metabolism. It is necessary to appropriate the diagnostic tools with dialysis method. The nutritional care is difficult in peritoneal dialysis. Indeed, studies are limited and practical nutrition is complex. In this point of view, we propose to treat guidelines for protein energy wasting, in peritoneal dialysis patients.

Impact of dialysis modality on technique survival in end-stage renal disease patients

BACKGROUND/AIMS

This study analyzed the risk factors for technique survival in dialysis patients and compared technique survival rates between hemodialysis (HD) and peritoneal dialysis (PD) in a prospective cohort of Korean patients.

METHODS

A total of 1,042 patients undergoing dialysis from September 2008 to June 2011 were analyzed. The dialysis modality was defined as that used 90 days after commencing dialysis. Technique survival was compared between the two dialysis modalities, and the predictive risk factors were evaluated.

RESULTS

The dialysis modality was an independent risk factor predictive of technique survival. PD had a higher risk for technique failure than HD (hazard ratio [HR], 10.8; 95% confidence interval [CI], 1.9 to 62.0; p = 0.008) during a median follow-up of 11.0 months. In the PD group, a high body mass index (BMI) was an independent risk factor for technique failure (HR, 1.3; 95% CI, 1.0 to 1.8; p = 0.036). Peritonitis was the most common cause of PD technique failure. The difference in technique survival between PD and HD was more prominent in diabetic patients with a good nutritional status and in non-diabetic patients with a poor nutritional status.

CONCLUSIONS

In a prospective cohort of Korean patients with end-stage renal disease, PD was associated with a higher risk of technique failure than HD. Diabetic patients with a good nutritional status and non-diabetic patients with a poor nutritional status, as well as patients with a higher BMI, had an inferior technique survival rate with PD compared to HD.

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.

Plasma Transthyretin as a Biomarker of Lean Body Mass and Catabolic States

Plasma transthyretin (TTR) is a plasma protein secreted by the liver that circulates bound to retinol-binding protein 4 (RBP4) and its retinol ligand. TTR is the sole plasma protein that reveals from birth to old age evolutionary patterns that are closely superimposable to those of lean body mass (LBM) and thus works as the best surrogate analyte of LBM. Any alteration in energy-to-protein balance impairs the accretion of LBM reserves and causes early depression of TTR production. In acute inflammatory states, cytokines induce urinary leakage of nitrogenous catabolites, deplete LBM stores, and cause an abrupt decrease in TTR and RBP4 concentrations. As a result, thyroxine and retinol ligands are released in free form, creating a second frontline that strengthens that primarily initiated by cytokines. Malnutrition and inflammation thus keep in check TTR and RBP4 secretion by using distinct and unrelated physiologic pathways, but they operate in concert to downregulate LBM stores. The biomarker complex integrates these opposite mechanisms at any time and thereby constitutes an ideally suited tool to determine residual LBM resources still available for metabolic responses, hence predicting outcomes of the most interwoven disease conditions.

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.

Essential amino acid ingestion as an efficient nutritional strategy for the preservation of muscle mass following gastric bypass surgery

Loss of skeletal muscle in patients who have undergone gastric bypass is a consistent observation. Skeletal muscle constitutes the largest protein/amino acid pool in the body, and loss of skeletal muscle has important implications in health and disease. Sustaining a given level of muscle protein requires a balance between the rates of muscle protein synthesis and breakdown. Current evidence suggests that reduced rate of protein synthesis is implicated in the loss of muscle after gastric bypass. This is not surprising given a less than optimal dietary protein intake after the procedure and because, unlike other macronutrients, protein/amino acids are not stored in the body. Ingesting essential amino acids (EAAs), which cannot be synthesized de novo and have the primary role in the regulation of muscle protein synthesis, can potentially ameliorate loss of muscle protein after gastric bypass. At the same time, ingestion of EAAs provides a more efficient nutritional approach (i.e., greater stimulation of protein synthesis relative to the amount of amino acids ingested) to enhance muscle protein synthesis compared with the ingestion of intact protein. Changing current dietary practices toward increasing ingestion of EAAs provides an approach that can potentially prevent loss of lean body tissue and ultimately achieve a more sustained level of health in patients who have undergone gastric bypass.

Visceral fat area is associated with HbA1c but not dialysate-related glucose load in nondiabetic PD patients

Factors associated with increased visceral fat area (VFA) have been well documented in the general population but rarely explored in nondiabetic individuals on peritoneal dialysis (PD). As glycosylated hemoglobin (HbA1c) is positively correlated with VFA in diabetic patients, we hypothesized that the same correlation would exist in nondiabetic PD patients. We enrolled 105 nondiabetic patients who had undergone chronic PD for more than 3 months. Each subject underwent an abdominal computed tomography (CT) scan, and the umbilicus cut was analyzed for VFA. VFA values, corrected for body mass index and subjected to natural logarithm transformations, were examined to determine whether they were correlated with HbA1c and other parameters. PD dialysates prescribed at the time of enrollment were recorded to calculate glucose load. We found that when 105 nondiabetic PD patients were classified according to tertiles of HbA1c, higher HbA1c was associated with larger VFA. Multiple linear regression analysis revealed that HbA1c was an independent determinant of VFA, while glucose load and other PD-specific factors were not. In summary, HbA1c, but not PD-related glucose load, was positively correlated with VFA in nondiabetic PD patients, suggesting clinical utility of HbA1c in the PD population.

Bone is Not Alone: the Effects of Skeletal Muscle Dysfunction in Chronic Kidney Disease

Chronic kidney disease (CKD) is associated with a decline in muscle mass, strength, and function, collectively called "sarcopenia." Sarcopenia is associated with hospitalizations and mortality in CKD and is therefore important to understand and characterize. While the focus of skeletal health in CKD has traditionally focused on bone and mineral aberrations, it is now recognized that sarcopenia must also play a role in poor musculoskeletal health in this population. In this paper, we present an overview of skeletal muscle changes in CKD, including defects in skeletal muscle catabolism and anabolism in uremic tissue. There are many gaps in knowledge in this field that should be the focus for future research to unravel pathogenesis and therapies for musculoskeletal health in CKD.

Subjective global assessment for the diagnosis of protein-energy wasting in nondialysis-dependent chronic kidney disease patients

OBJECTIVES

Subjective global assessment (SGA) has been demonstrated to be a reliable method for protein-energy wasting (PEW) evaluation in chronic kidney disease (CKD) patients on dialysis. Few data are available on PEW evaluation in nondialysis stages of CKD, and the validity of SGA has been scarcely investigated in this population. Herein, we aimed to evaluate in nondialysis-dependent CKD patients (NDD-CKD): (1) the prevalence of PEW by SGA; (2) the most common abnormalities of the SGA components; and (3) the agreement of SGA with the traditional anthropometric parameters.

DESIGN AND SUBJECTS

This is a retrospective cross-sectional study including 922 NDD-CKD patients referred to the renal dietitians in the period of 2001 to 2012. Nutritional status was assessed by 7-point SGA. Body mass index (BMI), midarm circumference, midarm muscle circumference, and triceps skinfold thickness were available from 494 patients.

RESULTS

From the 922 patients, 58.6% were men, mean age was 63.8 ± 13.6 years, BMI was 27.7 ± 5.3 kg/m(2). The majority of the patients were in CKD Stages 3 (48.9%) or 4 (40.3%). PEW (SGA ≤5) was present in 11% of the patients and 32% had signs of PEW (SGA 6). In the logistic regression analysis, the presence of comorbidities and worse renal function were independently associated with PEW. Among the SGA components, the most frequent abnormality in patients with PEW was muscle and fat wasting (88.6%). BMI, midarm circumference, midarm muscle circumference, and triceps skinfold thickness were lower across the worse SGA scores, and a moderate to good level of agreement was found between the anthropometric parameters and presence of PEW evaluated by SGA.

CONCLUSIONS

The prevalence of PEW was 11% in our unselected cohort of NDD-CKD patients. The physical examination component (muscle/fat wasting) was the most frequent alteration found in those patients. When compared with anthropometric parameters, 7-point SGA has shown to be a valid tool to assess PEW in NDD-CKD population.

Creatinine index as a surrogate of lean body mass derived from urea Kt/V, pre-dialysis serum levels and anthropometric characteristics of haemodialysis patients

Background and Objectives

Protein-energy wasting is common in long-term haemodialysis (HD) patients with chronic kidney disease and is associated with increased morbidity and mortality. The creatinine index (CI) is a simple and useful nutritional parameter reflecting the dietary skeletal muscle protein intake and skeletal muscle mass of the patient. Because of the complexity of creatinine kinetic modeling (CKM) to derive CI, we developed a more simplified formula to estimate CI in HD patients.

Design, Setting, Participants & Measurements

A large database of 549 HD patients followed over more than 20 years including monthly CKM-derived CI values was used to develop a simple equation based on patient demographics, predialysis serum creatinine values and dialysis dose (_spKt/V) using mixed regression models.

Results

The equation to estimate CI was developed based on age, gender, pre-dialysis serum creatinine concentrations and _spKt/V urea. The equation-derived CI correlated strongly with the measured CI using CKM (correlation coefficient  = 0.79, p-value <0.001). The mean error of CI prediction using the equation was 13.47%. Preliminary examples of few typical HD patients have been used to illustrate the clinical relevance and potential usefulness of CI.

Conclusions

The elementary equation used to derive CI using demographic parameters, pre-dialysis serum creatinine concentrations and dialysis dose is a simple and accurate surrogate measure for muscle mass estimation. However, the predictive value of the simplified CI assessment method on mortality deserves further evaluation in large cohorts of HD patients.

Metabolic syndrome and abdominal fat are associated with inflammation, but not with clinical outcomes, in peritoneal dialysis patients

Background

In the general population, metabolic syndrome (MetS) is correlated with visceral fat and a risk factor for cardiovascular disease (CVD); however, little is known about the significance of abdominal fat and its association with inflammation and medication use in peritoneal dialysis (PD) patients. We investigated the relationship of visceral fat area (VFA) with C-reactive protein (CRP) levels and medication use in PD patients and followed their clinical outcomes.

Methods

In a prospective study from February 2009 to February 2012, we assessed diabetes mellitus (DM) status, clinical and PD-associated characteristics, medication use, CRP levels, components of MetS, and VFA in 183 PD patients. These patients were categorized into 3 groups based on MetS and DM status: non-MetS (group 1, n = 73), MetS (group 2, n = 65), and DM (group 3, n = 45). VFA was evaluated by computed tomography (CT) and corrected for body mass index (BMI).

Results

Patients in group 1 had smaller VFAs than patients in groups 2 and 3 (3.2 ± 1.8, 4.6 ± 1.9, and 4.9 ± 2.0 cm²/[kg/m²], respectively, P < 0.05) and lower CRP levels (0.97 ± 2.31, 1.27 ± 2.57, and 1.11 ± 1.35 mg/dL, respectively, P < 0.05). VFA increased with the number of criteria met for MetS. After adjusting for age, body weight, and sex, CRP and albumin levels functioned as independent positive predictors of VFA; on other hand, the use of renin-angiotensin system blockers was inversely correlated with VFA in PD patients without DM. In the survival analysis, DM patients (group 3) had the poorest survival among the 3 groups, but no significant differences were found between groups 1 and 2.

Conclusion

This study showed that VFA and MetS are associated with CRP levels but cannot predict survival in PD patients without DM. The complex relationship of nutritional parameters to VFA and MetS may explain these results. The type of antihypertensive medication used was also associated with the VFA. The mechanisms behind these findings warrant further investigation.