Clinical value of body composition monitor to evaluate lean and fat tissue mass in peritoneal dialysis

Sarcopenic obesity in predialysis chronic kidney disease: Muscle strength is a predictor of mortlity and disease progression in a six-year prospective cohort

INTRODUCTION

Sarcopenic obesity (SO) is a poorly defined physiological condition that is associated with increased morbimortality in the general population. The prevalence of SO has increased, making it an important public health issue; however, its effects when associated with other chronic conditions are still unclear. Therefore, it is necessary to comprehend the potential outcomes in chronic kidney disease (CKD) patients.

OBJECTIVE

To assess the associations of predialysis CKD patients with SO and its components with death and disease progression to renal replacement therapy (RRT).

METHODS

Prospective six-year cohort with 100 patients with predialysis CKD (stages one through five). Participants were older than 18 years and signed an informed consent form. The data were collected in an outpatient clinic specializing in predialysis care, and demographic, clinical, laboratory and inflammatory variable data were collected. A descriptive analysis was performed, and the SO and non-SO groups were compared with Student's t test, Mann‒Whitney U test and Cox regression, taking into consideration all relevant confounding variables. Body composition variables utilized to diagnose SO were separately analyzed along with the outcomes.

RESULTS

Sixteen percent of our sample were diagnosed with SO, but this was not associated with death or RRT, while lower BMI values were negatively associated with these outcomes. However, in an isolated analysis, handgrip strength was correlated with both RRT (p = 0.029) and death (p = 0.003). We recommend that health professionals pay greater attention to muscle strength, striving for earlier assessment, in an effort to better counsel patients and implement actions to increase or preserve strength through nonpharmacological treatment, such as resistance training.

Bioimpedance spectroscopy: Is a picture worth a thousand words?

Volume status can be difficult to assess in dialysis patients. Peripheral edema, elevated venous pressure, lung crackles, and hypertension are taught as signs of fluid overload, but sensitivity and specificity are poor. Bioimpedance technology has evolved from early single frequency to multifrequency machines which apply spectroscopic analysis (BIS), modeling data to physics-based mixture theory. Bioimpedance plots can aid the evaluation of hydration status and body composition. The challenge remains how to use this information to manage dialysis populations, particularly as interventions to improve over hydration, sarcopenia, and adiposity are not without side effects. It is therefore of no surprise that validation studies for BIS use in peritoneal dialysis patients are limited, and results from clinical trials are inconsistent and conflicting. Despite these limitations, BIS has clinical utility with potential to accurately evaluate small changes in body tissue components. This article explains the information a BIS plot ("picture") can provide and how it can contribute to the overall clinical assessment of a patient. However, it remains the role of the clinician to integrate information and devise treatment strategies to optimize competing patient risks, fluid and nutrition status, effects of high glucose PD fluids on membrane function, and quality of life issues.

Probiotic treatment induces changes in intestinal microbiota but does not alter SCFA levels in peritoneal dialysis patients-a randomized, placebo-controlled trial

The gut microbiota alterations interact with the pathogenesis and progression of chronic kidney disease (CKD). Probiotics have received wide attention as a potential management in CKD. We investigated the effects of Lactobacillus paracasei N1115 (LP N1115) on intestinal microbiota and related short-chain fatty acids (SCFAs) in end stage kidney disease patients on peritoneal dialysis (PD) in a single-center, prospective, randomized, double-blind, placebo-controlled study. The patients were randomly allocated into two groups. The intervention group (n = 38, PR group) was given the probiotics (two bags) containing fructooligosaccharide (FOS) (additive amount > 80%), maltosaccharin, and LP N1115 (additive amount > 3 × 1010 CFU/bag) every day whereas the control group (n = 19, PL group) received placebo (two bags) containing only pregelatinized starch and lactose, both for 12 weeks. In addition to collecting fecal samples for 16S rRNA gene high-throughput sequencing and SCFAs analysis, gastrointestinal (GI) symptoms were also assessed at baseline and after the intervention. Probiotics administration caused significant changes in the composition of gut microbiota, as indicated by increased abundance of beneficial bacteria (Firmicutes), decreased Bacteroidetes, and opportunistic pathogens (Fusobacterium, Bilophila) (p < 0.05). However, there was no significant difference in intestinal microbial diversity. SCFAs levels increased in PR group although the change was not statistically significant between the two groups (P > 0.05). In addition, probiotics administration could effectively reduce GI symptoms, particularly in dyspepsia and constipation (p < 0.05). Together, the results suggest that probiotics administration caused significant changes in the composition of gut microbiota and also could effectively reduce GI symptoms, particularly in dyspepsia and constipation in PD patients. Trial registration: This study was registered with the Chinese Clinical Trial Registry (Trial registration number: ChiCTR-INR-17011718; Date of the first registration: 21/06/2017).

Association of changes in body composition with all-cause mortality in patients undergoing hemodialysis: A prospective cohort study

OBJECTIVES

This study aimed to explore the effect of longitudinal body composition changes on mortality risk in patients undergoing hemodialysis and identify whether changes in body composition can more accurately predict mortality than baseline status.

METHODS

A prospective cohort study was conducted on 340 patients undergoing hemodialysis. Lean mass and body fat were determined using a bioimpedance spectroscopy (BIS) device and expressed as the lean tissue index (LTI) or fat tissue index (FTI), respectively. The patients were subjected to BIS at baseline and after 1 year. The hazard ratio (HR) for death was calculated using Cox regression analysis.

RESULTS

Among 340 patients, 289 were tested with a repeat BIS. LTI loss and FTI gain were observed in 51.2% and 47.1% of the patients, respectively. Low baseline LTI was a significant predictor of all-cause mortality after adjusting for demographic and biochemical parameters (HR, 2.41; P = 0.047), but not when comorbidities were included in the multivariate analysis. However, after adjusting for various confounding factors, LTI loss (HR, 3.40; P = 0.039) and FTI gain (HR, 4.06; P = 0.024) were independent risk factors for all-cause mortality, and the adjusted HR for LTI loss and FTI gain vs. no LTI loss and no FTI gain was 5.34 (P = 0.016).

CONCLUSIONS

LTI loss and FTI gain, particularly their combination, are important predictors of survival in patients undergoing hemodialysis. Our results emphasize that longitudinal changes in LTI and FTI are more strongly associated with all-cause mortality than single-point values. Therefore, it is important to dynamically assess the muscle and fat tissues and develop potential targeted treatment strategies for this population.

Comparing bioimpedance spectrometry and traditional creatinine kinetics methods for the assessment of muscle mass in peritoneal dialysis patients

Background

Sarcopenia is a common and serious problem in patients receiving peritoneal dialysis (PD). Lean tissue mass (LTM) by bioimpedance spectrometry is a reasonably accurate method for measuring muscle mass. Fat-free edema-free body mass (FEBM) as determined by the creatinine kinetics method is a traditional method but evidence to support its use is limited.

Methods

We studied 198 new PD patients. Their serial LTM and FEBM were reviewed and compared by the Bland and Altman method. Multi-variable regression model was used to determine factors associated with the disparity between the two methods.

Results

There was a significant but moderate correlation between LTM and FEBM (r = 0.309, P < .0001). LTM was consistently higher than FEBM, with an average difference 13.98 kg (95% confidence interval -5.90 to 33.86 kg), and the difference strongly correlated with LTM (r = 0.781, P < .0001). By multivariable linear regression analysis, LTM and residual renal function were independent predictors of the LTM-FEBM difference. Where the measurements were repeated in 12 months, there was no significant correlation between ∆LTM and ∆FEBM (r = -0.031, P = .799).

Conclusion

There is a significant difference between LTM and FFBM. This discrepancy correlated with LTM and residual renal function, highlighting the limitations of FFBM in assessing skeletal muscle mass.

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

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

Relation between myostatin levels and malnutrition and muscle wasting in hemodialysis patients

BACKGROUND AND AIM

Malnutrition is one of the most troublesome comorbidities among hemodialysis patients (HD). Myostatin (MSTN) belongs to the transforming growth factor-β superfamily. In HD patients, MSTN effects are not limited to skeletal muscle growth. The present study aimed to assess MSTN levels in HD patients and its relation to various clinical and biochemical parameters.

PATIENTS AND METHODS

The present case control study included 60 patients on HD for at least three years. In addition, there were age and sex-matched healthy subjects who constitutes the control group. Nutritional status was evaluated using the malnutrition inflammation score (MIS). Muscle wasting in the present study was evaluated using the lean tissue index (LTI) as assessed by the body composition monitor (BCM). Rectus Femoris Muscle (RFM) thickness was also measured as indicator for nutritional status of patient.

RESULTS

The present study included 60 HD patients, and ageand sex-matched healthy controls. Patients expressed significantly higher myostatin levels when compared to controls [median (IQR): 221.3 (153.5-688.2) versus 144.8 (97.0-281.7), p < 0.001]. According to MIS, patients were classified into those with no/mild malnutrition (n = 22) and others with moderate/severe malnutrition (n = 38). Comparison between the two subgroups revealed that the former group had significantly lower myostatin levels [167.7 (150.3-236.3) versus 341.7 (160.9-955.9), p = 0.004]. According to LTI, patients were classified into those with muscle wasting (n = 23) and others without muscle wasting (n = 37). Comparative analysis showed that patients in the former group had significantly higher myostatin levels [775.1 (325.1-2133.7) versus 161.8 (142.6-302.3), p < 0.001].

CONCLUSIONS

Myostatin seems to be a promising marker for identification of malnutrition and muscle wasting in HD patients.

Nutritional Assessments by Bioimpedance Technique in Dialysis Patients

Bioelectrical impedance analysis (BIA) has been extensively applied in nutritional assessments on the general population, and it is recommended in establishing the diagnosis of malnutrition and sarcopenia. The bioimpedance technique has become a promising modality through which to measure the whole-body composition in dialysis patients, where the presence of subclinical volume overload and sarcopenic obesity may be overlooked by assessing body weight alone. In the past two decades, bioimpedance devices have evolved from applying a single frequency to a range of frequencies (bioimpedance spectroscopy, BIS), in which the latter is incorporated with a three-compartment model that allows for the simultaneous measurement of the volume of overhydration, adipose tissue mass (ATM), and lean tissue mass (LTM). However, clinicians should be aware of common potential limitations, such as the adoption of population-specific prediction equations in some BIA devices. Inherent prediction error does exist in the bioimpedance technique, but the extent to which this error becomes clinically significant remains to be determined. Importantly, reduction in LTM has been associated with increased risk of frailty, hospitalization, and mortality in dialysis patients, whereas the prognostic value of ATM remains debatable. Further studies are needed to determine whether modifications of bioimpedance-derived body composition parameters through nutrition intervention can result in clinical benefits.

Sex Differences in the Association of Weight-Adjusted-Waist Index with Sarcopenic Obesity: A Cross-Sectional Study of Hemodialysis Patients

Objective: To explore the association between weight-adjusted-waist index (WWI) and sarcopenic obesity (SO) in patients with maintenance hemodialysis (MHD). Methods: A multicenter, cross-sectional study that included 3311 adult MHD patients was conducted in 20 hemodialysis (HD) centers from June 1, 2021, to August 30, 2021. Body composition was evaluated by body composition monitor based on bioimpedance spectroscopy. Hand grip strength was measured by CAMRY® dynamometer. WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Multiple logistic regression models, spearman correlation analysis, and receiver-operating characteristic (ROC) analyses were conducted. Results: The median age of the study was 55 years, and 39.4% of patients were female. The prevalence of SO was 22.7% in the total population, and patients with SO had higher WWI. Higher WWI quartiles were independently associated with a higher risk of SO in men after adjusting for potential confounders, including age, dialysis vintage, body mass index, biochemical indicators, and various medical histories; the odds ratio (OR) of SO was highest in the fourth quartile of the WWI (OR: 4.08, 95% confidence interval: 2.65-6.27, P for trend <0.001). Age-adjusted WWI provided a better diagnostic power than WWI only for SO in men (area under the ROC curve: 0.72 vs. 0.68, P < 0.001). WWI was not associated with SO in female HD patients. Conclusion: WWI is independently associated with SO in male but not female MHD patients. This anthropometric index is simple to calculate, making it applicable in clinical practice.

Lean-to-fat tissue ratio as a risk factor for cognitive impairment in patients undergoing maintenance hemodialysis

OBJECTIVE

The relationship between body mass index (BMI) and cognitive impairment (CI) remains controversial, and no research has been done to explore the effect of lean-to-fat (L/F) tissue ratio on the risk of CI in patients undergoing maintenance hemodialysis (MHD) so far. This study aimed to explore the effect of L/F tissue ratio on the risk of incident CI in patients undergoing MHD.

METHODS

In this observational cohort study, 3356 patients were recruited and followed up for a median of 2 years. Global cognitive function was measured using Mini-Mental State Examination score. Lean tissue mass (LTM) and fat tissue mass (FTM) were analyzed using body composition monitor based on bioimpedance spectroscopy (BCM-BIS), and L/F tissue ratio was calculated by LTM divided by FTM. Hazard ratios (HRs) for incident CI were determined by Cox regression.

RESULTS

The median age of the cohort was 55 years, and 68.7% patients were less educated. During the follow-up period, 1249 patients (37.2%) experienced incident CI. Patients with lower L/F tissue ratios had significantly higher risks of CI (HR 1.51, 95% confidence interval 1.24-1.84; p < 0.001) than those with higher L/F tissue ratios. The association between L/F tissue ratio and incident CI persisted in all subgroups stratified by sex, age, education status, especially in older and less educated participants. Both in all our patients and subgroups, BMI and CI occurrence were not independently relevant.

CONCLUSION

The L/F tissue ratio rather than BMI was an independent risk factor of incident cognitive impairment in patients undergoing MHD.

Association of sarcopenia and its components with clinical outcomes in patients undergoing peritoneal dialysis

Background: Further studies are needed to identify whether muscle mass, muscle strength, or sarcopenia is the best indicator of survival in patients undergoing peritoneal dialysis (PD). We aimed to compare the association of sarcopenia and its components with survival in patients undergoing PD.Methods: We identified all patients with prevalent PD (n = 199). We routinely recommended handgrip strength (HGS) and lean mass measurements using dual energy X-ray absorptiometry in all patients with PD. Sarcopenia was defined using cutoff values from the Asian Working Group for Sarcopenia. We evaluated the patient and technique survival rates.Results: The number of patients with low HGS was 95 (47.7%). The median follow-up interval was 17 months (interquartile range, 13–21 months). Kaplan-Meier curve analysis showed that patients with low HGS or sarcopenia had poorer patient and technique survival compared with patients with normal HGS or without sarcopenia. Cox regression analysis showed that patients with low HGS had greater hazard ratios for patient death and technique failure compared with those with normal HGS. However, patients with low muscle mass did not show significant hazard ratios for patient death or technique failure compared with those with normal muscle mass. Patients with sarcopenia had significantly greater hazard ratios for patient death or technique failure than those without sarcopenia only in univariate analysis.Conclusion: The present study demonstrated that HGS may be superior to muscle mass or sarcopenia for predicting patient or technique survival in patients undergoing PD.

Associations among body composition parameters and quality of life in peritoneal dialysis patients

Health-related quality of life (HRQOL) is an important issue among patients undergoing dialysis treatment. Peritoneal dialysis (PD) is associated with a number of adverse body composition changes. However, whether body composition is associated with HRQOL is uncertain. The purpose of this study was to analyze the effects of body composition on HRQOL in PD patients. We performed a cross-sectional observational study on the association between body composition and HRQOL in PD patients at a single center. Body composition was determined by multifrequency bioimpedance spectroscopy. HRQOL is summarized to three composite scores: kidney disease component summary (KDCS), physical component summary (PCS), and mental component summary (MCS). The relationships between HRQOL and the hydration index, lean tissue index (LTI), and fat tissue index (FTI) were analyzed by regression analysis. One hundred and ninety-seven PD patients were included in the present study. Patients with severe fluid overload showed a lower PCS. The hydration index and FTI showed statistically significant negative associations with PCS. In subgroup analysis, the associations between the hydration index and PCS remained robust after stratifying according to sex, age, and residual urine. Our results indicated that both the hydration index and FTI were negatively associated with HRQOL, especially PCS.

Muscle strength performed better than muscle mass in identifying cognitive impairment risk in maintenance hemodialysis patients

OBJECTIVES

The association between muscle mass and cognitive impairment (CI) is conflicting. We aimed to evaluate and compare the associations of muscle strength, muscle mass and CI risk in maintenance hemodialysis (MHD) patients.

METHODS

We conducted a multicenter, cross-sectional study. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) score. Muscle strength was assessed by hand grip strength (HGS), muscle mass was assessed by lean tissue mass (LTM). Education status was divided into two groups: lower education status (senior middle school and below) and higher education status (high school and above). Multivariable logistic regression models and subgroup analyses were performed. Receiver-operating characteristic (ROC) analyses were conducted to compare their predictive power in discriminating CI.

RESULTS

2827 adult MHD patients were included in our final analysis. Patients in the lowest quartile of HGS was 2.82-fold as likely to have CI as compared to those in the highest quartile, while participants in the lowest quartile of LTM group were 1.52-fold as likely to have CI, when compared with the highest quartile group of LTM after adjusting for age, gender and education level. The association persisted in all subgroups except for women and well-educated participants. There was a significant interaction between HGS and education status on CI and age played an interactive role in the association between LTM and incident CI (P for interaction < 0.05). The AUC value of the HGS was significantly higher than that of LTM (0.69 VS 0.63, P < 0.001).

CONCLUSIONS

Muscle strength performed better than muscle mass in identifying individuals at high risk of CI, particularly in male and less educated Chinese MHD patients.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

The Impact of Volume Overload on the Longitudinal Change of Adipose and Lean Tissue Mass in Incident Chinese Peritoneal Dialysis Patients

Patients treated with peritoneal dialysis (PD) experience complex body composition changes that are not adequately reflected by traditional anthropometric parameters. While lean and adipose tissue mass can be readily assessed by bioimpedance spectroscopy (BIS), there is concern about the potential confounding effect of volume overload on these measurements. This study aimed to assess the influence of fluid status (by echocardiography) on body composition parameters measured by BIS and to describe the longitudinal changes in adipose and lean tissue mass. We conducted a prospective observational study in a tertiary hospital. Incident Chinese PD patients underwent baseline echocardiography and repeated BIS measurements at baseline and 12 months later. Among 101 PD patients, lean tissue index (LTI) or fat tissue index (FTI) was not associated with echocardiographic parameters that reflected left ventricular filling pressure (surrogate of volume status). Sixty-eight patients with repeated BIS had a significant increase in body weight and FTI, while LTI remained similar. Gains in fat mass were significantly associated with muscle wasting (beta = −0.71, p < 0.0001). Moreover, progressive fluid accumulation independently predicted decrease in FTI (beta = −0.35, p < 0.0001) but not LTI. Body composition assessments by BIS were not affected by fluid status and should be considered as part of comprehensive nutrition assessment in PD patients.

[Prevalence of malnutrition and absolute and functional iron deficiency anemia in nondialysis-dependent chronic kidney disease and hemodialysis Algerian patients]

In chronic kidney disease, anemia and malnutrition coupled with inflammation as malnutrition-inflammation complex syndrom are common and considered as morbidity-mortality factors. The link between these two factors has been described at length in the literature highlighting an association of malnutrition with iron deficiency considered itself as one of the causes of anemia in chronic kidney disease (non-dialysis and hemodialysis). Our study aims to know the prevalence of these two factors in a population of chronic kidney disease (non-dialysis and hemodialysis) of Algiers and to highlight the possible associations between them.

PATIENTS AND METHODS

This is a multicentre, cross-sectional and descriptive study carried out over a period of 6months (August 2018 to January 2019). Anemia and malnutrition were assessed by various biological and clinical tools such as the malnutrition inflammation score and the International Society of Renal Nutrition and Metabolism criteria. Statistical tests were performed on the R studio software, considering P<0.05 as a statistically significant value.

RESULTS

Two hundred and nine patients on chronic kidney disease were included (90 non dialysis and 119 hemodialysis). The median age was 70 (IQR=16) for non dialysis and 56 (IQR=16.5) for hemodialysis. The prevalence of anemia was 66.66% (n=60) in non dialysis and 70.58% (n=84) in hemodialysis. Absolute iron deficiency anemia was higher in non dialysis (48.33%; n=29) while functional iron deficiency anemia was higher in hemodialysis (34.52%; n=29). The prevalence of malnutrition by malnutrition inflammation score was relatively low. Only functional iron deficiency anemia was associated with malnutrition.

CONCLUSION

The prevalence of anemia was higher in Algerian chronic kidney disease (non-dialysis and hemodialysis) unlike malnutrition which remains associated with functional iron deficiency anemia.

Association of Prescription With Body Composition and Patient Outcomes in Incident Peritoneal Dialysis Patients

Objective: The nutritional status of patients on peritoneal dialysis (PD) is influenced by patient- and disease-related factors and lifestyle. This analysis evaluated the association of PD prescription with body composition and patient outcomes in the prospective incident Initiative for Patient Outcomes in Dialysis–Peritoneal Dialysis (IPOD-PD) patient cohort.

Design and Methods: In this observational, international cohort study with longitudinal follow-up of 1,054 incident PD patients, the association of PD prescription with body composition was analyzed by using the linear mixed models, and the association of body composition with death and change to hemodialysis (HD) by means of a competing risk analysis combined with a spline analysis. Body composition was regularly assessed with the body composition monitor, a device applying bioimpedance spectroscopy.

Results: Age, time on PD, and the use of hypertonic and polyglucose solutions were significantly associated with a decrease in lean tissue index (LTI) and an increase in fat tissue index (FTI) over time. Competing risk analysis revealed a U-shaped association of body mass index (BMI) with the subdistributional hazard ratio (HR) for risk of death. High LTI was associated with a lower subdistributional HR, whereas low LTI was associated with an increased subdistributional HR when compared with the median LTI as a reference. High FTI was associated with a higher subdistributional HR when compared with the median as a reference. Subdistributional HR for risk of change to HD was not associated with any of the body composition parameters. The use of polyglucose or hypertonic PD solutions was predictive of an increased probability of change to HD, and the use of biocompatible solutions was predictive of a decreased probability of change to HD.

Conclusion: Body composition is associated with non-modifiable patient-specific and modifiable treatment-related factors. The association between lean tissue and fat tissue mass and death and change to HD in patients on PD suggests developing interventions and patient counseling to improve nutritional markers and, ultimately, patient outcomes.

Study Registration: The study has been registered at Clinicaltrials.gov (NCT01285726).

Comparison of lean mass indices as predictors of mortality in incident peritoneal dialysis patients

Background

Few studies have considered optimal adjusted lean mass indices for prediction of clinical outcomes in peritoneal dialysis (PD) patients. We aimed to evaluate clinical variables using various adjusted indices in PD patients.

Methods

Total 528 incident PD patients were included. Lean mass was measured using dual energy X-ray absorptiometry. Appendicular lean mass (ALM) was calculated using the sum for both upper and lower extremities. Each ALM index was calculated using ALM per body weight (ALM/BW), height squared (ALM/Ht²), or body mass index (ALM/BMI). Limb/trunk lean mass (LTLM) ratio was defined as the sum for both upper and lower extremities divided by trunk lean mass.

Results

A total of 528 patients were analyzed men: 286, women: 242. In area under the receiver operating characteristic curve analyses, LTLM alone was associated with 1 year mortality. In the LTLM ratio, the cut-off value for 1-year mortality was ≤ 0.829 in men and ≤ 0.717 in women, respectively. In both sexes, LTLM ratio alone showed statistical significance in all-cause mortality in both univariate and multivariate Cox-regression analyses. Compared with other indices, the LTLM ratio was independent of edema and fat in both sexes. Edema- and C-reactive protein-adjusted correlation analysis showed that LTLM ratio alone was associated with serum albumin in men. Although statistical significance was not obtained for women, the correlation coefficient was highest for the LTLM ratio compared with other indices.

Conclusion

Among various indices using lean mass, LTLM ratio was independent of volume status and fat mass and was associated with mortality in incident PD patients.

Association analysis of body composition with survival among prevalent peritoneal dialysis patients

PURPOSE

Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or its longitudinal changes contribute to increased mortality among prevalent PD patients.

METHODS

This was a retrospective cohort study. Body composition was assessed using bioelectrical impedance spectroscopy (BIS). Lean and fat tissue indices were derived from lean and fat mass indexed to height-squared, respectively. The patient's baseline BIS results were used to explore its mortality risk prediction for the entire cohort. Among patients with subsequent BIS measurements, changes of lean and fat mass over time were also examined with survival outcomes.

RESULTS

Among all participants (n = 555, PD vintage 38 months), higher baseline lean tissue index was associated with lower mortality after adjusting for fat tissue index and confounders (HR 0.90; 95% CI 0.84-0.97, p = 0.01). However, this association was no longer significance after the final adjustment with serum albumin level (p = 0.06). A total of 136 patients had repeated BIS data. After the interval of 10.1 months during two consecutive BIS measurements, there was a strong inverse correlation between the percentage changes of lean and fat tissue indices (r = - 0.73, p < 0.001). The longitudinal changes in lean mass, either high or low categories, were not significantly associated with all-cause mortality. In contrast, patients who were classified as having low values of fat tissue index (below median) from baseline to the next BIS measurements had a lower odds of death in the univariable (HR 0.32; 95% CI 0.12-0.84, p = 0.02) but not in the adjusted models.

CONCLUSION

Among prevalent PD patients, higher baseline lean mass was independently associated with better survival. However, the longitudinal changes in lean mass were not significantly associated with mortality. In contrast, the maintenance of low fat status over time appeared to be associated with a lower likelihood of death among PD population.

Relationship between sodium removal, hydration and outcomes in peritoneal dialysis patients

BACKGROUND

Fluid overload (FO) in peritoneal dialysis (PD) patients is associated with mortality. We explore if low daily sodium removal is an independent risk factor for mortality. We examined severely FO PD patients established for >1 year in expectation that PD prescription would have been optimized for solute clearance and ultrafiltration. We also wish to determine the relationship between kt/v and sodium removal.

METHODS

Retrospective analysis of 231 PD patients with FO ≥2.0 L and compared with 218 PD patients who were euvolaemic throughout their PD treatment. Patients were followed up until death censored for transplantation.

RESULTS

Mean daily sodium removal in overhydrated patients was only 75 mmoles (=1.7 g). CAPD usage was more common in patients with the highest sodium removal. Achievement of UK guidelines for solute clearance and daily fluid removal were not independent predictors of mortality. Markers of sarcopenia (low serum albumin and high CRP) were associated with increased mortality, but these parameters were not independent predictors in a model that included functional assessment (Karnofsky score). Daily sodium removal was not predictive of mortality but the imprecision of clinically used sodium assay should be noted. The correlation between Na and kt/v is statistically significant but R² was weak at .07.

CONCLUSION

While diabetic males were more likely to become overhydrated, these factors did not increase mortality further. Traditional targets of 'dialysis adequacy' did not predict survival. Kt/v is not a good indicator of sodium removal which can be surprisingly low. Measuring sodium clearance may help clinicians optimize PD modality (CAPD vs. APD).

The cut-off values of handgrip strength and lean mass index for sarcopenia among patients on peritoneal dialysis

Background

Sarcopenia is common and contributes to a high risk of mortality among general population. There is no consensus regarding the cut-off values for sarcopenia in terms of mortality among chronic kidney disease patients. This study aimed to explore and validate cut-off points of handgrip strength (HGS) and lean mass index (LMI) for estimating the risk of mortality in peritoneal dialysis (PD) patients.

Methods

This single-center prospective cohort study enrolled 1089 incident PD patients between October 2002 and July 2019. All patients were followed until death, transfer to hemodialysis, receiving renal transplantation or the end date of study (December 2019). All participants were randomly sampled to development cohort (70% participants) and validation cohort (30% participants), matched by gender and diabetes. Lean body mass was calculated by using the equation published by our center. Cubic spline regression analysis was used to examine the relationship between HGS or LMI values and mortality, and explore the cut-off points after adjusting for age, diabetes, cardiovascular disease and serum albumin in the development cohort. The derived cut-off values were verified by the agreement rate for predicting mortality and then compared with cut-off values from various clinical guidelines in the validation cohort.

Results

All 1089 patients were followed up with the median of 36.0 (18.0, 71.0) months. In the development cohort, cut-off points for predicting the higher mortality were derived as 24.5 kg and 14 kg of HGS for males and females, 16.7 kg/m² and 13.8 kg/m² of LMI for males and females respectively. In the validation cohort, these cut-off values significantly predicted worse outcomes, with HR 1.96 (1.35, 2.84) of HGS and HR 1.76 (1.26, 2.47) of LMI for all-cause mortality after multivariate adjustment. The newly derived cut-off points of HGS have numerically higher prognostic values in all-cause mortality compared with those from current clinical guidelines, and agreement rates of HGS were 65.2 versus 62.5–64.6 respectively.

Conclusions

The derived cut-off values of HGS and LMI have sufficient and better prognostic value in predicting all-cause mortality in PD patients compared with the cut-off values in the existing guidelines. These cut-off values are only validated in a single population, thus limiting the generalizability.

Comparative Performance of Body Composition Parameters in Prediction of Death in Hospitalized Patients on Maintenance Hemodialysis: A Cohort Study

We compared the prognostic value of nutritional or volumetric parameters measured by body composition in hospitalized patients on maintenance hemodialysis. We conducted a cohort study to assess the association of different parameters of body composition with all-cause mortality in inpatients admitted to our nephrology department from January 2014 to December 2016. Of the 704 study patients, 160 (22.7%) died during a median follow-up of 33 months. In multivariate adjusted Cox models, higher ratio of extracellular water to body cell mass (ECW/BCM) (adjusted HR per 1-SD, 1.49; 95% CI, 1.19 to 1.85), lower lean tissue index (LTI) (adjusted HR per 1-SD, 0.70; 95% CI, 0.57 to 0.86) and lower body cell mass index (BCMI) (adjusted HR per 1-SD, 0.70; 95% CI, 0.58 to 0.85) were associated with a significantly greater risk of death. When these parameters were added to the fully adjusted model, BCMI performed best in improving the predictability for all-cause mortality (integrated discrimination improvement = 0.02, P = 0.04; net reclassification index = 0.11, P = 0.04). Among body composition indexes, ECW/BCM was the most relevant fluid volume indices to mortality and BCMI and LTI were the most relevant nutritional status indices to mortality in maintenance hemodialysis patients.

Three compartment bioimpedance spectroscopy in the nutritional assessment and the outcome of patients with advanced or end stage kidney disease: What have we learned so far?

Bioimpedance spectroscopy (BIS) is an easily applicable tool to assess body composition. The three compartment model BIS (3C BIS) conventionally expresses body composition as lean tissue index (LTI) (lean tissue mass [LTM]/height in meters squared) and fat tissue index (FTI) (adipose tissue mass/height in meters squared), and a virtual compartment reflecting fluid overload (FO). It has been studied extensively in relation to diagnosis and treatment guidance of fluid status disorders in patients with advanced‐stage or end‐stage renal disease. It is the aim of this article to provide a narrative review on the relevance of 3C BIS in the nutritional assessment in this population. At a population level, LTI decreases after the start of hemodialysis, whereas FTI increases. LTI below the 10th percentile is a consistent predictor of outcome whereas a low FTI is predominantly associated with outcome when combined with a low LTI. Recent research also showed the connection between low LTI, inflammation, and FO, which are cumulatively associated with an increased mortality risk. However, studies toward nutritional interventions based on BIS data are still lacking in this population. In conclusion, 3C BIS, by disentangling the components of body mass index, has contributed to our understanding of the relevance of abnormalities in different body compartments in chronic kidney disease patients, and appears to be a valuable prognostic tool, at least at a population level. Studies assessing the effect of BIS guided nutritional intervention could further support its use in the daily clinical care for renal patients.

Monitoring of Intraperitoneal Fluid Volume during Peritoneal Equilibration Testing using Segmental Bioimpedance

BACKGROUND

Ultrafiltration failure and fluid overload are common in peritoneal dialysis (PD) patients. Knowledge of intraperitoneal volume (IPV) and time to peak IPV during a dwell would permit improved PD prescription. This study aimed to utilize trunk segmental bioimpedance analysis (SBIA) to quasi-continuously monitor IPV (IPVSBIA) during the peritoneal dwell.

METHODS

IPVSBIA was measured every minute using lower-trunk SBIA (Hydra 4200; Xitron Technologies Inc., CA, USA) in 10 PD patients during a standard 240-min peritoneal equilibration test (PET). The known dialysate volume (2 L) rendered IPVSBIA calibration and calculation of instantaneous ultrafiltration volume (UFVSBIA) possible. UFVSBIA was defined as IPVSBIA - 2 L.

RESULTS

Based on dialysate-to-plasma creatinine ratio, 2 patients were high, 7 high-average, and 1 low-average transporters. Technically sound IPVSBIA measurements were obtained in 9 patients (age 59.0 ± 8.8 years, 7 females, 5 African Americans). Drained ultrafiltration volume (UFVdrain) was 0.47 ± 0.21 L and correlated (r = 0.74; p < 0.05) with end-dwell UFVSBIA (0.55 ± 0.17 L). Peak UFVSBIA was 1.04 ± 0.32 L, it was reached 177 ± 61 min into the dwell and exceeded end-dwell UFVSBIA by 0.49 ± 0.28 L (95% CI: 0.27-0.7) and UFVdrain by 0.52 ± 0.31 L (95% CI: 0.29-0.76), respectively.

CONCLUSION

This pilot study demonstrates the feasibility of trunk segmental bioimpedance to quasi-continuously monitor IPVSBIA and identify the time to peak UFVSBIA during a standard PET. Such new insights into the dynamics of intraperitoneal fluid volume during the dwell may advance our understanding of the underlying transport physiology and eventually assist in improving PD treatment prescriptions.