Shortage of Appendicular Skeletal Muscle Is an Independent Risk Factor for Mortality in Peritoneal Dialysis Patients

Modifiable Physical Factors That Influence Physical Function for People Receiving Peritoneal Dialysis

Introduction

People receiving peritoneal dialysis experience physical function decline, impairing their ability to complete everyday activities, leading to poorer quality of life. Physical factors, including cardiorespiratory fitness, muscle strength, physical activity, and sedentary behavior are associated with physical function. However, little is known about this relationship, or temporal changes of these factors in this cohort. This study aimed to explore modifiable physical factors that are associated with physical function, identify which factor has the strongest influence, and explore temporal changes.

Methods

Adults receiving peritoneal dialysis underwent objective and self-reported physical function, cardiorespiratory fitness, muscle strength, physical activity and sedentary behavior assessments 3 times over a 12-month observation period (at baseline, 6 months, and 12 months).

Results

Eighty-two participants underwent assessments. All modifiable physical factors were predominantly moderate to strongly associated with physical function at baseline. Cardiorespiratory fitness had the strongest and most consistent influence with every meter conferring a 0.08-unit (P < 0.01) and 0.01-unit (P < 0.05) increase in self-report and objective physical function score, respectively. Temporal changes were observed for modifiable physical factors with significant mean changes in cardiorespiratory fitness (-9.8%), quadricep strength (-5%), moderate-to-vigorous (-25.9%) and total (-16.2%) physical activity, and sedentary behavior (+7.1%).

Conclusion

The results of this study indicate that cardiorespiratory fitness could be routinely monitored to detect risk of physical function decline and targeted through intervention to enhance physical function for people receiving peritoneal dialysis. Nevertheless, all factors should be considered when designing interventions to mitigate temporal changes and induce the numerous health benefits offered by being physically active.

Characteristics and Frequency of Physical Activity and Exercise-Related Side Effects in People Receiving Peritoneal Dialysis

OBJECTIVE

People receiving peritoneal dialysis may receive health benefits from physical activity or exercise. However, on-going uncertainty and fear regarding safety may result in this population missing out on the health benefits of participation. The aim of this study was to explore the characteristics and frequency of physical activity and/or exercise-related side effects (e.g., symptoms such as pain or shortness of breath) and negative health events (e.g., stroke or hyper/hypoglycemia) experienced by people receiving peritoneal dialysis.

METHODS

An international online survey involving adults receiving peritoneal dialysis was conducted with questions related to nature, occurrence, and impact of side effects and/or negative health events experienced during or soon after participation in physical activity or exercise.

RESULTS

Fifty-two people completed the survey reporting 151 side effects that were related to physical activity and exercise and 67 that were possibly related. Fatigue (58% of respondents), muscle/joint soreness or pain (54%), and dizziness (43%) were the most frequently reported side-effect types. The majority occurred occasionally (58% of all side effects), if not rarely (24%) and participation in on-going physical activity or exercise was typically prevented only occasionally (39%) or not at all (31%). Side effects were mainly self-managed (54% of all side effects) or did not require treatment (19%) and had low (38%) or no effect (30%) on ability to do daily activities.

CONCLUSIONS

People receiving peritoneal dialysis generally experience side effects that can be considered a normal response to physical activity or exercise engagement. Furthermore, the risk of serious or peritoneal dialysis-specific side effects as a result of physical activity or exercise appears to be low. The results add to the emerging evidence suggesting physical activity and exercise appear to be safe for people receiving peritoneal dialysis.

Exercise intolerance and malnutrition associated with all-cause mortality in elderly patients undergoing peritoneal dialysis: a single-center prospective cohort study

BACKGROUND

Low physical function and malnutrition in elderly patients undergoing peritoneal dialysis (PD) are important issues that may be associated with prognosis. We aimed to determine the association between physical function and nutritional status and survival in elderly patients undergoing PD.

METHODS

This single-center, prospective cohort study included 45 stable, ambulatory patients undergoing PD. Physical function was measured using the 6-min walk distance (6MWD) test, 10-m walk speed, handgrip strength, lower extremity muscle strength, and short physical performance battery. Nutritional status was assessed using albumin levels and the Geriatric Nutritional Risk Index (GNRI). Patients were divided into two groups according to adverse events. Receiver operating characteristic curve analysis was used to predict mortality. The relationships between all-cause mortality and physical function and nutritional status were studied using Kaplan-Meier analysis and the log-rank test.

RESULTS

The mean patient age was 75.3 ± 6.5 years. The median follow-up time was 32 (interquartile range 18-51) months, during which 11 deaths occurred. Death during follow-up was significantly associated with lower 6MWD (237.4 ± 120.2 vs. 355.2 ± 105.9 m), lower GNRI (77.3 ± 16.3 vs. 89.3 ± 8.1), and lower albumin levels (2.8 ± 0.6 vs. 3.3 ± 0.4 mg/dL) at baseline (p < 0.05). The cut-off values were 338 m, 83.3, and 2.95 g/dL for the 6MWD, GNRI, and albumin levels, respectively. The 6MWD test, GNRI, and albumin levels were significantly associated with all-cause mortality (p < 0.05). Additionally, the group with combined exercise intolerance and malnutrition had a lower survival rate (p < 0.05).

CONCLUSION

Lower 6MWD and malnutrition are predictors of mortality in elderly patients undergoing PD.

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.

Exercise or physical activity-related adverse events in people receiving peritoneal dialysis: A systematic review

People receiving peritoneal dialysis (PD) may benefit from participation in exercise or physical activity. However, exercise therapy for people receiving PD is not typically included in routine care, in part, due to ongoing uncertainties about risk. The aim of this review was to systematically collate and explore data on adverse events experienced by people receiving PD while undertaking an exercise or physical activity intervention. Searches yielded 25 exercise or physical activity intervention studies involving people receiving PD. Of these 25 studies, 17 studies provided adverse event data and were included in the final review. No serious adverse events (e.g. death, hospitalisation) were found attributable to the intervention. From 50 reported adverse events during the intervention period, 32 were attributable to the exercise or physical activity intervention with most being musculoskeletal (e.g. muscle/joint pain, etc.) followed by fatigue. Most events were mild to moderate in severity and resolved by exercise programme modification, education, rest or medication. The results from this review did not uncover signals of harm for people receiving PD who engage in exercise with risk of adverse events appearing to be low, however, improved adverse events reporting and further interventional studies are required before robust guidelines can be produced.

Diagnosis, prevalence, and mortality of sarcopenia in dialysis patients: a systematic review and meta-analysis

There is no consensus on the prevalence of sarcopenia or its impact on mortality in end-stage renal disease patients undergoing dialysis. This review aimed to summarize the diagnostic criteria of sarcopenia and its prevalence and impact on the mortality of end-stage renal disease patients undergoing dialysis. Embase, MEDLINE, PubMed, and Cochrane Library were searched from inception to 8 May 2021 to retrieve eligible studies that assessed muscle mass by commonly used instruments, such as dual-energy X-ray absorptiometry, bioelectrical impedance analysis, magnetic resonance imaging, and body composition monitor. Two assessment tools matched to study designs were employed to evaluate study quality. Pooled sarcopenia prevalence was calculated with 95% confidence interval (CI), and heterogeneity was estimated using the I2 test. Associations of sarcopenia with mortality were expressed as hazard ratio (HR) and 95% CI. The search identified 3272 studies, and 30 studies (6162 participants, mean age from 47.5 to 77.5 years) were analysed in this review. The risk of bias in the included studies was low to moderate. Twenty-two studies defined sarcopenia based on low muscle mass (LMM) plus low muscle strength and/or low physical performance, while eight studies used LMM alone. Muscle mass was assessed by different instruments, and a wide range of cut-off points were used to define LMM. Overall, sarcopenia prevalence was 28.5% (95% CI 22.9-34.1%) and varied from 25.9% (I2  = 94.9%, 95% CI 20.4-31.3%; combined criteria) to 34.6% (I2  = 98.1%, 95% CI 20.9-48.2%; LMM alone) (P = 0.247 between subgroups). The statistically significant differences were not found in the subgroups of diagnostic criteria (P > 0.05) and dialysis modality (P > 0.05). Additionally, the sarcopenia prevalence could not be affected by average age [regression coefficient 0.004 (95% CI: -0.005 to 0.012), P = 0.406] and dialysis duration [regression coefficient 0.002 (95% CI -0.002 to 0.005), P = 0.327] in the meta-regression. The pooled analyses showed that combined criteria of sarcopenia were related to a higher mortality risk [HR 1.82 (I2  = 26.3%, 95% CI 1.38-2.39)], as was LMM [HR 1.61 (I2  = 26.0%, 95% CI 1.31-1.99)] and low muscle strength [HR 2.04 (I2  = 80.4%, 95% CI 1.19-3.5)]. Although there are substantial differences in diagnostic criteria, sarcopenia is highly prevalent in dialysis patients and is linked to increased mortality. The standardization of sarcopenia diagnostic criteria would be beneficial, and future longitudinal studies are needed to investigate the prevalence and prognostic value of sarcopenia in dialysis patients.

Protein-Energy Wasting and Mortality Risk Prediction Among Peritoneal Dialysis Patients

OBJECTIVES

Protein-energy wasting (PEW) is defined as the loss of body protein and energy reserves associated with kidney disease. However, the extent to which PEW contributes to increased mortality among peritoneal dialysis (PD) patients remains unclear.

METHODS

This is a retrospective cohort study from 2012 to 2020. The PEW was diagnosed by applying at least 3 of the 4 following criteria: (1) altered serum biochemistry indicated by a serum albumin level of <3.5 g/L; (2) decreased body mass status identified by a body mass index (BMI) of <23 kg/m² or <10% total body fat; (3) muscle wasting defined by the lean tissue index, calculated as a lean tissue mass normalized to the height-squared in the <10th percentile of the reference population; and (4) low dietary protein intake determined by the normalized protein equivalent of a total nitrogen appearance of <0.8 g/kg/day. The Malnutrition Inflammation Score (MIS) was also examined as an alternative tool for assessment of PEW.

RESULTS

The average age of the 555 participants was 57.5 ± 12.6 years. The prevalence of PEW was 27.3%, with 196 deaths observed during the mean follow-up of 25.5 months. Patients with PEW who fulfilled at least 3 of the 4 listed criteria had a higher risk of death in the unadjusted model (hazard ratio 1.61, 95% confidence interval 1.19-2.18, P = .002). However, these associations were attenuated after adjusting for potential confounders. Regarding the individual PEW criterion, decreased serum albumin and low muscle mass were significantly associated with mortality in the multivariable models. In contrast, decreased body mass and low protein intake were not associated with a higher risk of death. High MIS (≥5 points) and each one-point increase in the MIS were also significantly associated with higher risk of death in both unadjusted and adjusted models.

CONCLUSIONS

Among PD patients, the presence of PEW was not a better predictor of all-cause mortality than either the altered serum biochemistry (albumin) or low muscle mass criteria. The MIS performed well as an independent predictor of death and might be an option for assessment of PEW status in the PD population.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Change in appendicular lean mass in patients established on peritoneal dialysis as measured by dual x-ray absorptiometry (DXA) scanning

BACKGROUND/OBJECTIVES

Peritoneal dialysis (PD) patients are at increased risk of malnutrition and cachexia, definitions of which include weight loss. However, PD patients can absorb glucose from the dialysate and loss of muscle mass may be overlooked by fat weight gain. As such, we wished to review changes in body composition in prevalent PD patients.

SUBJECTS/METHODS

We compared changes in body composition measured by dual x-ray absorptiometry (DXA) in adult PD patients, and calculated glucose absorption based on 24-h collections of PD dialysate.

RESULTS

Overall, 73 prevalent PD patients, 60.3% male, mean age 62.5 ± 16.4 years, had DXA scans a median of 24 (15-27) months apart. Weight did not change (70.7 ± 16.8 vs. 70.9 ± 16.8 kg), with a median 198 (88-295) mmol glucose absorbed/day. Appendicular lean mass (ALM) decreased in most of the male (59%) and female (52%) patients, and the change in ALM was negatively associated with the change in percentage body fat mass (%BFM) r = -0.54, p < 0.001. Overall, 56 patients (76.7%) were admitted to hospital with intercurrent illnesses. Women who lost ALM and gained %BFM had more hospital admissions and those with an increase in %BFM had more admissions due to PD peritonitis while, in males, these outcomes were not seen.

CONCLUSION

Although overall weight did not change, the majority of PD patients lost ALM, and this loss of muscle mass was masked by a gain in fat mass. Definitions of malnutrition and cachexia, which include unintentional weight loss criteria will underestimate the prevalence of PD patients with loss of muscle mass.

The effect of oral nutritional supplement on muscle fitness of patients undergoing dialysis: A systematic review and meta-analysis

AIM

To summarize evidence regarding the effects of oral nutritional supplement on muscle fitness of patients undergoing dialysis.

DESIGN

A systematic review and meta-analysis.

REVIEW SOURCES

Five English databases (CENTRAL, PubMed, EMBASE, CINHAL, and Web of Science) and four Chinese databases (CNKI, WanFang, SinoMed, and VIP) were searched from inception to 31 July 2019 and only randomized controlled trials were included.

REVIEW METHODS

Two reviewers independently searched these databases, selected trials, conducted bias assessment, extracted the data. Random-effects meta-analysis was conducted to assess the effect size. The predetermined subgroup included type of oral nutritional supplement (a mixture of macronutrients, whey protein, essential amino-acids, and other nutrients) and intervention duration (over and less than 48 weeks). The subgroup analyses and sensitivity analyses were conducted to explore source of heterogeneity and robustness of results.

RESULTS

Sixteen studies (910 participants) meeting the inclusion criteria were identified and included in this systematic review. Subgroup analysis showed that supplying a mixture of macronutrients (MD [MD] = 2.36 kg, 95% CI [0.45, 4.26], I²  = 0.00%), an intervention duration of 48 weeks (MD = 4.05 kg, 95% CI [1.43, 6.67], I²  = 0.00%) had some effects on increasing lean body mass. No effects of oral nutritional supplement were found on improving muscle strength or physical performance.

CONCLUSION

A mixture of macronutrients and an intervention duration as long as 48 weeks had some significant effects on improving lean body mass of patients undergoing dialysis. No effect of oral nutritional supplement on muscle strength or physical performance were found but with limited evidence.

IMPACT

No existing reviews have ever focused on improving muscle fitness of patients undergoing dialysis. This systematic review and meta-analysis provided evidence of oral nutritional supplement on keeping muscle fitness of these patients and suggested possible type of oral nutritional supplement and intervention duration for clinical practice.

The Association between Serum Uric Acid and Appendicular Skeletal Muscle Mass and the Effect of Their Interaction on Mortality in Patients on Peritoneal Dialysis

BACKGROUND

Serum uric acid (SUA) has been revealed to be positively associated with the body composition parameters in hemodialysis patients, but few studies have investigated that in patients on peritoneal dialysis (PD). The aim of this study was to identify the relationship between SUA and appendicular skeletal muscle mass (ASM) and the effect of their interaction on mortality in PD patients.

METHODS

This was a single-center retrospective cohort study. Patients who underwent multifrequency bioelectrical impedance analysis between January 1, 2013, and December 31, 2016, and had data on SUA values were enrolled. All patients were followed up until December 31, 2019.

RESULTS

In total, 802 prevalent PD patients (57.9% male), with mean age of 46.2 ± 14.2 years were enrolled. The average SUA and ASM were 6.8 ± 1.3 mg/dL and 21.2 ± 4.9 kg. According to multiple linear regression models, SUA was positively associated with relative ASM in middle-aged and older PD patients (standardized coefficients [β] 0.117; 95% confidence interval [CI] 0.027, 0.200; p = 0.010). Further sex-stratified analysis showed that the association existed only in males (β 0.161; 95% CI 0.017, 0.227; p = 0.023). Moreover, the presence of hyperuricemia was found to predict lower risk of all-cause mortality (hazard ratio [HR] 0.514, 95% CI 0.272, 0.970; p = 0.040) only in patients with lower relative ASM. And, the adjusted HR of every 1 mg/dL elevated SUA level was 0.770 (95% CI 0.609, 0.972; p = 0.028) for all-cause mortality in the lower relative ASM subgroup.

CONCLUSIONS

There exists a positive association between the SUA and ASM, and the ASM significantly affected the association between SUA and all-cause PD mortality.

Gender-specific associations of skeletal muscle mass and arterial stiffness among peritoneal dialysis patients

Decreased skeletal muscle has been identified as a relevant factor for arterial stiffness but has not been thoroughly investigated in peritoneal dialysis (PD) patients. The aim of this study was to investigate the relationship between skeletal muscle and arterial stiffness in PD patients. A cross-sectional study of 658 prevalent PD patients with a mean brachial-ankle pulse wave velocity (baPWV) of 1714 (±501) cm/s and mean skeletal muscle mass of 26.6 (±5.4) kg was performed. Skeletal muscle mass level was significantly higher in males than in females. When examining skeletal muscle mass as a continuous variable, skeletal muscle mass was significantly associated with baPWV in fully adjusted linear regression models in total patients [standardized coefficients (β), −0.181; 95% confidence interval (95% CI), −0.276 to −0.056; P = 0.003] or female patients (β, −0.119; 95% CI, −0.350 to −0.015; P = 0.03) but not in male patients (β, −0.117; 95% CI, −0.300 to 0.011; P = 0.07). Furthermore, in females, a significant association between the middle or highest tertile of skeletal muscle mass and baPWV was found in fully adjusted models (β, −0.123; 95% CI, −0.204 to −0.008; P = 0.03; β, −0.140; 95% CI, −0.228 to −0.016; P = 0.02, respectively). In conclusion, decreased skeletal muscle mass was independently associated with increased baPWV in PD patients, and this association was significant in females but not in males.