Physical function and all-cause mortality in patients with chronic kidney disease and end-stage renal disease: a systematic review and meta-analysis

Multiomic Analysis of Calf Muscle in Peripheral Artery Disease and Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) has emerged as a significant risk factor that accelerates atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the modulators underlying this exacerbated pathobiology are ill-defined. Recent work has demonstrated that uremic toxins are associated with limb amputation in PAD and have pathological effects in both the limb muscle and vasculature. Herein, we use multiomics to identify novel modulators of disease pathobiology in patients with PAD and CKD.

METHODS

A cross-sectional study enrolled 4 groups of participants: controls without PAD or CKD (n=28), patients with PAD only (n=46), patients with CKD only (n=31), and patients with both PAD and CKD (n=18). Both targeted (uremic toxins) and nontargeted metabolomics in plasma were performed using mass spectrometry. Calf muscle biopsies were used to measure histopathology, perform bulk and single-nucleus RNA sequencing, and assess mitochondrial function. Differential gene and metabolite analyses, as well as pathway and gene set enrichment analyses, were performed.

RESULTS

Patients with both PAD and CKD exhibited significantly lower calf muscle strength and smaller muscle fiber areas compared with controls and those with only PAD. Compared with controls, mitochondrial function was impaired in patients with CKD, with or without PAD, but not in PAD patients without CKD. Plasma metabolomics revealed substantial alterations in the metabolome of patients with CKD, with significant correlations observed between uremic toxins (eg, kynurenine and indoxyl sulfate) and both muscle strength and mitochondrial function. RNA sequencing analyses identified downregulation of mitochondrial genes and pathways associated with protein translation in patients with both PAD and CKD. Single-nucleus RNA sequencing further highlighted a mitochondrial deficiency in muscle fibers along with unique remodeling of fibro-adipogenic progenitor cells in patients with both PAD and CKD, with an increase in adipogenic cell populations.

CONCLUSIONS

CKD significantly exacerbates ischemic muscle pathology in PAD, as evidenced by diminished muscle strength, reduced mitochondrial function, and altered transcriptome profiles. The correlation between uremic toxins and muscle dysfunction suggests that targeting these metabolites may offer therapeutic potential for improving muscle health in PAD patients with CKD.

Gait Speed and All-Cause Mortality in Whole-Spectrum Chronic Kidney Disease: A Systematic Review and Meta-Analysis Included 6217 Participants

BACKGROUND

The quantitative relationship between gait speed and mortality risk in patients with chronic kidney disease remains unclear. This study aimed to conduct a meta-analysis to estimate the risk of mortality associated with gait speed in chronic kidney disease (CKD) patients.

METHODS

Relevant studies published were identified through literature searches using Embase, PubMed and Web of Science. Prospective cohort studies of adult CKD patients that examined the relationship between gait speed and mortality were included. Random effects meta-analyses based on restricted maximum likelihood to were used to calculate relative risk (RR) and 95% confidence interval (95% CI). The results of meta-analyses were assessed using Grading of Recommendations, Assessment, Development and Evaluation framework.

RESULTS

Seventeen prospective cohort studies involving 6217 CKD patients (mean age range: 51.6-81.85 years; 44.3%-84% male) were included. Pooled analysis of 12 studies (n = 4233) showed that lower gait speed was associated with a higher risk of all-cause mortality compared to higher gait speed (RR = 2.138; 95% CI: 1.794-2.548; p < 0.001; I2 = 16.0%; high-certainty evidence) in CKD patients. Dose-response meta-analysis of 6 studies (n = 1650) revealed that each 0.1 m/s increase in gait speed was associated with a 25.7% lower risk of all-cause mortality (RR = 0.743; 95% CI: 0.580-0.955; p = 0.018; I2 = 45.0%; high-certainty evidence).

CONCLUSIONS

Slower gait speed is a strong predictor of all-cause mortality in CKD patients, including those undergoing dialysis or kidney transplantation. Gait speed assessment should be incorporated into routine clinical evaluations to identify high-risk patients and guide interventions aimed at improving physical function and survival outcomes.

TRIAL REGISTRATION

PROSPERO registration number: CRD42022340135.

Survival in patients with CKD 3-5 after 12 months of exercise training - a post-hoc analysis of the RENEXC trial

BACKGROUND

Physical performance is low and physical activity declines in people with chronic kidney disease (CKD). Both factors are associated with decreased survival. Our hypothesis was that improved physical performance after 12 months of exercise training would result in better survival in patients with CKD stages 3 to 5 not on kidney replacement therapy (KRT). Our aims in this study were to investigate the survival effects of (1) baseline physical performance and (2) physical performance after 12 months of exercise training.

METHODS

This is a post-hoc analysis of the RENEXC trial, a randomized controlled study comparing 12 months of strength- and balance training both in combination with aerobic training. Both groups improved physical performance with no between group differences. Patients were categorized into five groups: improved ≥ 5%, unchanged, deteriorated ≥ 5%, non-completers, missing data. Univariate and multivariate Cox regression analyses were used and adjusted for age, sex, comorbidity, time on dialysis and time with a kidney transplant.

RESULTS

151 patients participated, mean age 66 ± 14 years, 65% men, eGFR 22.5 ± 8.2 ml/min/1.73m2, average follow-up 60 months.

MULTIVARIATE ANALYSES

The baseline 6-minute walk test (6MWT) (HR 0.996; 95% CI [0.993-0.998]) and 30-second sit-to-stand (30s-STS) (HR 0.94 CI [0.89-1.0]) were positively associated with survival. After 12 months of exercise improved handgrip strength (HGS) right (HR 2.66; 95% CI [1.07-6.59]) was associated with better survival compared with deterioration. Improvement compared with noncompletion was associated with better survival (6MWT (HR 2.88; 95% CI [1.4-5.88]), HGS right (HR 4.44; 95% CI [1.79-10.98]), functional reach (HR 3.69; 95% CI [1.82-7.48]), isometric quadriceps strength right (HR 2.86; 95% CI [1.43-5.72]), 30s-STS (HR 3.44; 95% CI [1.66-7.11]).

CONCLUSION

Baseline walking distance, muscular strength and endurance in the legs were independently associated with survival in people with CKD stages 3-5 without KRT. After completing 12 months of exercise training improved walking distance, muscular strength and endurance, and balance were positively associated with survival, compared with noncompleters. Better physical performance at baseline and the ability to complete 12 months of exercise training conferred survival benefits. There are probably several factors affecting better survival. These factors require elucidation in future studies.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02041156. Registration date 20,240,107.

Determinants of moderate-to-high physical activity levels in hemodialysis patients: A multicenter cross-sectional study

Moderate physical activity is related to reduced mortality in hemodialysis patients. However, most hemodialysis patients have low physical activity levels for complex reasons. This study investigated the determinants of moderate-to-high physical activity levels and whether psychosocial correlates are associated with engagement in moderate-to-high physical activity among hemodialysis patients. A cross-sectional survey was conducted with 134 hemodialysis outpatients, aged 64.7 years, in three hemodialysis centers in Taiwan. Data on sociodemographics, comorbidities, lifestyles, and psychosocial correlates, including perceived benefits, barriers, and self-efficacy of physical activity, were collected. Multiple logistic regression analyses were performed. Results showed that patients with moderate-to-high physical activity levels constituted a significantly lower proportion of current smokers and had fewer perceived physical activity barriers and higher self-efficacy of physical activity compared with those with low levels. After adjusting for potential sociodemographic covariates, current employment, nonsmoking status, and high self-efficacy of physical activity were significantly associated with moderate-to-high physical activity levels. Developing strategies to improve the self-efficacy of physical activity, support employment, and enhance anti-smoking campaigns in hemodialysis patients can help them engage in moderate-to-high levels of physical activity.

Can Functional Motor Capacity Influence Mortality in Advanced Chronic Kidney Disease Patients?

Alterations in the body's nutritional status or composition may be observed as the kidney disease advances, which could influence the kidney's functional capacity and, consequently, could increase the risk of mortality. The aim of the study is to determine the influence of functional capacity on mortality assessed by different functional tests in patients with advanced chronic kidney disease (ACKD). A prospective observational study was designed, which included 225 patients followed for 8 years in a CKD clinic. The study assessed functional capacity by using a range of tests, which included the Short Physical Performance Battery, the 6 minutes walking gait test, the timed up and go, and the four versions of the sit-to-stand test. Additionally, body composition and nutritional conditions were considered, taking into consideration various biochemical indicators such as albumin, prealbumin, c-reactive protein (CRP), lymphocytes, and transferrin, muscle strength, comorbidity, and frailty. The relationship between functionality and all-cause mortality was investigated using a Cox proportional hazard model. A total of fifty patients died during the duration of the study. Patients who performed worse on the function and muscle strength tests showed a worse body composition and nutritional status, and exhibited a reduced life expectancy. Inflammation (CRP) was associated with an increased risk of mortality (model 1: hazard ratio (HR) = 1.246; 95% confidence interval (95% CI = 1.014-1.531; model 2: HR = 1.333; 95% CI = 1.104-1.610). Good functional capacity as determined by the SPPB test decreased the risk of mortality (model 1: HR = 0.764; 95% CI = 0.683-0.855; model 2 HR = 0.778; 95% CI = 0.695-0.872). Cut-off points of maximum sensitivity and specificity for mortality were obtained with different tests. The study demonstrated that functional capacity influences mortality in patients with ACKD, being higher in those patients with impaired functionality regardless of the test used, although the SPPB allows a larger number of patients to be assessed. Therefore, it is essential to incorporate the assessment of functionality into the comprehensive care of patients with CKD.

Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies

OBJECTIVE

To examine and summarise evidence from meta-analyses of cohort studies that evaluated the predictive associations between baseline cardiorespiratory fitness (CRF) and health outcomes among adults.

DESIGN

Overview of systematic reviews.

DATA SOURCE

Five bibliographic databases were searched from January 2002 to March 2024.

RESULTS

From the 9062 papers identified, we included 26 systematic reviews. We found eight meta-analyses that described five unique mortality outcomes among general populations. CRF had the largest risk reduction for all-cause mortality when comparing high versus low CRF (HR=0.47; 95% CI 0.39 to 0.56). A dose-response relationship for every 1-metabolic equivalent of task (MET) higher level of CRF was associated with a 11%-17% reduction in all-cause mortality (HR=0.89; 95% CI 0.86 to 0.92, and HR=0.83; 95% CI 0.78 to 0.88). For incident outcomes, nine meta-analyses described 12 unique outcomes. CRF was associated with the largest risk reduction in incident heart failure when comparing high versus low CRF (HR=0.31; 95% CI 0.19 to 0.49). A dose-response relationship for every 1-MET higher level of CRF was associated with a 18% reduction in heart failure (HR=0.82; 95% CI 0.79 to 0.84). Among those living with chronic conditions, nine meta-analyses described four unique outcomes in nine patient groups. CRF was associated with the largest risk reduction for cardiovascular mortality among those living with cardiovascular disease when comparing high versus low CRF (HR=0.27; 95% CI 0.16 to 0.48). The certainty of the evidence across all studies ranged from very low-to-moderate according to Grading of Recommendations, Assessment, Development and Evaluations.

CONCLUSION

We found consistent evidence that high CRF is strongly associated with lower risk for a variety of mortality and incident chronic conditions in general and clinical populations.

Risk factors associated with weak and asymmetric handgrip strength in older Chinese adults

OBJECTIVES

This study sought to investigate the potential risk factors associated with weak and asymmetric handgrip strength (HGS) in older Chinese adults.

METHODS

A total of 2702 participants aged ≥65 years from the two waves of data (2011 and 2013) from the China Health and Retirement Longitudinal Study were analyzed. The highest recorded HGS values (Method A) or the average HGS values (Method B) for the dominant hand were used to compute the HGS asymmetry (nondominant HGS/dominant HGS out of 0.9-1.1) and HGS weakness (male <28 kg, female <18 kg). Risk factors associated with the weak and asymmetric HGS were identified by logistic regression analysis.

RESULTS

Risk factors associated with weak and asymmetric HGS of varying severity differed between the two methods. Both methods identified age and illiteracy as risk factors for weak HGS with 10%-20% asymmetry. Method A also identified speech impediment, stroke, and sleep duration as additional risk factors. Similarly, both methods identified age, illiteracy, primary school education and below, diabetes, and stroke as risk factors for weak HGS and asymmetry over 30.1%. Method B additionally identified a history of falls as a risk factor. However, apart from age, the risk factors for weak HGS with 20.1%-30% asymmetry differed between the two methods-Method A identified kidney disease, while Method B identified illiteracy and asthma.

CONCLUSIONS

The results revealed that risk factors associated with the abnormal HGS in older adults varied based on the methods used to define these conditions.

A Current State of the Art and Science of Exercise in Dialysis: A Narrative Review

Purpose of the review

The purpose of the review is to discuss current proven benefits and problems of integrating exercise in the care of people receiving dialysis by reviewing literature from the last few years and identifying important questions that still need to be asked and answered.

Methods

A focused review and appraisal of the literature were done. Original peer-reviewed articles, review articles, opinion pieces and guidelines were identified from PubMed and Google Scholar databases. Only sources in English were accessed. Search terms "exercise" and "dialysis" were used to find active recruiting randomized trials in various clinical trial registry platforms.

Key findings

Numerous studies have demonstrated the benefits of exercise training in individuals receiving dialysis, limited by factors such as short duration of follow-up and inconsistent adverse event reporting and outcomes selected. Notable gaps in exercise research in dialysis include ways to maintain programs and patient motivation, studies in peritoneal dialysis and home hemodialysis patients, and how best to define and measure outcomes of interest.

Implications

This review summarizes the current state of exercise in people receiving dialysis and serves as a call to action to conduct large, randomized controlled trials to improve the quality of evidence needed to implement and sustain innovative, exercise interventions, and programs for this population.

Clinical features and molecular mechanism of muscle wasting in end stage renal disease

Muscle wasting in end-stage renal disease (ESRD) is an escalating issue due to the increasing global prevalence of ESRD and its significant clinical impact, including a close association with elevated mortality risk. The phenomenon of muscle wasting in ESRD, which exceeds the rate of muscle loss observed in the normal aging process, arises from multifactorial processes. This review paper aims to provide a comprehensive understanding of muscle wasting in ESRD, covering its epidemiology, underlying molecular mechanisms, and current and emerging therapeutic interventions. It delves into the assessment techniques for muscle mass and function, before exploring the intricate metabolic and molecular pathways that lead to muscle atrophy in ESRD patients. We further discuss various strategies to mitigate muscle wasting, including nutritional, pharmacological, exercise, and physical modalities intervention. This review seeks to provide a solid foundation for future research in this area, fostering a deeper understanding of muscle wasting in ESRD, and paving the way for the development of novel strategies to improve patient outcomes. [BMB Reports 2023; 56(8): 426-438].

Clinical features and molecular mechanism of muscle wasting in end stage renal disease

Muscle wasting in end-stage renal disease (ESRD) is an escalating issue due to the increasing global prevalence of ESRD and its significant clinical impact, including a close association with elevated mortality risk. The phenomenon of muscle wasting in ESRD, which exceeds the rate of muscle loss observed in the normal aging process, arises from multifactorial processes. This review paper aims to provide a comprehensive understanding of muscle wasting in ESRD, covering its epidemiology, underlying molecular mechanisms, and current and emerging therapeutic interventions. It delves into the assessment techniques for muscle mass and function, before exploring the intricate metabolic and molecular pathways that lead to muscle atrophy in ESRD patients. We further discuss various strategies to mitigate muscle wasting, including nutritional, pharmacological, exercise, and physical modalities intervention. This review seeks to provide a solid foundation for future research in this area, fostering a deeper understanding of muscle wasting in ESRD, and paving the way for the development of novel strategies to improve patient outcomes. [BMB Reports 2023; 56(8): 426-438].