Association between physical activity and mortality in end-stage kidney disease: a systematic review of observational studies

Barriers and Facilitators to Exercise in Older Adults Awaiting Kidney Transplantation and Their Care Partners

Rationale & Objective

Despite guidelines calling to improve physical activity in older adults, and evidence suggesting that prekidney transplant physical function is highly associated with posttransplant outcomes, only a small percentage of older patients treated with dialysis are engaged in structured exercise. We sought to elucidate barriers and facilitators of exercise among older adults treated with dialysis awaiting transplant and their care partners.

Study Design

Individual, in-depth, cognitive interviews were conducted separately for patients and care partners through secure web-conferencing.

Setting & Participants

Twenty-three patients (≥50 years of age, treated with dialysis from the University of San Francisco kidney transplantation clinic, with a short physical performance battery of ≤10) and their care partners.

Analytical Approach

All audio interviews were transcribed verbatim. Three investigators independently coded data and performed qualitative thematic content. The interview guide was updated iteratively based on the Capability Opportunity Motivation Behavior model.

Results

Patients' median age was 60 years (57 ± 63.5) and care partners' median ages was 57 years (49.5 ± 65.5). Thirty-nine percent of patients and 78% of care partners were female, 39% of patients and 30% of care partners self-identified as African American, and 47% of dyads were spouse or partner relationships. Major themes for barriers to pretransplant exercise included lack of understanding of an appropriate regimen, physical impairments, dialysis schedules, and safety concerns. Major facilitators included having individualized or structured exercise programs, increasing social support for patients and care partners, and motivation to regain independence or functionality or to promote successful transplantation.

Limitations

Participants geographically limited to Northern California.

Conclusions

Although patients and care partners report numerous barriers to pretransplant exercise and activity, they also reported many facilitators. An individualized, structured, home-based exercise program could circumvent many of the reported barriers and allow older patients to improve pretransplant physical function.

Exercise for patients with chronic kidney disease: from cells to systems to function

Chronic kidney disease (CKD) is among the leading causes of death and disability, affecting an estimated 800 million adults globally. The underlying pathophysiology of CKD is complex creating challenges to its management. Primary risk factors for the development and progression of CKD include diabetes mellitus, hypertension, age, obesity, diet, inflammation, and physical inactivity. The high prevalence of diabetes and hypertension in patients with CKD increases the risk for secondary consequences such as cardiovascular disease and peripheral neuropathy. Moreover, the increased prevalence of obesity and chronic levels of systemic inflammation in CKD have downstream effects on critical cellular functions regulating homeostasis. The combination of these factors results in the deterioration of health and functional capacity in those living with CKD. Exercise offers protective benefits for the maintenance of health and function with age, even in the presence of CKD. Despite accumulating data supporting the implementation of exercise for the promotion of health and function in patients with CKD, a thorough description of the responses and adaptations to exercise at the cellular, system, and whole body levels is currently lacking. Therefore, the purpose of this review is to provide an up-to-date comprehensive review of the effects of exercise training on vascular endothelial progenitor cells at the cellular level; cardiovascular, musculoskeletal, and neural factors at the system level; and physical function, frailty, and fatigability at the whole body level in patients with CKD.

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.

The phase angle cut-off point capable of discriminating hemodialysis patients with reduced exercise tolerance: a cross-sectional study

BACKGROUND

Phase angle (PhA) is a prognostic marker of all-cause mortality in chronic kidney disease. However, no study has investigated this marker as a predictor of exercise intolerance in hemodialysis (HD) patients. The aim of this study was to determine a cut-off point for the PhA capable of discriminating HD patients with reduced exercise tolerance.

METHODS

Thirty-one patients (80.6% men, median age 69 years) were included. The evaluations were performed on three different days, before the HD session. The outcomes evaluated were: biochemical markers, inflammatory and nutritional status, body composition, peripheral muscle strength and exercise tolerance. Performance ≤50% of the predicted value in the six-minute step test (6MST) was defined as reduced exercise tolerance.

RESULTS

Patients presented an average of 67.6 steps (50.5% of predicted) in the 6MST. Fifteen patients (48.4%) were classified with reduced exercise tolerance. The receiver operating characteristic curve indicated a cut-off point of 3.73° for the PhA (sensitivity = 87%, specificity = 81%, and area under the curve = 0.88 [95% CI: 0.76-1.00]; p < 0.001). Patients with reduced exercise tolerance had worse inflammatory and nutritional status, lower PhA and greater impairment of peripheral muscle strength.

CONCLUSION

The cut-off point of 3.73° for the PhA is sensitive and specific to discriminate HD patients with reduced exercise tolerance.

TRIAL REGISTRATION

This study was registered in the Clinical Trials database (no. NCT03779126, date of first registration 19/12/2018).

Association of Sedentary Lifestyle with All-Cause and Cause-Specific Mortality in Adults with Reduced Kidney Function

Key Points

Nearly half of individuals with reduced kidney function had sedentary lifestyle, defined as more than 6 hours of sitting a day. Non-Hispanic White individuals and individuals with younger age, obesity, and with diabetes were more likely to have sedentary lifestyles. Spending more than 6 hours a day sedentary increases the future risk of death from all causes and cardiovascular diseases in individuals with reduced kidney function.

Background

Individuals with CKD tend to have sedentary behavior and decreased physical activity; both are independent predictors of mortality in general population. While physical inactivity correlates to adverse health outcomes in patients with reduced kidney function, it is unclear whether this relationship remains significant for sedentary behavior. Our study purpose was to evaluate the association of sedentary lifestyle with mortality risk in individuals with renal insufficiency.

Methods

The study population were adult participants of 2007–2016 National Health and Nutrition Examination Survey with eGFR <60 ml/min per 1.73 m2 or self-reporting receiving dialysis (N =1419). Sedentary lifestyle was defined as sedentary time >6 hours per day. Outcome of interest was all-cause and cardiovascular disease (CVD)–related or cancer-related mortality.

Results

We observed that non-Hispanic White individuals and individuals with younger age and higher educational level were more likely to have sedentary lifestyle. During a median follow-up of 99 (interquartile range, 70–128) months, a total of 458 participants died (3.98 deaths per 1000 person-months); 120 died from CVD and 92 from cancer, respectively. The crude analysis showed that individuals with sedentary lifestyle have higher risk of all-cause and CVD-related but not cancer-related mortality compared with the nonsedentary population. After adjusting for potential confounders, we showed that all-cause mortality and CVD-related mortality were 1.64-fold (95% confidence interval, 1.26 to 2.12) and 1.66-fold (95% confidence interval, 1.03 to 2.67) higher, respectively, in the sedentary population compared with the nonsedentary population. Similar results were observed in the sensitive analyses, in which we excluded individuals with dialysis, eGFR <15 ml/min per 1.73 m2, or mobility disability.

Conclusions

Our findings suggest that sedentary lifestyle correlated to greater risk of all-cause and CVD-related mortality among individuals with reduced kidney function. Interventions targeting the individuals with risky behaviors may have practical importance for public health.

Cardiorespiratory fitness and mortality risk in patients receiving hemodialysis: a prospective cohort

BACKGROUND

Kidney failure reduces life expectancy by one-third compared with the general population, and cardiovascular complications and poor cardiorespiratory fitness (CRF) are the main causes. We aimed to evaluate the association between severely low CRF and all-cause mortality risk in HD patients.

METHODS

This observational prospective cohort study followed-up patients receiving HD from August 2015 until March 2022. Cardiorespiratory fitness was evaluated through the cardiopulmonary exercise test, and the peak oxygen uptake (VO2peak) value was used to determine severely low CRF (< 15 mL∙kg-1∙min-1). Cox regression and univariate Kaplan-Meier analysis were used to evaluate the association of severely low CRF with mortality risk and survival rate.

RESULTS

Forty-eight patients were followed-up for a median of 33.0 [14.3 - 49.3] months. A total of 26 patients had severely low CRF. During the follow-up period, 11 patients (22.92%) died from all causes. From these, eight (30.8%) had severely low CRF. Even so, severely low CRF was not associated with crude death rates for patients stratified by CRF levels (p = 0.189), neither in unadjusted (HR 2.18; CI 95% 0.58-8.23) nor in adjusted (HR 1.32; CI 95% 0.31-5.59) Cox proportional hazard models. As a continuous variable, VO2peak was not associated with mortality risk (HR 1.01; CI 95% 0.84-1.21). Univariate Kaplan-Meier analysis showed that patients with severely low CRF did not have significantly worse survival rates than those with mild-moderate CRF (p = 0.186).

CONCLUSION

Our findings indicated that severely low CRF was not associated with all-cause mortality in patients on HD. Despite severely low CRF being prevalent, larger cohort studies are needed to establish strong conclusions on its association with all-cause mortality.

Prevention of Cardiovascular Events in Patients With Chronic Kidney Disease

OBJECTIVE

To examine the evidence base for lifestyle and pharmacologic interventions to reduce the risk of cardiovascular events in patients with chronic kidney disease, with an emphasis on reporting available data in distinct subtypes.

DATA SOURCES

A PubMed search (origin to February 2023) was conducted and references for selected studies were reviewed to identify additional articles. Search terms included chronic kidney disease, major adverse cardiovascular events, and heart failure hospitalization.

STUDY SELECTION AND DATA ANALYSIS

English language studies reporting cardiovascular outcomes data in patients with chronic kidney disease were included.

DATA SYNTHESIS

Much of the data on interventions to prevent cardiovascular events in patients with chronic kidney disease are derived from observational studies or subgroup analyses of trials of broader populations. Some common recommendations, such as weight loss, may be harmful in certain patients. Others may only offer benefits in subgroups, such as those with albuminuria. Newer agents, such as SGLT2 inhibitors and finerenone, have clearer evidence of cardiovascular benefit, but these may also apply only to specific subgroups.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Given the prevalence of chronic kidney disease and its attendant cardiovascular risk, it is important to understand which interventions offer the greatest benefit.

CONCLUSIONS

Patients diagnosed with chronic kidney disease have markedly increased risk of cardiovascular events, including myocardial infarction, stroke, heart failure, and cardiovascular death. However, until recently, there were few cardiovascular outcome studies that targeted enrollment specifically to those patients. Certain drugs now have shown benefits to cardiovascular end points in this population.

Association of physical activity with endothelial dysfunction among adults with and without chronic kidney disease: The Maastricht Study

BACKGROUND AND AIMS

Physical activity (PA) constitutes an established protective factor while sedentary behavior (SB) an emerging independent risk factor for cardiovascular diseases. This study evaluated the association of PA and SB with endothelial dysfunction (ED) depending on kidney function status.

METHODS

Cross-sectional data from the prospective, population-based Maastricht Study were used. PA and SB were measured using the ActivPAL3 accelerometer 24h/day for eight consecutive days. ED was evaluated by plasma levels of soluble vascular cell adhesion protein-1, intercellular adhesion molecule-1, E-selectin and von Willebrand factor, which were combined into an ED score with higher values depicting higher ED.

RESULTS

Overall, 2,668 participants, 323 with chronic kidney disease, were included. In normal kidney function individuals, the ED score presented a significant negative association with total, lower-intensity and moderate-to-vigorous PA duration and a positive association with total sedentary time, sedentary breaks and sedentary bout duration. In participants with chronic kidney disease, a significant negative association of ED score with total [β: -4.42, 95% confidence intervals (95% CI): -7.98; -0.87] and lower-intensity (β: -7.08, 95% CI: -13.41; -0.74) PA duration, as well as a positive association of ED score with sedentary bout duration (β: 43.72, 95% CI: 9.85; 77.59) were noted. The strength of associations did not significantly differ across kidney function subgroups (p > 0.05).

CONCLUSIONS

This analysis showed that PA duration is inversely associated with ED both among patients with normal kidney function and chronic kidney disease. In chronic kidney disease, longer sedentary bouts were associated with greater endothelial dysfunction.

Cardiovascular complications in chronic kidney disease: a review from the European Renal and Cardiovascular Medicine Working Group of the European Renal Association

Chronic kidney disease (CKD) is classified into five stages with kidney failure being the most severe stage (stage G5). CKD conveys a high risk for coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. Cardiovascular complications are the most common causes of death in patients with kidney failure (stage G5) who are maintained on regular dialysis treatment. Because of the high death rate attributable to cardiovascular (CV) disease, most patients with progressive CKD die before reaching kidney failure. Classical risk factors implicated in CV disease are involved in the early stages of CKD. In intermediate and late stages, non-traditional risk factors, including iso-osmotic and non-osmotic sodium retention, volume expansion, anaemia, inflammation, malnutrition, sympathetic overactivity, mineral bone disorders, accumulation of a class of endogenous compounds called 'uremic toxins', and a variety of hormonal disorders are the main factors that accelerate the progression of CV disease in these patients. Arterial disease in CKD patients is characterized by an almost unique propensity to calcification and vascular stiffness. Left ventricular hypertrophy, a major risk factor for heart failure, occurs early in CKD and reaches a prevalence of 70-80% in patients with kidney failure. Recent clinical trials have shown the potential benefits of hypoxia-inducible factor prolyl hydroxylase inhibitors, especially as an oral agent in CKD patients. Likewise, the value of proactively administered intravenous iron for safely treating anaemia in dialysis patients has been shown. Sodium/glucose cotransporter-2 inhibitors are now fully emerged as a class of drugs that substantially reduces the risk for CV complications in patients who are already being treated with adequate doses of inhibitors of the renin-angiotensin system. Concerted efforts are being made by major scientific societies to advance basic and clinical research on CV disease in patients with CKD, a research area that remains insufficiently explored.

The effect of intradialytic exercise on dialysis patient survival: a randomized controlled trial

BACKGROUND

Patients with kidney failure have a high mortality rate. This study aimed to evaluate the effect of intradialytic exercise on survival in patients receiving hemodialysis (HD).

METHODS

In this randomized controlled trial conducted in a HD center in Iran, adult patients receiving chronic HD were randomized to intradialytic exercise (60 min) in the second hour of thrice weekly dialysis for 6 months (intervention) or no intradialytic exercise (control). The primary outcome was survival rate at 12 months. Secondary outcomes were serum albumin, hemoglobin, hematocrit, red blood cell count, serum calcium, serum phosphorous, parathyroid hormone, physical function (6-min walk test) and nutritional status (Geriatric Nutritional Risk Index) during the first 6 months. The trial follow-up period was 12 months.

RESULTS

The study included 74 participants (44 males) with an age average of 64 ± 12 years old and a dialysis history of 27 ± 12 months, randomized to intervention (n = 37) or control (n = 37). Compared with controls, 1-year survival was higher in the intervention group (94% vs 73%, P = 0.01). The hazard ratio in univariate analysis in intervention group was 0.17 (95% CI 0.04-0.8; P = 0.02) compared to that in control group. During the 6-month intervention period, significant between-group changes were observed in all secondary outcomes between the intervention and control groups.

CONCLUSION

Intradialytic exercise performed for at least 60 min during thrice weekly dialysis sessions improves survival in adult patients receiving HD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04898608. Retrospectively registered on 24/05/2021. Registered trial name: The Effect of Intradialytic Exercise on Dialysis Patients Survival.

Nine Months of Hybrid Intradialytic Exercise Training Improves Ejection Fraction and Cardiac Autonomic Nervous System Activity

Cardiovascular disease is the most common cause of death in hemodialysis (HD) patients. Intradialytic aerobic exercise training has a beneficial effect on cardiovascular system function and reduces mortality in HD patients. However, the impact of other forms of exercise on the cardiovascular system, such as hybrid exercise, is not clear. Briefly, hybrid exercise combines aerobic and strength training in the same session. The present study examined whether hybrid intradialytic exercise has long-term benefits on left ventricular function and structure and the autonomous nervous system in HD patients. In this single-group design, efficacy-based intervention, twelve stable HD patients (10M/2F, 56 ± 19 years) participated in a nine-month-long hybrid intradialytic training program. Both echocardiographic assessments of left ventricular function and structure and heart rate variability (HRV) were assessed pre, during and after the end of the HD session at baseline and after the nine-month intervention. Ejection Fraction (EF), both assessed before and at the end of the HD session, appeared to be significantly improved after the intervention period compared to the baseline values (48.7 ± 11.1 vs. 58.8 ± 6.5, p = 0.046 and 50.0 ± 13.4 vs. 56.1 ± 3.4, p = 0.054 respectively). Regarding HRV assessment, hybrid exercise training increased LF and decreased HF (p < 0.05). Both conventional Doppler and tissue Doppler imaging indices of diastolic function did not change after the intervention period (p > 0.05). In conclusion, long-term intradialytic hybrid exercise training was an effective non-pharmacological approach to improving EF and the cardiac autonomous nervous system in HD patients. Such exercise training programs could be incorporated into HD units to improve the patients’ cardiovascular health.

The Potential Modulatory Effects of Exercise on Skeletal Muscle Redox Status in Chronic Kidney Disease

Chronic Kidney Disease (CKD) is a global health burden with high mortality and health costs. CKD patients exhibit lower cardiorespiratory and muscular fitness, strongly associated with morbidity/mortality, which is exacerbated when they reach the need for renal replacement therapies (RRT). Muscle wasting in CKD has been associated with an inflammatory/oxidative status affecting the resident cells' microenvironment, decreasing repair capacity and leading to atrophy. Exercise may help counteracting such effects; however, the molecular mechanisms remain uncertain. Thus, trying to pinpoint and understand these mechanisms is of particular interest. This review will start with a general background about myogenesis, followed by an overview of the impact of redox imbalance as a mechanism of muscle wasting in CKD, with focus on the modulatory effect of exercise on the skeletal muscle microenvironment.

Bicycle ergometer exercise during hemodialysis and its impact on quality of life, aerobic fitness and dialysis adequacy: A pilot study

BACKGROUND

Chronic kidney disease patients on hemodialysis commonly have a worse quality of life (QoL) due to complications of the disease and dialysis procedure. Physical exercise has emerged as a strategy to improve this scenario. The objective of this study was to evaluate the effect of an intradialytic aerobic exercise program on QoL and aerobic fitness in hemodialysis patients.

MATERIAL AND METHODS

These are a secondary analysis of clinical trial data previously published in which hemodialysis patients were randomized into "bike group" (using an adapted exercise bicycle) or "control group" (usual care). The exercise sessions lasted 45 min (5 min of warm-up, 35 min of moderate-intensity and 5 min of cool-down) three times/week for three months. The QoL domains were assessed using the SF-36 QoL questionnaire. Aerobic fitness was evaluated using the 6-min walk test (6MWT). Circulating cytokines, biochemical parameters and Kt/V were also assessed.

RESULTS

Nine patients completed three months of exercise (5 men, 44 ± 11 years), and nine were in the control group (6 men, 44 ± 14 years). In the bike group, there was a trend to improve the physical role domain (p = 0.06) regarding QoL, an improvement in the 6MWT (p = 0.02), and in the Kt/V (p = 0.03) after three months. There was a positive correlation between the general health domain and Kt/V (r = 0.691; p = 0.003) and an inverse correlation between the physical functioning domain and plasma TNF-α levels (r = -0.514; p = 0.04).

CONCLUSIONS

12 weeks of intradialytic aerobic exercise was enough to benefit hemodialysis patients' quality of life, aerobic fitness, and quality of dialysis.

CLINICALTRIALS

gov id: NCT04375553.

Long-Term Effect of Physical Exercise on the Risk for Hospitalization and Death in Dialysis Patients: A Post-Trial Long-Term Observational Study

BACKGROUND AND OBJECTIVES

In the EXerCise Introduction to Enhance Performance in Dialysis (EXCITE) trial, a simple, personalized 6-month walking exercise program at home during the day off of dialysis improved the functional status and the risk for hospitalization in patients with kidney failure. In this post-trial observational study, we tested whether the same intervention was associated with a lower long-term risk of death or hospitalization (combined end point) during a follow-up extended up to 36 months.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 227 patients (exercise, n=104; control, n=123) completed the 6-month trial and entered the post-trial observational study. Data were analyzed by unadjusted and adjusted Cox regression analyses and Bayesian analysis.

RESULTS

In the long-term observation (up to 36 months), 134 events were recorded (eight deaths not preceded by hospitalization and 126 hospitalizations, which were followed by death in 38 cases). The long-term risk for hospitalization or death was 29% lower (hazard ratio, 0.71; 95% confidence interval, 0.50 to 1.00), and in an analysis stratified by adherence to the walking exercise program during the 6-month trial, the subgroup with high adherence (>60% of prescribed sessions) had a 45% lower risk as compared with the control group (hazard ratio, 0.55; 95% confidence interval, 0.35 to 0.87). A Bayesian analysis showed that the posterior probability of a hazard ratio of 0.71 (95% confidence interval, 0.50 to 1.00) for the risk of the composite outcome observed in the post-trial observational study was 93% under the conservative prior and 97% under the optimistic prior. Sensitivity analyses restricted to the risk of hospitalization only or censoring patients at the time of transplantation fully confirmed these findings.

CONCLUSIONS

A simple, personalized, home-based, low-intensity exercise program was associated with a lower risk of hospitalization.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

EXerCise Introduction to Enhance Performance in Dialysis (EXCITE), NCT01255969.

Physical activity and the 'pediatric inactivity triad' in children living with chronic kidney disease: a narrative review

The ‘paediatric inactivity triad’ (PIT) framework consists of three complex inter-related conditions that influence physical inactivity and related health risks. In those living with chronic kidney disease (CKD), a multi-factorial milieu of components likely confound the PIT elements, resulting in a cycle of decreased physical functioning and reduced physical activity. In this review, we explore and summarize previous research on each of the three principal PIT components (exercise deficit disorder, dynapenia, and physical illiteracy) in the pediatric CKD population. We found those living with CKD are significantly physically inactive compared to their peers. Physical inactivity occurs early in the disease process and progressively gets worse as disease burden increases. Although physical activity appears to increase post-transplantation, it remains lower compared to healthy controls. There is limited evidence on interventions to increase physical activity behaviour in this population, and those that have attempted have had negligible effects. Studies reported profound reductions in muscle strength, physical performance, and cardiorespiratory fitness. A small number of exercise-based interventions have shown favourable improvements in physical function and cardiorespiratory fitness, although small sample sizes and methodological issues preclude the generalization of findings. Physical activity must be adapted and individualized to the needs and goals of the children, particularly those with acute and chronic medical needs as is the case in CKD, and further work is needed to define optimal interventions across the life course in this population if we aim to prevent physical activity declining further.

The Effect of Nutrition and Exercise on Body Composition, Exercise Capacity, and Physical Functioning in Advanced CKD Patients

Patients with stages 4 and 5 chronic kidney disease (CKD), and particularly chronic dialysis patients, commonly are found to have substantially reduced daily physical activity in comparison to age- and sex-matched normal adults. This reduction in physical activity is associated with a major decrease in physical exercise capacity and physical performance. The CKD patients are often physically deconditioned, and protein energy wasting (PEW) and frailty are commonly present. These disorders are of major concern because physical dysfunction, muscle atrophy, and reduced muscle strength are associated with poor quality of life and increased morbidity and mortality in CKD and chronic dialysis patients. Many randomized controlled clinical trials indicate that when CKD and chronic dialysis are provided nutritional supplements or undergo exercise training their skeletal muscle mass and exercise capacity often increase. It is not known whether the rise in skeletal muscle mass and exercise capacity associated with nutritional support or exercise training will reduce morbidity or mortality rates. A limitation of these clinical trials is that the sample sizes of the different treatment groups were small. The aim of this review is to discuss the effects of nutrition and exercise on body composition, exercise capacity, and physical functioning in advanced CKD patients.

Physical Activity and Mortality in Patients With Chronic Kidney Disease: A Protocol for Systematic Review and Dose-Response Meta-Analysis

Objective

To examine the dose-response associations between total physical activity, different intensity of physical activity, and all-cause mortality in patients with chronic kidney disease (CKD).

Methods and Analysis

PubMed, Embase, Web of Science, and the Cochrane library will be searched from inception to June 2022. Only cohort studies assessing physical activity associations with all-cause mortality among CKD patients will be considered for inclusion. The quality of included cohort studies will be evaluated according to the Newcastle-Ottawa Scale (NOS). The robust error meta-regression (REMR) model will be used to establish dose-response relationships between physical activity and mortality. Additional statistical analysis including Egger's test, subgroup analysis, sensitivity analysis. The strengths of evidence will be evaluated with the Grading of Recommendation, Assessment, Development, and Evaluation approach.

Ethics and Dissemination

Ethics approval is not required as no private information from individuals is collected.

PROSPERO Registration Number

CRD 42021283630.

Obesity, Weight Loss, Lifestyle Interventions, and Autosomal Dominant Polycystic Kidney Disease

Obesity remains a growing public health concern in industrialized countries around the world. The prevalence of obesity has also continued to rise in those with chronic kidney disease. Epidemiological data suggests those with overweight and obesity, measured by body mass index, have an increased risk for rapid kidney disease progression. Autosomal dominant polycystic kidney disease causes growth and proliferation of kidney cysts resulting in a reduction in kidney function in the majority of adults. An accumulation of adipose tissue may further exacerbate the metabolic defects that have been associated with ADPKD by affecting various cell signaling pathways. Lifestyle interventions inducing weight loss might help delay disease progression by reducing adipose tissue and systematic inflammation. Further research is needed to determine the mechanistic influence of adipose tissue on disease progression.

Daily Step Counts in Patients With Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Observational Studies

Background

Physical inactivity is an essential factor in the prognosis of patients with chronic kidney disease (CKD). Daily step count is a straightforward measure to assess physical activity levels. Understanding the step counts among different CKD stages is essential to change sedentary behavior.

Objectives

This systematic review and meta-analysis aimed to investigate the daily step counts in patients with CKD at a different stage.

Design

A systematic review and meta-analysis.

Data Sources

The literature search was performed in PubMed, Embase, and Web of Science from inception to November 3rd, 2021.

Review Methods

Observational studies (cross-sectional, case-control, or cohort studies) reported specific values of step counts in CKD patients by the wearable device were included. A random-effects model was used to pool the data. Subgroup analysis explored differences in outcomes by stage of CKD. Heterogeneity between studies was assessed using the χ2 test of Cochrane's Q statistic. A contour-enhanced funnel plot was conducted to investigate publication bias. Univariate and multivariate meta-regression was conducted to examine possible sources of heterogeneity.

Results

Twenty-eight articles were identified and used for quantitative analysis. The result showed that the daily step count in patients with CKD was 4642.47 (95% CI: 4274.18–5010.76), and significantly lower than the healthy population. Subgroup analysis revealed that the step counts decreased before dialysis, dropped to a freezing point at the hemodialysis phase, and increased after kidney transplantation. Meta-regression analysis showed that daily step counts were relatively higher in the Americas or younger than 60 or kidney transplant recipients.

Conclusion

The status of daily step counts in patients with CKD decreases with CKD severity and increases after kidney transplantation. Although studies have begun to focus on strategies to improve step counts in patients with CKD, future studies should focus more on step counts in pre-dialysis patients and changing their physically inactive lifestyle early to alleviate deteriorating renal function.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=291551, identifier: CRD42021291551.

The Role of Physical Activity and Mortality in Hemodialysis Patients: A Review

Available data indicated that physical activity was related to improved outcomes in hemodialysis patients. Multiple observational studies involving different cohorts have reported that increased physical activity level was associated with decreased mortality among hemodialysis patients. Therefore, promoting physical activity has become an increasingly critical and promising approach to improving cardiovascular health and clinical outcomes in hemodialysis patients. This review summarizes the published articles regarding physical activity and hemodialysis patients, focusing on mortality and strategy to promote physical activity.

Association between metabolic scores for visceral fat and chronic kidney disease: A cross-sectional study

INTRODUCTION

Central obesity is closely linked to the risk of chronic kidney disease (CKD). This study aimed to evaluate the association between the novel central obesity index- metabolic score for visceral fat (METS-VF) and the risk of CKD in a Chinese population, and to compare its ability to predict CKD with other central obesity indices including waist circumference (WC), waist-to-height ratio (WHtR), lipid accumulation product (LAP), visceral adiposity index (VAI), a body shape index (ABSI), body roundness index (BRI), and cardiometabolic index (CMI).

METHODS

This cross-sectional study included 8866 individuals from China. Demographic information, lifestyle data, and medical history data were collected, and physical examinations, anthropometric measurements and laboratory tests were performed for each participant. CKD was defined as an estimated GFR< 60 ml/min/1.73m². Multivariate logistic regression models were used to evaluate the association between the METS-VF and the prevalence of CKD. Receiver operating characteristic (ROC) analyses were performed to assess and compare the predictive abilities of the central obesity indices and determine the optimal cut-off points.

RESULTS

A graded increase in the prevalence of CKD was observed with increasing METS-VF tertiles. Moreover, the METS-VF was independently associated with the risk of CKD after adjustment for current smoking, current drinking, physical activity level, diabetes, hypertension, CVD history and BMI. Compared with participants with a METS-VF in the lowest tertile, the multivariate-adjusted ORs and 95% CIs for participants with a METS-VF in the highest tertile were 3.943 (2.435-6.385) in the overall population, 3.585 (1.585-8.109) for men and 4.627 (2.485-8.616) for women. Significant interactions were found between the METS-VF and the risk of CKD by age (P value for interaction = 0.023). In ROC analysis, the METS-VF had a higher AUC value than other indices for predicting CKD in men and had comparable or higher AUC than other indices for women. For predicting CKD, the optimal cut-off value of the METS-VF was 6.891 for men and 6.744 for women. The METS-VF yielded the greatest Youden index among all indices for both sexes.

CONCLUSION

A higher METS-VF was independently associated with a greater risk of CKD. The METS-VF can be a useful clinical indicator for identifying CKD, as it had superior predictive power for CKD when compared with other central obesity indices.

Physical activity is associated with nutritional biomarkers in hemodialysis patients: A cross-sectional study

OBJECTIVE

To explore the association between physical activity levels and nutritional biomarkers in hemodialysis patients.

METHODS

Eighty-six patients responded to the short version of the International Physical Activity Questionnaire to estimate the metabolic equivalent of tasks (MET) per week. A MET-min per week <600 was considered as sedentary. The nutritional biomarkers (i.e., albumin, globulin, and albumin/globulin ratio) were collected.

RESULTS

Sixty-five patients (75.6%) were sedentary. Binary logistic regression showed that patients with low albumin levels had an 89% lower chance to be physically active (p = 0.037), but it was not significant in the adjusted analysis (p = 0.052). Albumin and albumin/globulin ratio levels were correlated with MET-min per week (r = 0.34 and 0.30; both p < 0.05). Additionally, lower median albumin and albumin/globulin ratio levels were found in the sedentary patients (p = 0.021 and p = 0.031), respectively.

CONCLUSION

The physical activity levels were associated with albumin and albumin/globulin ratio, surrogates of nutritional status in hemodialysis patients. These nutritional biomarkers were lower in sedentary patients.