Habitual physical activity measured by accelerometer and survival in maintenance hemodialysis patients

The impact of malnutrition on the effectiveness of intradialytic exercise in hemodialysis patients: amulticenter cohort study

PURPOSE

Low physical function can be effectively improved via intradialytic exercise. However, the association between the effects of intradialytic exercise on physical function and malnutrition severity has not been studied extensively. This study aimed to investigate the impact of nutritional status severity on physical function in patients undergoing hemodialysis with low physical function to whom intradialytic exercise was prescribed.

METHODS

The participants were patients with decreased mobility [walking speed < 1.0 m/s and/or Short Physical Performance Battery (SPPB) < 12] who had been undergoing hemodialysis thrice a week for 6 months and performing intradialytic exercise program. Patients were divided into groups based on the Geriatric Nutritional Risk Index (GNRI) [Non-malnutrition group (GNRI > 98), Gentle/slim malnutrition group (GNRI ≤ 98, GNRI ≥ 92), Mild malnutrition group (GNRI < 92, GNRI ≥ 82), Severe malnutrition group (GNRI < 82)]. The primary outcomes were Grip strength, isometric knee extension strength (IKES), SPPB, and 10-m walking speed measured at baseline and at 6 months. Statistical analyses were performed using a linear mixed-effects model with the intention-to-treat analysis, including within-group analysis and between-group comparison.

RESULTS

A total of 805 participants were included in the study. Within-group comparisons showed significantly improved IKES, 10-m walking speed, and SPPB improved, except in the Severe malnutrition group. Grip strength significantly improved in the Gentle/slim and mild malnutrition groups. Between-group comparison with controls showed that the improvement in Grip strength was significantly bigger in the Gentle/slim malnutrition group [0.98 (0.15 to 1.82) kg] than in the non-malnutrition group. However, IKES in the Severe malnutrition group [- 5.14 (- 9.18 to - 1.10) %] less significantly improve than that in the non-malnutrition group. No significant differences were found in the other indices.

CONCLUSION

In patients with severe malnutrition, the changes in IKES scores resulting from Intradialytic exercise were significantly smaller than those observed in non-malnourished patients. Therefore, it is necessary to initiate suitable nutritional and exercise therapy based on the severity of malnutrition.

Physical activity, exercise habits and health-related quality of life in maintenance hemodialysis patients: a multicenter cross-sectional study

BACKGROUND

Although exercise has the potential to yield numerous benefits for maintenance hemodialysis patients, the relationship between physical activity, exercise habits, and health-related quality of life (HRQOL) has not been thoroughly investigated. This study aimed to characterize the physical activity, exercise habits, and HRQOL of maintenance hemodialysis patients while examining the associations between these factors.

METHODS

A convenience sampling was used to recruit 827 patients from 74 dialysis units in China. The structured questionnaire included sociodemographics, the International Physical Activity Questionnaire, exercise habits, and the Kidney Disease Quality of Life Short Form 1.3. An independent samples t-test, multivariable logistic regression analysis, and multivariable linear regression analysis were used.

RESULTS

The physical activity levels of 69% of participants were found to be below the recommendation of the World Health Organization. Despite 62.4% of participants reporting regular exercise, 73.8% reported light exercise intensity, and 92.6% engaged in walking or jogging. Participants' HRQOL was higher in the low-intensity exercise group compared with the moderate-to-hard-intensity exercise group. Moderate-to-high physical activity was associated with better HRQOL in 13 of the 19 domains and regular exercise was linked to higher HRQOL in four of the 19 domains.

CONCLUSIONS

This study identified a low level of physical activity, light exercise intensity, and walking as the primary exercise type among the participants. A significant correlation was found between higher physical activity levels, regular exercise, and better HRQOL for maintenance hemodialysis patients. It is advisable to implement strategies to enhance physical activity levels and design exercise programs for maintenance hemodialysis patients based on their real-world physical activity levels and exercise habits.

Age-associated effects of intradialytic exercise on physical function and nutritional status in patients receiving ambulatory hemodialysis: A multicenter cohort study

INTRODUCTION

Intradialytic exercise is essential for improving physical function for older patients. This study aimed to examine the relationship between the effects of exercise therapy and aging.

METHODS

This multicenter cohort study included 1176 patients aged 40-89 years, who participated in an intradialytic exercise program, comprising stretching and resistance training, three times per week for 12 months. Isometric knee extension strength (IKES), 10-m walking speed, Short Physical Performance Battery (SPPB), and Geriatric Nutritional Risk Index (GNRI) were measured at baseline and after 12 months. The patients were divided according to age as follows: 40-59, 60-69, 70-79, and 80-89 years. A linear mixed-effects model examined the improvement within-group and between-control differences, as the 40-59 age group was the control group.

FINDINGS

The 40-59, 60-69, 70-79, and 80-89 age groups comprised 180, 317, 466, and 213 participants, respectively. Within-group differences, all the age groups significantly improved IKES and SPPB. The 10-m walking speed [0.02 (0.02) m/s] and GNRI [0.38 (0.33)] did not improved only in the 80-89 age group despite other age groups significantly improved. Between-control differences, IKES of the 70-79 age group [-0.24 (-0.42 to -0.06) %] was significantly lower improvement than control. GNRI of all the older groups were significantly smaller improvement than control (p < 0.05).

DISCUSSION

The older group demonstrated difficulty in improving walking ability and nutritional status compared with the younger groups. Clinicians need to consider the difference in effectiveness due to age and prescribe intradialytic exercises accordingly.

Combining exercise and nutrition in chronic kidney disease and dialysis: Can we learn from the performance nutrition of athletes?

The benefits of exercise interventions in individuals with chronic kidney disease have been widely reviewed; however, exercise has not yet been incorporated into routine clinical practice. In athletic populations, the goals of exercise training are to improve a specific aspect of physical performance such as strength or endurance, to ultimately optimize physical performance. This contrasts with many chronic kidney disease exercise studies where the goals are more aligned to a minimal effect, such as prevention of decline in physical function, frailty or protein energy wasting (PEW), weight loss for cardiovascular disease risk reduction, and risk minimization for mortality. In athletic populations, there are common targeted nutrition strategies used to optimize physical performance. In this review, we consider the evidence for and potential benefits of targeted nutrition strategies to complement well-designed exercise interventions to improve physical performance in people with chronic kidney disease and dialysis. Overall, we found a small number of studies using targeted protein supplementation in combination with a variety of exercise protocols; however, results were mixed. Future studies in people with chronic kidney disease should optimize acute (pre, during, and postexercise) and chronic nutritional status, utilizing targeted nutrition interventions proven in athletes to have benefit.

A Simple Exercise Program for Patients With End-Stage Kidney Disease to Improve Strength and Quality of Life: Clinical Research Protocol

Background

Most patients with end-stage kidney disease (ESKD) appreciate the importance of exercise and would like to increase their physical activity; however, they report a few key barriers, including (1) lack of physician advice to do so, (2) lack of safe and convenient programs (ie, appropriate for home or neighborhood), and (3) cost. Importantly, patients indicated in a previous survey that they would prefer an exercise program that improves muscle strength and symptoms, and are less interested in cardiovascular disease prevention.

Objective

To test the feasibility of a simple, prescribed exercise program using Nordic walking poles in patients with ESKD treated with dialysis.

Design

Randomized multicenter pilot trial of an exercise intervention that includes Nordic walking poles, personalized physician exercise prescriptions, pedometers, and access to exercise videos, compared with standard of care, in patients being treated with maintenance dialysis.

Setting

Multicenter tertiary care centers in Canada.

Patients

Ambulatory adult patients with ESKD treated with peritoneal dialysis or hemodialysis (HD) for at least 6 months at participating sites are potentially eligible. Inclusion criteria include ability to use Nordic walking poles (either de novo or in place of mobility aid) and to provide informed consent in English or in French. Exclusion criteria include (1) any absolute contraindication to exercise, (2) baseline step count >8000 steps/day, (3) planned living donor kidney transplant, and (4) participation in another interventional trial that may affect the results of this study.

Methods

This is a randomized multicenter pilot trial of an exercise intervention that consists of a prescription to exercise using Nordic walking poles, a pedometer to track activity, and access to exercise videos, with the comparator of standard of care (dialysis unit staff encouragement to exercise) in patients being treated with maintenance dialysis. Randomization is concealed and uses a 1:1 ratio for group assignment. Our specific aims are to determine the feasibility of patient recruitment, adherence to the exercise program (verified by step counts), and efficacy of the intervention on patient-important outcomes that were assessed as a priority by patients in a prior survey-specifically strength, fatigue, and sleep. We record days spent in hospital and loss of independent living to inform sample size calculations for a definitive trial of exercise in patient with ESKD treated with dialysis. Adverse events are closely monitored.

Outcomes

Primary: Our recruitment goal is 90 to 150 patients over 27 months; adherence success will be defined if >75% of randomized patients, excluding those who are transplanted or deceased, achieve >80% of their prescribed steps at 6 and 12 months. Secondary Efficacy Outcomes: (1) strength-hand grip strength and 5 times sit to stand, (2) energy-Short Form (SF)-36 vitality subscale, and (3) sleep-Pittsburg Sleep Quality Index will be assessed at baseline, 6, and 12 months.

Results

Trial recruitment started before the COVID-19 pandemic and the pandemic led to many interruptions and delays. Online exercise Web sites and a tailored video were added to the protocol to encourage activity when participants were unable or reluctant to walk in public places.

Limitations

This trial was designed to include ambulatory patients with ESKD and does not address the burden of disease in patients with very restricted mobility.

Trial Registration

NCT03787589.

Impacts of cognition of exercise on physical activity participation in hemodialysis patients

INTRODUCTION

Physical inactivity is a strong predictor of mortality in hemodialysis patients. Although regular physical activity reduces mortality, patients remain inactive. Comparing the cognition of exercise in hemodialysis patients with different physical activity status could highlight domains where inactive people experience heightened barriers to physical activity. We therefore assessed patients' perceived benefits and barriers to exercise using a standardized way, thereby informing future exercise interventions to address these barriers experienced by inactive patients.

METHODS

ESRD patients undergoing hemodialysis were recruited and asked to complete a human activity profile, wear a pedometer for seven consecutive days, and complete the Dialysis Patient-perceived Exercise Benefits and Barriers Scale (DPEBBS). Binominal Logistic regression analysis was conducted to determine which benefits and barriers are associated with physical activity. This cross-sectional observational study was registered as NCT05189795.

RESULTS

A total of 505 patients completed the survey, most of whom were male (67.1%), with an average age of 49.69 ± 13.96 years. And 52.67-76.63% patients on HAP questionnaire were inactive. The co-benefits in active patients were improving mood and prevention of muscle wasting but did not reach significance in physical activity level. Tiredness, muscle fatigue, and lack of knowledge of exercise were common barriers to patients, and all have a significant impact on a patient's physical activity level.

CONCLUSIONS

For inactive patients, exercise during hemodialysis can not only improve physical activity but also reduce family burden. And improving physical activity is a long-term project that cannot be separated from the support of hemodialysis medical staff.

The Impact of a Wearable Activity Tracker and Structured Feedback Program on Physical Activity in Hemodialysis Patients: The Step4Life Pilot Randomized Controlled Trial

RATIONALE & OBJECTIVE

People with end-stage kidney disease (ESKD) have very low physical activity, and the degree of inactivity is strongly associated with morbidity and mortality. We assessed the feasibility and effectiveness of a 12-week intervention coupling a wearable activity tracker (FitBit) and structured feedback coaching versus wearable activity tracker alone on changes in physical activity in hemodialysis patients.

STUDY DESIGN

Randomized controlled trial.

SETTING & PARTICIPANTS

55 participants with ESKD receiving hemodialysis who were able to walk with or without assistive devices recruited from a single academic hemodialysis unit between January 2019 and April 2020.

INTERVENTIONS

All participants wore a Fitbit Charge 2 tracker for a minimum of 12 weeks. Participants were randomly assigned 1:1 to a wearable activity tracker plus a structured feedback intervention versus the wearable activity tracker alone. The structured feedback group was counseled weekly on steps achieved after randomization.

OUTCOME

The outcome was step count, and the main parameter of interest was the absolute change in daily step count, averaged per week, from baseline to completion of 12 weeks intervention. In the intention-to-treat analysis, mixed-effect linear regression analysis was used to evaluate change in daily step count from baseline to 12-weeks in both arms.

RESULTS

Out of 55 participants, 46 participants completed the 12-week intervention (23 per arm). The mean age was 62 (± 14 SD) years; 44% were Black, and 36% were Hispanic. At baseline, step count (structured feedback intervention: 3,704 [1,594] vs wearable activity tracker alone: 3,808 [1,890]) and other participant characteristics were balanced between the arms. We observed a larger change in daily step count in the structured feedback arm at 12 weeks relative to use of the wearable activity tracker alone arm (Δ 920 [±580 SD] versus Δ 281 [±186 SD] steps; between-group difference Δ 639 [±538 SD] steps; P<0.05).

LIMITATIONS

Single-center study and small sample size.

CONCLUSION

This pilot randomized controlled trial demonstrated that structured feedback coupled with a wearable activity tracker led to a greater daily step count that was sustained over 12 weeks relative to a wearable activity tracker alone. Future studies are required to determine longer-term sustainability of the intervention and potential health benefits in hemodialysis patients.

FUNDING

Grants from industry (Satellite Healthcare) and government (National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK).

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT05241171.

Influence of Malnutrition on the Improvement of Physical Function by Intradialytic Resistance Exercise in Patients Undergoing Hemodialysis

OBJECTIVE

Intradialytic exercise improves physical function. However, malnutrition may be an essential factor affecting the effectiveness of exercise to improve physical function. Few studies of the relationship between malnutrition and the effectiveness of intradialytic exercise to improve physical function exist. Therefore, this study investigated malnutrition at the beginning of intradialytic exercise and how it affects the subsequent improvement in physical function.

METHODS

Patients who performed intradialytic exercise for 12 months were enrolled in this study. A Geriatric Nutritional Risk Index of 91.2 was defined as malnutrition. Patients were assigned to 2 groups using propensity score matching to adjust for confounding factors. Physical function outcomes were handgrip strength, isometric knee extension strength, short physical performance battery, and 10-m walking speed; these were compared at baseline, 3 months, 6 months, and 12 months. The 2 groups were further divided into another 2 groups as per whether the nutritional status had improved after 12 months; therefore, a total of 4 groups were analyzed.

RESULTS

After matching, the data of 154 patients in each group were analyzed. During the intragroup comparison, isometric knee extension strength, short physical performance battery, and 10-m walking speed improved significantly in both groups after intradialytic exercise was started compared with before intradialytic exercise was started. However, there was no significant improvement in handgrip strength in the malnutrition group. There were no significant differences in any of the physical function measurements or changes from the baseline values among the 4 groups divided as per subsequent recovery of the nutritional status.

CONCLUSION

Malnutrition may not impact the effectiveness of intradialytic exercise to improve lower-leg physical function. Its effect on the improvement of handgrip strength requires further investigation.

Physical function management for elderly dialysis patients: prevention and improvement of frailty and disability

Frailty has become an emerging public health problem in the aging society and is regarded as a state of vulnerability to developing increased dependency and/or mortality when exposed to a stressor. As the proportion of elderly dialysis patients is increasing worldwide, frailty has recently influenced on the clinical outcomes among those patients also caused great attention. The prevalence of frailty among dialysis patients has ranged from 3.0- to 10-fold higher than in community-dwelling elderly. Since frailty has been found to be associated with higher mortality, independent of clinical characteristics and comorbidity, interventions to improve frailty have the potential to contribute to better quality of life and lower mortality among dialysis patients. Moreover, clinical research should be focused on the possibility that early rehabilitation of dialysis patients might improve poor outcomes. Current clinical question should aim to take an appropriate strategy to address frailty, including identifying the optimal timing for intervention.

Physical function and physical activity in hemodialysis patients with peripheral artery disease

INTRODUCTION

Peripheral artery disease (PAD) is commonly observed in patients undergoing hemodialysis. PAD impairs the vasculature and leads to pathophysiologic changes in the skeletal muscles, causing physical function impairment and physical inactivity in general. However, it is unclear whether PAD adversely affects physical function and physical activity in patients on hemodialysis.

METHODS

We performed a cross-sectional study with a retrospective review of the data to determine whether PAD is associated with impaired physical function and physical activity in patients undergoing hemodialysis. The study population comprised 310 patients and 88 healthy subjects. PAD was diagnosed based on an ankle-brachial index of <1.00 in patients on hemodialysis. Measurements of physical function included maximum walking speed, muscle strength in the lower extremities, and balance while standing.

FINDINGS

Of the 310 patients, 84 (27.1%) had PAD. When patients undergoing hemodialysis were divided into those without PAD and those with PAD, both groups had poorer physical function and physical activity than the healthy control subjects. After adjustments for potential confounders, it was found that patients on hemodialysis with PAD had slower walking speed, poorer standing balance, and less physical activity than those without PAD. However, there was no significant difference in lower extremity muscle strength between the two groups.

DISCUSSION

PAD diagnosed based on an ankle-brachial index of <1.00 was independently associated with impaired physical function and reduced physical activity in patients undergoing hemodialysis.

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.

Physical activity and its trajectory over time and clinical outcomes in hemodialysis patients

PURPOSE

We examined whether physical activity measured at starting point and its trajectory over time were simultaneously associated with vital prognosis.

METHODS

This retrospective cohort study included 295 ambulatory maintenance hemodialysis patients (mean age 63.9 years; 54.6% male). We measured physical activity at index date (starting point) and its change over 1 year as predictors, and all-cause death and cardiovascular events were assessed as the outcomes. Two groups each of high versus low physical activity at starting point (based on 4000 steps per day) and no decline versus decline (based on a predicted mean slope) were created. Cox proportional-hazards regression and Fine-Gray proportional sub-distribution hazards model were used to examine associations between physical activity and its trajectory and clinical outcomes.

RESULTS

Decline in physical activity over 1 year was associated with a higher risk of all-cause death and cardiovascular events, irrespective of the physical activity at starting point. Furthermore, both lower physical activity at starting point and decrease in physical activity over time were independently associated with a higher risk of all-cause death and cardiovascular events in models in which each exposure was mutually adjusted. Compared to other groups that worsened in either exposure, the lowest risk for death/cardiovascular events was observed in the high at starting point/no decline over time group.

CONCLUSIONS

Both physical activity at starting point and its change over time were independently associated with vital prognosis. The assessment of both exposures provides additional prognostic information for the assessment of each exposure.

Renal rehabilitation as a management strategy for physical frailty in CKD

An aging population and the increasing prevalence of lifestyle-related diseases have led to a worldwide increase in the rate of chronic kidney disease requiring renal replacement therapy. The mean age of individuals requiring dialysis therapy has been increasing, and Japanese patients are aging more rapidly than those in the USA and Europe. Patients undergoing renal replacement therapy are at increased risk of sarcopenia/frailty compared with people with normal kidney function due to comorbid burden, long-standing malnutrition, chronic inflammation, metabolic acidosis, anabolic resistance, hormonal changes, physical inactivity and amino acid loss via dialysis treatment in addition to aging. Sarcopenia and frailty are serious global health problems that can decrease access to kidney transplantation and lead to various adverse health outcomes, including functional dependence, hospitalizations and deaths in patients on dialysis treatment. However, sarcopenia/frailty fortunately is potentially modifiable by early identification of poor physical functioning, sustainment and enhancement of daily physical activity, and participation in exercise treatments. The Japanese Society of Renal Rehabilitation was established in 2011 and published a clinical practice guideline for “Renal Rehabilitation” targeting nondialysis-dependent and dialysis-dependent patients and renal transplant recipients, in 2019. The guideline emphasized the importance of physical management for patients with kidney diseases in addition to nutritional supports and anemia management. Kidney health professionals should manage sarcopenia and physical frailty as a part of routine clinical care for patients undergoing hemodialysis to improve poor physical functioning, functional dependence, decreased quality of life and poor prognosis.

Intradialytic hypotension and objectively measured physical activity among patients on hemodialysis

BACKGROUND

Intradialytic hypotension is related to patient-reported outcomes such as post-dialysis fatigue, but its impact on physical activity has not been fully studied. We aimed to examine the relationship between intradialytic blood pressure (BP) and objectively measured physical activity.

METHODS

In this cross-sectional study, 192 hemodialysis patients underwent 4 weeks of physical activity measurement using triaxial accelerometers to measure step counts and moderate-to-vigorous physical activity (MVPA). Intradialytic BP parameters (pre-dialysis BP, post-dialysis BP, nadir BP, and fall in BP) were measured during all dialysis sessions. Mixed-effects linear regression models were used to analyze associations between intradialytic BP parameters and physical activity (1) after dialysis sessions on dialysis days and (2) on the following non-dialysis days.

RESULTS

The mean age of the patients was 71 years, and 47% had diabetes mellitus. Valid physical activity data were obtained in a total of 1938 dialysis days and 2629 non dialysis days. Lower nadir diastolic BP was significantly associated with lower step counts and shorter moderate-to-vigorous physical activity not only on dialysis days but also on the following non-dialysis days. Nadir diastolic BP showed a higher discrimination capacity for physical inactivity, defined as a step count < 4000 on non-dialysis days, than the other BP parameters. The optimal cutoff point of nadir diastolic BP for discriminating physical inactivity was 68 mmHg; its sensitivity and specificity were 66% and 67%, respectively.

CONCLUSIONS

Lower nadir diastolic BP was strongly associated with lower physical activity on both dialysis and non-dialysis days. Nadir diastolic BP may be a predictor for physical inactivity.

Snow Removal Maintains Physical Function in Hemodialysis Patients after One Year: A Pilot Study

Objectives:

Physical activity is an important prognostic factor in managing hemodialysis patients. During winter, physical activity decreases, which necessitates interventions to maintain physical function. This study investigated whether snow removal is an effective physical activity to maintain physical function in hemodialysis patients.

Methods:

This retrospective cohort study examined 32 patients (aged 68.9 ± 14.2 years, 21 men) who underwent hemodialysis at Uonuma Kikan Hospital from March 2021 to March 2022. The patients were divided into snow-remover and non-snow-remover groups. The primary outcome was the Short Physical Performance Battery (SPPB). Secondary outcomes were grip strength, skeletal muscle index, and physical activity level. Differences in outcomes between the groups were investigated at 1 year of follow-up.

Results:

The snow-remover group had significantly high SPPB score, grip strength (men), skeletal muscle index (men), and physical activity at baseline. The decline in SPPB after 1 year was significantly smaller in the snow-remover group than in the non-snow-remover group. The level of physical activity in the non-snow-remover group decreased over time.

Conclusions:

Snow removal contributed to the maintenance of physical function in hemodialysis patients after 1 year. However, snow removal is not recommended for all hemodialysis patients, and further studies should identify other safe winter activities to maintain physical function.

Motivation, Barriers, and Suggestions for Intradialytic Exercise-A Qualitative Study among Patients and Nurses

Background: Intradialytic exercise is an effective intervention to reduce morbidity and mortality and increase quality of life among patients with chronic kidney disease undergoing dialysis. However, implementing and sustaining it in clinical practice has proved challenging. To identify how to best design an effective and sustainable intervention in clinical practice, we aimed to explore hemodialysis patients’ and nurses’ attitudes towards intradialytic exercise, including their motivation, anticipated barriers, and suggestions for the design of a proposed exercise program. Methods: Data were collected through qualitative semistructured interviews with patients and focus group interviews with nurses and analyzed inductively with content analysis. Results: Overall, patients’ and nurses’ attitudes towards intradialytic exercise were positive. Patients were motivated by their expectations about perceived benefits, such as improved quality of life and reduced musculoskeletal pain. Their main concern was triggering dialysis machine alarms and disturbing nurses. Nurses were more skeptical of intradialytic exercise and concerned about patient safety. Patients and nurses had several ideas on how to design a safe and motivating intradialytic exercise intervention. Conclusion: The analysis of patients’ and nurses’ experiences and attitudes generated recommendations for an intradialytic exercise program. Recommendations include individually tailored programs that are safe and that patients can do independently, continuous collaboration between patients, nurses, physicians, and physiotherapists, and educating nurses about the benefits and safety of intradialytic exercise.

Circulating irisin level in chronic kidney disease patients: a systematic review and meta-analysis

BACKGROUND

Irisin is not only a myokine but also an adipokine that is critical in many diseases including in the development of such diseases as obesity, diabetes mellitus, metabolic syndrome, coronary artery disease, and chronic inflammation. However, the association between irisin and chronic kidney disease (CKD) is unclear. This systematic review aimed to assess circulating irisin levels in patients with CKD and compare them with those in non-CKD patients.

METHODS

PubMed, EMBASE, CENTRAL, ISI Web of Science, and CNKI were searched to identify observational studies of circulating irisin levels in patients with CKD. Two reviewers independently searched the databases and screened studies according to the inclusion criteria. Data were extracted using a standardized collection form. Meta-analysis was performed to compare the differences in circulating irisin levels between CKD and non-CKD patients.

RESULTS

A total of 9 studies (6 cross-sectional and 3 case controls) involving 859 CKD patients and 393 non-CKD individuals were selected. The pooled data indicated that circulating irisin concentrations were significantly lower in CKD nondialysis patients (WMD = - 84.79, 95% CI - 170.23, 0.50; p < 0.05), peritoneal dialysis patients (WMD = - 235.81, 95% CI - 421.99, - 49.62; p = 0.01), and hemodialysis patients (WMD = - 217.46, 95% CI - 381.35, - 53.57; p = 0.009) than in healthy controls.

CONCLUSIONS

This study confirmed that irisin levels were decreased in patients with CKD. Moreover, circulating irisin levels were lower in dialysis patients than in nondialysis patients.

Pre-Frailty and Frailty in Dialysis and Pre-Dialysis Patients: A Systematic Review of Clinical and Biochemical Markers

Patients under dialysis are known to be more vulnerable to frailty, a dynamic geriatric syndrome defined as a state of vulnerability to stressors, due to numerous metabolic changes. With rise of life expectancy globally, it is important to understand the complexity of the pathophysiology of frailty and identify possible markers that can help with the prognosis and diagnosis of frailty. The aim of this systematic review is to give an overview of the knowledge regarding clinical and biochemical markers associated with pre-frailty and frailty in dialysis and pre-dialysis patients. In November 2020, PubMed, Embase and Web of Science were searched. Studies regarding biomarkers associated with (pre-)frailty in (pre-)dialysis patients were included. This systematic review identified clinical and biochemical markers in pre-frail and frail patients under dialysis or pre-dialysis published in the literature. This study shows that more investigation is necessary to identify markers that can differentiate these processes to be used as a diagnostic and prognostic tool in routine care and management of geriatric needs. Interventions that can improve health outcomes in pre-frail and frail older adults under dialysis or pre-dialysis are essential to improve not only the individual’s quality of life but also to reduce the burden to the health systems.

Effects of Intradialytic Exercise on Dialytic Parameters, Health-Related Quality of Life, and Depression Status in Hemodialysis Patients: A Randomized Controlled Trial

Exercise is fundamentally important in managing chronic diseases and improving health-related quality of life (HRQL). However, whether intradialytic exercise is safe through assessment of changes in dialytic parameters and has a positive impact on HRQL and depression status of hemodialysis patients requires further research with diverse racial and cultural populations to identify. This study aimed to evaluate the effects of intradialytic exercise on dialytic parameters, HRQL, and depression status in hemodialysis patients. A randomized controlled trial was conducted at a medical center in Northern Taiwan. Sixty-four hemodialysis patients were recruited using stratified random sampling. Participants were randomized into an experimental group (EG, n = 32) or a control group (CG, n = 32). The EG received a 12-week intradialytic exercise program while the CG maintained their usual lifestyles. Dialytic parameters, HRQL, and depression status were collected at baseline and at 12 weeks. The results indicated no differences in the dialytic parameters from the baseline between both groups. However, the EG had increased HRQL (ß = 22.6, p < 0.001) and reduced depression status (ß = −7.5, p = 0.02) at 12 weeks compared to the CG. Therefore, a 12-week intradialytic exercise regime is safe and effective in improving HRQL and reducing depression status for hemodialysis patients.

Renal Rehabilitation: Exercise Intervention and Nutritional Support in Dialysis Patients

With the growing number of dialysis patients with frailty, the concept of renal rehabilitation, including exercise intervention and nutrition programs for patients with chronic kidney disease (CKD), has become popular recently. Renal rehabilitation is a comprehensive multidisciplinary program for CKD patients that is led by doctors, rehabilitation therapists, diet nutritionists, nursing specialists, social workers, pharmacists, and therapists. Many observational studies have observed better outcomes in CKD patients with more physical activity. Furthermore, recent systematic reviews have shown the beneficial effects of exercise intervention on exercise tolerance, physical ability, and quality of life in dialysis patients, though the beneficial effect on overall mortality remains unclear. Nutritional support is also fundamental to renal rehabilitation. There are various causes of skeletal muscle loss in CKD patients. To prevent muscle protein catabolism, in addition to exercise, a sufficient supply of energy, including carbohydrates, protein, iron, and vitamins, is needed. Because of decreased digestive function and energy loss due to dialysis treatment, dialysis patients are recommended to ingest 1.2-fold more protein than the regular population. Motivating patients to join in activities is also an important part of renal rehabilitation. It is essential for us to recognize the importance of renal rehabilitation to maximize patient satisfaction.

Sex Difference in the Association between Physical Activity and All-Cause Mortality in Ambulatory Patients with Chronic Kidney Disease

(1) Background: The purpose of this article was to investigate the association between self-reported physical activity (PA) and all-cause mortality in ambulatory patients with chronic kidney disease (CKD), stage 4–5 including maintenance dialysis. (2) Methods: Ambulatory patients with CKD (eGFR < 30 mL/min/1.73 m²) with conservative treatment or chronic dialysis were included. PA was assessed using the Saltin–Grimby Physical Activity Level Scale. A Cox proportional hazards regression model––adjusted for age, sex, plasma–albumin, body mass index, socioeconomic status, and treatment––was applied. (3) Results: Participants (n = 374) were followed 39 ± 15 months from entry to death or censoring. Throughout the study period of 39 months, 156 deaths (42%) were registered. Regarding physical activity, 128 (34%) of the participants were inactive, 212 (57%) were moderately active, and 34 (9%) were highly or vigorously active. Moderate PA was associated with a decreased mortality risk in women (n = 150) compared to inactivity (HR 0.27 (0.15; 0.51), p < 0.001), whereas a high/vigorous level of PA was not significantly associated with mortality risk compared to inactivity. In men (n = 224), the associations between PA levels and mortality risk were not significant. (4) Conclusions: Moderate PA was associated with reduced all-cause mortality in ambulatory women with stage 4–5 CKD with or without maintenance dialysis treatment. Physical activity was not significantly associated with mortality in men.

Bridging the gap from research to practice for enhanced health-related quality of life in people with chronic kidney disease

Improving the health status of people with chronic kidney disease (CKD) through physical activity (PA) or exercise interventions is challenging. One of the gaps in the process of translating the general public PA activity guidelines as well as the CKD-specific guidelines into routine clinical practice is the lack of systematic recording and monitoring of PA and physical function attributes, which can also be used to develop individualized and measurable plans of action to promote PA for health. We aim to present an overview of key considerations for PA, physical function and health-related quality of life (HRQoL) evaluation in people with CKD, with the aim of encouraging health professionals to integrate assessment of these outcomes in routine practices. Physical inactivity and impaired physical function, sometimes to the extent of physical and social disability levels, and subsequently lower perceived HRQoL, are highly prevalent in this population. Enhanced PA is associated with better physical function that also translates into multiple health benefits. Breaking the vicious circle of inactivity and physical dysfunction as early as possible in the disease trajectory may confer huge benefits and enhanced life satisfaction in the longer term. With this in mind, the importance of PA/exercise interventions in CKD to improve HRQoL is also summarized.

The reliability and validity of the 30-seconds sit-to-stand test and its capacity for assessment of the functional status of hemodialysis patients

PURPOSE

To investigate the validity of the 30-seconds sit-to-stand test (STS-30) and its reliability in hemodialysis patients.

METHODS

Patients receiving hemodialysis treatment three times a week for at least six months were evaluated using STS-30, Incremental Shuttle Walking Test, and health-related quality of life by KDQOL-SF questionnaire. The data obtained from the Incremental Shuttle Walking Test were divided into tertiles, and the STS-30 results were compared among tertiles. The accuracy of the STS-30 to identify low exercise capacity was evaluated. A second STS-30 was performed after 6 to 8-weeks for the reliability analyses using Intraclass Correlation Coefficient (ICC). Minimal detectable change scores were calculated.

RESULTS

Sixty-three individuals (66.7% men) aged 48.3 years (95%CI 44.6-51.9) were evaluated. There were significant correlations between STS-30, exercise capacity (r = 0.72), and physical domains of health-related quality of life (0.30 ≤ r ≤ 0.51). Tertile 1 of the Incremental Shuttle Walking Test was different from tertiles 2 and 3 for STS-30 [difference of 3.4 repetitions (95%CI 1.5-5.4) and 4.7 repetitions (95%CI 2.8-6.7), respectively]. The value of 12 repetitions was the cut-off points for stratification of individuals with low exercise capacity. The STS-30 had a high test-retest reliability (ICC = 0.93) and the minimal detectable change was 2.1 repetitions.

CONCLUSION

The STS-30 is a reliable test, associated with exercise capacity and physical domains of health-related quality of life. Thus, is a valid method for functional evaluation in hemodialysis patients.

Intradialytic exercise in the treatment of social frailty: a single-center prospective study-preliminary results during the unexpected COVID-19 pandemic

Background

Social frailty—the lack of a connection to society and infrequent social activities—has been reported to be associated with future declines in physical function in elderly individuals. This study aimed to evaluate both the association of social frailty with the physical function and the efficacy of intradialytic exercise as a therapy for social frailty among hemodialysis patients.

Methods

All 16 outpatient hemodialysis patients in the hemodialysis department of a single medical center were enrolled in this single-center prospective single-arm interventional study. Patients received five questions which asked about going out infrequently, lack of visiting friends, feeling unhelpful to friends or family, living alone, and lack of talking with someone. Those to whom two or more of the above were applicable were categorized as socially frail. All patients were placed into exercise therapy to be performed during their thrice-weekly hemodialysis visits. Participants’ physical function (walking speed), muscle strength (grip strength), muscle mass (appendicular skeletal muscle mass index), and social frailty were evaluated at baseline and after 3 months of therapy.

Results

Four (25%) of the 16 participants (median age 71.5 years, 8 women) were categorized as being socially frail. In comparison to the non-socially frail group (non-SF), the socially frail group (SF) had a significantly lower walking speed (0.70 ± 0.12 m/s vs 1.15 ± 0.26 m/s, p = 0.005) and significantly worse performance on the Short Physical Performance Battery. Three months of intradialytic exercise therapy significantly improved their walking speed, from 1.04 ± 0.30 m/s to 1.16 ± 0.29 m/s (p = 0.003). intradialytic exercise therapy significantly improved walking speed in both the SF group and the non-SF group. The 2019 coronavirus disease pandemic unexpectedly occurred in the middle of the intervention period of this study, and although it was not statistically significant, the number of socially frail individuals among our participants increased to seven (43.8%, p = 0.248).

Conclusions

Social frailty was associated with reduced physical function among hemodialysis patients. Intradialytic exercise therapy improved physical function regardless of the presence of social frailty.

Trial registration

UMIN-CTR, UMIN-CTR000038313. Registered November 1, 2019, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000043639.

Impact of Physical Activity on Dialysis and Nondialysis Days and Clinical Outcomes Among Patients on Hemodialysis

OBJECTIVE

Patients undergoing hemodialysis (HD) have different physical activity (PA) patterns on HD and non-HD days. Nonetheless, whether these differences are associated with clinical outcomes remains unclear. We examined the association of PA levels on HD and non-HD days with cardiovascular (CV) hospitalizations and mortality.

METHODS

Outpatients undergoing HD from 2002 to 2019 were retrospectively enrolled. The number of steps performed over 3 HD days and 4 non-HD days was recorded via accelerometry. Outcomes were all-cause mortality and a composite of CV hospitalizations and mortality. Patients were divided into two groups, each according to the median number of steps performed on HD (2371 steps/day) and non-HD days (3752 steps/day). Further, we categorized them into 4 groups according to each median values: "more active on HD/more active on non-HD (MM)," "more active on HD/less active on non-HD (ML)," "less active on HD/more active on non-HD (LM)," and "less active on HD/less active on non-HD (LL)." Cox and mixed-effects Poisson regression models were used for these outcomes.

RESULTS

We analyzed 512 patients (median follow-up, 3.4 years). Higher PA on HD (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.54-0.65), and non-HD (HR, 0.84; 95% CI, 0.80-0.88) was associated with lower mortality risk, respectively. Further, the ML group (HR, 1.20; 95% CI, 1.13-1.28), LM group (HR, 1.82; 95% CI, 1.53-2.17), and LL group (HR, 1.83; 95% CI, 1.65-2.02) had higher mortality risks than the MM group. Associations of PA with multiple CV hospitalizations and mortality were similar to those between PA and mortality.

CONCLUSIONS

Higher PA on HD and non-HD days was associated with lower risks of CV hospitalizations and mortality. However, higher PA levels on either HD or non-HD days alone did not improve clinical outcomes.

The Association between time spent in performing physical activity and physical function in outpatients with type 2 diabetes who may have diabetic neuropathy

AIMS

To determine the relationship between physical activity time and physical function according to the Japanese Clinical Practice Guideline for Diabetes, which recommended 150 min of activity for outpatients with type 2 diabetes who may have diabetic neuropathy.

METHODS

We examined a cross-sectional study with 79 outpatients with Type 2 diabetes participated. A short version, Japanese language edition of the International Physical Activity Questionnaire (IPAQ) was used to evaluate physical activity. Isometric knee extensor strength, grip strength, maximum 10-m walking speed, the Michigan Neuropathy Screening Instrument score, and the Short Physical Performance Battery (SPPB). Each evaluation item was compared between time spent performing physical activity ≥150 min group and <150 min group, and multiple regression analysis was performed to determine the factors associated with time spent performing physical activity. Further, the correlation between time spent performing physical activity and isometric knee extensor strength was examined.

RESULTS

The ≥150 min group had significantly higher isometric knee extensor strength than the <150 min group. In addition, the ≥150 min group had significantly faster maximum 10-m walking speed and sit-to-stand time than the <150 min group. Isometric knee extensor strength was determined to be an independent factor associated with the IPAQ score. A positive correlation was found between the IPAQ score and isometric knee extensor strength.

CONCLUSIONS

Among the patients with type 2 diabetes who may have diabetic neuropathy, those who performed physical activity for ≥150 min per week were suggested to have higher physical function than those with <150 min of activity.

The Effects of Chronic Dialysis on Physical Status, Quality of Life, and Arterial Stiffness: A Longitudinal Study in Prevalent Dialysis Patients

INTRODUCTION

It is widely known that dialysis patients have significantly impaired functional outcomes and arterial stiffness, but still few studies have investigated the effects of dialysis longitudinally by a multidimensional approach. We aimed to assess longitudinal patterns of physical activity (PA), physical functioning (PF), health-related quality of life (HrQoL), body composition (BC), and arterial stiffness in prevalent dialysis patients.

MATERIALS AND METHODS

Thirty-nine prevalent dialysis patients (23 conventional hemodialysis [CHD] and 16 peritoneal dialysis) with a mean vintage of 25.7 (±22.1) months were included in this observational prospective study with a 2-year follow-up, and at baseline 20 healthy controls were included. Measurements were performed every 6 months. HrQoL was assessed using the Short Form-36 (SF-36) questionnaire. PA was assessed using the SenseWear™ Pro3 accelerometer. PF was assessed by walking speed, the PF subscale of the SF-36, and handgrip strength (HGS). BC was assessed using the Body Composition Monitor® and arterial stiffness by measuring carotid-femoral pulse wave velocity (PWV). The longitudinal trend was assessed using linear mixed models, correcting for sex, age, and dialysis vintage. For PWV, the trend was additionally corrected for diabetes and systolic blood pressure.

RESULTS

After correction, no statistically significant changes over time were observed for the parameters of PA, PF, HrQoL, and BC. In the combined group and in the group of CHD patients only, a significant change was observed for PWV (overall trend: p = 0.007 and p = 0.008, respectively). A statistically significant difference at baseline was observed between dialysis patients and healthy controls in all parameters, except for HGS and PWV.

DISCUSSION/CONCLUSION

We observed no statistically significant changes in functional outcomes during a 2-year follow-up period, but a significant increase was observed for arterial stiffness. These results might suggest that after a certain period in time, a relatively stable course is present in functional outcomes, but an ongoing deterioration in arterial stiffness occurs, which might increase the risk of cardiovascular disease and all-cause mortality in these patients.

Assessing physical activity and function in patients with chronic kidney disease: a narrative review

Physical activity potentially improves health outcomes in patients with chronic kidney disease (CKD) and recipients of kidney transplants. Although studies have demonstrated the beneficial effects of physical activity and exercise for primary and secondary prevention of non-communicable diseases, evidence for kidney patients is limited. To enlarge this evidence, valid assessment of physical activity and exercise is essential. Furthermore, CKD is associated with a decline in physical function, which may result in severe disabilities and dependencies. Assessment of physical function may help clinicians to monitor disease progression and frailty in patients receiving dialysis. The attention on physical function and physical activity has grown and new devices have been developed and (commercially) launched on the market. Therefore the aims of this review were to summarize different measures of physical function and physical activity, provide an update on measurement instruments and discuss options for easy-to-use measurement instruments for day-to-day use by CKD patients. This review demonstrates that large variation exists in the different strategies to assess physical function and activity in clinical practice and research settings. To choose the best available method, accuracy, content, preferable outcome, necessary expertise, resources and time are important issues to consider.

The Glittre activities of daily living as a potential test for functional evaluation of patients on hemodialysis: a validation study

PURPOSE

To investigate the validity and within-day reliability of the Glittre activities of daily living test (Glittre ADL-test) in patients on hemodialysis.

METHODS

Ninety-one patients on hemodialysis were evaluated using Glittre ADL-test, functional tests, health-related quality of life, human activity profile, and social participation. Convergent validity was analyzed by the correlation analysis. The Glittre ADL-test results were compared among different levels of the functional tests, human activity profile, and participation (known-groups validity). Within-day reliability was examined by Intra-class Correlation Coefficient (ICC).

RESULTS

There was a significant moderate to strong correlation between Glittre ADL-test and functional tests (r = 0.62 to 0.66 and -0.70 to -0.44). A significant weak correlation was found between Glittre ADL-test, health-related quality of life (r = 0.28 to 0.32), and human activity profile (r=-0.33). There was no significant correlation with participation. Except for participation level, the Glittre ADL-test results were able to identify individuals with low performance in all evaluated tests and were able to differentiate among inactive and active individuals by human activity profile (p < 0.05). Within-day reliability was evaluated in 42 patients. The ICC was 0.97.

CONCLUSION

The Glittre ADL-test is a reliable test associated with functional parameters and physical aspects related to health-related quality of life, with potential value in the functional evaluation of patients on hemodialysis.Implications for rehabilitationFunctional impairment is a common clinical finding and is an important predictor of poor prognosis in patients on hemodialysis.The Glittre ADL-test has excellent within-day reliability and is a valid instrument for functional assessment in patients on hemodialysis.Activity limitations of patients on hemodialysis can be assessed by Glittre ADL-test.

Perceptions of Physical Activity in African American Older Adults on Hemodialysis: Themes From Key Informant Interviews

OBJECTIVE

To determine key themes underlying the perceptions of older (≥65y) adults on hemodialysis regarding physical activity using qualitative methodology.

DESIGN

Semistructured key informant interviews.

SETTING

Academic medical center.

PARTICIPANTS

Convenience sample of older adults on hemodialysis (N=10).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Interview transcripts were coded and analyzed using the framework method to extract themes and subthemes. Participants also answered Likert statements regarding their perceptions of physical activity, and the responses were tallied.

RESULTS

Ten older adults on hemodialysis participated (mean age 73±5y; 60% women); all were African American. All participants stated physical activity would make them feel better. The major themes that emerged were barriers and facilitators. Facilitators included internal motivators, family and friend support, and feasibility of incorporating physical activity into routine activities. Barriers were lack of motivation, health issues, and environmental restrictions.

CONCLUSIONS

Physical activity potentially could prevent the physical decline commonly seen in older adults on hemodialysis. Yet information regarding the perceptions of this population toward physical activity is sparse. Although the study is limited by selection bias, our study presents qualitative evidence that black older adults on hemodialysis desire physical activity for their health. Future interventions to increase physical activity in this population should consider leveraging existing facilitators, such as the support of family and friends, and use strategies to address barriers like minimal motivation.

Accelerometer-measured physical activity and functional behaviours among people on dialysis

BACKGROUND

The feasibility of wrist-worn accelerometers, and the patterns and determinants of physical activity, among people on dialysis are uncertain.

METHODS

People on maintenance dialysis were fitted with a wrist-worn AxivityAX3 accelerometer. Subsets also wore a 14-day electrocardiograph patch (Zio^®PatchXT) and wearable cameras. Age-, sex- and season-matched UK Biobank control groups were derived for comparison.

RESULTS

Median (interquartile range) accelerometer wear time for the 101 recruits was 12.5 (10.4-13.5) days, of which 73 participants (mean age 66.5 years) had excellent wear on both dialysis and non-dialysis days. Mean (standard error) overall physical activity levels were 15.5 (0.7) milligravity units (mg), 14.8 (0.7) mg on dialysis days versus 16.2 (0.8) mg on non-dialysis days. This compared with 28.1 (0.5) mg for apparently healthy controls, 23.4 (0.4) mg for controls with prior cardiovascular disease (CVD) and/or diabetes mellitus and 22.9 (0.6) mg for heart failure controls. Each day, we estimated that those on dialysis spent an average of about 1 hour (h/day) walking, 0.6 h/day engaging in moderate-intensity activity, 0.7 h/day on light tasks, 13.2 h/day sedentary and 8.6 h/day asleep. Older age and self-reported leg weakness were associated with decreased levels of physical activity, but the presence of prior CVD, arrhythmias and listing for transplantation were not.

CONCLUSIONS

Wrist-worn accelerometers are an acceptable and reliable method to measure physical activity in people on dialysis and may also be used to estimate functional behaviours. Among people on dialysis, who are broadly half as active as general population controls, age and leg weakness appear to be more important determinants of low activity levels than CVD.

Perceived difficulty in activities of daily living and survival in patients receiving maintenance hemodialysis

PURPOSE

Most patients receiving hemodialysis have perceived difficulty in mobility tasks, such as basic activities of daily living (ADL), ambulation, and walking up or down stairs, even if they can ambulate independently. Perceived difficulty in performing ADL (ADL difficulty) is reportedly a useful predictor of mortality in older community-dwelling people. However, very few studies have examined the association of ADL difficulty with clinical outcomes in patients receiving hemodialysis. This study aimed to identify the association between ADL difficulty related to mobility tasks of lower limbs and all-cause mortality in patients receiving hemodialysis who are able to ambulate independently.

METHODS

This retrospective study analyzed 300 clinically stable outpatients (median age, 65.0 years) receiving hemodialysis. ADL difficulty was evaluated at baseline with a novel questionnaire developed for patients receiving hemodialysis. Lower scores indicated lower ADL, i.e., greater ADL difficulty. The patients were divided into two groups by the median ADL score: a higher ADL group and a lower ADL group. The association between ADL difficulty and all-cause mortality was estimated by Cox regression analyses.

RESULTS

Median follow-up duration was 58 months. The incident rates were 0.02 per person-year in the higher ADL group and 0.06 per person-year in the lower ADL group (P < 0.001). After adjusting for the effects of clinical characteristics, the hazard ratio for all-cause mortality in the lower ADL group was 2.70 (95% confidence interval 1.57-4.64) compared with that in the higher ADL group.

CONCLUSIONS

Perceived difficulty in mobility tasks was independently associated with all-cause mortality among ambulatory patients receiving hemodialysis.

The dominant prognostic value of physical functioning among quality of life domains in end-stage kidney disease

BACKGROUND

The prognostic relevance of health-related quality of life (HRQoL) has been scarcely studied in the dialysis population and the prognostic power for mortality of the HRQoL domains is unknown.

METHODS

We tested the prognostic value for mortality of the HRQoL domains included in the 36-item Short Form Health Survey (SF-36) by Cox's regression analysis and by state-of-the-art prognostic techniques {explained variation in mortality [R2], calibration, discrimination [Harrell's C], risk reclassification [Net Reclassification Index (NRI)], Integrated Discrimination Index [IDI]} in a cohort of 951 patients on chronic haemodialysis.

RESULTS

In multivariable Cox models, all but two domains (role limitation due to physical health and due to emotional problems) were independently related with mortality. Physical functioning was the domain adding the highest explanatory power (R2+5.3%) to a basic model including established risk factors for mortality in the dialysis population. The same domain improved risk calibration and showed the highest Harrell's C (+1.7%) and the highest reclassification power (categorical NRI + 8.7%, continuous NRI +46%, P ≤ 0.006) and the highest IDI (+3.4%, P < 0.001). These results were fully confirmed in analyses testing the additional prognostic power of SF-36 domains when combined to a well-validated risk score in dialysis patients.

CONCLUSIONS

Physical functioning holds the highest prognostic power for mortality among the domains of SF-36. The gain in prognostic ability by this domain is relevant for clinical practice. Physical functioning has the potential for refining the prognosis and for informing exercise programmes in the dialysis population.

Canadian Society of Nephrology Commentary on the Kidney Disease Improving Global Outcomes 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder

Purpose of review:

(1) To provide commentary on the 2017 update to the Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD); (2) to apply the evidence-based guideline update for implementation within the Canadian health care system; (3) to provide comment on the care of children with chronic kidney disease (CKD); and (4) to identify research priorities for Canadian patients.

Sources of information:

The KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of CKD-MBD.

Methods:

The commentary committee co-chairs selected potential members based on their knowledge of the Canadian kidney community, aiming for wide representation from relevant disciplines, academic and community centers, and different geographical regions.

Key findings:

We agreed with many of the recommendations in the clinical practice guideline on the diagnosis, evaluation, prevention, and treatment of CKD-MBD. However, based on the uncommon occurrence of abnormalities in calcium and phosphate and the low likelihood of severe abnormalities in parathyroid hormone (PTH), we recommend against screening and monitoring levels of calcium, phosphate, PTH, and alkaline phosphatase in adults with CKD G3. We suggest and recommend monitoring these parameters in adults with CKD G4 and G5, respectively. In children, we agree that monitoring for CKD-MBD should begin in CKD G2, but we suggest measuring ionized calcium, rather than total calcium or calcium adjusted for albumin. With regard to vitamin D, we suggest against routine screening for vitamin D deficiency in adults with CKD G3-G5 and G1T-G5T and suggest following population health recommendations for adequate vitamin D intake. We recommend that the measurement and management of bone mineral density (BMD) be according to general population guidelines in CKD G3 and G3T, but we suggest against routine BMD testing in CKD G4-G5, CKD G4T-5T, and in children with CKD. Based on insufficient data, we also recommend against routine bone biopsy in clinical practice for adults with CKD or CKD-T, or in children with CKD, although we consider it an important research tool.

Limitations:

The committee relied on the evidence summaries produced by KDIGO. The CSN committee did not replicate or update the systematic reviews.

Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

BACKGROUND

Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis.

METHODS

Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome.

RESULTS

Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76-0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis.

CONCLUSIONS

Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.

Comparison of intradialytic versus home-based exercise programs on physical functioning, physical activity level, adherence, and health-related quality of life: pilot study

Intradialytic exercise (ID) programs are effective and safe for hemodialysis (HD) patients to avoid functional deterioration. However, exercise is not routinely undertaken in most HD units, and we do not know if home-based (HB) programs are as effective as ID programs. The purpose of this study was to compare the effects of 16 weeks of ID exercise versus a HB exercise program for HD patients. A total of 46 patients were randomly assigned to the ID group (n = 24) or HB group (n = 22). They completed a 16-week combined exercise program 3 times/week. We measured physical activity level, physical functioning, depression level, and health-related quality of life at baseline and after 16 weeks. A significant time effect was found in both groups for the physical activity level (p = 0.012). There was also a significant group-time interaction effect for the one-leg standing test (OLST) (p = 0.049) and a significant time effect for the Short Physical Performance Battery (p = 0.013), timed up-and-go test (p = 0.005), sit-to-stand-10 (p = 0.027), right and left hand handgrip (p = 0.044, p < 0.001), one-heel left leg raise (p = 0.019), and 6-minute walking (p = 0.006), depression (p = 0.017). HRQoL remained unchanged. There was no difference between the two interventions on the tested outcomes (besides OLST). Both interventions were associated with positive changes of the physical activity levels and physical function.

The Impact of Home-Based Exercise Program on Physical Function of Chronic Kidney Disease Patients: A Meta-Analysis of Randomized Controlled Trials

Background Home-based exercise program showed the potential in improving physical function of chronic kidney disease patients, and it might need low associated costs. We conducted a systematic review and meta-analysis to explore the impact of home-based exercise program on physical function of chronic kidney disease patients.

Methods PubMed, EMBASE, Web of science, EBSCO, and Cochrane library databases were systematically searched. This meta-analysis included randomized controlled trials (RCTs) assessing the effect of home-based exercise program on physical function of chronic kidney disease patients. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were 6-min walk test and grip strength change.

Results Seven RCTs were included in the meta-analysis. Overall, compared with control intervention in chronic kidney disease patients, home-based exercise program could significantly improve 6-min walk test (MD=79.01; 95% CI=22.39–135.62; P=0.006) and grip strength (SMD=0.52; 95% CI=0.14–0.89; P=0.007), but showed no impact on pain scores (SMD=−1.43; 95% CI=−3.75 to 0.88; P=0.22), Kidney Disease Quality of life including symptom/problem list (SMD=1.92; 95% CI=−1.06 to 4.90; P=0.21), effects of kidney disease (SMD=−3.69; 95% CI=−8.56 to 1.19; P=0.14), or burden of kidney disease (SMD=1.04; 95% CI=−0.75 to 2.82; P=0.26).

Conclusions Home-based exercise program might improve physical function for chronic kidney disease, and more RCTs should be conducted to confirm this issue.

Standardising the measurement of physical activity in people receiving haemodialysis: considerations for research and practice

BACKGROUND

Physical activity (PA) is exceptionally low amongst the haemodialysis (HD) population, and physical inactivity is a powerful predictor of mortality, making it a prime focus for intervention. Objective measurement of PA using accelerometers is increasing, but standard reporting guidelines essential to effectively evaluate, compare and synthesise the effects of PA interventions are lacking. This study aims to (i) determine the measurement and processing guidance required to ensure representative PA data amongst a diverse HD population, and; (ii) to assess adherence to PA monitor wear amongst HD patients.

METHODS

Clinically stable HD patients from the UK and China wore a SenseWear Armband accelerometer for 7 days. Step count between days (HD, Weekday, Weekend) were compared using repeated measures ANCOVA. Intraclass correlation coefficients (ICCs) determined reliability (≥0.80 acceptable). Spearman-Brown prophecy formula, in conjunction with a priori ≥  80% sample size retention, identified the minimum number of days required for representative PA data.

RESULTS

Seventy-seven patients (64% men, mean ± SD age 56 ± 14 years, median (interquartile range) time on HD 40 (19-72) months, 40% Chinese, 60% British) participated. Participants took fewer steps on HD days compared with non-HD weekdays and weekend days (3402 [95% CI 2665-4140], 4914 [95% CI 3940-5887], 4633 [95% CI 3558-5707] steps/day, respectively, p < 0.001). PA on HD days were less variable than non-HD days, (ICC 0.723-0.839 versus 0.559-0.611) with ≥ 1 HD day and ≥  3 non-HD days required to provide representative data. Using these criteria, the most stringent wear-time retaining ≥ 80% of the sample was ≥7 h.

CONCLUSIONS

At group level, a wear-time of ≥7 h on ≥1HD day and ≥ 3 non-HD days is required to provide reliable PA data whilst retaining an acceptable sample size. PA is low across both HD and non- HD days and future research should focus on interventions designed to increase physical activity in both the intra and interdialytic period.

A Location-Based Objective Assessment of Physical Activity and Sedentary Behavior in Ambulatory Hemodialysis Patients

Background:

Dialysis patients have reduced moderate to vigorous physical activity, and light physical activity. This has been shown in self-reported surveys and objective accelerometer studies. Less attention has been directed toward sedentary behavior, which is characterized by low energy expenditure (≤1.5 metabolic equivalents). Furthermore, locations where physical activity and sedentary behavior occur are largely unknown for dialysis patients.

Objectives:

The objectives of this study were (1) to determine the minutes per day of moderate to vigorous physical activity, light physical activity, and sedentary behavior for hemodialysis patients; (2) to describe differences in moderate to vigorous physical activity, light physical activity, and sedentary behavior comparing dialysis versus nondialysis days; and (3) to describe the locations where moderate to vigorous physical activity, light physical activity, and sedentary behavior occur using global positioning system (GPS) data.

Design:

Cross-sectional study.

Setting:

The study was performed at a tertiary care hospital in Nova Scotia, Canada.

Patients:

A total of 50 adult in-center hemodialysis patients consented to the study.

Measurements:

Physical activity and sedentary behavior were measured with an Actigraph-GT3X accelerometer. Location was determined using a Qstarz BT-Q1000X GPS receiver.

Methods:

Minutes of daily activity were described as was percentage of wear time for each activity level across different locations during waking hours. Physical activity intensity, quantity, and location were also analyzed according to dialysis vs nondialysis days.

Results:

Forty-three patients met requirements for accelerometer analysis, of whom 42 had GPS data. Median wear time was 836.5 min/day (interquartile range [IQR]: 788.3-918.3). Median minutes of daily wear time spent in sedentary behavior, light physical activity, and moderate to vigorous physical activity was 636 minutes (IQR: 594.1-730.1), 178 minutes (IQR: 144-222.1), and 1.6 minutes (IQR: 0.6-7.7), respectively. Proportion of daily wear time spent in sedentary behavior, light physical activity, and moderate to vigorous physical activity was 78.4% (IQR: 70.7-84.0), 21.5% (IQR: 16.0-26.9), and 0.2% (IQR: 0.1-1.1), respectively. Home was the dominant location for total linked accelerometer-GPS time (59.4%, IQR: 46.9-69.5) as well as for each prespecified level of activity. Significantly more sedentary behavior and less light physical activity occurred on dialysis days compared with nondialysis days (P ≤ .01, respectively). Moderate to vigorous physical activity did not differ significantly between dialysis and nondialysis days.

Limitations:

Small sample size from a single academic center may limit generalizability. Difficult to engage population as less than half of eligible dialysis patients provided consent. Physical activity may have been underestimated as devices were not worn for all waking hours or aquatic activities, and hip-based accelerometers may not capture stationary exercise.

Conclusions:

Ambulatory, in-center hemodialysis patients exhibit substantial sedentary behavior and minimal physical activity across a limited range of locations. Given the sedentary tendencies of this population, focus should be directed on increasing physical activity at any location frequented. Home-based exercise programs may serve as a potential adjunct to established intradialytic-based therapies given the amount of time spent in the home environment.

Physical performance in patients treated with nocturnal hemodialysis - a systematic review of the evidence

Background

Patients treated with conventional hemodialysis have poor physical performance, explained by insufficient metabolic clearance and shortage of time by time-consuming dialysis. Nocturnal hemodialysis improves metabolic control and results in increased spare time. Our aim is to investigate whether physical performance in nocturnal hemodialysis is superior to conventional hemodialysis.

Methods

A systematic search was conducted in MEDLINE, Embase, CINAHL, PhycInfo and Web of Science until January 2018. Primary outcomes were physical performance, activity, strength and muscle mass in home or in-center nocturnal hemodialysis. Methodological quality was assessed with the Newcastle-Ottawa scale.

Results

Ten studies met the inclusion criteria, including 2 RCTs, evaluating 526 nocturnal hemodialysis patients with a mean follow-up of 15, 3 months. The methodological quality of 4 studies was limited. Physical capacity tests were done in 3 studies with different methodology: short-physical performance battery, exercise spirometry and 6-min walk test. The latter 2 showed significant improvements in physical performance. Four studies assessed lean mass using dual-energy X-ray absorptiometry (2×) and bioelectrical impedance analysis (2×), of which 1 demonstrated increased lean body and skeletal muscle mass. In 5 studies a Quality of Life questionnaire was used, of which 2 showed improved physical component score.

Conclusions

The evidence on the effect of nocturnal hemodialysis on physical performance is either of insufficient methodological quality or only measures isolated aspects of physical performance. As literature emphasizes the importance of physical activity on clinical outcomes, it is necessary to conduct larger studies of high methodological quality using capacity tests for answering the question whether nocturnal hemodialysis can improve physical performance of patients with end-stage renal disease.

Trial registration

NTR4715, Netherlands Trial Register. Registered 30 July 2014.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1518-4) contains supplementary material, which is available to authorized users.

Frailty, Quality of Life, Anxiety, and Other Factors Affecting Adherence to Physical Activity Recommendations by Hemodialysis Patients

Hemodialysis patients perform little physical activity. We formulated a hypothesis that some factors, i.e., frailty, medical and functional factors, psychological factors, quality of life, awareness of recommendations, and sociodemographic factors influence the decisions of taking up physical activity. This prospective study comprised 72 dialysis patients aged 57.8 ± 16.0 ( x ¯ ± SD; in the range of 19-87 years of age). The following research tools were used: an interview about awareness of the physical activity recommendations, the Canadian Study of Health and Aging Scale (CSHA-CFS), scales for the assessment of functional status, State-Trait Anxiety Inventory (STAI), Acceptance of Illness Scale (AIS), and the questionnaire of Kidney Disease Quality of Life (KDQOL-SF 1.3). The majority of patients diagnosed with frailty did not follow the physical activity recommendations (79.3%). Quality of life was better in active patients compared to inactive patients, especially in the domains of sleep and physical performance. The severity of trait anxiety was significantly higher in patients who did not follow the recommendations compared to patients who adhered to physical activity recommendations (46.0 ± 10.5 vs. 40.0 ± 8.2; p = 0.021 ). The likelihood of adherence decreased by 1% after each subsequent month of dialysis (odds ratio = 0.99; 95% confidence interval = 0.972-0.999; p = 0.047 ). Adherence was most limited by frailty. Adherence to recommendations on physical activity was affected by: motivation, lower levels of trait anxiety, and better quality of life. Age modified the effect of awareness and acceptance of the disease on adherence to physical activity recommendations.

Decline in the Functional Status and Mortality in Patients on Hemodialysis: Results from the Japan Dialysis Outcome and Practice Patterns Study

OBJECTIVES

Patients with end-stage renal disease (ESRD) treated with hemodialysis suffer a high burden of poor functional status. Poor functional status is known as a strong, consistent predictor of mortality. However, little is known about the trajectory of functional status and its association with clinical outcomes in the ESRD population. We examined the association between a change in the functional status over time and all-cause mortality among patients on hemodialysis.

DESIGN AND METHODS

This was a prospective cohort study of 817 patients with ESRD on hemodialysis with repeat measures of functional status, who enrolled in the Japan Dialysis Outcomes and Practice Patterns Study phase V. The functional status was assessed based on the Katz Index and Lawton-Brody instrumental activities of daily living scale, and the assessments were conducted twice over a median of 361 (range: 339-378) days between 2012 and 2013. We classified patients into 2 groups based on having or not having at least a 1-point decline in the functional status score. To evaluate the association between the decline in the functional status and all-cause mortality with adjustment for potential confounders, a Cox regression analysis was conducted.

RESULTS

Over the study period, 19.9% of the patients showed a decline in the functional status score. During the follow-up period, 44 (5.4%) patients died. Using the Cox regression analysis and adjusting for potential confounders, it was determined that the decline in functional status score was significantly associated with higher mortality (incidence rate: 2.2 vs. 7.0 per 100 person-years; adjusted hazard ratio: 2.68; 95% confidence interval: 1.31-5.50).

CONCLUSIONS

The present study provides evidence that ESRD patients on hemodialysis demonstrating a decline in the functional status are at elevated risk of mortality. Our findings strengthen the evidence underpinning the importance of interventions to maintain the functional status in this vulnerable population.

Patients receiving dialysis do not have increased energy needs compared with healthy adults

BACKGROUND

Patients receiving dialysis are thought to have increased energy needs due to stress from the dialysis process or uraemic toxins. However, certain conditions may induce hypometabolic states potentially leading to unwanted weight gains when increased calorie intake is recommended.

OBJECTIVES

Since there is conflicting research, this study aims to assess total energy expenditure (TEE) of patients receiving dialysis through analysis of resting energy expenditure (REE) and physical activity levels.

DESIGN

Comprehensive review of the current literature on REE and physical activity levels.

METHODS

Two electronic databases (PubMed and CINAHL) were searched using keywords to find papers published within the last 10 years for physical activity studies and within the last five years for REE.

INCLUSION CRITERIA

Adults undergoing long-term dialysis treatments who do not have comorbidities that influence energy expenditure such as inflammation, hyperthyroidism or cancers. Participants were also required to ambulate without assistance.

RESULTS

Only seven of the 325 studies found were included in this review. Most studies were controlled trials with one being a prospective study. Patients receiving dialysis had rest energy expenditures comparable to healthy adults. There was not a consensus between studies as to which predictive energy equation produced accurate energy recommendations. Overall, patients receiving dialysis were significantly less active compared with healthy adults and this related to muscle mass.

CONCLUSION

Patients receiving dialysis tend to be sedentary or lightly active and do not have increased energy expenditure compared with healthy adults. Therefore, stable patients should not be prescribed increased calorie intake.

Intradialytic Exercise: One Size Doesn't Fit All

Purpose: Hemodialysis patients commonly have impaired physical performance and mental health. We studied the effects of an intradialytic exercise program on these variables.

Methods: 27 patients (33% women; 68 ± 13 years) were enrolled in a 14-week intradialytic endurance-resistance training program (‘exercise’ group, 40 programmed sessions per patient); 40 hemodialysis patients (28% women; 68 ± 11 years) performing no exercise during the same time length were used as controls. Endpoints included physical performance (6-min walk test [6MWT], 10-repetition sit to stand [STS-10] and handgrip strength), emotional status (Beck’s depression inventory and State-Trait Anxiety Inventory), and mental and physical component scores of the short-from (SF)-12 Health Survey.

Results: There were no differences (p> 0.05) between groups at baseline for sex distribution, or mean age, body mass index and time spent on dialysis. Exercise benefits were observed for 6MWT (11 and −3% for the exercise and control groups, respectively; p < 0.001), STS-10 performance time (-22 and 6%; p < 0.001) and handgrip strength (4 and −4%; p < 0.02). No significant benefits (p> 0.05) were observed for emotional status endpoints or SF-12 component scores. Despite significant benefits on physical performance, the proportion of clinically meaningful responders was low (<50%). Responsiveness was dependent on baseline physical performance (p < 0.05) but not on age or sex (p > 0.05).

Conclusion: A 14-week intradialytic training program induced significant improvements on physical performance. However, the rate of clinically meaningful responders observed in the present study was low, being the level of responsiveness dependent on baseline physical status. Efforts to individualize exercise prescription are needed in clinical practice.

Physical Activity in Patients Treated With Peritoneal Dialysis: A Systematic Review and Meta-analysis

BACKGROUND

Exercise has been shown to be of benefit in the general population and in patients with chronic diseases. Despite a lack of compelling evidence, patients with end-stage kidney disease (ESKD) treated with peritoneal dialysis (PD) are often discouraged from participating in exercise programs that include weight lifting due to concerns about the development of hernias and leaks. The actual effects of physical activity with or without structured exercise programs for patients on PD remain unclear.

OBJECTIVE

To determine the risks and benefits of physical activity in the ESKD population treated with PD.

DESIGN

Systematic review and meta-analysis.

SETTING

Included all studies that met our criteria regardless of country of origin.

PATIENTS

Adult patients with ESKD treated with PD.

MEASUREMENTS

Descriptive and quantitative analysis of our primary and secondary outcome variables.

METHODS

We searched MEDLINE, Embase, CINAHL, and Cochrane Central Register of Controlled Trials for observational and interventional studies examining the effects of physical activity in patients on PD. A systematic review and meta-analysis was conducted of the identified studies. The primary outcomes of interest included patient-centered outcomes of mental health, physical functioning, fatigue, quality of life, and adverse events. Secondary outcomes included nutritional measures, lipid profile, blood pressure changes, maximum heart rate, resting heart rate, maximal oxygen consumption, muscle development, cognitive function, and markers of inflammation.

RESULTS

Of 1828 studies identified by the literature search, 12 met the inclusion criteria including 6 interventional and 6 observational studies. There was limited information on the patient important outcomes. However, there is some evidence for improvements in burden of kidney disease, physical function, and some mental health measures with physical activity.

LIMITATIONS

Lack of well-designed randomized controlled trials impaired our ability to determine the benefits and risks of increasing physical activity.

CONCLUSIONS

There is limited evidence of benefit with increased levels of physical activity in PD patients. Further research is needed to define the exercise program that is likely to be of most benefit to patients treated with PD.