Muscle strength impairments and gait performance deficits in kidney transplantation candidates

Circulating small non-coding RNA profiling for identification of older adults with low muscle strength and physical performance: A preliminary study

BACKGROUND

Small non-coding RNAs (ncRNAs) have recently emerged as potential biomarkers of sarcopenia. However, previous studies have rarely explored the association of small ncRNAs with sarcopenic components, especially muscle strength and physical performance. We aimed to examine circulating small ncRNA profiles to detect low muscle strength and physical performance in older adults.

METHODS

Ninety-eight older adults were randomly selected from Korean Frailty and Aging Cohort Study and classified into the "Normal," "Low muscle strength (MS) only," "Low physical performance (PP) only," and "Low MS and PP" groups by Asian Working Group for Sarcopenia 2019 criteria. We used high-throughput sequencing to delineate small ncRNA profiles in plasma. Differentially expressed small ncRNAs were analyzed to reveal distinct patterns based on muscle strength and physical performance status.

RESULTS

In "Low MS and PP" group, 119 miRNAs, 86 piRNAs, 92 snoRNAs, 106 snRNAs, and 15 tRNAs were differentially expressed compared to "Normal" group (p < 0.05). After Benjamini-Hochberg adjustment, 39 miRNAs, 2 piRNAs, 75 snoRNAs, 48 snRNAs, and 15 tRNAs showed differential expression in "Low MS and PP" group compared to than "Normal" group (adjusted p < 0.05). No significant differences were observed in comparisons between the other groups (adjusted p > 0.05).

CONCLUSION

The expression of circulating small ncRNAs were comprehensively characterized, revealing distinct signatures in older adults with both low muscle strength and physical performance compared to normal individuals. Although preliminary, this characterization can advance small ncRNA research on age-related declines in muscle strength and physical performance by providing foundational data for further investigation.

Development and validation of prediction model for fall accidents among chronic kidney disease in the community

Background

The population with chronic kidney disease (CKD) has significantly heightened risk of fall accidents. The aim of this study was to develop a validated risk prediction model for fall accidents among CKD in the community.

Methods

Participants with CKD from the China Health and Retirement Longitudinal Study (CHARLS) were included. The study cohort underwent a random split into a training set and a validation set at a ratio of 70 to 30%. Logistic regression and LASSO regression analyses were applied to screen variables for optimal predictors in the model. A predictive model was then constructed and visually represented in a nomogram. Subsequently, the predictive performance was assessed through ROC curves, calibration curves, and decision curve analysis.

Result

A total of 911 participants were included, and the prevalence of fall accidents was 30.0% (242/911). Fall down experience, BMI, mobility, dominant handgrip, and depression were chosen as predictor factors to formulate the predictive model, visually represented in a nomogram. The AUC value of the predictive model was 0.724 (95% CI 0.679-0.769). Calibration curves and DCA indicated that the model exhibited good predictive performance.

Conclusion

In this study, we constructed a predictive model to assess the risk of falls among individuals with CKD in the community, demonstrating good predictive capability.

Gait disorders in CKD patients: muscle wasting or cognitive impairment? A cross-sectional pilot study to investigate gait signatures in Stage 1-5 CKD patients

BACKGROUND

Instrumental gait analysis in nephrology is widely neglected, although patients with chronic kidney disease (CKD) show brain changes due to cerebrovascular disease and metabolic disorders that can potentially influence gait quality. Our study assesses the association between CKD stages and gait parameters, to understand the prevalent status of brain related gait parameters (i.e. variability) and of performance related parameters (i.e. gait speed, stride length). We hypothesize that gait changes are detectable already in early stages of CKD.

METHODS

Forty-five participants distributed in 5 CKD severity groups underwent an instrumental gait analysis via a triaxial accelerometer affixed to the lower trunk under single- and dual-task conditions. In addition to spatio-temporal parameters, variability and dual-task cost of gait were extracted. A battery of clinical assessments was conducted with the aim of helping to better explain the findings of the gait analysis. A correlation analysis was made to investigate a linear relation between gait parameters and CKD severity.

RESULTS

Statistically significant correlations (Pearson correlation coefficient) with CKD severity were found for gait speed (p < 0.01, r = -0.55, 95% CI [-0.73;-0.30]), stride length ( p < 0.01, r = -0.40, 95% CI [-0.62;-0.12]), step length (p < 0.01, r = -0.41, 95% CI [-0.63;-0.13], coefficient of variance (CV) of step length (p = 0.01, r = 0.36, 95% CI [0.08;0.59]), gait regularity (p < 0.01, r = -0.38, 95% CI [-0.61;-0.10]), dual-task cost of gait speed (p < 0.01, r = 0.40, 95% CI [0.13;0.62]) and dual-task cost of stride time (p = 0.03, r = 0.32, 95% CI [0.03;0.57]). Adjustment for age and gender confirmed all results except for gait regularity. With increasing severity of renal failure, Handgrip strength, Time for the Expanded Timed Get Up and Go test, executive functions, haemoglobin, and haematocrit, worsen.

CONCLUSIONS

The correlation of CKD severity with spatio-temporal parameters (performance indices mainly relatable to peripheral functionality) and with variability of gait (related to central factors) supported by the results of the clinical assessments, suggests that gait disturbance in CKD patients is not only due to metabolic factors that lead to muscle wasting, but also to brain changes that affect motor control. This suggests that the treatment of renal disease should include cognitive aspects in addition to metabolic and functional factors.

Risk factors for high fall risk in elderly patients with chronic kidney disease

PURPOSE

Patients with chronic kidney disease (CKD) usually represent an aging population, and both older age and CKD are associated with a higher risk of falling. Studies on risk factors among subjects with CKD are lacking.

METHODS

Records of outpatients from one geriatric clinic in Turkey were retrospectively reviewed. A result of ≥ 13.5 s on the timed up and go (TUG) test was accepted as a high risk of falls. Independent predictors of an increased risk of falls among subjects with CKD (estimated glomerular filtration rate of < 60 mL/min/1.73 m²) were identified using logistic regression models.

RESULTS

Patients with CKD (n = 205), represented the 20.2% of the entire cohort and was identified as an independent predictor of increased fall risk (OR 2.59). Within the CKD cohort, serum folic acid levels and frailty were independent predictors of an increased risk of falls. The CKD/fall risk group was older, had a lower median years of education, lower vitamin D levels, and lower serum folic acid levels than the CKD/non-fall risk group. In addition to higher serum creatinine and potassium levels, the only significant difference between patients with CKD/fall risk and a matched non-CKD/fall risk was a lower median folic acid level in the former group.

CONCLUSIONS

Frailty and low folic acid levels are independently associated with an increased risk of falls among elderly outpatients with CKD. Prevention of frailty may reduce the risk of falls in these subjects. Possible benefit of folic acid supplementation requires further studies.

Effects of graded exercise training on functional capacity, muscle strength, and fatigue after renal transplantation: a randomized controlled trial

Successful renal transplantation (RT) recipients suffer residual muscle weakness, fatigue, and low functional capacity. A safe, feasible, structured, early graded exercise training to improve functional capacity, muscle strength, and fatigue is the need of the hour. The aim of the study is to assess the effectiveness of graded exercise training on the functional capacity, muscle strength, and fatigue after RT. It is a randomized controlled trial conducted at a tertiary care hospital from January 2012 to December 2016. This trial included 104 consented, stable renal transplant recipients without cardiopulmonary/neuromuscular impairment. They received either routine care (51) or graded exercise training (53) for 12 weeks after randomization. The functional capacity, isometric quadriceps muscle strength, and fatigue score were measured at baseline, six, and 12 weeks later to induction. The outcomes of the study and control groups were analyzed using the /-test, Wilcoxon signed-rank test, ANOVA, and Pearson's correlation. For all analyses, P <0.05 was fixed acceptable. The functional capacity improved by 147 and 255 m, the muscle strength by 6.35 and 9.27 kg, and fatigue score by 0.784 and 1.781 in the control and the study group (SG), respectively, significantly more in the SG. Functional capacity had a positive and negative correlation with muscle strength and fatigue, respectively (P <0.05). The graded exercise training significantly improved the functional capacity, fatigue levels, and muscle strength after RT.

Gait characteristics of CKD patients: a systematic review

BACKGROUND

People with Chronic Kidney Disease (CKD) often present with prevalent gait impairment and high fall rates, particularly in advanced CKD stages. Gait impairment and its consequences is associated with increased hospital admission, institutionalization, and greater need for health care. The objective of this systematic review was to evaluate the quality of studies investigating CKD patients' gait characteristics at different CKD stages, to highlight areas of agreement and contradiction between studies reporting aspects of gait in CKD, and to discuss and emphasize gait parameters associated with fall risk.

METHODS

We performed a literature search of trials in CINAHL (EBSCO), Cochrane Library, EMBASE, Medline (EBSCO), PEDro, PubMed, and Scopus databases from their inception to June 30th 2018 using a two-stage process for the identification of studies. We retrieved English-, German-, Italian-, Spanish-, Portuguese and Dutch-language articles for review. Methodological quality of randomized and non-randomized studies was assessed with an adapted version of the Downs and Black checklist.

RESULTS

Thirty-one studies (22 cross-sectional with 3901 participants) and 9 longitudinal intervention studies (1 randomized control trial, 5 controlled clinical trials and 3 one-group pre-post-test; with 659 participants) were considered. The studies revealed a primary emphasis on gait speed measures within clinical tests, and a neglect of spatiotemporal gait variables. Most of the studies showed that CKD progression is associated with slowing of walking speed. No studies analysed the relation between gait parameters and fall risk.

CONCLUSIONS

There was a paucity of studies investigating aspects of gait quality in patients with CKD. In the majority of studies, only gait speed is analysed as a performance indicator. The relation between gait parameters and fall risk in CKD is not investigated. We formulate several recommendations to fill the current research gap, encourage the use of standardized gait analysis protocols that include assessment of spatiotemporal parameters in clinical care of patients with CKD, aimed at prevention of mobility decline and falls risk.

Effects of inspiratory muscle training on pulmonary functions and muscle strength in sedentary hemodialysis patients

[Purpose] This study was conducted to evaluate the effect of Inspiratory Muscle Trainer (IMT) on respiratory muscle strength and pulmonary functions. [Subjects and Methods] Fifteen sedentary unemployed patients were recruited from both genders who received regular hemodialysis sessions from at least three months. Those patients received Threshold IMT program for 12 weeks. Pulmonary functions and respiratory muscle strength in form of (PImax) and (PEmax) were measured by electronic spirometry and digital pressure vacuum meter respectively. Additionally oxygen saturation was measured by Finger pulse oximeter. All measurements were performed before and at the end of the treatment program after 12 weeks. [Results] The results of this study revealed significant improvement in FVC%, FEV1%, PEF%, PImax and PEmax after three months of treatment by using inspiratory muscle trainer while no significant difference was recorded regarding to FEV1/FVC% ratio and SpO₂. [Conclusion] Inspiratory muscle trainer is an effective therapeutic technique to improve respiratory muscle strength and pulmonary functions in patients undergoing hemodialysis.

Standardized Method to Measure Muscle Force at the Bedside in Hemodialysis Patients

OBJECTIVES

In hemodialysis, diminution of muscle strength constitutes a major prognostic factor of mortality. Currently, measurement of quadriceps isometric maximal voluntary force (MVF) represents the reference method to investigate muscle strength. However, reduction of MVF is rarely detected in these patients due to the absence of portative bedside tools in clinical practice. The purposes of this study were therefore to assess the agreement of a belt-stabilized handheld dynamometer (HHD) with the dynamometer chair (reference method) and to determine intratester and intertester reliability of the quadriceps MVF measurements using belt-stabilized HHD in healthy subjects and in hemodialysis patients.

DESIGN

Repeated-measures cross-sectional study.

SETTING

Clinical and academic hospital.

PARTICIPANTS

Fifty-three healthy adult subjects (23 males, 36.5 + 12.5 y.o.) and 21 hemodialysis patients (14 males, 72.4 + 13.3 y.o., dialysis vintage 30 + 75.1 months).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE

MVF measurements were assessed with belt-stabilized HHD and dynamometer chair, by two independent investigators. The agreement between the two devices would be quantified using the Bland-Altman 95% limits of agreement (LOA) method and the Spearman correlation.

RESULTS

For healthy subjects and hemodialysis patients, Spearman coefficients between belt-stabilized HHD and dynamometer chair were 0.63 and 0.75, respectively (P < .05). In hemodialysis group, reliability was excellent for both the intratester and intertester reliability R² = 0.85 (P < .01) and R² = 0.90 (P < .01), respectively. In all individuals, the mean difference between the dynamometer chair and the belt-stabilized HHD was -13.07 ± 21.77 N.m. (P < .001). The LOA for the upper and the lower was 29.59 and -55.73 N.m., respectively.

CONCLUSION

In healthy subjects and in hemodialysis patients, the belt-stabilized HHD dynamometer appears as a valid and reliable method to measure in clinical practice isometric MVF of quadriceps in hemodialysis patients. Therefore, the belt-stabilized HHD appears as a suitable and a relevant diagnostic tool for the identification of muscle dysfunction in hemodialysis patients.

Assessment of sit-to-stand movement in nonspecific low back pain: a comparison study for psychometric properties of field-based and laboratory-based methods

One of the most difficult tasks associated with the management of nonspecific low back pain (LBP) is its clinical assessment. Objective functional methods have been developed for assessment. However, few studies have used daily activities such as sit-to-stand (STS). The aim was to compare the psychometric properties of two commonly used STS assessment methods. A test-retest reliability study design was used. Participants with nonspecific LBP performed the 30-s chair stand test (30CST) and the STS test in Balance Master, which measures weight transfer, rising index and centre of gravity sway velocity. The same tests were reperformed after 48-72 h. The intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change and coefficient of variation were calculated to compare the reliability. The correlations between the tests, the Oswestry Disability Index and pain intensity were examined for validation. The 30CST had very high intrarater reliability (ICC=0.94). The variables of STS test in Balance Master had moderate intrarater reliability (ICC=0.62-0.69). There were significant correlations between the 30CST, Oswestry Disability Index and pain intensity at activity (P<0.01). The rising index was the only one variable that was significantly correlated with pain intensity at activity (P<0.05). The 30CST as the field-based method to measure STS movement was better than the laboratory-based method in terms of their psychometric properties. Moreover, the 30CST was associated with disability and pain related to LBP. The 30CST is a simple, cheap, less time consuming and psychometrically appropriate method to use in individuals with nonspecific LBP.

A prospective 2-site parallel intervention trial of a research-based film to increase exercise amongst older hemodialysis patients

Background

Evidence suggests that exercise training for hemodialysis patients positively improves morbidity and mortality outcomes, yet exercise programs remain rare and are not systematically incorporated into care. We developed a research-based film, Fit for Dialysis, designed to introduce, motivate, and sustain exercise for wellness amongst older hemodialysis patients, and exercise counseling and support by nephrologists, nurses, and family caregivers. The objective of this clinical trial is to determine whether and in what ways Fit for Dialysis improves outcomes and influences knowledge/attitudes regarding the importance of exercise for wellness in the context of end-stage renal disease.

Methods/Design

This 2-site parallel intervention trial will recruit 60 older hemodialysis patients from two urban hospitals. The trial will compare the film + a 16-week exercise program in one hospital, with a 16-week exercise-only program in another hospital. Physical fitness and activity measures will be performed at baseline, 8 and 16 weeks, and 12 weeks after the end of the program. These include the 2-min Walk Test, Grip Strength, Duke Activity Status Index, and the Timed Up-and-Go Test, as well as wearing a pedometer for one week. Throughout the 16-week exercise program, and at 12 weeks after, we will record patients’ exercise using the Godin Leisure-time Exercise Questionnaire. Patients will also keep a diary of the exercise that they do at home on non-dialysis days. Qualitative interviews, conducted at baseline, 8, and 16 weeks, will explore the impact of Fit for Dialysis on the knowledge/attitudes of patients, family caregivers, and nephrology staff regarding exercise for wellness, and in what ways the film is effective in educating, motivating, or sustaining patient exercise during dialysis, at home, and in the community.

Discussion

This research will determine for whom Fit for Dialysis is effective, why, and under what conditions. If Fit for Dialysis is proven beneficial to patients, nephrology staff and family caregivers, research-based film as a model to support exercise promotion and adherence could be used to support the National Kidney Foundation’s guideline recommendation (NKF-KDOQI) that exercise be incorporated into the care and treatment of dialysis patients.

Trial registration

NCT02754271 (ClinicalTrials.gov), retroactively registered on April 21, 2016.

Relationship between performances of 10-time-repeated sit-to-stand and maximal walking tests in non-disabled older women

Aim

Sit-to-stand (STS) test is extensively used to assess the functionality of the lower body in elderly people. This study aimed to examine how the score of STS can be associated with that of maximal walking (MW) tests through a cross-sectional as well as longitudinal analysis for non-disabled older women.

Method

Times taken for a 10-time-repeated STS (STS time) and 5-m MW (MW time) were determined before (pre) and after (post) a 3-month body mass-based exercise program in 154 non-disabled women aged 60 to 79 years. In addition to the time scores, STS and MW power indexes (STS-PI and MW-PI, respectively) were calculated using the following equations: STS-PI = (body height − 0.4) × body mass × 10/STS time and MW-PI = body mass × 5/MW time.

Results

At pre- and post-intervention, STS-PI was significantly correlated to MW-PI, with higher correlation coefficients (r = 0.545–0.567, P < 0.0001) than those between the two time scores (r = 0.271–0.309, P < 0.001). The intervention significantly improved STS-time (13.6 ± 3.2 s at pre to 9.4 ± 1.8 s at post, P < 0.0001), MW time (2.4 ± 0.3 s to 2.2 ± 0.3 s, P < 0.0001), STS-PI (46.5 ± 12.5 to 65.7 ± 12.7, P < 0.0001), and MW-PI (112.1 ± 20.2 to 124.2 ± 24.4, P < 0.0001). There were significant correlations between the changes of STS and MW times (r = 0.281, P < 0.001) and between those of STS-PI and MW-PI (r = 0.366, P < 0.0001).

Conclusion

In elderly women, the performance of sit-to-stand task and its training-induced gain are associated with those of the maximal walking task. In addition, the current results indicated that translation of the performance scores of the sit-to-stand and maximal walking tasks to power indexes may be a useful approach for examining the association between the two tasks.

New Method of Evaluating Muscular Strength of Lower Limb Using MEMS Acceleration and Gyro Sensors

The purpose of this study was to develop a home-use method of evaluating muscular strength of the lower limb of a physically diverse range of people. Through a survey of previous findings regarding the mechanical load of daily activities, we propose that rapidly standing from an initial low squat posture is an appropriate movement to evaluate muscular strength of the lower limb. Additionally, we define a new index of muscular strength of the lower limb called “muscular strength margin.” This index shows the muscular strength relative to the minimum required muscular strength for activities of daily living. For easy measurement in a home setting, we utilize Micro-Electro-Mechanical Systems (MEMS) acceleration and gyro sensors to measure muscle strength. The MEMS sensor method highly correlates (r = 0.996) with optical motion capture system method, indicating that the MEMS sensor method has sufficient reliability for home use. The validity of the method developed in this study was verified through kinematic and kinetic analyses of 98 subjects whose age ranged from 14 to 98 yrs and from data of previous studies.

Effects of hemodialysis therapy on sit-to-walk characteristics in end stage renal disease patients

Patients with end stage renal diseases (ESRD) undergoing hemodialysis (HD) have high morbidity and mortality due to multiple causes; one of which is dramatically higher fall rates than the general population. In spite of the multiple efforts aiming to decrease the high mortality and improve quality of life in ESRD patients, limited success has been achieved. If adequate interventions for fall prevention are to be achieved, the functional and mobility mechanisms consistent with falls in this population must be understood. Human movements such as sit-to-walk (STW) tasks are clinically significant, and analysis of these movements provides a meaningful evaluation of postural and locomotor performance in elderly patients with functional limitations indicative of fall risks. In order to assess the effects of HD therapy on fall risks, 22 sessions of both pre- and post-HD measurements were obtained in six ESRD patients utilizing customized inertial measurement units (IMU). IMU signals were denoised using ensemble empirical mode decomposition and Savistky-Golay filtering methods to detect relevant events for identification of STW phases. The results indicated that patients were slower to get out of the chair (as measured by trunk flexion angular accelerations, time to peak trunk flexion, and overall STW completion time) following the dialysis therapy session. STW is a frequent movement in activities of daily living, and HD therapy may influence the postural and locomotor control of these movements. The analysis of STW movement may assist in not only assessing a patient's physical status, but in identifying HD-related fall risk as well. This preliminary study presents a non-invasive method of kinematic measurement for early detection of increased fall risk in ESRD patients using portable inertial sensors for out-patient monitoring. This can be helpful in understanding the pathogenesis better, and improve awareness in health care providers in targeting interventions to identify individuals at risk for fall.

Solid-organ transplantation in older adults: current status and future research

An increasing number of patients older than 65 years are referred for and have access to organ transplantation, and an increasing number of older adults are donating organs. Although short-term outcomes are similar in older versus younger transplant recipients, older donor or recipient age is associated with inferior long-term outcomes. However, age is often a proxy for other factors that might predict poor outcomes more strongly and better identify patients at risk for adverse events. Approaches to transplantation in older adults vary across programs, but despite recent gains in access and the increased use of marginal organs, older patients remain less likely than other groups to receive a transplant, and those who do are highly selected. Moreover, few studies have addressed geriatric issues in transplant patient selection or management, or the implications on health span and disability when patients age to late life with a transplanted organ. This paper summarizes a recent trans-disciplinary workshop held by ASP, in collaboration with NHLBI, NIA, NIAID, NIDDK and AGS, to address issues related to kidney, liver, lung, or heart transplantation in older adults and to propose a research agenda in these areas.

Exercise training for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a worldwide public health problem. In the National Kidney Foundation Disease Outcomes Quality Initiative guidelines it is stressed that lifestyle issues such as physical activity should be seen as cornerstones of the therapy. The physical fitness in adults with CKD is so reduced that it impinges on ability and capacity to perform activities in everyday life and occupational tasks. An increasing number of studies have been published regarding health effects of various regular exercise programmes in adults with CKD and in renal transplant patients.

OBJECTIVES

We aimed to: 1) assess the effects of regular exercise in adults with CKD and kidney transplant patients; and 2) determine how the exercise programme should be designed (e.g. type, duration, intensity, frequency of exercise) to be able to affect physical fitness and functioning, level of physical activity, cardiovascular dimensions, nutrition, lipids, glucose metabolism, systemic inflammation, muscle morphology and morphometrics, dropout rates, compliance, adverse events and mortality.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science, Biosis, Pedro, Amed, AgeLine, PsycINFO and KoreaMed. We also handsearched reference lists of review articles and included studies, conference proceeding's abstracts. There were no language restrictions.Date of last search: May 2010.

SELECTION CRITERIA

We included any randomised controlled trial (RCT) enrolling adults with CKD or kidney transplant recipients undergoing any type of physical exercise intervention undertaken for eight weeks or more. Studies using less than eight weeks exercise, those only recommending an increase in physical activity, and studies in which co-interventions are not applied or given to both groups were excluded.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study and data quality were performed independently by the two authors. Continuous outcome data are presented as standardised mean difference (SMD) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

Forty-five studies, randomising 1863 participants were included in this review. Thirty two studies presented data that could be meta-analysed. Types of exercise training included cardiovascular training, mixed cardiovascular and resistance training, resistance-only training and yoga. Some studies used supervised exercise interventions and others used unsupervised interventions. Exercise intensity was classed as 'high' or 'low', duration of individual exercise sessions ranged from 20 minutes/session to 110 minutes/session, and study duration was from two to 18 months. Seventeen per cent of studies were classed as having an overall low risk of bias, 33% as moderate, and 49% as having a high risk of bias.The results shows that regular exercise significantly improved: 1) physical fitness (aerobic capacity, 24 studies, 847 participants: SMD -0.56, 95% CI -0.70 to -0.42; walking capacity, 7 studies, 191 participants: SMD -0.36, 95% CI-0.65 to -0.06); 2) cardiovascular dimensions (resting diastolic blood pressure, 11 studies, 419 participants: MD 2.32 mm Hg, 95% CI 0.59 to 4.05; resting systolic blood pressure, 9 studies, 347 participants: MD 6.08 mm Hg, 95% CI 2.15 to 10.12; heart rate, 11 studies, 229 participants: MD 6 bpm, 95% CI 10 to 2); 3) some nutritional parameters (albumin, 3 studies, 111 participants: MD -2.28 g/L, 95% CI -4.25 to -0.32; pre-albumin, 3 studies, 111 participants: MD - 44.02 mg/L, 95% CI -71.52 to -16.53; energy intake, 4 studies, 97 participants: SMD -0.47, 95% CI -0.88 to -0.05); and 4) health-related quality of life. Results also showed how exercise should be designed in order to optimise the effect. Other outcomes had insufficient evidence.

AUTHORS' CONCLUSIONS

There is evidence for significant beneficial effects of regular exercise on physical fitness, walking capacity, cardiovascular dimensions (e.g. blood pressure and heart rate), health-related quality of life and some nutritional parameters in adults with CKD. Other outcomes had insufficient evidence due to the lack of data from RCTs. The design of the exercise intervention causes difference in effect size and should be considered when prescribing exercise with the aim of affecting a certain outcome. Future RCTs should focus more on the effects of resistance training interventions or mixed cardiovascular- and resistance training as these exercise types have not been studied as much as cardiovascular exercise.

The evolving challenge of evaluating older renal transplant candidates

The demographic factor over age 65 years represents the fastest growing segment of the end-stage kidney disease, wait-listed for kidney transplant, and transplanted populations. As a result, transplant physicians are increasingly asked to evaluate candidacy in older patients. Relatively little attention has been paid to the unique aspects of the pretransplant evaluation in older persons. The natural tendency is to focus on individual comorbidities as isolated entities, such as a history of coronary heart disease, while ignoring factors more specific to the aging process itself. Assessment of the burden of comorbidity along with the application of standardized geriatric assessment tools, such as the measurement of physical and cognitive function, has the potential to refine the pretransplant evaluation process in older kidney transplant candidates.

Physical function in older candidates for renal transplantation: an impaired population

BACKGROUND AND OBJECTIVES

Although physical function is a major determinant of health outcomes and quality of life in older adults, standard tools for its assessment have not been routinely applied to the fastest growing segment of the kidney transplant candidate population, which is at high risk of comorbidity and disability--people over age 60. The objective of this study was to describe the baseline physical function in older adults with renal failure referred for transplantation and compare them with older adults with other significant comorbidity.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

An observational sample comparing physical performance in renal transplant candidates over age 60 (Renal Failure) to older people with diastolic heart failure (Heart Failure), chronic obstructive pulmonary disease (COPD), or at high risk for cardiovascular disease (High CV Risk) was studied.

RESULTS

Older people with Renal Failure were significantly impaired by objective measures of physical function, including lower Short Physical Performance Battery, slower gait speed, and lower grip strength.

CONCLUSIONS

Older people referred for renal transplantation had poorer physical performance than older adults with other common chronic diseases and may be at high risk for disability while awaiting transplantation.

A comparison of aerobic exercise and resistance training in patients with and without chronic kidney disease

The morbidity and mortality associated with chronic kidney disease (CKD) are primarily caused by atherosclerosis and cardiovascular disease, which may be in part caused by inflammation and oxidative stress. Aerobic exercise and resistance training have been proposed as measures to combat obesity, inflammation, endothelial dysfunction, oxidative stress, insulin resistance, and progression of CKD. In non-CKD patients, aerobic exercise reduces inflammation, increases insulin sensitivity, decreases microalbuminuria, facilitates weight loss, decreases leptins, and protects against oxidative injury. In nondialysis CKD, aerobic exercise decreases microalbuminuria, protects from oxidative stress, and may increase the glomerular filtration rate (GFR). Aerobic exercise in hemodialysis patients has been reported to enhance insulin sensitivity, improve lipid profile, increase hemoglobin, increase strength, decrease blood pressure, and improve quality of life. Resistance training, in the general population, decreases C-reactive protein, increases insulin sensitivity, decreases body fat content, increases insulin-like growth factor-1 (IGF-1), and decreases microalbuminuria. In the nondialysis CKD population, resistance training has been reported to reduce inflammation, increase serum albumin, maintain body weight, increase muscle strength, increase IGF-1, and increase GFR. Resistance training in hemodialysis increases muscle strength, increases physical functionality, and improves IGF-1 status. Combined aerobic exercise and resistance training during dialysis improves muscle strength, work output, cardiac fitness, and possibly dialysis adequacy. There is a need for more investigation on the role of exercise in CKD. If the benefits of aerobic exercise and strength training in non-CKD populations can be shown to apply to CKD patients as well, renal rehabilitation will begin to play an important role in the approach to the treatment, prevention, and slowed progression of CKD.

A case study of gait compensations for hip muscle weakness in idiopathic inflammatory myopathy

BACKGROUND

The purpose of this case series was to quantify different strategies used to compensate in gait for hip muscle weakness.

METHODS

An instrumented gait analysis was performed of three females diagnosed with idiopathic inflammatory myopathies and compared to a healthy unimpaired subject. Lower extremity joint moments obtained from the gait analysis were used to drive an induced acceleration model which determined each moment's contribution to upright support, forward progression, and hip joint acceleration.

FINDINGS

Results showed that after midstance, the ankle plantar flexors normally provide upright support and forward progression while producing hip extension acceleration. In normal gait, the hip flexors eccentrically resist hip extension, but the hip flexor muscles of the impaired subjects (S1-3) were too weak to control extension. Instead S1-3 altered joint positions and muscle function to produce forward progression while minimizing hip extension acceleration. S1 increased knee flexion angle to decrease the hip extension effect of the ankle plantar flexors. S2 and S3 used either a knee flexor moment or gravity to produce forward progression, which had the advantage of accelerating the hip into flexion rather than extension, and decreased the demand on the hip flexors.

INTERPRETATION

Results showed how gait compensations for hip muscle weakness can produce independent (i.e. successful) ambulation, although at a reduced speed as compared to normal gait. Knowledge of these successful strategies can assist the rehabilitation of patients with hip muscle weakness who are unable to ambulate and potentially be used to reduce their disability.

Walking ability and its relationship to lower-extremity muscle strength in children with idiopathic inflammatory myopathies

OBJECTIVE

To describe gait deficits and their association with lower-extremity muscle strength in children with juvenile idiopathic inflammatory myopathies (IIM).

DESIGN

Cross-sectional, descriptive study.

SETTING

Clinical research center.

PARTICIPANTS

Consecutive sample of 25 ambulatory children diagnosed with juvenile IIM.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Manual muscle test (MMT) of bilateral hip flexor, extensor, and abductor; knee extensor; and ankle plantarflexor strength, all measured on a 0- to 10-point scale and summary strength measures. Video-based movement analysis to determine walking speed; gait cycle time; right and left step time; stride length; right and left step length; and stance, swing, and double-limb support phase durations.

RESULTS

Walking speed (1.03+/-0.27 m/s) was reduced because of shortened stride lengths (1.03+/-0.21 m) more than prolonged gait cycle times (1.05+/-0.22s). Walking speed highly correlated with the number of muscle groups weaker than grade 7 out of 10 (r=-.89) and the strength of the hip flexors (r=.85).

CONCLUSIONS

Lower-extremity strength measures, including MMT scores of individual muscle groups and the number of weak muscle groups, were predictive of gait limitations in children with juvenile IIM.

Preoperative predictors of locomotor ability two months after total knee arthroplasty for severe osteoarthritis

OBJECTIVE

To identify preoperative predictors of locomotor ability 2 months after total knee arthroplasty (TKA).

METHODS

Sixty-five participants scheduled for a first TKA were recruited. The dependent variable was the distance covered during the 6-minute gait test 2 months after TKA. The independent variables, measured before surgery, were grouped into 3 categories: 1). personal; 2). organic system, and 3). capability variables. Multiple regression analyses were conducted to determine the best predictors of the dependent variable. Modified cross-validation of the model combining predictors from the three categories was obtained with 10 random samples derived from the original cohort by resampling with replacement.

RESULTS

Predictors were identified in the 3 categories: 1). gender, number of comorbidities, body mass index, 2). knee pain, flexion and strength, lower limb mechanical power, and 3). preoperative 6-minute gait distance. When these variables were modeled together only the preoperative 6-minute gait distance and knee pain and flexion remained significant (adjusted R(2) = 0.66).

CONCLUSION

Using variables easily measured before surgery, it is possible to predict with good accuracy locomotor ability 2 months after TKA.

Resistance training improves strength and functional measures in patients with end-stage renal disease

BACKGROUND

The current study was designed to examine the effect of 12 weeks of resistance training on strength and functional ability in 10 medically stable hemodialysis patients (age, 42.8 +/- 4.4 years).

METHODS

Subjects were tested on four separate occasions, each separated by 6 weeks. The first (T1) and second tests (T2) were controls with no exercise intervention between them. T3 followed 6 weeks of resistance training, and T4 occurred after 12 weeks of training. Variables tested included percentage of body fat, distance covered in the 6-minute walk test, peak torque of quadriceps muscles of the dominant leg, maximal handgrip strength, normal and maximal walking speeds, and time to complete 10 repetitions of the sit-to-stand-to-sit test. Data were analyzed by means of a one-way repeated-measures analysis of variance procedure.

RESULTS

Results indicate that after 12 weeks of training, there was a significant (P < 0.05) increase (12.7%) in peak torque at 90 degrees /s (139.1 +/- 19.3 nm) compared with T1 and T2 (mean, 124.1 +/- 18.7 [SEM]; 123.5 +/- 16.9 Nm), respectively. The distance covered during the 6-minute walk was increased ( approximately 5%; P < 0.05) compared with baseline (T1, 522.1 +/- 46.2 m; 521.9 +/- 48.5 m) after 6 weeks of training (548.3 +/- 52.1 m) and remained elevated at week 12 (546.5 +/- 54.2 m). Maximal walking speed was increased (P < 0.05) by week 12 (195.9 +/- 15.4 cm/s) compared with baseline (T1, 182.9 +/- 12.7; 185.5 +/- 13.0 cm/s). Time to complete 10 repetitions of the sit-to-stand-to-sit test decreased at 12 weeks (17.8 +/- 1.9 seconds) versus baseline (T1, 20.3 +/- 1.5 seconds; T2, 20.6 +/- 5.5 seconds).

CONCLUSION

Resistance training can be used safely to increase strength and functional capacity in stable hemodialysis patients.

Muscle analysis by measurement of maximal isometric grip force: new reference data and clinical applications in pediatrics

Skeletal muscle development is one of the key features of childhood and adolescence. Determining maximal isometric grip force (MIGF) using a hand-held Jamar dynamometer is a simple method to quantify one aspect of muscle function. Presently available reference data present MIGF as a function of chronological age. However, muscle force is largely determined by body size, and many children undergoing muscle performance tests in the clinical setting suffer from growth retardation secondary to a chronic disorder. Reference data were established from simple regressions between age or log height and log MIGF in a population of 315 healthy children and adolescents aged 6 to 19 y (157 girls). These data were used to calculate age- or height-dependent SD scores (SDS) for MIGF in three pediatric patient groups. In renal graft recipients (n = 14), the age-dependent MIGF SDS was markedly decreased (-2.5 +/- 1.9; mean +/- SD). However, these patients had short stature (height SDS, -2.5 +/- 1.2), and the height-dependent MIGF SDS was close to normal (-0.4 +/- 1.5). Similarly, in cystic fibrosis patients (n = 13) age-dependent MIGF SDS was -1.6 +/- 1.6, but height-dependent MIGF SDS was -0.5 +/- 1.1. Children with epilepsy who were taking anticonvulsant therapy (n = 34) had normal stature, and consequently age- and height-dependent MIGF SDS were similar (0.4 +/- 1.0 and 0.4 +/- 0.8, respectively). In conclusion, MIGF determination provides information on an important aspect of physical development. Height should be taken into account to avoid misinterpretation.

The role of physical therapy in improving physical functioning of renal patients

Although not traditionally a part of the dialysis team, physical therapists can play an important role in improving the quality of life for dialysis patients. Physical therapists are trained to evaluate the presence of a functional problem such as back pain, muscle weakness, limited range of motion, balance disorder, alteration in gait, joint pain, neuropathic pain, sensory disturbance, loss of functional mobility, or alteration in posture. Many of these conditions are prevalent in the dialysis population. This article describes how a patient is referred to physical therapy, and once referred, how the patient is evaluated and treated, including goal setting and progression. It is thought that early referral of dialysis patients to physical therapy may prevent some of the functional deterioration typically seen in this population. The incorporation of physical therapy as part of the routine treatment plan may help dialysis staff to address many of the regular nonspecific complaints of fatigue, malaise, pain, and discomfort commonly experienced by dialysis patients.

Intercorrelations and internal consistency of limb muscle-action strengths of patients with renal disease

This study involved the retrospective analysis of instrumented measurements of strength from six muscle actions of 15 patients with renal disease. Most measurements were correlated significantly (Cronbach alpha > .92). These findings extend those obtained in studies of healthy individuals and patients with stroke and suggest the presence of a common underlying construct, limb muscle strength.

Balance Deficits Accompanying Renal Disease are Related to Diabetic Status

Balance deficits were examined in a sample of kidney-transplant candidates (60 men, 30 women) using an ordinal scale. Normal performance was defined as unilateral standing for more than 20 sec. Only 52% of the subjects balanced normally. A significant relationship between balance performance and diabetic status was found. Diabetic patients were more likely to show impaired balance. This finding is consistent with prior reports of gait and strength deficits among kidney-transplant candidates.

Balance deficits accompanying renal disease are related to diabetic status

Balance deficits were examined in a sample of kidney-transplant candidates (60 men, 30 women) using an ordinal scale. Normal performance was defined as unilateral standing for more than 20 sec. Only 52% of the subjects balanced normally. A significant relationship between balance performance and diabetic status was found. Diabetic patients were more likely to show impaired balance. This finding is consistent with prior reports of gait and strength deficits among kidney-transplant candidates.

Measurement, nature, and implications of skeletal muscle strength in patients with neurological disorders

Muscle strength is frequently impaired in patients with neurological disorders. Numerous instrumented and non-instrumented options exist for measuring the strength of such patients. Such measurements are useful for clarifying patient status and documenting changes over time. Moreover the measurements are often informative of present or future function among a variety of diagnostic groups. Measurements of muscle strength are an essential component of the neurological evaluation and provide information of substantial importance to clinical care.

Deficits in lower extremity muscle and gait performance among renal transplant candidates

This study was performed to determine the reliability and convergent validity of two lower extremity muscle performance (LEMP) measurements and to describe deficits in and determinants of LEMP and gait performance. Cross-sectional case series and criterion standard designs were used. The study took place at a tertiary care center. The subjects were referred from a volunteer sample of 110 renal transplant candidates. There were no interventions. The main outcome measures were knee extension strength measured by hand-held dynamometry and a sit-to-stand-to-sit (STSTS) test; gait independence on level surfaces and stairs; comfortable and maximum gait speed. Dynamometer measurements were reliable within (intraclass correlation coefficient (ICC) > or = .976) and between (ICC > or = .953) testers. Repeated STSTS measurements were also reliable (ICC > or = .843). The LEMP measures correlated significantly (p < .001) with one another (r > or = .406, R > or = .445). Compared with values predicted by regression equations derived from healthy individuals, transplant candidates showed significant deficits in knee extension force (33.2% to 34.6%) and gait speed (20.5% to 22.7%). Consistent as determinants of LEMP were sex, weight, and diabetic status. STSTS performance was the most consistent determinant of gait performance. The results of this study support the use of the STSTS test to characterize LEMP in kidney transplant candidates, particularly those who are diabetic or have deficits in gait performance.

Sit-to-stand test for measuring performance of lower extremity muscles

When the intent is to quantify performance of lower extremity muscles, the sit-to-stand test is a practical alternative to manual muscle testing and various instrumented options. Several procedures for performing the test are presented in this review as is information relevant to test interpretation. Performance variables known to be associated with sit-to-stand performance are noted.

Grip strength in end stage renal disease

The grip strength of 110 patients with end stage renal disease was measured. Their grip strength tended to be low compared with published norms. Significant correlations were found between the patients' grip strength and their gender, height, weight, and diabetic status. A regression equation including gender, height, and diabetic status as independent variables explained more than 40% of the variance in patients' grip strength.