Physical performance and frailty in chronic kidney disease

Elucidating the causal nexus and immune mediation between frailty and chronic kidney disease: integrative multi-omics analysis

BACKGROUND

Empirical research has consistently documented the concurrent manifestation of frailty and chronic kidney disease (CKD). However, the existence of a reverse causal association or the influence of confounding variables on these correlations remains ambiguous.

METHODS

Our analysis of 7,078 participants from National Health and Nutrition Examination Survey(NHANES) (1999-2018) applied weighted logistic regression and Mendelian Randomization (MR) to investigate the correlation between the frailty index (FI) and renal function. The multivariate MR analysis was specifically adjusted for type 2 diabetes and hypertension. Further analysis explored 3282 plasma proteins to link FI to CKD. A two-step network MR highlighted immune cells' mediating roles in the FI-CKD relationship.

RESULT

Genetically inferred FI and various renal function markers are significantly correlated, as supported by NHANES analyses. Multivariate MR analysis revealed a direct causal association between the FI and CKD. Additionally, our investigation into plasma proteins identified Tmprss11D and MICB correlated with FI and CKD, respectively. A two-step network MR to reveal 15 immune cell types, notably Central Memory CD4+ T cells and Lymphocytes, as crucial mediators between FI and CKD.

CONCLUSION

Our work establishes a causal connection between frailty and CKD, mediated by specific immune cell profiles. These findings highlight the importance of immune mechanisms in the frailty-CKD interplay and suggest that targeting shared risk factors and immune pathways could improve management strategies for these conditions. Our research contributes to a more nuanced understanding of frailty and CKD, offering new avenues for intervention and patient care in an aging population.

Correlation of physical function and physical activity with muscle mass measured with computed tomography in adult hemodialysis patients

Introduction

Background: muscle mass (MM) plays an important role in the physical function of hemodialysis patients; however, muscle mass measurement can be unreliable and expensive. In contrast, the measurement of physical function (PF) is simple and inexpensive and may serve as an alternative. The aim of this study was to correlate the measurement of MM by computed tomography (CT) with physical function measurements and physical activity (PA) levels in HD patients. Methods: this was a cross-sectional study that included 38 HD patients from a single HD clinic. Each participant had a CT scan to measure mid-thigh muscle mass. Physical function tests were assessed using the six-minute walk test (SMWT), handgrip strength (HGS) test, 5 x sit-to-stand test (STS5), timed up and go test (TUGT) and Short Physical Performance Battery (SPPB), while physical activity levels were measured using the Godin-Shephard leisure-time physical activity questionnaire. Correlation analysis was used to examine the relationship between variables. Results: handgrip strength was strongly positively correlated with thigh muscle area (r = 0.656, p ≤ 0.001) and weakly correlated with arm muscle area (r = 0.396, p = 0.002), SMWT (r = 0.373, p = 0.004), SPPB (r = 0.269, p = 0.041) and physical activity (r = 0.323, p = 0.013). There was also a trend for an inverse correlation between handgrip strenght and TUGT (r = -0.235, p = 0.076). Positive correlations were found between the thigh muscle area and the SPPB (r = 0.339, p = 0.009) and PA (r = 0.293, p = 0.025), while there was a trend for an inverse correlation between thigh muscle area and STS5 (r = -0.256, p = 0.052). Conclusion: several measures of PF and strenght were correlated with objectives measurements of MM, thus provide options for low-cost measurements related to muscle mass.

Genetically predicted frailty index and risk of chronic kidney disease

Previous findings have reported the association between frailty and chronic kidney disease. However, the causality remains ambiguous. This study aimed to determine whether frailty index is causally associated with chronic kidney disease. We obtained the frailty genome-wide association study (GWAS) data and chronic kidney disease GWAS data from the FinnGen R5 (total n = 216,743; case = 3902, control = 212,841) as the exposure and outcome, respectively. A two-sample Mendelian randomization (MR) analysis was primarily conducted using the inverse-variance weighted (IVW), weighted median and MR-Egger regression analyses. Multivariable MR analysis (MVMR) was conducted for additional adjustment. In the two-sample Mendelian randomization analyses, a total of 14 single nucleotide polymorphisms (SNPs) were recognized as effective instrumental variables. The IVW method showed evidence to support a causal association between frailty index and chronic kidney disease (beta = 1.270; 95% CI 0.608 to 1.931; P < 0.001). MR-Egger revealed a causal association between frailty index and chronic kidney disease (beta = 3.612; 95% CI 0.805 to 6.419; P = 0.027). MR-Egger regression revealed that directional pleiotropy was unlikely to be biasing the result (intercept =  - 0.053; P = 0.119). The weighted median approach and weighted mode method also demonstrated a causal association between frailty index and chronic kidney disease (beta = 1.148; 95% CI 0.278 to 2.019; P = 0.011; beta = 2.194; 95% CI 0.598 to 3.790; P = 0.018). Cochran's Q test and the funnel plot indicated no directional pleiotropy. MVMR analysis revealed that the causal association between frailty index and chronic kidney disease remained after adjusting for potential confounders, body-mass index, inflammatory bowel disease, waist-hip ratio, and C-reactive protein. Our study provides evidence of causal association between frailty and chronic kidney disease from genetic perspectives.

Physical activity and exercise in chronic kidney disease: consensus statements from the Physical Exercise Working Group of the Italian Society of Nephrology

The Italian Society of Nephrology has tasked its Working Group on Physical Exercise with developing a consensus statement document on physical activity and exercise in patients with chronic kidney disease (CKD). This paper consists of 16 points that were discussed, and approved using the mini-Delphi method by 15 members of the working group. Each statement is based on a comprehensive review of the literature, clinical experience, and expert opinions. Overall, the statements affirm that regular physical activity and exercise training offer numerous benefits to CKD patients, including improved physical function, enhanced cardiometabolic and neuromuscular function, cognitive benefits, and an overall improvement in quality of life. Furthermore, exercise may provide nephroprotection and reduce mortality. These advantages are observed across all CKD stages, whether on conservative therapy or kidney replacement therapy (hemodialysis or peritoneal dialysis), and in kidney transplant recipients. Moreover, when physical activity and exercise training are implemented with appropriate precautions, they are safe in CKD patients. Gradual physical activity and customized exercise programs should be tailored to the patient's exercise tolerance, potentially enhancing compliance. Clinicians are encouraged to use a series of questionnaires and tests to assess the patient's level of physical activity and performance. However, exercise and physical activity are poorly implemented in clinical practice due to many barriers related to patients and healthcare staff. Overcoming these barriers requires the proactive role of the nephrologists, who should actively incorporate exercise training and promote physical activity within routine care plans. Adopting a multidisciplinary team approach, which includes nephrologists, nurses, exercise professionals, and dietitians, is crucial for providing comprehensive rehabilitation for CKD patients. Integrating new technologies and remote check ups could further enhance the effectiveness of these interventions.

Causal association of monocytes with chronic kidney disease and the mediation role of frailty: A study integrating large-scale two-sample Mendelian randomization and single-cell analysis

BACKGROUND

Recent research reported that frailty was prevalent among adults with chronic kidney disease (CKD) in clinical trials, and monocytes illustrated a similar difference in these two diseases compared to the normal. However, the scientific evidence for a causal relationship between these two diseases was lacking, with further exploration into whether monocytes co-regulate them.

METHODS

We aimed to integrate large-scale Mendelian randomization (MR) and single-cell transcriptome analysis to determine whether there was a causal relationship between frailty and CKD (Bidirectional two-sample Mendelian determined the causal direction), whether monocytes impacted them, and whether the two diseases shared genetic variation sites. Based on 441 Genome-wide association study datasets, this study utilized five MR methods, multiple sensitivity analysis, and corresponding single-cell transcriptome datasets as proof.

RESULTS

The association between frailty and CKD was significantly causal, and frailty increased the risk of CKD in patients (OR (95 %CI): 3.5597 (1.8369-6.8982), p = 0.000168909). The exposure monocyte can increase the risk of frailty and CKD in patients, especially with high expression of HLA genes in these cells. The existing two-sample MR results cannot reject the hypothesis that monocytes increase the risk of CKD by inducing frailty. rs9275271' 1mb genetic location above and below had been proven to be an effective genetic space for both frailty and CKD.

CONCLUSION

We conducted the largest MR to date on frailty, monocyte, and CKD, and found a significant causal association between frailty and CKD, with the single-cell analysis confirmed. The exposure monocytes increased the risk of frailty and CKD, particularly with high expression of HLA genes in these cells. We identified a potential common genetic variant space, rs9275271, associated with frailty and CKD, providing insights into the genetic basis of these conditions.

The Association of Intestinal Leak with Sarcopenia and Physical Disability in Patients with Various Stages of Chronic Kidney Disease

Sarcopenia is related to disease severity in chronic kidney disease (CKD) patients; however, its pathophysiology remains poorly known. We investigated the associations of biomarkers of intestinal leak with sarcopenia in various stages of CKD. We recruited 61-76-year-old male controls and patients with various stages of CKD (n = 36-57/group) for measuring plasma lipopolysaccharide-binding protein (LBP) and zonulin (markers of intestinal leak), handgrip strength (HGS), skeletal mass index (SMI), and gait speed (markers of sarcopenia), and short physical performance battery (SPPB; marker of physical capacity). CKD stages 4 and 5 were associated with lower HGS, SMI, gait speed, and cumulative SPPB scores and a higher sarcopenia prevalence than controls and patients with CKD stages 1 and 2 (all p < 0.05). CKD patients (stages 1 and 2) had elevated plasma zonulin and LBP when compared with CKD stages 4 and 5. Plasma zonulin and LBP exhibited significant correlations with renal function, HGS, gait speed, SPPB scores, and oxidative stress markers in CKD stages 4 and 5 (all p < 0.05). However, similar relations were not found in early CKD. Collectively, intestinal leak may be contributing to sarcopenia and physical disability in the advanced stages of CKD.

Development of a Conceptual Model of Physical Functioning Limitations Experienced by Patients with Late-Stage Chronic Kidney Disease: A Qualitative Interview Study

INTRODUCTION

Limitations in physical functioning are common in patients with late-stage chronic kidney disease (CKD) and can greatly affect their lives. Using patient interviews, this study reports experiences associated with physical functioning limitations for patients with late-stage CKD.

METHODS

A preliminary conceptual model on concepts relevant to physical functioning limitations in patients with CKD was developed using data from a targeted literature review (patients with CKD stages IV-V) and previous interviews (patients with CKD stages IIIa-IIIb). The preliminary conceptual model informed a semi-structured interview guide designed to capture experiences of physical functioning limitations in patients with CKD. Patients with CKD stages IV-V who were not receiving dialysis were interviewed; their responses were used to develop a comprehensive conceptual model summarizing their experiences associated with physical functioning limitations.

RESULTS

A total of 25 patients with CKD stage IV (n = 19) or V (n = 6) were interviewed. Based on patient responses, the reported concepts were grouped into one of six categories: physical functioning limitations/difficulties, behavioural impacts, activity participation restrictions, symptoms attributed to physical functioning limitations, impacts on sleep and emotional functioning impacts related to physical functioning limitations. Twenty-three patients reported concepts associated with physical functioning limitations, most frequently 'walking up and down stairs' (83%) and 'walking distances' (74%). All 23 patients also reported behavioural impacts, including 'need to rest/subsequent periods of rest' (100%) and 'participation in fewer activities' (91%). As well as summarizing the reported concepts, the comprehensive conceptual model shows how concepts may relate to one another; for example, challenging symptoms or difficulty completing tasks can lead to changes in patient behaviour such as purposely reducing or avoiding activities.

CONCLUSIONS

This study found that patients with late-stage CKD not receiving dialysis who experience physical functioning limitations report a range of impacts on their daily lives. The comprehensive conceptual model summarizes the concepts reported and the relationships between them, providing a holistic understanding of how patients with late-stage CKD are affected by physical functioning limitations. Infographic available for this article. INFOGRAPHIC.

Beyond sarcopenia: frailty in chronic haemodialysis patients

Background

Frailty, characterized by vulnerability, reduced reserves and increased susceptibility to severe events, is a significant concern in chronic haemodialysis (HD) patients. Sarcopenia, corresponding to the progressive loss of muscle mass and strength, may contribute to frailty by reducing functional capacity, mobility and autonomy. However, consensus lacks on the optimal bedside frailty index for chronic HD patients. This study investigated the influence of frailty on chronic HD patient survival and explored the associated factors.

Methods

A total of 135 patients were enrolled from January to April 2019 and then followed up prospectively until April 2022. At inclusion, frailty was assessed by the Timed Up and Go (TUG) and Short Physical Performance Battery (SPPB) tests including gait speed, standing balance and lower limb muscle strength.

Results

From a total of 114 prevalent chronic HD patients (66% men, age 67.6 ± 15.1 years), 30 died during the follow-up period of 23.7 months (range 16.8-34.3). Deceased patients were older, had more comorbidities and a higher sarcopenia prevalence (P < .05). The TUG and SPPB test scores were significantly reduced in patients who had died [SPPB total score: 7.2 ± 3.3 versus 9.4 ± 2.5; TUG time 8.7 ± 5.8 versus 13.8 ± 10.5 (P < .05)]. Multivariate analysis showed that a higher SPPB score (total value >9) was associated with a lower mortality risk [hazard ratio 0.83 (95% confidence interval 0.74-0.92); P < .03). Each component of the SPPB test was also associated with mortality in univariate analysis, but only the SPPB balance test remained protective against mortality in multivariate analysis. Older age, lower handgrip strength and lower protein catabolic rate were associated with SPPB total scores <9, SPPB balance score and TUG time >10 s.

Conclusions

Screening for frailty is crucial in chronic HD patients, and incorporating SPPB, especially the balance test, provides valuable insights. Diminished muscle strength and inadequate protein intake negatively influence the SPPB score and balance in chronic HD patients. Effective identification and management of frailty can therefore improve outcomes.

CLINICAL TRIAL REGISTRATION ClinicalTrialsgov

NCT03845452.

Frailty in Kidney Disease: A Comprehensive Review to Advance Its Clinical and Research Applications

Frailty is a multisystem syndrome of decreased physiologic reserve that has been shown to strongly and independently predict morbidity and mortality. Frailty is prevalent in patients living with kidney disease and occurs earlier in individuals with kidney disease as compared to the general population. In this comprehensive review, we examine clinical and research applications of frailty in kidney disease populations. Specifically, we clarify the definition of frailty and address common misconceptions, review the mechanisms and epidemiology of frailty in kidney disease, discuss challenges and limitations in frailty measurement, and provide updated evidence related to risk factors for frailty, its associated adverse outcomes, and interventions. We further add to the literature in this topic by highlighting the potential applications of frailty measurement in the care of patients with kidney disease and conclude with our recommendations for future research related to this important syndrome.

Investigating the relationship between FRailty And Quality of LIfe in patients with heart faiLure and CKD (FRAIL study)

AIMS

Patients with chronic kidney disease (CKD) or heart failure (HF) are disproportionally affected by frailty, an independent predictor of morbidity. The prevalence of frailty and its impact on quality of life (QoL) in a unique population of patients with both CKD and HF (CKD-HF) is unclear. The aim of this study was to investigate the association between frailty and QoL in patients with CKD-HF.

METHODS AND RESULTS

Patients were identified from a tertiary care cardiorenal clinic. Eligible patients had CKD-HF with a stable estimated glomerular filtration rate of <60 mL/min/1.732. Data were collected from each participant at one point in time using surveys delivered by study personnel between 14 July 2022 and 31 March 2023. Frailty was defined as Modified Frailty Phenotype (MFP) score ≥3. The Medical Outcomes Study 36-item Short Form Health Survey (SF-36) was used to assess QoL. Demographic data were retrospectively collected from electronic patient records. Demographics and QoL were compared between frail and non-frail cohorts using Pearson's R and Student's t-test (two-tailed, alpha-priori = 0.05). One hundred five participants consented, and 103 completed the questionnaires in full. Amongst the 103 participants, 49.5% (n = 51) were frail. Frailty was related to sex (P = 0.021) and medication count (P = 0.007), however not to other clinical measures, including estimated glomerular filtration rate (P = 0.437) and ejection fraction (P = 0.911). Frail patients reported poorer QoL across physical functioning (P < 0.001), general health (P < 0.001), bodily pain (P = 0.004), social functioning (P < 0.001), and energy levels (P < 0.001), however not emotional wellbeing (P = 0.058); 51.5% cited 'better quality of life' as their healthcare priority, over longer survival (23.3%) or avoiding hospital admissions (22.3%). This was consistent across frail and non-frail groups.

CONCLUSIONS

A large proportion of CKD-HF patients are frail, regardless of disease severity, and more susceptible to significantly poorer QoL across physical and social domains. Improving QoL is the priority of patients across both frail and non-frail cohorts, further emphasizing the need for prompt recognition of frailty as well as possible intervention and prevention.

Skeletal Muscle Injury in Chronic Kidney Disease-From Histologic Changes to Molecular Mechanisms and to Novel Therapies

Chronic kidney disease (CKD) is associated with significant reductions in lean body mass and in the mass of various tissues, including skeletal muscle, which causes fatigue and contributes to high mortality rates. In CKD, the cellular protein turnover is imbalanced, with protein degradation outweighing protein synthesis, leading to a loss of protein and cell mass, which impairs tissue function. As CKD itself, skeletal muscle wasting, or sarcopenia, can have various origins and causes, and both CKD and sarcopenia share common risk factors, such as diabetes, obesity, and age. While these pathologies together with reduced physical performance and malnutrition contribute to muscle loss, they cannot explain all features of CKD-associated sarcopenia. Metabolic acidosis, systemic inflammation, insulin resistance and the accumulation of uremic toxins have been identified as additional factors that occur in CKD and that can contribute to sarcopenia. Here, we discuss the elevation of systemic phosphate levels, also called hyperphosphatemia, and the imbalance in the endocrine regulators of phosphate metabolism as another CKD-associated pathology that can directly and indirectly harm skeletal muscle tissue. To identify causes, affected cell types, and the mechanisms of sarcopenia and thereby novel targets for therapeutic interventions, it is important to first characterize the precise pathologic changes on molecular, cellular, and histologic levels, and to do so in CKD patients as well as in animal models of CKD, which we describe here in detail. We also discuss the currently known pathomechanisms and therapeutic approaches of CKD-associated sarcopenia, as well as the effects of hyperphosphatemia and the novel drug targets it could provide to protect skeletal muscle in CKD.

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

Serum Growth Differentiation Factor 15 Levels Predict the Incidence of Frailty among Patients with Cardiometabolic Diseases

INTRODUCTION

Frailty is a crucial health issue among older adults. Growth differentiation factor 15 (GDF15) is associated with inflammation, oxidative stress, insulin resistance, and mitochondrial dysfunction, which are possible pathogeneses of frailty. However, few longitudinal studies have investigated the association between GDF15 and the incidence of frailty. Therefore, we investigated whether high serum GDF15 levels are associated with the incidence of frailty.

METHODS

A total of 175 older adults (mean age: 77 ± 6 years; 63% women) with cardiometabolic diseases and no frailty out of the two criteria at baseline participated. Individuals with severe renal impairment or severe cognitive impairment were excluded. Serum GDF15 levels were measured at baseline. Patients were asked to assess frailty status at baseline and annually during follow-up using the modified version of the Cardiovascular Health Study (mCHS) and the Kihon Checklist (KCL). We examined the association between GDF15 tertiles and each frailty measure during follow-up (median 38-39 months). In the multivariate Cox regression analysis, with the GDF15 tertile groups as the explanatory variables, hazard ratios (HRs) and 95% confidence intervals (CIs) for incident frailty were calculated after adjusting for covariates and using the lowest tertile group as the reference.

RESULTS

During the follow-up period, 25.6% and 34.0% of patients developed frailty, as defined by the mCHS and KCL, respectively. The highest GDF15 tertile group had a significantly higher incidence of mCHS- or KCL-defined frailty than the lowest GDF15 tertile group. Multivariate Cox regression analysis revealed that the adjusted HRs for incident mCHS- and KCL-defined frailty in the highest GDF15 tertile group were 3.9 (95% CI: 1.3-12.0) and 2.7 (95% CI: 1.1-6.9), respectively.

CONCLUSION

High serum GDF15 levels predicted the incidence of frailty among older adults with cardiometabolic diseases and could be an effective marker of the risk for frailty in interventions aimed at preventing frailty, such as exercise and nutrition.

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

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

Association of Frailty With Nutritional Status in Patients With Chronic Kidney Disease

OBJECTIVES

Frailty is commonly observed in patients with chronic kidney disease (CKD) and is associated with adverse outcomes. Protein-energy wasting (PEW), a state of decreased body stores of protein and energy fuels, may be associated with frailty. However, few data are available on the possible association between frailty and PEW in CKD.

METHODS

We examined the association between frailty and nutritional status assessed using anthropometric and body composition measurements, serum albumin, handgrip strength, the Malnutrition Inflammation Score (MIS), and dietary protein and calorie intake in a cross-sectional analysis of nondialysis patients with CKD stages 3-5. Body composition was assessed using multifrequency bioelectrical impedance. Frailty was defined as a Clinical Frailty Scale ≥4. We performed logistic regression with different nutrition assessment tools as the main predictors and age, sex, comorbidity, estimated glomerular filtration rate (eGFR), and hemoglobin as covariates.

RESULTS

A total of 157 patients (93 men and 64 women; mean age 64 years; diabetes prevalence 38.9%) with CKD (eGFR 24.4 ± 13.4 mL/min/1.73 m2) were included. Overall, 29.3% of patients were frail. Patients with frailty were older and had a significantly higher fat tissue index and MIS but a significantly lower lean tissue index, eGFR, hemoglobin value, serum albumin value, handgrip strength value, and dietary protein intake. In multivariate logistic regression analyses, a higher body mass index category (odds ratio [OR], 1.54; 95% confidence interval [CI], 1.03-2.31), higher fat tissue index (OR, 1.15; 95% CI, 1.03-1.28), larger waist circumference (OR, 1.05; 95% CI, 1.01-1.09), reduced handgrip strength (OR, 2.70; 95% CI, 1.17-6.21), PEW defined by MIS ≥5 (OR, 3.49; 95% CI, 1.35-9.01), and dietary protein intake ≤0.8 g/kg/day (OR, 2.70; 95% CI, 1.18-6.19) were associated with higher odds of frailty.

CONCLUSION

Frailty is associated with nutritional status in patients with CKD. A comprehensive nutrition assessment may allow the implementation of strategies to prevent or reduce frailty.

Frailty and Cardiovascular Outcomes in Adults With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes in adults with kidney failure requiring dialysis. However, this relationship has not been thoroughly evaluated among those with non-dialysis-dependent CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

2,539 adults in the Chronic Renal Insufficiency Cohort Study.

EXPOSURE

Frailty status assessed using 5 criteria: slow gait speed, muscle weakness, low physical activity, exhaustion, and unintentional weight loss.

OUTCOME

Atherosclerotic events, incident heart failure, all-cause death, and cardiovascular death.

ANALYTICAL APPROACH

Cause-specific hazards models.

RESULTS

At study entry, the participants' mean age was 62 years, 46% were female, the mean estimated glomerular filtration rate was 45.4mL/min/1.73m2, and the median urine protein was 0.2mg/day. Frailty status was as follows: 12% frail, 51% prefrail, and 37% nonfrail. Over a median follow-up of 11.4 years, there were 393 atherosclerotic events, 413 heart failure events, 497 deaths, and 132 cardiovascular deaths. In multivariable regression analyses, compared with nonfrailty, both frailty and prefrailty status were each associated with higher risk of an atherosclerotic event (HR, 2.03 [95% CI, 1.41-2.91] and 1.77 [95% CI, 1.35-2.31], respectively) and incident heart failure (HR, 2.22 [95% CI, 1.59-3.10] and 1.39 [95% CI, 1.07-1.82], respectively), as well as higher risk of all-cause death (HR, 2.52 [95% CI, 1.84-3.45] and 1.76 [95% CI, 1.37-2.24], respectively) and cardiovascular death (HR, 3.01 [95% CI, 1.62-5.62] and 1.78 [95% 1.06-2.99], respectively).

LIMITATIONS

Self-report of aspects of the frailty assessment and comorbidities, which may have led to bias in some estimates.

CONCLUSIONS

In adults with CKD, frailty status was associated with higher risk of cardiovascular events and mortality. Future studies are needed to evaluate the impact of interventions to reduce frailty on cardiovascular outcomes in this population.

PLAIN-LANGUAGE SUMMARY

Frailty is common in individuals with chronic kidney disease (CKD) and increases the risk of adverse outcomes. We sought to evaluate the association of frailty status with cardiovascular events and death in adults with CKD. Frailty was assessed according to the 5 phenotypic criteria detailed by Fried and colleagues. Among 2,539 participants in the CRIC Study, we found that 12% were frail, 51% were prefrail, and 37% were nonfrail. Frailty status was associated with an increased risk of atherosclerotic events, incident heart failure, and death.

Factors Associated With Non-vaccination for Influenza Among Patients With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Vaccination for influenza is strongly recommended for people with chronic kidney disease (CKD) due to their immunocompromised state. Identifying risk factors for not receiving an influenza vaccine (non-vaccination) could inform strategies for improving vaccine uptake in this high-risk population.

STUDY DESIGN

Longitudinal observational study.

SETTING & PARTICIPANTS

3,692 Chronic Renal Insufficiency Cohort Study (CRIC) participants.

EXPOSURE

Demographic factors, social determinants of health, clinical conditions, and health behaviors.

OUTCOME

Influenza non-vaccination, which was assessed based on a receipt of influenza vaccine ascertained during annual clinic visits in a subset of participants who were under nephrology care.

ANALYTICAL APPROACH

Mixed-effects Poisson models to estimate adjusted prevalence ratios (APRs).

RESULTS

Between 2009 and 2020, the pooled mean vaccine uptake was 72% (mean age, 66 years; 44% female; 44% Black race). In multivariable models, factors significantly associated with influenza non-vaccination were younger age (APR, 2.16 [95% CI, 1.85-2.52] for<50 vs≥75 years), Black race (APR, 1.58 [95% CI, 1.43-1.75] vs White race), lower education (APR, 1.20 [95% CI, 1.04-1.39 for less than high school vs college graduate]), lower annual household income (APR, 1.26 [95% CI, 1.06-1.49] for <$20,000 vs >$100,000), formerly married status (APR, 1.22 [95% CI, 1.09-1.35] vs currently married), and nonemployed status (APR, 1.13 [95% CI, 1.02-1.24] vs employed). In contrast, participants with diabetes (APR, 0.80 [95% CI, 0.73-0.87] vs no diabetes), chronic obstructive pulmonary disease (COPD) (APR, 0.80 [95% CI, 0.70-0.92] vs no COPD), end-stage kidney disease (APR, 0.64 [0.56 to 0.76] vs estimated glomerular filtration rate≥60mL/min/1.73m2), frailty (APR, 0.86 [95% CI, 0.74-0.99] vs no frailty), and ideal physical activity (APR, 0.90 [95% CI, 0.82-0.99] vs. physically inactive) were less likely to have non-vaccination status.

LIMITATIONS

Possible residual confounding.

CONCLUSIONS

Among adults with CKD receiving nephrology care, younger adults, Black individuals, and those with adverse social determinants of health were more likely to have the influenza non-vaccination status. Strategies are needed to address these disparities and reduce barriers to vaccination.

PLAIN-LANGUAGE SUMMARY

Identifying risk factors for not receiving an influenza vaccine ("non-vaccination") in people living with kidney disease, who are at risk of influenza and its complications, could inform strategies for improving vaccine uptake. In this study, we examined whether demographic factors, social determinants of health, and clinical conditions were linked to the status of not receiving an influenza vaccine among people living with kidney disease and receiving nephrology care. We found that younger adults, Black individuals, and those with adverse social determinants of health were more likely to not receive the influenza vaccine. These findings suggest the need for strategies to address these disparities and reduce barriers to vaccination in people living with kidney disease.

Physical Frailty Predicts Outcomes in Patients Undergoing Evaluation for Kidney Transplantation

INTRODUCTION

An increasing number of older patients are undergoing evaluation for kidney transplantation; however, older patients experience increased rates of complications compared with younger patients, leading to the study of frailty assessments. Although many centers have evaluated the Fried Frailty Phenotype (FFP), less is known about the ability of the Short Performance Physical Battery (SPPB) to predict outcomes.

METHODS

Frailty assessment by FFP and SPPB was introduced into routine outpatient evaluation for patients aged 55 years and older referred for transplantation. Transplant rate, length of stay, readmission up to 3 months posttransplant, and death were reviewed. Patients were evaluated in an initial cohort followed by a validation cohort by FFP and SPPB. Multivariate analysis correcting for demographic characteristics was applied.

RESULTS

Patient cohorts reflected the racial and ethnic diversity of our population, including approximately 40% Hispanic patients. The first cohort of 514 patients demonstrated a significant association between frailty as measured by SPPB and transplantation (odds ratio [OR], 2.27; 95% CI, 1.38-3.83; p = .002). The second cohort of 1408 patients validated the association between frailty measured by SPPB and transplantation (OR, 2.81; 95% CI, 1.83-4.48; p < .001). In addition, there was a significant association between nonfrail status measured by SPPB and death (OR, 0.16; 95% CI, 0.04-0.62; p = .006).

CONCLUSIONS

Frailty assessment is a potentially useful approach for the assessment of transplant candidates. Our real-world study examined the performance of 2 methods of frailty evaluation methods in a diverse population, demonstrating that SPPB but not FFP was predictive of clinical outcomes. Incorporation of frailty assessments into transplant evaluation may improve risk stratification and optimize outcomes for older patients.

Neurocirculatory regulation and adaptations to exercise in chronic kidney disease

Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated blood pressure reactivity during exercise. Classic mechanisms of exercise intolerance in CKD have been extensively described previously and include uremic myopathy, chronic inflammation, malnutrition, and anemia. We contend that these classic mechanisms only partially explain the exercise intolerance experienced in CKD and that alterations in cardiovascular and autonomic regulation also play a key contributing role. The purpose of this review is to examine the physiological factors that contribute to neurocirculatory dysregulation during exercise and discuss the adaptations that result from regular exercise training in CKD. Key neurocirculatory mechanisms contributing to exercise intolerance in CKD include augmentation of the exercise pressor reflex, aberrations in neurocirculatory control, and increased neurovascular transduction. In addition, we highlight how some contributing factors may be improved through exercise training, with a specific focus on the sympathetic nervous system. Important areas for future work include understanding how the exercise prescription may best be optimized in CKD and how the beneficial effects of exercise training may extend to the brain.

Frailty and Age-Associated Assessments Associated with Chronic Kidney Disease and Transplantation Outcomes

Background. Frailty is often defined as a decrease in physiological reserve and has been shown to be correlated with adverse health outcomes and mortality in the general population. This condition is highly prevalent in the chronic kidney disease (CKD) patient population as well as in kidney transplant (KT) recipients. Other age-associated changes include sarcopenia, nutrition, cognition, and depression. In assessing the contributions of these components to patient outcomes and their prevalence in the CKD and KT patient population, it can be determined how such variables may be associated with frailty and the extent to which they may impact the adverse outcomes an individual may experience. Objectives. We sought to perform a systematic literature review to review published data on frailty and associated age-associated syndromes in CKD and KT patients. Results. Over 80 references pertinent to frailty, sarcopenia, nutrition, cognition, or depression in patients with CKD or KT were identified. Systematic review was performed to evaluate the data supporting the use of the following approaches: Fried Frailty, Short Physical Performance Battery, Frailty Index, Sarcopenia Index, CT scan quantification of muscle mass, health-related quality of life, and assessment tools for nutrition, cognition, and depression. Conclusion. This report represents a comprehensive review of previously published research articles on this topic. The intersectionality between all these components in contributing to the patient’s clinical status suggests a need for a multifaceted approach to developing comprehensive care and treatment for the CKD and KT population to improve outcomes before and after transplantation.

Valoración de la fragilidad en un centro de diálisis. ¿son más frágiles los pacientes con diabetes?

Introducción: El incremento en la inclusión de personas de edad avanzada a los programas de hemodiálisis se relaciona con un aumento de la prevalencia de fragilidad, considerada predictora de discapacidad y asociada a eventos adversos de salud. Dado su carácter reversible, es importante hacer un cribaje para mejorar la práctica clínica. Objetivo: Evaluar el grado de fragilidad y estado funcional del paciente en nuestra unidad de hemodiálisis y analizar las diferencias entre diabéticos y no diabéticos. Material y Método: Estudio observacional de corte transversal. La fragilidad se midió utilizando el fenotipo de Fried y la valoración funcional mediante las escalas Barthel, Lawton, Downton y la Short Physical Performance Battery. Se evaluó comorbilidad y riesgo de caídas con las escalas Charlson y Downton respectivamente. Se comparó entre grupos de diabéticos y no diabéticos y se analizó la relación entre la fragilidad y la edad, dependencia, comorbilidad y riesgo de caídas. Resultados: Se incluyeron 128 pacientes. El 45% tenían Diabetes. Los pacientes con diabetes tenían una edad media mayor que los no diabéticos (74,2±11 vs 67,8±15 años) y mayor comorbilidad (Charlson 8,2±2,2 vs 5,8±2,4). El 25% de los pacientes presentaron fragilidad, observando una tendencia que sugirió mayor fragilidad, peor capacidad funcional y mayor grado de dependencia en los pacientes diabéticos, aunque de forma no significativa. Conclusiones: Una cuarta parte de la población estudiada presenta fragilidad, con una tendencia más acusada a padecerla los pacientes diabéticos, que podría estar relacionada con mayor edad, mayor comorbilidad y menor capacidad funcional que los no diabéticos.

Management of fracture risk in CKD-traditional and novel approaches

The coexistence of osteoporosis and chronic kidney disease (CKD) is an evolving healthcare challenge in the face of increasingly aging populations. Globally, accelerating fracture incidence causes disability, impaired quality of life and increased mortality. Consequently, several novel diagnostic and therapeutic tools have been introduced for treatment and prevention of fragility fractures. Despite an especially high fracture risk in CKD, these patients are commonly excluded from interventional trials and clinical guidelines. While management of fracture risk in CKD has been discussed in recent opinion-based reviews and consensus papers in the nephrology literature, many patients with CKD stages 3-5D and osteoporosis are still underdiagnosed and untreated. The current review addresses this potential treatment nihilism by discussing established and novel approaches to diagnosis and prevention of fracture risk in patients with CKD stages 3-5D. Skeletal disorders are common in CKD. A wide variety of underlying pathophysiological processes have been identified, including premature aging, chronic wasting, and disturbances in vitamin D and mineral metabolism, which may impact bone fragility beyond established osteoporosis. We discuss current and emerging concepts of CKD-mineral and bone disorders (CKD-MBD) and integrate management of osteoporosis in CKD with current recommendations for management of CKD-MBD. While many diagnostic and therapeutic approaches to osteoporosis can be applied to patients with CKD, some limitations and caveats need to be considered. Consequently, clinical trials are needed that specifically study fracture prevention strategies in patients with CKD stages 3-5D.

The Role of Mitochondrial and Redox Alterations in the Skeletal Myopathy Associated with Chronic Kidney Disease

Significance: An estimated 700 million people globally suffer from chronic kidney disease (CKD). In addition to increasing cardiovascular disease risk, CKD is a catabolic disease that results in a loss of muscle mass and function, which are strongly associated with mortality and a reduced quality of life. Despite the importance of muscle health and function, there are no treatments available to prevent or attenuate the myopathy associated with CKD. Recent Advances: Recent studies have begun to unravel the changes in mitochondrial and redox homeostasis within skeletal muscle during CKD. Impairments in mitochondrial metabolism, characterized by reduced oxidative phosphorylation, are found in both rodents and patients with CKD. Associated with aberrant mitochondrial function, clinical and preclinical findings have documented signs of oxidative stress, although the molecular source and species are ill-defined. Critical Issues: First, we review the pathobiology of CKD and its associated myopathy, and we review muscle cell bioenergetics and redox biology. Second, we discuss evidence from clinical and preclinical studies that have implicated the involvement of mitochondrial and redox alterations in CKD-associated myopathy and review the underlying mechanisms reported. Third, we discuss gaps in knowledge related to mitochondrial and redox alterations on muscle health and function in CKD. Future Directions: Despite what has been learned, effective treatments to improve muscle health in CKD remain elusive. Further studies are needed to uncover the complex mitochondrial and redox alterations, including post-transcriptional protein alterations, in patients with CKD and how these changes interact with known or unknown catabolic pathways contributing to poor muscle health and function. Antioxid. Redox Signal. 38, 318-337.

Dietary Patterns and Perceptions in Older Adults With Chronic Kidney Disease in the Canadian Frailty Observation and Interventions Trial (CanFIT): A Mixed-Methods Study

Background:

People living with chronic kidney disease (CKD) have identified diet as an important aspect of their life and care. Understanding current consumption patterns in this population, and how they relate to patient perspectives of dietary recommendations, may help identify and design potential dietary intervention strategies in CKD.

Objective:

To investigate the dietary intake patterns of people with advanced-stage CKD, as well as subjective perspectives regarding dietary recommendations from participants and their caregivers.

Design:

Mixed-methods study with a sequential explanatory design.

Setting:

Manitoba, Canada.

Participants:

Individuals with late-stage CKD (CKD stages G4-G5, including dialysis) participating in the Canadian Frailty Observation and Interventions Trial (CanFIT).

Methods:

First, quantitative data were collected via a cross-sectional dietary assessment, using three 24-hour dietary recalls, a 36-question short diet questionnaire (SDQ), and a Nutrition Quality of Life (NQoL) tool (n = 59). Second, qualitative data were collected during 2 focus groups (n₁ = 12 and n₂ = 7) held with a subsample of individuals who had completed the dietary surveys, along with their caregivers. Focus groups explored topics related to diet and CKD; transcribed data were analyzed thematically. In the interpretation stage, the qualitative findings were combined with the quantitative results to help explain the latter and reach a deeper understanding of the subjective experiences of adults with CKD.

Results:

Quantitatively, nearly all (48/51; 94%) participants (mean age 70.8 ± 10.8 years) reported energy intakes below recommendations and most (86%) did not achieve recommended fiber intake. In addition, 15/21 (71%) of patients on dialysis had low protein intake. Qualitatively, 2 themes were identified: (1) Lacking/Needing dietary guidance—incomplete “information overload,” and (2) Experiencing difficulty in adapting to restrictions. Within the former theme, participants spoke of getting too much information at once, often at the wrong time. Within the latter theme, participants spoke of a loss of appetite, and cheating on their dietary recommendations.

Limitations:

Potential recall bias recalling dietary patterns, small sample size limiting generalizability, self-selection bias.

Conclusion:

Despite the reported lifestyle changes made by individuals with CKD, which negatively impacted their lives, many had suboptimal nutrition, especially in terms of energy and fiber. In addition, those on dialysis were not eating enough protein, which could be due to changing dietary recommendations as CKD progresses. Qualitative findings provided additional insight into how requisite CKD-dietary changes were perceived and how participants coped with these changes. The timing and delivery of the dietary education within CKD care in Manitoba may not be working for people with CKD as they progress through the disease.

Decline in Walking Independence and Related Factors in Hospitalization for Dialysis Initiation: A Retrospective Cohort Study

Patients with chronic kidney disease require intervention planning because their physical function declines with worsening disease. Providers can work closely with patients during the induction phase of dialysis. This single-center, retrospective observational study aimed to investigate the rate of decline in walking independence during the induction phase of dialysis and the factors that influence this decline, and to provide information on prevention and treatment during this period. Of the 354 patients who were newly initiated on hemodialysis between April 2018 and January 2022, 285 were included in the analysis. The functional independence measure-walking score was used to sort patients into decreased walking independence (DWI; n = 46) and maintained walking independence (no DWI; n = 239) groups, and patient characteristics were compared. After adjusting for various factors by logistic regression analysis, we observed that age, high Charlson comorbidity index (CCI), C-reactive protein, and emergency dialysis start (EDS) were significant predictors of DWI. Even during the very short period of dialysis induction, as many as 16.1% of patients had DWI, which was associated with older age, higher CCI, higher inflammation, and EDS. Therefore, we recommend the early identification of patients with these characteristics and early rehabilitation.

Healthy aging and chronic kidney disease

The world population is aging and the prevalence of noncommunicable diseases such as diabetes, hypertension, and chronic kidney disease (CKD) will increase significantly. With advances in medical treatment and public health, the human lifespan continues to outpace the health span in such a way that the last decade of life is generally spent in poor health. In 2015, the World Health Organization defined healthy aging as 'the process of developing and maintaining the functional ability that enables wellbeing in older age.' CKD is increasingly being recognized as a model of accelerated aging and is associated with physical performance decline, cognitive decline, falls and fractures, poor quality of life, loss of appetite, and inflammation. Frailty and dementia are the final pathways and key determinants of disability and mortality independent of underlying disease. CKD, dementia, and frailty share a triangular relationship with synergistic actions and have common risk factors wherein CKD accelerates frailty and dementia through mechanisms such as uremic toxicity, metabolic acidosis and derangements, anorexia and malnutrition, dialysis-related hemodynamic instability, and sleep disturbance. Frailty accelerates glomerular filtration decline as well as dialysis induction in CKD and more than doubles the mortality risk. Anorexia is one of the major causes of protein-energy malnutrition, which is also prevalent in the aging population and warrants screening. Healthcare systems across the world need to have a system in place for the prevention of CKD amongst high-risk older adults, focusing on screening for poor prognostic factors amongst patients with CKD such as frailty, poor appetite, and cognitive impairment and providing necessary person-centered interventions to reverse underlying factors that may contribute to poor outcomes.

Physical Function in Middle-aged and Older Adults With Type 1 Diabetes: Long-term Follow-up of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study

OBJECTIVE

To describe the prevalence and clinical correlates of functional limitations in middle-aged and older adults with long-standing type 1 diabetes.

RESEARCH DESIGN AND METHODS

Functional limitations were assessed for 1,094 participants in the Epidemiology of Diabetes Interventions and Complications (EDIC) study, a multicenter, longitudinal, observational follow-up of participants with type 1 diabetes randomly assigned to intensive or conventional diabetes therapy during the Diabetes Control and Complications Trial (DCCT). The primary outcome measure was a score <10 on the Short Physical Performance Battery (SPPB). The secondary outcome, self-reported functional limitation, was assessed by written questionnaire. Logistic regression models were used to assess associations of both outcomes with demographic and clinical factors (glycemic and nonglycemic factors, micro- and macrovascular complications, DCCT cohort, and treatment assignment).

RESULTS

Participants were 53% male, with mean ± SD age 59.5 ± 6.8 years and diabetes duration 37.9 ± 4.9 years. The prevalence of SPPB score <10 was 21%. The prevalence of self-reported functional limitations was 48%. While DCCT treatment assignment was not associated with physical function outcomes measured ∼25 years after the end of the DCCT, the time-weighted mean DCCT/EDIC HbA1c was associated with both outcomes. Other clinical factors associated with both outcomes in multivariable analyses were BMI, general psychological distress, and cardiac autonomic neuropathy.

CONCLUSIONS

Almost half of the middle-aged and older adults with long-standing type 1 diabetes reported functional limitations, which were associated with higher HbA1c and BMI, general psychological distress, and cardiac autonomic neuropathy. Future research is needed to determine whether these findings are generalizable.

Effect of Intradialytic Oral Nutritional Supplementation with or without Exercise Improves Muscle Mass Quality and Physical Function in Hemodialysis Patients: A Pilot Study

Background: Oral nutritional supplementation (ONS) with or without exercise (EX) could improve muscle mass (MM) in chronic kidney disease. Methods: Patients were randomized into two groups: (1) ONS and (2) ONS + EX. Thigh muscle area (cm²) and intramuscular lipid content via attenuation were evaluated at baseline and 6 months with computed tomography (CT) to measure MM quantity and quality. Physical function was measured by six-minute walk test (6 MWT), gait speed, handgrip strength (HGS), and Time Up and Go test (TUG) at baseline and 3 and 6 months. Results: The ONS group (n= 14) showed statistically significant improvement in gait speed and HGS; ONS + EX group (n = 10) showed differences in gait speed, in 6 MWT, and HGS. In the ANOVA (3 times × 2 groups), no differences were observed between groups. Greater effect sizes in favor to ONS + EX group were observed in the 6 MWT (d = 1.02) and TUG test (d = 0.63). Muscle quality at six months revealed a significant trend in favor of the EX-group (p = 0.054). Conclusions: Both groups had improved physical function, and greater effect sizes were seen in the ONS + EX group for the 6 MWT and TUG test. Neither MM quantity or quality was improved in either group.

Prognostic Value of Exercise Capacity in Kidney Transplant Candidates

Background Exercise stress testing for cardiovascular assessment in kidney transplant candidates has been shown to be a feasible alternative to pharmacologic methods. Exercise stress testing allows the additional assessment of exercise capacity, which may have prognostic value for long-term cardiovascular outcomes in pre-transplant recipients. This study aimed to evaluate the prognostic value of exercise capacity on long-term cardiovascular outcomes in kidney transplant candidates. Methods and Results We retrospectively evaluated exercise capacity in 898 consecutive kidney transplant candidates between 2013 and 2020 who underwent symptom-limited exercise stress echocardiography for pre-transplant cardiovascular assessment. Exercise capacity was measured by age- and sex-predicted metabolic equivalents (METs). The primary outcome was incident major adverse cardiovascular events, defined as cardiac death, non-fatal myocardial infarction, and stroke. Cox proportional hazard multivariable modeling was performed to define major adverse cardiovascular events predictors with transplantation treated as a time-varying covariate. A total of 429 patients (48%) achieved predicted METs. During follow-up, 93 (10%) developed major adverse cardiovascular events and 525 (58%) underwent transplantation. Achievement of predicted METs was independently associated with reduced major adverse cardiovascular events (hazard ratio [HR] 0.49; [95% CI 0.29-0.82], P=0.007), as was transplantation (HR, 0.52; [95% CI 0.30-0.91], P=0.02). Patients achieving predicted METs on pre-transplant exercise stress echocardiography had favorable outcomes that were independent (HR, 0.78; [95% CI 0.32-1.92], P=0.59) and of similar magnitude to subsequent transplantation (HR, 0.97; [95% CI 0.42-2.25], P=0.95). Conclusions Achievement of predicted METs on pre-transplant exercise stress echocardiography confers excellent prognosis independent of and of similar magnitude to subsequent kidney transplantation. Future studies should assess the benefit on exercise training in this population.

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

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

Association of Physical Performance, Muscle Strength and Body Composition with Self-Assessed Quality of Life in Hemodialyzed Patients: A Cross-Sectional Study

(1) Patients on chronic hemodialysis (HD) experience impaired quality of life (QoL). We analyzed HD’s relationship with physical performance, body composition, and muscle strength; (2) QoL was assessed with the Short Form-36, composed of physical (PCS) and mental (MCS) health dimensions. Physical performance was assessed with the Short Physical Performance Battery (SPPB), body composition (lean tissue mass% (LTM%), fat tissue mass% (FTM%), and skeletal muscle mass% (SMM%)) was assessed with bioelectrical impedance, and lower extremity strength was assessed with a handheld dynamometer; and (3) we enrolled 76 patients (27 F, 49 M), age 62.26 ± 12.81 years, HD vintage 28.45 (8.65−77.49) months. Their QoL score was 53.57 (41.07−70.64); their PCS and MCS scores were 52.14 (38.69−65.95) and 63.39 (44.64−76.79) and strongly correlated (p < 0.0001, R = 0.738). QoL correlated positively with SPPB (R = 0.35, p ≤ 0.001), muscle strength (R from 0.21 to 0.41, p < 0.05), and LTM% (R = 0.38, p < 0.001) and negatively with FTM% (R = −0.32, p = 0.006). PCS correlated positively with SPPB (R = 0.42 p < 0.001), muscle strength (R 0.25−0.44, p < 0.05), and LTM% (R = 0.32, p = 0.006) and negatively with FTM% (R = −0.25, p = 0.031). MCS correlated positively with SPPB (R = 0.23, p = 0.047), SMM% (R = 0.25; p = 0.003), and LTM% (R = 0.39, p < 0.001) and negatively with FTM% (R = −0.34; p = 0.003). QoL was unrelated to sex (p = 0.213), age (p = 0.157), HD vintage (p = 0.156), and BMI (p = 0.202); (4) Better physical performance, leaner body composition, and higher muscle strength are associated with better mental and physical QoL in HD.

Comparison Between the Physical Performance Test and the Clinical Frailty Score in Adult Patients With Chronic Kidney Disease Treated by Haemodialysis

Elderly patients with chronic kidney disease treated by haemodialysis are at increased risk of malnutrition and cachexia, becoming frail, with associated greater mortality. The physical performance test (PPT), using nine tasks to assess multiple domains of physical function is robust and reproducible, but time consuming, whereas the clinical frailty score (CFS) is more rapid. We compared the results from independent blinded observers in 22 haemodialysis patients, 16 (72.7%) male, mean age 65 ± 12.5 years. The PPT and CFS scores were highly correlated (r = −0.88, p < .001), with a high level of agreement (kappa score 0.91) for classifying patients as frail. Both scores were strongly associated with serum creatinine (PPT r=0.76, CFS r=−0.86, p < .001), hand grip strength (PPT r = 0.68, p = .001 CFS r = 0.64, p = .002), lean body mass index (PPT r = 0.50, p = .02, CFS r = −0.46, p = .038). We found that the CFS performed favourably compared to the PPT for haemodialysis patients in identifying and screening patients for frailty.

Factors affecting health-related quality of life in older patients with chronic kidney disease: a single-center cross-sectional study

BACKGROUND

Health-related quality of life (HRQoL) assessment is important for patients with chronic kidney disease (CKD). However, few studies have examined factors related to HRQoL, such as physical function, in older patients with predialysis CKD. This study evaluated the relationship between physical function, renal function, and nutritional status on the HRQoL in this patient group.

METHODS

This cross-sectional study included 61 patients aged ≥ 65 years with stages 3-5 predialysis CKD who were admitted for CKD education purposes. Using the EuroQoL 5-dimension 5-level (EQ-5D-5L) health status measure, the percentages of each EQ-5D-5L item were investigated. Physical function was measured using the short physical performance battery (SPPB) and grip strength, and characteristics, such as age, sex, diabetes mellitus, estimated glomerular filtration rate, and Geriatric Nutrition Risk Index, were investigated. Factors associated with EQ-5D-5L were identified using multiple regression analysis.

RESULTS

More than half of respondents (34/61, 55.7%) selected the second or higher level "have a problem" for the pain/discomfort section. The EQ-5D-5L score was significantly correlated with grip strength (r = 0.34, p = 0.01) and SPPB (r = 0.59, p = 0.00) in a single correlation analysis. Only SPPB (β = 0.67, p = 0.00) remained a significant factor after adjustment for grip strength, SPPB, age, sex, diabetes mellitus, and estimated glomerular filtration rate.

CONCLUSION

Physical function may be an important factor influencing HRQoL in older patients with predialysis CKD.

Iron Supplementation Improves Skeletal Muscle Contractile Properties in Mice with CKD

Background

Patients with chronic kidney disease (CKD) frequently have compromised physical performance, which increases their mortality; however, their skeletal muscle dysfunction has not been characterized at the single-fiber and molecular levels. Notably, interventions to mitigate CKD myopathy are scarce.

Methods

The effect of CKD in the absence and presence of iron supplementation on the contractile function of individual skeletal muscle fibers from the soleus and extensor digitorum longus muscles was evaluated in 16-week-old mice. CKD was induced by the adenine diet, and iron supplementation was by weekly iron dextran injections.

Results

Maximally activated and fatigued fiber force production was decreased 24%-52% in untreated CKD, independent of size, by reducing strongly bound myosin/actin cross-bridges and/or decreasing myofilament stiffness in myosin heavy chain (MHC) I, IIA, and IIB fibers. Additionally, myosin/actin interactions in untreated CKD were slower for MHC I and IIA fibers and unchanged or faster in MHC IIB fibers. Iron supplementation improved anemia and did not change overall muscle mass in CKD mice. Iron supplementation ameliorated CKD-induced myopathy by increasing strongly bound cross-bridges, leading to improved specific tension, and/or returning the rate of myosin/actin interactions toward or equivalent to control values in MHC IIA and IIB fibers.

Conclusions

Skeletal muscle force production was significantly reduced in untreated CKD, independent of fiber size, indicating that compromised physical function in patients is not solely due to muscle mass loss. Iron supplementation improved multiple aspects of CKD-induced myopathy, suggesting that timely correction of iron imbalance may aid in ameliorating contractile deficits in CKD patients.

Results From a Physical Activity Intervention Feasibility Study With Kidney Inpatients

Background:

Individuals with end-stage kidney disease requiring dialysis are often physically inactive, resulting in reduced physical functioning, increased frailty, and reduced quality of life. Furthermore, extended hospital stays and frequent readmissions are common, exacerbating health care costs. Physical activity may improve physical functioning, disability, and frailty but is not part of standard care of patients requiring dialysis. Research is required to determine the feasibility of implementing physical function assessments and physical activity programs in kidney inpatients requiring dialysis.

Objective:

To assess the feasibility and preliminary efficacy of an early-physical activity intervention (Move More study) in the care of kidney inpatients requiring dialysis. It was hypothesized that the intervention would be feasible with regards to administration and participation, meeting a priori feasibility criteria, and that kidney inpatients would benefit from participating.

Design:

Pilot study.

Setting:

Patient Unit 37, Foothills Medical Center, Calgary, AB, Canada.

Patients:

Kidney in-patients receiving dialysis.

Measurements:

Feasibility data were collected for recruitment, participation, assessment completion, physical activity completion, and adverse events. Participant and healthcare practitioner (HCP) satisfaction with the intervention was assessed using a questionnaire. Frailty and physical function were assessed by the kinesiologist at baseline and postintervention prior to hospital discharge.

Methods:

The study was a single-arm pilot intervention examining feasibility and preliminary efficacy. Kidney inpatients requiring dialysis were recruited to an individualized in-hospital physical activity intervention for the duration of their hospital stay. The intervention was led by a kinesiologist and supported by the clinical care team, including physiotherapists and nurse clinicians. Individualized exercise programs were created for patients to perform daily during their stay. These programs focused on strength, mobility, balance, and general movement and were tailored to each patient’s needs.

Results:

Thirty-six percent of eligible patients (n = 23/64) consented to participate in the Move More study, of whom 78% (n = 18/23) completed the intervention. The a priori level for consent to participate in the intervention was set at 60%. In addition, the a priori level for completion of assessments pre and postintervention was 50%. Ninety-five percent (n = 22/23) of preintervention assessments were completed compared to 65% of postintervention assessments. All participants who completed the survey (100%, n = 14/14) and most of the staff (77%, n = 24/31) reported being satisfied or very satisfied with the program. There were no adverse events related to the intervention. On average, Move More patients demonstrated improvements in frailty status and specific subsets of quality of life.

Limitations:

Firstly, as a feasibility study, the research was not powered to address the effectiveness of the intervention and lacked a comparison group to definitively link observed changes to the intervention itself. The voluntary nature of recruitment may have been biased toward ESKD inpatients with above-average motivation and baseline function. Furthermore, the small sample size from a single site limits the generalizability of findings. An additional limitation was the fact that postassessments were missed on a large number of patients, due to them being discharged prior to research staff knowing and being able to complete the assessments. Finally, studying the length of stay across the institution, as opposed to just the individual ward, would provide insight into hospitalization impact for these patients.

Conclusions:

The administration of and participation in a physical activity intervention for kidney inpatients requiring dialysis was initially not feasible primarily due to low recruitment and adherence challenges. The study was modified by including a research team member on the unit to increase recruitment efforts and support exercise adherence. The intervention impact includes potentially benefits on frailty and quality of life.

Klotho: An Emerging Factor With Ergogenic Potential

Sarcopenia and impaired cardiorespiratory fitness are commonly observed in older individuals and patients with chronic kidney disease (CKD). Declines in skeletal muscle function and aerobic capacity can progress into impaired physical function and inability to perform activities of daily living. Physical function is highly associated with important clinical outcomes such as hospitalization, functional independence, quality of life, and mortality. While lifestyle modifications such as exercise and dietary interventions have been shown to prevent and reverse declines in physical function, the utility of these treatment strategies is limited by poor widespread adoption and adherence due to a wide variety of both perceived and actual barriers to exercise. Therefore, identifying novel treatment targets to manage physical function decline is critically important. Klotho, a remarkable protein with powerful anti-aging properties has recently been investigated for its role in musculoskeletal health and physical function. Klotho is involved in several key processes that regulate skeletal muscle function, such as muscle regeneration, mitochondrial biogenesis, endothelial function, oxidative stress, and inflammation. This is particularly important for older adults and patients with CKD, which are known states of Klotho deficiency. Emerging data support the existence of Klotho-related benefits to exercise and for potential Klotho-based therapeutic interventions for the treatment of sarcopenia and its progression to physical disability. However, significant gaps in our understanding of Klotho must first be overcome before we can consider its potential ergogenic benefits. These advances will be critical to establish the optimal approach to future Klotho-based interventional trials and to determine if Klotho can regulate physical dysfunction.

Current status of the assessment of sarcopenia, frailty, physical performance and functional status in chronic kidney disease patients

PURPOSE OF REVIEW

Low physical function, frailty, and sarcopenia are common complications of chronic kidney disease (CKD). In this article, we review the epidemiology and pathogenesis of low physical function, as well as its associations with adverse outcomes in CKD patients. Additionally, we present various traditional and novel methods for assessment of physical function in CKD patients.

RECENT FINDINGS

In nondialysis dependent (NDD) and dialysis-dependent CKD patients, the prevalence of low physical function, frailty, and sarcopenia are substantially higher than in the general population. The potential mechanisms of low physical function, frailty, and sarcopenia in CKD patients are due to various factors including underlying kidney disease, co-existing comorbidities, and certain therapeutic interventions utilized in CKD. Increasing evidence has also uncovered the ill effects of impaired physical function on clinical outcomes in CKD patients.

SUMMARY

Routine assessment of physical function is an under-utilized yet important component in the management of CKD patients. Future studies are needed to determine how prescription of exercise and increased daily physical activity can be tailored to optimize the health and well-being of NDD and dialysis-dependent CKD patients in pursuit of successful aging.

Exploring New Kingdoms: The Role of Extracellular Vesicles in Oxi-Inflamm-Aging Related to Cardiorenal Syndrome

The incidence of age associated chronic diseases has increased in recent years. Although several diverse causes produce these phenomena, abundant evidence shows that oxidative stress plays a central role. In recent years, numerous studies have focused on elucidating the role of oxidative stress in the development and progression of both aging and chronic diseases, opening the door to the discovery of new underlying mechanisms and signaling pathways. Among them, senolytics and senomorphics, and extracellular vesicles offer new therapeutic strategies to slow the development of aging and its associated chronic diseases by decreasing oxidative stress. In this review, we aim to discuss the role of extracellular vesicles in human cardiorenal syndrome development and their possible role as biomarkers, targets, or vehicles of drugs to treat this syndrome.

Left atrial strain: A novel "biomarker" for chronic kidney disease patients?

Cardiovascular disease and chronic kidney disease are frequently inter-connected and this association leads to an exponential growth of cardiovascular risk. This risk is currently underestimated by the existing algorithms and there is a constant need for new markers to predict adverse outcomes in this special population. In general population left atrial strain has emerged as an important tool for both the diagnosis and prognostic stratification, but data regarding its role in chronic kidney disease patients is scarce. The purpose of this review is to summarize the current evidence regarding this matter. Left atrial size and function mirror the duration and severity of increased left ventricular filling pressures. Increased left atrial volume index and impaired left atrial strain parameters are independent predictors for adverse cardiovascular events. Left atrial strain is impaired before changes in volume appear, thus being able to predict both diastolic and systolic function in chronic kidney disease patients. Finally, left atrial strain can identify renal patients with impaired exercise capacity and this could have clinical applications in the rehabilitation of this patients.

Muscle fibrosis and maladaptation occur progressively in CKD and are rescued by dialysis

BACKGROUND

Skeletal muscle maladaptation accompanies chronic kidney disease (CKD) and negatively impacts physical function. Emphasis in CKD has historically been placed on muscle fiber intrinsic deficits, such as altered protein metabolism and atrophy. However, targeted treatment of fiber intrinsic dysfunction has produced limited improvement, whereas alterations within the fiber extrinsic environment have scarcely been examined.

METHODS

We investigated alterations to the skeletal muscle interstitial environment with deep cellular phenotyping of biopsies from patients with CKD compared to age-matched control participants and performed transcriptome profiling to define the molecular underpinnings of CKD-associated muscle impairments. We further examined changes in the observed muscle maladaptation following initiation of dialysis therapy for kidney failure.

RESULTS

Patients with CKD exhibited a progressive fibrotic muscle phenotype, which was associated with impaired regenerative capacity and lower vascular density. The severity of these deficits was strongly associated with the degree of kidney dysfunction. Consistent with these profound deficits, CKD was associated with broad alterations to the muscle transcriptome, including altered extracellular matrix organization, downregulated angiogenesis, and altered expression of pathways related to stem cell self-renewal. Remarkably, despite the seemingly advanced nature of this fibrotic transformation, dialysis treatment rescued these deficits, restoring a healthier muscle phenotype. Furthermore, after accounting for muscle atrophy, strength and endurance improved after dialysis initiation.

CONCLUSION

These data identify a dialysis-responsive muscle fibrotic phenotype in CKD and suggest that the early dialysis window presents a unique opportunity of improved muscle regenerative capacity during which targeted interventions may achieve maximal impact.

TRIAL REGISTRATION

NCT01452412FUNDING. NIH.

Comparison of muscle strength between hemodialysis patients and non-dialysis patients with chronic kidney disease

[Purpose] Muscle weakness in patients with chronic kidney disease is associated with several disease-related factors, and this study aimed to examine whether hemodialysis is one of risk factors for muscle weakness in patients with chronic kidney disease. [Participants and Methods] We conducted a cross-sectional study with 74 non-dialysis and 84 hemodialysis patients. Muscle strength evaluations were performed by measuring isometric knee extensor muscle strength and grip strength. Each evaluation item was compared between the hemodialysis and non-dialysis groups, and multiple regression analysis was performed to determine the factors associated with muscle strength. In addition, the correlation between lower-extremity muscle strength and grip strength was examined in each group. [Results] Isometric knee extensor muscle strength was significantly lower in the hemodialysis group than in the non-dialysis group. Grip strength was also significantly lower in the hemodialysis group than in the non-dialysis group. Hemodialysis was determined to be an independent risk factor associated with lower limb muscle strength as well as grip strength. The positive correlation between isometric knee extensor muscle strength and grip strength was almost the same in the groups. [Conclusion] Hemodialysis treatment was an independent risk factor for muscle weakness. Regular monitoring of grip strength may facilitate better management with physical therapy in hemodialysis patients.

Changes in Functional Status Among Kidney Transplant Recipients: Data From the Scientific Registry of Transplant Recipients

BACKGROUND

With stressors of dialysis prekidney transplantation (KT) and restoration of kidney function post-KT, it is likely that KT recipients experience a decline in functional status while on the waitlist and improvements post-KT.

METHODS

We leveraged 224 832 KT recipients from the national registry (SRTR, February 1990-May 2019) with measured Karnofsky Performance Status (KPS, 0%-100%) at listing, KT admission, and post-KT. We quantified the change in KPS from listing to KT using generalized linear models. We described post-KT KPS trajectories using adjusted mixed-effects models and tested whether those trajectories differed by age, sex, race, and diabetes status using a Wald test among all KT recipients. We then quantified risk adverse post-KT outcomes (mortality and all-cause graft loss [ACGL]) by preoperative KPS and time-varying KPS.

RESULTS

Mean KPS declined from listing (83.7%) to admission (78.9%) (mean = 4.76%, 95% confidence interval [CI]: -4.82, -4.70). After adjustment, mean KPS improved post-KT (slope = 0.89%/y, 95% CI: 0.87, 0.91); younger, female, non-Black, and diabetic recipients experienced greater post-KT improvements (Pinteractions < 0.001). Lower KPS (per 10% decrease) at admission was associated with greater mortality (adjusted hazard ratio [aHR] = 1.11, 95% CI: 1.10, 1.11) and ACGL (aHR = 1.08, 95% CI: 1.08, 1.09) risk. Lower post-KT KPS (per 10% decrease; time-varying) were more strongly associated with mortality (aHR = 1.93, 95% CI: 1.92, 1.94) and ACGL (aHR = 1.84, 95% CI: 1.83, 1.85).

CONCLUSIONS

Functional status declines pre-KT and improves post-KT in the national registry. Despite post-KT improvements, poorer functional status at KT and post-KT are associated with greater mortality and ACGL risk. Because of its dynamic nature, clinicians should repeatedly screen for lower functional status pre-KT to refer vulnerable patients to prehabilitation in hopes of reducing risk of adverse post-KT outcomes.

Social Support in Older Adults With CKD: A Report From the CRIC (Chronic Renal Insufficiency Cohort) Study

RATIONALE & OBJECTIVE

Social support in older adults with chronic kidney disease (CKD) is a potentially modifiable factor that may affect important clinical outcomes such as health-related quality of life, cognitive function, and frailty. However, limited data about the effects of social support in older patients with non-dialysis-dependent CKD exist. Our objective was to evaluate the association of social support with health-related quality of life, cognitive function, and frailty in older adults with CKD.

STUDY DESIGN

Cross-sectional analysis of a prospective cohort study.

SETTING & POPULATION

1,851 participants older than 65 years with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.

EXPOSURE

Social support (Lubben Social Network Scale [LSNS]).

OUTCOMESS

Health-related quality of life (Kidney Disease Quality of Life-36), cognitive function (Modified Mini-Mental State Examination, Trail Making Test A & B, and Buschke Selective Reminder Tests), and frailty (modified Fried frailty criteria).

ANALYTIC APPROACH

Multivariable, linear, and logistic regression to determine the association between social support and health-related quality of life, cognitive function, and frailty.

RESULTS

Low social support, defined as LSNS score < 12, was present in 22% of participants. On multivariable analysis, higher social support was associated with higher health-related quality of life (β coefficient per 1-SD increase in LSNS score; burden subscale, 2.57 (95% CI, 1.57-3.56); effects subscale, 2.21 (95% CI, 1.52-2.9); symptoms subscale, 1.64 (95% CI, 0.88-2.41); mental health composite subscale, 1.91 (95% CI, 1.40-2.43); and physical health composite score, 0.64 (95% CI, 0.03-1.24)). Higher social support was associated with better cognitive function (β coefficient per 1-SD increase in LSNS score; Modified Mini-Mental State Examination, 0.81 (95% CI, 0.44 to 1.19); Trail Making Test A & B, -2.53 (95% CI, -4.29 to -0.76) and -6.53 (95% CI, -10.07 to -2.99), respectively; Buschke Selective Reminder Test 1, 2, and 3, 0.19 (95% CI, 0.07 to 0.30); 1.59 (95% CI, 0.96 to 2.22); and 0.40 (95% CI, 0.23 to 0.56), respectively. Higher social support was associated with higher likelihood of being nonfrail (OR, 1.77; 95% CI per 1-SD higher LSNS score, 1.24-2.53).

LIMITATIONS

Conclusions about causality cannot be drawn from an observational cross-sectional study.

CONCLUSIONS

In older patients with CKD, higher social support was associated with higher health-related quality of life and cognitive function and less frailty.

According to Revised EWGSOP Sarcopenia Consensus Cut-Off Points, Low Physical Function Is Associated With Nutritional Status and Quality of Life in Maintenance Hemodialysis Patients

OBJECTIVE

The aim of this study is to assess the association of nutritional status and quality of life with low physical function, according to the revised European Working Group on Sarcopenia in Older People (EWGSOP) - sarcopenia consensus cut-offs in maintenance hemodialysis patients.

DESIGN AND METHODS

This is a cross-sectional study including patients on maintenance hemodialysis. Participants were submitted to a single evaluation of physical function, nutritional status, and quality of life. Handgrip strength, Short Physical Performance Battery (SPPB), sit-to-stand test, and gait speed were performed to evaluate physical function. Cut-offs proposed by the revised EWGSOP consensus were considered. Malnutrition Inflammation Score was used to assess nutritional status. Quality of life was assessed by the 36-Item Short Form Health Survey.

RESULTS

Seventy-seven patients were enrolled, 64.9% male, mean age 55 ± 14 years. According to the cut-offs proposed by the most recent EWGSOP consensus, 55.8% of patients presented SPPB <8, 48.1% gait speed test ≤0.8 m/seconds, sit-to-stand test >15 seconds, and 39.0% handgrip strength <27 kg and <16 kg for men and women, respectively. Malnutrition Inflammation Score was significantly associated with all physical function parameters, except gait speed, in receiver operating characteristic curve and logistic regression. The 36-Item Short Form Health Survey domains or component summary were associated with SSPB, gait speed, and handgrip strength in logistic regression.

CONCLUSION

Poor nutritional status and quality of life are associated with low physical function (according to the cut-offs proposed by EWGSOP) in hemodialysis patients.

Ratio of serum creatinine to cystatin C is related to leg strength in predialysis CKD patients

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) patients have lower levels of physical function. Especially, leg strength is important for daily living and preventing falls. However, physical function screenings are difficult to perform at clinical sites. To find clinically useful method to evaluate physical function in predialysis CKD patients, we tried to evaluate the relationship between the ratio of serum creatinine to serum cystatin C (Cre/CysC), and knee extensor muscle strength/body weight (KEMS) which reflects their leg strength.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We recruited 147 outpatients with CKD (87 men; mean age, 61.6 ± 9.8 years; mean eGFRcreat, 40.7 ± 12.9 mL/min/1.73m²) in this cross-sectional study. KEMS was assessed using a wire strain gauge dynamometer. Skeletal muscle mass and body fat mass were assessed by bioelectrical impedance analysis.

RESULTS

The mean value of Cre/CysC was 1.01 ± 0.18. The mean value of KEMS was 1.60 ± 0.47 Nm/kg. In multivariate linear regression analysis, skeletal muscle mass (p < 0.01), body fat mass (p < 0.01), hemoglobin (p = 0.01), and Cre/CysC (p < 0.01) was independently related to KEMS. The correlation between Cre/CysC and KEMS is stronger in high quantile of Cre/CysC.

CONCLUSIONS

In predialysis CKD patients, KEMS showed lower as CKD stage advanced. Cre/CysC is significantly related to KEMS independently. Cre/CysC may be an alternative marker for leg strength in CKD patients and even more valuable to utilize in cases with high Cre/CysC.

Home-based exercise for people living with frailty and chronic kidney disease: A mixed-methods pilot randomised controlled trial

Background

Frailty is associated with adverse health outcomes in people with chronic kidney disease (CKD). Evidence supporting targeted interventions is needed. This pilot randomised controlled trial (RCT) aimed to inform the design of a definitive RCT evaluating the effectiveness of a home-based exercise intervention for pre-frail and frail older adults with CKD.

Methods

Participants were recruited from nephrology outpatient clinics to this two-arm parallel group mixed-methods pilot RCT. Inclusion criteria were: ≥65 years old; CKD G3b-5; and Clinical Frailty Scale score ≥4. Participants categorised as pre-frail or frail using the Frailty Phenotype were randomised to a 12-week progressive multi-component home-based exercise programme or usual care. Primary outcome measures included eligibility, recruitment, adherence, outcome measure completion and participant attrition rate. Semi-structured interviews were conducted with participants to explore trial and intervention acceptability.

Results

Six hundred and sixty-five patients had an eligibility assessment with 217 (33%; 95% CI 29, 36) eligible. Thirty-five (16%; 95% CI 12, 22) participants were recruited. Six were categorised as robust and withdrawn prior to randomisation. Fifteen participants were randomised to exercise and 14 to usual care. Eleven (73%; 95% CI 45, 91) participants completed ≥2 exercise sessions/week. Retained participants completed all outcome measures (n = 21; 100%; 95% CI 81, 100). Eight (28%; 95% CI 13, 47) participants were withdrawn. Fifteen participated in interviews. Decision to participate/withdraw was influenced by perceived risk of exercise worsening symptoms. Participant perceived benefits included improved fitness, balance, strength, well-being, energy levels and confidence.

Conclusions

This pilot RCT demonstrates that progression to definitive RCT is possible provided recruitment and retention challenges are addressed. It has also provided preliminary evidence that home-based exercise may be beneficial for people living with frailty and CKD.

Trial registration

ISRCTN87708989; https://clinicaltrials.gov/.

Risk of Potentially Inappropriate Medications in Adults With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Adults with chronic kidney disease (CKD) may be at increased risk of adverse effects from use of potentially inappropriate medications (PIMs). Our objective was to assess whether PIM exposure has an independent association with CKD progression, hospitalizations, mortality, or falls.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

Chronic Renal Insufficiency Cohort (CRIC) study; 3,929 adults with CKD enrolled 2003-2008 and followed prospectively until December 2011.

EXPOSURE

PIM exposure was defined as prescriptions for any medications to be avoided in older adults as defined by the 2015 American Geriatrics Society Beers Criteria.

OUTCOME

Hospitalization count, death, a composite kidney disease end point of CKD progression or initiation of kidney replacement therapy (KRT), KRT, and fall events assessed 1 year after PIM exposure.

ANALYTICAL APPROACH

Logistic regression and Poisson regression to estimate the associations of PIM exposure with each outcome.

RESULTS

The most commonly prescribed PIMs were proton pump inhibitors and α-blockers. In unadjusted models, any PIM exposure (compared to none) was associated with hospitalizations, death, and fall events. After adjustment, exposure to 1, 2, or≥3 PIMs had a graded association with a higher hospitalization rate (rate ratios of 1.09 [95% CI, 1.01-1.17], 1.18 [95% CI, 1.07-1.30], and 1.35 [95% CI, 1.19-1.53], respectively) and higher odds of mortality (odds ratios of 1.19 [95% CI, 0.91-1.54], 1.62 [95% CI, 1.21-2.17], and 1.65 [95% CI, 1.14-2.41], respectively). In a cohort subset reporting falls (n=1,109), prescriptions for≥3 PIMs were associated with an increased risk of falls (adjusted OR, 2.85 [95% CI, 1.54-5.26]). PIMs were not associated with CKD progression or KRT. Age did not modify the association between PIM count and outcomes.

LIMITATIONS

Measurement bias; confounding by indication.

CONCLUSIONS

Adults of any age with CKD who are prescribed PIMs have an increased risk of hospitalization, mortality, and falls with the greatest risk occurring after more than 1 PIM prescription.

The FRAILMar Study Protocol: Frailty in Patients With Advanced Chronic Kidney Disease Awaiting Kidney Transplantation. A Randomized Clinical Trial of Multimodal Prehabilitation

Introduction: Frailty is very frequent among patients with chronic kidney disease (CKD) who are awaiting deceased donor kidney transplantation (KT), and transplant outcomes are worsened in those frail recipients. Frailty and poor fitness powerfully predict mortality, kidney graft survival, and healthcare utilization after KT. Intervention is essential to improve survival and quality of life for frail CKD patients, regardless of their age. Studies of post-transplant physical therapy intervention have been met with limited success, in large part due to high dropout rates. A pre-transplant clinical framework for multimodal prehabilitation interventions including physical therapy, nutritional measures, and psychological support scheduled during the KT waiting list period may improve patient retention and compliance, better mitigate the effects of frailty and poor fitness after KT, and improve main outcomes in frail CKD patients.

Main Objective: To study the effectiveness, feasibility, and safety of multimodal prehabilitation (exercise, nutritional plans, psychological advice) in KT candidates.

Methods: Randomized controlled clinical trial in 38 frail and 76 non-frail KT candidates. The prehabilitation program will consist of physical exercise (24 sessions, 8 weeks), nutritional supplementation, and psychological advice. The primary endpoint will be a composite achievement of clinical and functional main outcomes in frail and non-frail KT candidates at 90 days post-transplantation. Secondary outcomes include changes in exercise capacity, physical activity, gait speed, respiratory and peripheral muscle strength, muscle size, body composition, performance in activities of daily living (basic and instrumental), anxiety and depression symptoms, and health-related quality of life. Feasibility of the intervention will be also analyzed.

Expected Results: Multimodal prehabilitation is a feasible and effective intervention to decrease bad outcomes at 90 days post-KT by 25 and 12.5% in frail and non-frail patients, respectively.

Clinical Trial Registration:clinicaltrials.gov (NCT04701398), date: 2021, January 8th (Protocol version: Frailmar_vers2).