Prevalence and correlates of physical activity across kidney disease stages: an observational multicentre study

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study

Background

Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs.

Methods

Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m²; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O_2peak), HIITB (4×4 min intervals; 80–90% V̇O_2peak) or MICT (~40 min; 50–60% V̇O_2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence.

Results

Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O_2peak (mL/kg^-1/min^-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported.

Conclusions

This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.

Trial registration

ISRCTN, ISRCTN17122775. Registered on 30 January 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01067-3.

Implementing a resistance training programme for patients on short daily haemodialysis: A feasibility study

BACKGROUND

Kidney failure patients receiving haemodialysis experience protein-energy wasting, muscle mass loss and physical function impairment. Intradialytic exercise interventions seem to modify these features, but they are often not implemented as a clinical routine.

OBJECTIVE

To investigate the feasibility of implementing a supervised intradialytic resistance training programme as a clinical routine for patients receiving short daily haemodialysis.

DESIGN

A prospective longitudinal study.

PARTICIPANTS

Eighteen patients in a supervised intradialytic resistance training programme for 8 months.

MEASUREMENTS

It consisted of a warm-up, lower- and upper-limb resistance exercises and a cool-down. Patients performed the resistance training during the first half of haemodialysis, twice a week, supervised by exercise physiologists and physiotherapists. The feasibility was assessed by the total and partial adherences, the reasons for refusing or for not exercising and the intradialytic complications.

RESULTS

From a total of 953 potential exercise sessions, 759 were performed, with a 79.6% adherence rate. In the first 9 weeks, the adherence rate was 86.6% and the lowest rate was in the 19-27 weeks (73.5%). The main intradialytic complication during exercise sessions was hypotension (n = 31; 4.1%). The highest number of complications was reported during the first 9 weeks (n = 27; 9.1%). The main reasons for refusing or for not performing the intradialytic exercise sessions were clinical complications previous to exercise time (n = 63; 32.5%) and self-reported indisposition (n = 62; 32.0%).

CONCLUSIONS

The intradialytic resistance training programme, supervised by exercise physiologists and physiotherapists, had very low complications, achieved a high long-term adherence rate and showed to be feasible as a clinical routine for patients receiving short daily haemodialysis.

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.

Exercise-Based Renal Rehabilitation: A Bibliometric Analysis From 1969 to 2021

Chronic kidney disease (CKD) is a growing global health challenge with an increasing incidence rate. Exercise-based renal rehabilitation is an evidence-based, multidisciplinary, and comprehensive intervention designed to improve the physical and psychological condition of patients with CKD. The knowledge structure, research hotspots, and development trends in exercise-based renal rehabilitation have not been systematically described. The aim of this study was to provide a bibliometric perspective of the progress in this field. Publications about exercise-based renal rehabilitation were retrieved from the Web of Science Core Collection, using the terms "exercise," "physical activity," and "chronic kidney disease." Annual publications, subject categories, countries, authors, references, and keywords in this field were visually analyzed using the Citespace, VOSview, and Excel software. A total of 4,610 publications were analyzed, with a steady increase in publications in the field. Overall, the United States is the major contributor to the study of exercise-based renal rehabilitation. Johansen KL and Painter P are the key researchers in this field. Keyword analysis shows that research hotspots in this field include exercise/physical activity for different stages of CKD, exercise-based renal rehabilitation for frailty, and physical activity management for CKD. These findings will make understanding exercise-based renal rehabilitation research better and inform about future research ideas.

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

Background

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

Objectives

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

Design

A systematic review and meta-analysis.

Data Sources

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

Review Methods

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

Results

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

Conclusion

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

Systematic Review Registration

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

Cultural influences on physical activity and exercise beliefs in patients with chronic kidney disease: 'The Culture-CKD Study'-a qualitative study

OBJECTIVES

This study used a mixed-method approach to explore cultural and ethnic influences on the perception of, and decision to engage with or not to engage with, physical activity and exercise therapy in patients with chronic kidney disease (CKD).

DESIGN

Qualitative research was conducted through the use of semistructured interviews and focus groups. Self-reported physical activity levels were measured using the General Practice Physical Activity Questionnaire (GPPAQ), and self-efficacy for exercise with Bandura's Self-Efficacy for Exercise Scale.

SETTING

This study was conducted in a non-clinical setting of a single National Health Service Hospital Trust between April 2018 and July 2019.

PARTICIPANTS

Participants >18 years of age with a diagnosis of CKD, from black African, black Caribbean, South Asian or white ethnicity were eligible for the study. 84 patients with a diagnosis of CKD (stages 2-5), aged 25-79 (mean age 57) were recruited. Semistructured interviews (n=20) and six single-sex, ethnic-specific focus group discussions were undertaken (n=36).

OUTCOMES

Primary outcome was to explore the perceptions, attitudes and values about exercise and physical activity in different ethnic groups through qualitative interviews, analysed using an inductive thematic analysis approach. Questionnaires were analysed using Pearson correlation to determine if there was a significant relationship between the self-efficacy and GPPAQ levels.

RESULTS

Qualitative analysis provided four primary themes: I am who I am, Change of identity, Influences to physical activity and exercise and Support and education. Quantitative analysis using Pearson correlation revealed a significant correlation between GPPAQ levels of activity and self-efficacy to regulate exercise behaviour (r=-0.40, p=0.001).

CONCLUSION

Understanding the cultural, attitudes and beliefs of individuals with CKD from a variety of ethnic backgrounds is complex. Understanding of patients' experiences, thoughts and beliefs may be of relevance to clinicians when designing CKD exercise services.

TRIAL REGISTRATION NUMBER

NCT03709212; Pre-results.

Perceived barriers and facilitators to exercise in kidney transplant recipients: A qualitative study

Background

Exercise has the potential to attenuate the high levels of cardiovascular morbidity and mortality present in kidney transplant recipients (KTRs). Despite this, activity levels in KTRs remain low. The aim of this qualitative study was to explore the barriers and facilitators of exercise in KTRs.

Methods

Thirteen KTRs (eight males; mean ± SD; age 53 ± 13 years; estimated glomerular filtration rate 53 ± 21 ml/min/1.73 m²) were recruited and completed semistructured one‐to‐one interviews at University Hospitals of Leicester NHS Trust. All KTRs were eligible if their kidney transplant was completed >12 weeks before interview and their consultant considered them to have no major contraindications to exercise. All interviews were audio recorded, transcribed verbatim and subject to framework analysis to identify and report themes.

Results

Themes were organized into personal, behavioural and environmental factors based on social cognitive theory. Facilitators of exercise were largely internal: enjoyment, exercise for general health and health of the transplanted kidney and desire to maintain normality. Social interaction, support and guidance of healthcare professionals and goal setting were perceived as motivational. Harming the kidney, a lack of guidance, self‐motivation and accessibility were barriers to exercise.

Conclusion

These results provide detailed insight into the development of interventions designed to increase physical activity in KTRs. They provide strong evidence that specific exercise guidelines are required for this population and that the healthcare system could have a key role in supporting KTRs to become more physically active. Interventions need to be multifaceted to appeal to the differing levels of support desired by KTRs.

Patient or Public Contribution

KTRs were involved in the development of the interview topic guide to ensure all relevant topics were explored.

A pilot randomised controlled trial of a structured, home-based exercise programme on cardiovascular structure and function in kidney transplant recipients: the ECSERT study design and methods

BACKGROUND

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in kidney transplant recipients (KTRs). CVD risk scores underestimate risk in this population as CVD is driven by clustering of traditional and non-traditional risk factors, which lead to prognostic pathological changes in cardiovascular structure and function. While exercise may mitigate CVD in this population, evidence is limited, and physical activity levels and patient activation towards exercise and self-management are low. This pilot study will assess the feasibility of delivering a structured, home-based exercise intervention in a population of KTRs at increased cardiometabolic risk and evaluate the putative effects on cardiovascular structural and functional changes, cardiorespiratory fitness, quality of life, patient activation, healthcare utilisation and engagement with the prescribed exercise programme.

METHODS AND ANALYSIS

Fifty KTRs will be randomised 1:1 to: (1) the intervention; a 12week, home-based combined resistance and aerobic exercise intervention; or (2) the control; usual care. Intervention participants will have one introductory session for instruction and practice of the recommended exercises prior to receiving an exercise diary, dumbbells, resistance bands and access to instructional videos. The study will evaluate the feasibility of recruitment, randomisation, retention, assessment procedures and the intervention implementation. Outcomes, to be assessed prior to randomisation and postintervention, include: cardiac structure and function with stress perfusion cardiac MRI, cardiorespiratory fitness, physical function, blood biomarkers of cardiometabolic health, quality of life and patient activation. These data will be used to inform the power calculations for future definitive trials.

ETHICS AND DISSEMINATION

The protocol was reviewed and given favourable opinion by the East Midlands-Nottingham 2 Research Ethics Committee (reference: 19/EM/0209; 14 October 2019). Results will be published in peer-reviewed academic journals and will be disseminated to the patient and public community via social media, newsletter articles and presentations at conferences.

TRIAL REGISTRATION NUMBER

NCT04123951.

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/.

Association of sarcopenia with mortality and end-stage renal disease in those with chronic kidney disease: a UK Biobank study

BACKGROUND

Sarcopenia, a degenerative and generalized skeletal muscle disorder involving the loss of muscle function and mass, is an under-recognized problem in clinical practice, particularly in chronic kidney disease (CKD). We aimed to investigate the prevalence of sarcopenia in individuals with CKD, its risk factors, and its association with all-cause mortality and progression to end-stage renal disease (ESRD).

METHODS

UK Biobank participants were grouped according to the presence of CKD (defined as an estimated glomerular filtration rate <60 mL/min/1.73 m² ) and as having probable (low handgrip strength), confirmed (plus low muscle mass), and severe sarcopenia (plus poor physical performance) based on the 2019 European Working Group of Sarcopenia in Older People and Foundation for the National Institutes of Health criteria. Risk factors were explored using logistic regression analysis. Survival models were applied to estimate risk of mortality and ESRD.

RESULTS

A total of 428 320 participants, of which 8767 individuals with CKD (46% male, aged 62.8 (standard deviation 6.8) years, median estimated glomerular filtration rate 54.5 (interquartile range 49.0-57.7) mL/min/1.72 m² ) were included. Probable sarcopenia was present in 9.7% of individuals with CKD compared with 5.0% in those without (P < 0.001). Sarcopenia was associated with being older; inflammation; poorer renal function; and lower serum albumin, total testosterone, and haemoglobin. The largest risk factors for sarcopenia were having three or more comorbidities (odds ratio: 2.30; 95% confidence interval: 1.62 to 3.29; P < 0.001) and physical inactivity: participants in the highest quartile of weekly activity were 43% less likely to have sarcopenia compared to the lowest quartile (odds ratio: 0.57; 0.42 to 0.76; P < 0.001). Participants with CKD and sarcopenia had a 33% (7% to 66%; P = 0.011) higher hazard of mortality compared with individuals without. Sarcopenic CKD individuals had a 10 year survival probability of 0.85 (0.82 to 0.88) compared with 0.89 (0.88 to 0.30) in those without sarcopenia, an absolute difference of 4%. Those with sarcopenia were twice as likely to develop ESRD (hazard ratio: 1.98; 1.45 to 2.70; P < 0.001).

CONCLUSIONS

Participants with reduced kidney function are at an increased risk of premature mortality. The presence of sarcopenia increases the risk of mortality and ESRD. Appropriate measurement of sarcopenia should be used to identify at-risk individuals. Interventions such as physical activity should be encouraged to mitigate sarcopenia.

Risk Factors Associated with All-Cause Death Among Dialysis Patients with Diabetes

BACKGROUND Patients receiving dialysis who also have diabetes mellitus have high mortality. This study aimed to investigate the risk factors associated with all-cause death among Polish patients with diabetes receiving dialysis. MATERIAL AND METHODS This prospective observational study included 100 patients with type 1 or type 2 diabetes who were treated with peritoneal dialysis or hemodialysis. Blood laboratory tests, the occurrence of diabetes complications, and comorbidity, using the Charlson Comorbidity Index, were estimated. Survival analysis was performed using the multivariate Cox proportional hazard model, and Kaplan-Meyer survival analyses with log-rank tests were performed to show differences between groups. RESULTS During 16.0±5.0 months, 23 patients died. The deceased group had significantly higher levels of HbA1c (P=0.046) and fructosamine (P=0.011) than the surviving group. The deceased patients also had higher comorbidity scores (P=0.013). In the stepwise multivariate Cox proportional hazard regression model, history of stroke or transient ischemic attack was an independent risk factor of all-cause death (hazard ratio [HR] 3.15, 95% CI 1.34-7.39; P=0.009), while regular physical activity significantly reduced the risk of all-cause death (HR 0.26, 95% CI 0.08-0.87; P=0.029). CONCLUSIONS Deceased patients had higher HbA1c and fructosamine levels and higher comorbidity. However, history of stroke or transient ischemic attack was an independent risk factor of all-cause death, while regular physical activity was associated with the reduction of the risk of all-cause death in patients with type 1 and type 2 diabetes treated with peritoneal dialysis or hemodialysis. Regular physical activity should be recommended to improve survival in this population.

The cardiovascular determinants of physical function in patients with end-stage kidney disease on haemodialysis

Patients with end-stage kidney disease (ESKD) are often sedentary and decreased functional capacity associates with mortality. The relationship between cardiovascular disease (CVD) and physical function has not been fully explored. Understanding the relationships between prognostically relevant measures of CVD and physical function may offer insight into how exercise interventions might target specific elements of CVD. 130 patients on haemodialysis (mean age 57 ± 15 years, 73% male, dialysis vintage 1.3 years (0.5, 3.4), recruited to the CYCLE-HD trial (ISRCTN11299707), underwent cardiovascular phenotyping with cardiac MRI (left ventricular (LV) structure and function, pulse wave velocity (PWV) and native T1 mapping) and cardiac biomarker assessment. Participants completed the incremental shuttle walk test (ISWT) and sit-to-stand 60 (STS60) as field-tests of physical function. Linear regression models identified CV determinants of physical function measures, adjusted for age, gender, BMI, diabetes, ethnicity and systolic blood pressure. Troponin I, PWV and global native T1 were univariate determinants of ISWT and STS60 performance. NT pro-BNP was a univariate determinant of ISWT performance. In multivariate models, NT pro-BNP and global native T1 were independent determinants of ISWT and STS60 performance. LV ejection fraction was an independent determinant of ISWT distance. However, age and diabetes had the strongest relationships with physical function. In conclusion, NT pro-BNP, global native T1 and LV ejection fraction were independent CV determinants of physical function. However, age and diabetes had the greatest independent influence. Targeting diabetic care may ameliorate deconditioning in these patients and a multimorbidity approach should be considered when developing exercise interventions.

Exercise training in chronic kidney disease-effects, expectations and adherence

There is increasing evidence showing the health benefits of physical activity, such as better survival and possibly even a slower decline in kidney function, in people with chronic kidney disease (CKD). There is convincing evidence that exercise training improves physical function measured as aerobic capacity, muscle endurance strength and balance at all ages and all stages of CKD. In fact, long-term adherence to well-designed and adequately monitored exercise training programmes is high. In general, patients express interest in exercise training and are motivated to improve their physical function and health. A growing number of nephrologists regard physical activity and exercise training as beneficial to patients with CKD. However, many feel that they do not have the knowledge to prescribe exercise training and suppose that patients are not interested. Patients state that support from healthcare professionals is crucial to motivate them to participate in exercise training programmes and overcome medical, physical and psychological barriers such as frailty, fatigue, anxiety and fear. Equally important is the provision of funding by healthcare providers to ensure adequate prescription and follow-up by trained exercise physiologists for this important non-pharmacological treatment.

Perceptions of exercise benefits and barriers: the influence on physical activity behaviour in individuals undergoing haemodialysis and peritoneal dialysis

Background

Despite growing evidence about the benefits of physical activity and exercise in patients receiving dialysis, physical inactivity is highly prevalent. This may be due to uncertainty and lack of appropriate guidance about exercise, or driven by the relative barriers and benefits that patients perceive. Understanding these perceptions in dialysis patients may inform interventions aimed to increase exercise participation.

Methods

Perceived benefits and barriers to exercise were measured by the ‘Dialysis Patient-perceived Exercise Benefits and Barriers Scale’ (DPEBBS). Self-reported physical activity status was assessed by the ‘General Practice Physical Activity Questionnaire’. Barriers and benefits to exercise were classed as binary variables (i.e. yes and no). Frequency analyses and chi-squared tests were conducted to compare the differences perceived by people on haemodialysis (HD) and peritoneal dialysis (PD). Binominal logistical regression was performed to determine which perceived barriers and benefits had the biggest impact on physical activity status.

Results

One thousand twenty-two HD and 124 PD patients completed the DPEBBS. A greater proportion of HD than PD patients reported ‘reduces body pain’ (P = 0.013), ‘delays decline in body function’ (P = 0.01), and ‘improves quality of life’ (P = 0.033) as benefits of exercise. No differences in barriers were observed. Tiredness was the most reported barrier to exercise. Patients who perceived ‘other comorbidities’ (OR 3.389, P < 0.001) or ‘burden of family’ (OR 3.168, P < 0.001) as barriers were 3 times more likely to be inactive.

Conclusions

Dialysis patients perceive several barriers which may prevent them from engaging in physical activity. Addressing these barriers may be key to increasing participation in physical activity and exercise.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01024-y.

Exercise training in patients after kidney transplantation

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. Next to the risk of allograft failure, major obstacles for disease-free survival after kidney transplantation include a higher incidence of cancer, infection and cardiovascular events. Risk factors for adverse clinical outcomes include pre-existent comorbidities, the introduction of an immunodeficient status and (lack of) lifestyle changes after transplantation. Indeed, physical inactivity and poor physical fitness are important targets to address in order to improve clinical outcomes after kidney transplantation. This review summarizes the current evidence on exercise training after kidney transplantation, derived from randomized controlled trials. As much as possible, results are discussed in the perspective of the Standardized Outcomes in Nephrology-Transplantation core outcomes, which were recently described as critically important outcome domains for trials in kidney transplant recipients.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

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

The validity of the 'General Practice Physical Activity Questionnaire' against accelerometery in patients with chronic kidney disease

Background: The majority of patients with chronic kidney disease (CKD) are physically inactive. Simple yet accurate assessment of physical activity is important in identifying those in need of intervention. The 'General Practice Physical Activity Questionnaire' (GPPAQ) is a well-used clinical and research tool, but has not been validated.Methods: Forty individuals with CKD (age 62.5 (SD: 11.1) years, estimated glomerular filtration rate (eGFR) 33.2 (SD:19.1) ml/min/1.73 m²) completed the GPPAQ and objective physical activity was measured using a GENEActiv accelerometer for 7 days. Physical activity status was grouped as 'Active' (i.e. meeting current physical activity UK guidelines) or 'Inactive.' Sensitivity and specificity were calculated. Accuracy was defined as the probability the GPPAQ could correctly classify a patient as either 'Active' or 'Inactive' (based on accelerometery).Results: Using accelerometery, 18% of participants met the current UK guidelines, whereas 27% were classed as 'Active' according to GPPAQ. Sensitivity of the GPPAQ was 54.6% and specificity was 96.6%. The 'accuracy' of the GPPAQ was 85.0%. The accuracy of the GPPAQ was greater in males and those not in employment/retired, although these differences were not statistically significant.Conclusions: The GPPAQ may be a useful tool to identify CKD patients who would benefit most from a physical activity intervention. In particular, the GPPAQ can accurately identify those not sufficiently active.

Symptom-burden in people living with frailty and chronic kidney disease

Background

Frailty is independently associated with worse health-related quality of life (HRQOL) in chronic kidney disease (CKD). However, the relationship between frailty and symptom experience is not well described in people living with CKD. This study’s aim was to evaluate the relationship between frailty and symptom-burden in CKD.

Methods

This study is a secondary analysis of a cross-sectional observational study, the QCKD study (ISRCTN87066351), in which participants completed physical activity, cardiopulmonary fitness, symptom-burden and HRQOL questionnaires. A modified version of the Frailty Phenotype, comprising 3 self-report components, was created to assess frailty status. Multiple linear regression was performed to assess the association between symptom-burden/HRQOL and frailty. Logistic regression was performed to assess the association between experiencing symptoms frequently and frailty. Principal Component Analysis was used to assess the experienced symptom clusters.

Results

A total of 353 patients with CKD were recruited with 225 (64%) participants categorised as frail. Frail participants reported more symptoms, had higher symptom scores and worse HRQOL scores. Frailty was independently associated with higher total symptom score and lower HRQOL scores. Frailty was also independently associated with higher odds of frequently experiencing 9 out of 12 reported symptoms. Finally, frail participants experienced an additional symptom cluster that included loss of appetite, tiredness, feeling cold and poor concentration.

Conclusions

Frailty is independently associated with high symptom-burden and poor HRQOL in CKD. Moreover, people living with frailty and CKD have a distinctive symptom experience. Proactive interventions are needed that can effectively identify and address problematic symptoms to mitigate their impact on HRQOL.

A Pilot Randomized Controlled Trial Using SystemCHANGE™ Approach to Increase Physical Activity in Older Kidney Transplant Recipients

BACKGROUND

Cardiovascular disease is the leading cause of death in kidney transplant recipients. Physical activity after transplant is the most modifiable nonpharmacological factor for improving cardiovascular outcomes. Few studies have tested walking interventions to enhance daily steps and health outcomes in older kidney recipients.

METHODS

Using a pilot feasibility randomized clinical trial design, we tested the feasibility and efficacy of a 6-month SystemCHANGE™ (Change Habits by Applying New Goals and Experience) + Activity Tracker intervention for recruitment, retention, daily steps, and health outcomes (blood pressure, heart rate, body mass index, waist circumference, and physical function). The SystemCHANGE™ + Activity Tracker intervention taught participants to use a multicomponent intervention that connects person-centered systems solutions combined with visual feedback from a mobile activity tracker to achieve daily step goals.

RESULTS

Fifty-three participants (mean age 65 years, 66% male, and 57% white) participated with 27 in the intervention and 26 in the control group. The study protocol was feasible to deliver with high adherence to the protocol in both groups. The intervention group increased daily steps at 3 months (mean difference, 608; standard error = 283, P = .03) compared to the control group. The secondary outcome of heart rate decreased for the intervention group (baseline [mean] 74.4+ 10.8 [standard deviation, SD;] vs 6 months [mean] 67.6+ 11.3 [SD]; P = .002) compared to the control group (baseline [mean] 70.67+ 10.4 [SD]; vs 6 months [mean] 70.2 + 11.1 [SD]; P = .83).

CONCLUSIONS

SystemCHANGE™ + Activity Tracker intervention appears to be feasible and efficacious for increasing daily steps in older kidney recipients.

Advances in exercise therapy in predialysis chronic kidney disease, hemodialysis, peritoneal dialysis, and kidney transplantation

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is characterized by poor levels of physical activity which contribute to increased morbidity across the disease trajectory. The short nature, small samples, and poor methodology across most studies have failed to translate the role of exercise in CKD into its adoption as a frontline adjunct therapeutic option. This review focuses on recent advances surrounding the benefits of exercise interventions across the CKD spectrum.

RECENT FINDINGS

Key recent advances in exercise studies have focused on the efficacy of novel intervention strategies across the CKD spectrum. These include high-intensity interval training, virtual reality gaming, intradialytic yoga, electrical stimulation of muscles, blood flow restriction training, and protocols combining exercise with nutritional supplementation. Research is also beginning to explore the role of prehabilitation for patients prior to dialysis and kidney transplantation.

SUMMARY

Studies continue to demonstrate wide-ranging benefits of exercise across CKD; however, implementation of exercise remains scarce. Future research needs include evaluating the efficacy of larger and/or more comprehensive interventions on clinically important outcomes. It is hoped with increasing global evidence, high-quality clinical studies, and sustained clinician and patient engagement, exercise programs will become better prioritized in the nephrology field.