Intradialytic periodized exercise improves cardiopulmonary fitness and respiratory function: A randomized controlled trial

Comparisons of Intradialytic Exercise Versus Home-Based Exercise in Hemodialysis Patients: A Narrative Review

With the increasing prevalence of end-stage kidney disease, the number of patients requiring hemodialysis (HD) continues to rise. While life-sustaining, HD is often associated with adverse effects such as muscle loss, physical deconditioning, fatigue, and compromised health-related quality of life (HRQoL). Recent research suggests that intradialytic exercise (IDE) and home-based exercise (HBE) may mitigate these adverse effects and improve patient outcomes. However, the existing literature mainly focuses on the outcomes of both exercises, whereas the comparison of types is often omitted. Hence, this review consolidates findings from studies investigating the effectiveness, implementation, safety, feasibility, and adherence of different types of IDE and HBE in HD patients. Overall, the current literature bolsters the significance of IDE and HBE for improving health in HD patients. IDE and HBE enhance physical function, cardiopulmonary capacity, HRQoL, and cognitive well-being. Some research proposed an indirect link between IDE and survival rates. Despite these benefits, challenges remain in implementing these exercise modalities, including patient adherence and the feasibility of routine exercise during HD sessions. Integrating these exercises into routine care allows healthcare providers to enhance outcomes for HD patients. Further research is suggested to optimize exercise protocols and explore long-term effects and cost-effectiveness.

Quantifying the dose-response relationship between exercise and health-related quality of life in patients undergoing haemodialysis: A meta-analysis

Objective

This meta-analysis aims to explore the dose-response relationship of aerobic exercise or aerobic combined resistance exercise on cardiopulmonary function in maintenance hemodialysis（MHD）, with the goal of aiding in the formulation of precise exercise prescriptions.

Methods

A literature search up to August 18, 2023, was conducted in databases including Web of Science, among others, focusing on the effects of exercise interventions on cardiopulmonary function in hemodialysis patients.Two researchers independently conducted literature screening, data extraction, and an assessment of study methodology quality. A dose-response meta-analysis was carried out using a one-stage cubic spline mixed-effects model, followed by stratified analyses based on intervention period, intervention method, and exercise environment.

Results

A nonlinear dose-response relationship was observed between exercise and 6-minute walk test (6WMT) as well as peak oxygen uptake (VO2Peak) in hemodialysis patients. The optimal exercise dose for the 6WMT across the full exposure range was 922 METs-min/week, with VO2Peak increasing with the dose. The effects were influenced by the type of exercise, intervention period, and exercise environment. An exercise dose of 500 METs-min/week and 619 METs-min/week was found sufficient to achieve the minimal clinically important differences (MCID) for 6WMT and VO2Peak, respectively.

Conclusion

There is a significant association between the dose of exercise and its effects. With appropriate adjustment of variables, even low-dose exercise can lead to clinically significant improvements in cardiopulmonary function.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficacy of six exercise-based interventions for individuals undergoing hemodialysis: a network meta-analysis of randomized clinical trials

BACKGROUND

Evidence comparing different exercise modalities in individuals undergoing hemodialysis remains incipient. Our aim was to conduct a systematic review and network meta-analysis of randomized clinical trials to compare and synthesize the efficacy of five different intradialytic exercise modalities and home-based training in this population.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Studies were searched in PubMed/MEDLINE, Cochrane Library, Embase, Cinahl, and Scopus from their inception to 19 September 2022. We used traditional random-effects models and Bayesian network meta-analysis models. The risk of bias was assessed using the RoB v.2.0 tool, and the assessment of confidence in the results through the Confidence in Network Meta-Analysis (CINeMA) tool.

RESULTS

Seventy-eight studies involving 3326 participants were included. Our network meta-analysis showed that combined training was the intervention with the best performance to increase VO2 peak [mean difference (MD) = 3.94 ml/kg/min; 95% credible interval (CrI), 2.38 to 5.76] and to reduce diastolic blood pressure (MD = -5.19 mmHg; 95%CrI, -9.35 to -0.96) compared to the usual care group. Inspiratory muscle training was the intervention that most improved the 6-minute walk test distance (MD = 70.97 m; 95%CrI, 18.09 to 129.87). C-reactive protein decreased in resistance training (MD = -2.6 mg/l; 95%CrI, -4.97 to -0.33) and aerobic training (MD = -1.4 mg/l; 95%CrI, -3.15 to -0.06). Kt/V improved in aerobic training (MD = 0.11; 95%CrI, 0.02 to 0.18), and SF-36 physical functioning outcomes improved in resistance training (MD = 10.66 points; 95%Crl, 1.91 to 20.22). No intradialytic exercise modality was superior to others or comparable with home-based training in improving the evaluated outcomes. Subgroup analysis revealed that exercise interventions >12 weeks improved functional capacity more than interventions ≤12 weeks, and that combined training reduces diastolic blood pressure only after 12 weeks of follow-up. Furthermore, our results suggest that moderate or moderate-to-vigorous intensity training leads to more pronounced improvements in functional capacity, whereas mild or mild-to-moderate intensity training does not have the same effect. In this review, most of the included studies were assessed as having some concern, which resulted in a low to very low level of confidence in the overall findings.

CONCLUSIONS

Both intradialytic training and home-based training can promote benefits for individuals undergoing hemodialysis, with no evidence of the superiority of either training modality over the other.

Combined aerobic and resistance exercise in maintenance hemodialysis patients: A meta-analysis

Exercise brings many benefits to patients undergoing maintenance hemodialysis (MHD), but the effect of combined aerobic and resistance exercise remains unclear. English and Chinese databases (PubMed, Cochrane Library, Embase, Web of Science, CNKI, VIP, Wan Fang, and CBM) were searched from inception to January 2023 to retrieve qualified randomized controlled trials. The literature selection, data extraction, and risk of bias assessment of included studies were conducted independently by two reviewers. Meta-analysis was performed using RevMan 5.3 software. A total of 23 studies with 1214 participants were included, and 17 of the interventions were conducted during dialysis. Results showed that combined aerobic and resistance exercise (CARE) improved the peak oxygen uptake, six-minute walking test, 60 s sit-to-stand test (STS), 30 s STS, dialysis adequacy, five (out of eight) domains and physical component summary of health-related quality of life (HRQOL) measured by the Medical Outcomes Study Short Form-36, blood pressure, and hemoglobin for MHD patients compared with usual care. No significant changes were found in the mental component summary of HRQOL, C-reactive protein, creatinine, potassium, sodium, calcium, and phosphate. Subgroup analysis showed that intradialytic CARE ameliorated more outcomes, except for handgrip strength and hemoglobin, than non-intradialytic ones. CARE is an effective way to improve physical function, aerobic capacity, dialysis adequacy, and HRQOL for MHD patients. Strategies should be implemented by clinicians and policymakers to motivate patients to do more exercise. Well-designed clinical trials are warranted to explore the effectiveness of non-intradialytic CARE.

How is exercise being prescribed for patients on hemodialysis? A scoping review

BACKGROUND

Exercise is important for patients on hemodialysis, but details and descriptions on how it is prescribed are lacking. We reviewed the existing literature and described how exercise is being prescribed for patients on hemodialysis.

METHODS

A scoping review according to the JBI and PRISMA-ScR guidelines was conducted. MEDLINE, EMBASE and other databases were searched from inception until December 2021. Websites, books, and guidelines were also searched. We included evidence from patients on hemodialysis, describing exercise protocols, in all settings and designs.

RESULTS

Two hundred and eighty-five studies were included, yielding 327 exercise protocols. Aerobic (38.8%) and strength (21.4%) were the most prescribed exercise types. Exercise was mainly prescribed during dialysis (71.0%) and delivered within the first half of the session (94.6%). Although 33.3% of the exercise protocols did not report whether there was supervision or not, those that did were mostly delivered by physiotherapists (20.5%) and exercise physiologists (17.4%). The most followed exercise training principles were type (99.0%) and frequency (93.2%), whereas progression was adopted in 40.7% protocols. The most prescribed frequency and duration were three times/week (79.9%) and 30-60-min (69.2%) sessions, respectively. Exercise intensity was predominantly prescribed in moderate cut-offs (72.3%), mostly assessed by subjective methods (47.5%).

CONCLUSIONS

Aerobic and strength were the most prescribed exercise types, mainly during dialysis. Interventions were mostly supervised by physiotherapists and exercise physiologists. Future exercise protocols for patients on hemodialysis should adopt recommended exercise principles, especially with systematic progression.

Estimation of pulmonary artery systolic pressure in hemodialysis patients and its association with cardiorespiratory fitness and pulmonary function

PURPOSE

To evaluate the estimated pulmonary arterial systolic pressure (PASP) through transthoracic echocardiography in hemodialysis (HD) patients and associate it with cardiorespiratory fitness and pulmonary function.

METHODS

This study was a cross-sectional analysis of HD patients that performed evaluations of cardiac function, cardiorespiratory fitness, and pulmonary function, through transthoracic echocardiography, cardiopulmonary exercise test, spirometry, and manovacuometry, respectively. All patients underwent the evaluations on a non-dialysis day.

RESULTS

Thirty-five HD patients were evaluated and separated according to the presence of probable pulmonary hypertension (PH) (estimated PASP ≥ 35 mmHg) or not (estimated PASP < 35 mmHg). Those HD patients with probable PH had the worst cardiorespiratory fitness, evaluated by the peak oxygen consumption (VO_2peak) (17.11 ± 4.40 versus 12.90 ± 2.73 mL/kg/min; p = 0.011), and pulmonary function, evaluated by absolute and predicted of forced vital capacity (FVC) (85.52 ± 12.29 versus 71.38 ± 11.63%; p = 0.005) and absolute and predicted of forced expiratory volume in the first second (FEV₁) (83.37 ± 14.98 versus 69.21 ± 13.48%; p = 0.017). The secondary analysis showed that estimated PASP was correlated with VO_2peak (r = - 0.508; p = 0.002), FVC (r = - 0.450; p = 0.007), and FEV₁ (r = - 0.361; p = 0.033). Moreover, the adjusted odds ratio by HD vintage, dry weight and gender showed that increments in VO_2peak (OR 1.62; CI 95% 1.04-2.54; p = 0.034), FVC (OR 39.67; CI 95% 1.74-902.80; p = 0.021), and FEV₁ (OR 39.54; CI 95% 1.89-826.99; p = 0.018) were associated with 1-fold and 39-fold higher chance, respectively, for not having PH. However, all these associations were lost when age was included in the analysis.

CONCLUSIONS

The HD patients with probable PH had the worst cardiorespiratory fitness and pulmonary function. Exploratory analyses showed that greater cardiopulmonary fitness was associated with better cardiac function. Moreover, increments in cardiorespiratory fitness and pulmonary function may increase the chance of not having PH.

Six-minute walk test may be a reliable predictor of peak oxygen uptake in patients undergoing hemodialysis

Background

Cardiorespiratory fitness seems to play an important role in the general health of patients undergoing hemodialysis (HD). However, the prediction of peak oxygen uptake (V̇O2peak) in a clinical setting is not widely adopted for these patients.

Objectives

Evaluate the agreement and reliability between directly and indirectly V̇O2peak measurements in patients undergoing HD.

Methods

This is a cross-sectional study with patients undergoing HD that performed a cardiopulmonary exercise test (CPET) with 5/10 watts incremental load in each minute using a cycle ergometry to directly evaluate the V̇O2peak, and the 6-min walk test (6MWT) in a 30-m corridor to indirect measures it. Both tests were performed on a midweek non-dialysis day. Bland–Altman analysis of agreement limits was used with direct and indirect V̇O2peak values. Intraclass correlation coefficient (ICC) and Cronbach’s Alpha was used to evaluate the reproducibility and reliability between direct and indirect V̇O2peak values.

Results

Twenty-six patients (54.4 ± 14.5 years, 53.8% of male) were evaluated. The V̇O2peak direct mean obtained through CPET was 15.91 ± 5.26 (ml/kg/min), while the indirect mean obtained through 6MWT was V̇O2peak of 14.89 ± 4.21 (ml/kg/min). There was a strong positive correlation between both V̇O2peak values (r = 0.734; p < 0.001). The Bland–Altman analysis demonstrated that the methods agreed with each other (p = 0.103). Also, the ICC (0.829) and Cronbach's Alpha (0.846) showed excellent reproducibility and reliability.

Conclusions

6MWT is a reliable tool for estimating V̇O2peak in patients undergoing HD.

Comparative efficacy of exercise modalities for cardiopulmonary function in hemodialysis patients: A systematic review and network meta-analysis

Background

To provide reliable evidence to exercise rehabilitation therapists and clinicians, we compared and analyzed the effects of different exercise modalities on cardiopulmonary function in hemodialysis patients using Bayesian network meta-analysis.

Methods

PubMed, OVID, Web of Science, Cochrane Library, Embase, Scopus, CINAHL, SPORT Discus, SinoMed, CNKI, Wanfang, and VIP were searched from inception to July 20, 2022. We included randomized controlled trials comparing 12 exercise modalities to improve cardiorespiratory fitness in hemodialysis patients. All statistical analysis was performed using STATA and R.

Result

A total of 82 randomized controlled trials involving 4146 maintenance hemodialysis patients were included in this study. The pair-wise meta-analysis showed that all exercise modalities had a positive effect on all indicators of cardiorespiratory capacity. The network meta-analysis demonstrated that Blood flow restriction training (BFRT), Cycle exercise (CE), Inspiratory muscle training (IMT), Combined aerobic and resistance training (CT), and Aerobic training (AT) were significantly better than usual care for 6-min walkability; Medium intensity continuous training (MICT), CT, CE, and AT were considerably better than usual care for VO2Peak; body and mind training (MBT) and CT significantly improved SBP compared to usual care; and only MBT was significantly better than usual care for DBP. Both the two-dimensional plot and the radar plot demonstrated that CT had the best combined-effect on each index of cardiorespiratory fitness. Subgroup and sensitivity analyses demonstrated the robustness of the results. The evidence was mainly “low” to “very low” for this network meta-analysis.

Conclusion

There is no one exercise that can achieve the best effect on all of the outcomes. The benefits of MBT in decreasing arterial blood pressure are unsurpassed by other exercise methods. The intervention effect of the CT is better and more stable. Electrical muscle stimulation training (MEST) can be employed in individuals who do not wish to exercise actively but may cause an increase in blood pressure. On the basis of the characteristics of different exercise types, guidelines developers, clinicians, and patients may employ them appropriately.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails.

Comparative efficacy of exercise modalities for cardiopulmonary function in hemodialysis patients: A systematic review and network meta-analysis

Background

To provide reliable evidence to exercise rehabilitation therapists and clinicians, we compared and analyzed the effects of different exercise modalities on cardiopulmonary function in hemodialysis patients using Bayesian network meta-analysis.

Methods

PubMed, OVID, Web of Science, Cochrane Library, Embase, Scopus, CINAHL, SPORT Discus, SinoMed, CNKI, Wanfang, and VIP were searched from inception to July 20, 2022. We included randomized controlled trials comparing 12 exercise modalities to improve cardiorespiratory fitness in hemodialysis patients. All statistical analysis was performed using STATA and R.

Result

A total of 82 randomized controlled trials involving 4146 maintenance hemodialysis patients were included in this study. The pair-wise meta-analysis showed that all exercise modalities had a positive effect on all indicators of cardiorespiratory capacity. The network meta-analysis demonstrated that Blood flow restriction training (BFRT), Cycle exercise (CE), Inspiratory muscle training (IMT), Combined aerobic and resistance training (CT), and Aerobic training (AT) were significantly better than usual care for 6-min walkability; Medium intensity continuous training (MICT), CT, CE, and AT were considerably better than usual care for VO₂Peak; body and mind training (MBT) and CT significantly improved SBP compared to usual care; and only MBT was significantly better than usual care for DBP. Both the two-dimensional plot and the radar plot demonstrated that CT had the best combined-effect on each index of cardiorespiratory fitness. Subgroup and sensitivity analyses demonstrated the robustness of the results. The evidence was mainly "low" to "very low" for this network meta-analysis.

Conclusion

There is no one exercise that can achieve the best effect on all of the outcomes. The benefits of MBT in decreasing arterial blood pressure are unsurpassed by other exercise methods. The intervention effect of the CT is better and more stable. Electrical muscle stimulation training (MEST) can be employed in individuals who do not wish to exercise actively but may cause an increase in blood pressure. On the basis of the characteristics of different exercise types, guidelines developers, clinicians, and patients may employ them appropriately.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails.

Profile of professionals working in intradialytic exercise programs in Brazil: a national survey

OBJECTIVE

This survey was designed to assess the profile of professionals working in intradialytic exercise programs (IEPs) in Brazil and reveal the motivators and barriers they face.

METHODS

The survey was sent to physiotherapists and exercise physiologists working in IEPs in Brazil. Phone interviews and electronic forms were used to collect the answers to the survey questionnaire.

RESULTS

Forty-one of the 261 included dialysis centers had IEPs; 44 professionals answered the questionnaire over the phone and 26 used the electronic form to do it. A total of 70 professionals (mean age 33.4±7.4 years; 84.3% physiotherapists) answered the questionnaire. Resistance training was the preferred mode of therapy. Most of the IEPs were connected to research and were paid for by private health insurance. The desire to work in a different field (30.0%) and lack of resources (31.4%) were the most prevalent motivator and barrier cited by IEP professionals working in dialysis centers, respectively.

CONCLUSION

The majority of the few professionals that work in IEPs in Brazil are physiotherapists. Lack of resources was the most commonly reported barrier faced by survey respondents.