Long-Term Effect of Physical Exercise on the Risk for Hospitalization and Death in Dialysis Patients: A Post-Trial Long-Term Observational Study

Association of Physiological Reserve Obtained from Cardiopulmonary Exercise Testing and Frailty with All-Cause Mortality in Patients on Hemodialysis

Key Points

This study analyzed the prognostic value of reserves obtained from cardiopulmonary exercise testing in patients on hemodialysis. Each reserve (cardiac, autonomic, and muscular) was associated with mortality, with muscle reserve having the highest prognostic accuracy. Patients with physical frailty also had a fairly good prognosis if their physiological reserve is preserved by exercise testing.

Background

Potential impairment of exercise capacity is prevalent even in patients undergoing hemodialysis without frailty. Cardiopulmonary exercise testing (CPET) can detect physiological reserves, such as cardiopulmonary, muscle, and autonomic function. We hypothesized that these indices could accurately determine the prognosis of patients on hemodialysis and analyzed them on the basis of their relationship to frailty.

Methods

In this two-center prospective cohort study of patients on hemodialysis from Japan, patients underwent CPET and physical assessment to evaluate peak oxygen uptake (peak VO2, indicator of exercise capacity), peak work rate (WR, indicator of muscle function), ventilatory equivalent for carbon dioxide (VE/VCO2) slope (indicator of cardiac reserve), heart rate reserve (indicator of chronotropic incompetence), and frailty phenotype. Survival was followed up for up to 5 years.

Results

Data from 189 patients (median [interquartile range] age: 71 [62–77] years) were analyzed. All CPET indicators showed a consistent nonlinear relationship with all-cause mortality after adjustment: for peak VO2, hazard ratio (HR), 0.79 (95% confidence interval [CI], 0.71 to 0.88), P < 0.001; for peak WR, HR, 0.95 (95% CI, 0.93 to 0.97), P < 0.001; for VE/VCO2 slope, HR, 1.09 (95% CI, 1.05 to 1.13), P < 0.001; and for heart rate reserve, HR, 0.96 (95% CI, 0.93 to 0.99), P = 0.02. Frailty phenotype was associated with mortality after adjustment (HR, 1.73 [95% CI, 1.06 to 2.81], P = 0.03); however, this association was not statistically significant in the model after adding peak VO2 (P = 0.41). Furthermore, in both subgroups with and without frailty, CPET measures were significantly associated with mortality risk (peak VO2, peak WR, and VE/VCO2 slope: P < 0.05). The peak VO2 (Δ area under the curve, 0.09; 95% CI, 0.02 to 0.16) or the peak WR (Δ area under the curve, 0.09; 95% CI, 0.02 to 0.15) most significantly improved the prognostic accuracy.

Conclusions

Results showed the fragile aspect of the frailty phenotype in the hemodialysis population and the superior ability of CPET to indicate death risk complementing that aspect.

The role of exercise training on cardiovascular risk factors and heart disease in patients with chronic kidney disease G3-G5 and G5D: a Clinical Consensus Statement of the European Association of Preventive Cardiology of the ESC and the European Association of Rehabilitation in Chronic Kidney Disease

Cardiovascular (CV) morbidity and mortality is high in patients with chronic kidney disease (CKD). Most patients reveal a high prevalence of CV risk factors such as diabetes or arterial hypertension and many have manifest cardiovascular disease (CVD), such as coronary artery disease and chronic heart failure with an increased risk of clinical events including sudden cardiac death. Diabetes mellitus and hypertension contribute to the development of CKD and the prevalence of CKD is in the range of 20-65% in diabetic and 30-50% in hypertensive patients. Therefore, prevention and optimal treatment of CV risk factors and comorbidities are key strategies to reduce CV risk and improve survival in CKD. Beyond common CV risk factors, patients with CKD are often physically inactive and have low physical function leading to subsequent frailty with muscle fatigue and weakness, sarcopenia and increased risk of falling. Consequently, the economic health burden of CKD is high, requiring feasible strategies to counteract this vicious cycle. Regular physical activity and exercise training (ET) have been shown to be effective in improving risk factors, reducing CVD and reducing frailty and falls. Nonetheless, combining ET and a healthy lifestyle with pharmacological treatment is not frequently applied in clinical practice. For that reason, this Clinical Consensus Statement reviews the current literature and provides evidence-based data regarding the role of ET in reducing CV and overall burden in patients with CKD. The aim is to increase awareness among cardiologists, nephrologists, and healthcare professionals of the potential of exercise therapy in order to encourage implementation of ET in clinical practice, eventually reducing CV risk and disease, as well as reducing frailty in patients with CKD G3-G5D.

Exercise, Dialysis, and Environment: A Narrative Review in an Ecological Perspective

BACKGROUND

Patient empowerment and environmental sustainability may contribute to creating efficient and resilient healthcare models. Chronic kidney diseases call for a sustainable approach aimed at improving physical function and mental health of patients and possibly contributing to the slowing down of the evolution toward the end stage of renal disease (ESRD) with a reduction of the environmental and economic impact.

SUMMARY

Multidisciplinary interventions should be implemented particularly, at the final stages when patients are exposed to sedentariness, reduced health-related quality of life (HR-QoL), high cardiovascular morbidity and mortality, and the healthcare services to high costs, and participation in environmental pollution. Ecological strategies based on specific nutritional approaches, exercise, and environment should be designed and tested. In particular, the introduction to physical exercise represents a useful replacement therapy to counteract the hazards derived from the sedentary behavior of ESRD patients, with low physical function associated with poor clinical outcomes. A more active and healthy lifestyle, particularly in the natural environment, could impact HR-QoL, mental and physical well-being but also on socialization, with lower anxiety and fatigue stress levels. Otherwise, combining sustainable exercise models into the patient's daily routine can be enhanced by the biophilic design called to reproduce a natural environment in the dialysis center. Finally, the involvement of the personnel and the health professionals in properly managing the exercise interventions and the related factors (location, modality, dose, intensity, and duration) might improve the patients' participation. In particular, ecological programs should be broadly inclusive and aimed to target the lowest performing populations through minimal feasible doses of exercise.

KEY MESSAGES

Moving toward an ecological framework of lifestyle change in the very advanced stages of kidney disease, the potential synergies between environment, diet, and exercise may improve the physical and mental health of the patients and reduce the impact of dialysis.

Physical exercise in haemodialysis patients: which type of exercise is more convenient?

Randomized intra-haemodialysis and home-based exercise trials have demonstrated similar efficacy in improving physical performance, particularly in increasing walking distance. During dialysis sessions, patients can engage in structured, supervised activities such as cycling or resistance exercises, ensuring safety and immediate feedback from healthcare professionals. This structured nature can significantly enhance adherence, making exercise a regular part of the patient's treatment schedule. Home-based exercise offers flexibility and convenience. Patients can incorporate activities like walking, stretching or using resistance bands into their daily lives. This flexibility allows patients to exercise at their own pace and according to their preferences, fostering independence and self-management. By continuing physical activity at home, patients can maintain continuity in their exercise regimen, which is crucial for long-term health benefits. Combining both intra-haemodialysis and home-based exercises has the potential to improve overall adherence to exercise programs. Strategies such as patient education, customized plans, monitoring and feedback, and support systems can help combine these two exercise types. By integrating these two modalities, healthcare providers can create a comprehensive and balanced exercise regimen that enhances adherence, promotes independence and maximizes health benefits for dialysis patients, fostering long-term health and well-being through sustained physical activity. However, this dual approach, which caters to both the need for medical supervision and the desire for personal autonomy, has yet to be tested in randomized trials.

A Current State of the Art and Science of Exercise in Dialysis: A Narrative Review

Purpose of the review

The purpose of the review is to discuss current proven benefits and problems of integrating exercise in the care of people receiving dialysis by reviewing literature from the last few years and identifying important questions that still need to be asked and answered.

Methods

A focused review and appraisal of the literature were done. Original peer-reviewed articles, review articles, opinion pieces and guidelines were identified from PubMed and Google Scholar databases. Only sources in English were accessed. Search terms "exercise" and "dialysis" were used to find active recruiting randomized trials in various clinical trial registry platforms.

Key findings

Numerous studies have demonstrated the benefits of exercise training in individuals receiving dialysis, limited by factors such as short duration of follow-up and inconsistent adverse event reporting and outcomes selected. Notable gaps in exercise research in dialysis include ways to maintain programs and patient motivation, studies in peritoneal dialysis and home hemodialysis patients, and how best to define and measure outcomes of interest.

Implications

This review summarizes the current state of exercise in people receiving dialysis and serves as a call to action to conduct large, randomized controlled trials to improve the quality of evidence needed to implement and sustain innovative, exercise interventions, and programs for this population.

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.

The long-term benefits of early intensive therapy in chronic diseases-the legacy effect

The 'legacy effect' refers to the long-term benefits of intensive therapy that are observed long after the end of clinical trials and trial interventions in chronic diseases such as diabetes, hyperlipidaemia and hypertension. It emphasizes the importance of intensive treatment to prevent long-term complications and mortality. In chronic kidney disease (CKD), the legacy effect is evident in various studies. Long-term nephroprotection in diabetes is well documented in major studies in the early stages of diabetes, such as Diabetes Control and Complications Trial-Epidemiology of Diabetes Interventions and Complications (DCCT-EDIC), UK Prospective Diabetes Study (UKPDS) and Intensified Multifactorial Intervention in Patients with Type 2 Diabetes and Microalbuminuria (STENO-2). These studies highlight the importance of intensive glycaemic control in reducing microvascular complications, including nephropathy, in patients with recently diagnosed type 1 and type 2 diabetes. However, the legacy effect is less evident in patients with long-term, established diabetes. In chronic glomerulonephritis, studies on immunoglobulin A nephropathy showed that early immunosuppressive treatment could have long-term beneficial effects on kidney function in children and adults with CKD. The Frequent Hemodialysis (FH) and the EXerCise Introduction To Enhance Performance in Dialysis (EXCITE) trials indicated that frequent haemodialysis and a personalized walking exercise program could improve clinical outcomes and reduce the long-term risk of death and hospitalization. The legacy effect concept underscores the importance of intensive intervention in chronic diseases, including CKD. This concept has significant implications for public health and warrants in-depth basic and clinical research to be better understood and exploited in clinical practice. However, its limitations should be considered when interpreting long-term observational data collected after a clinical trial. Appropriate study designs are necessary to investigate an unbiased legacy effect.

Home-based exercise in patients on maintenance dialysis: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

The impact of home-based exercise on physical performance and quality of life (QoL) in patients on maintenance dialysis has not yet been fully established.

METHODS

We searched four large electronic databases to identify randomized controlled trials (RCTs) reporting the impact of home-based exercise interventions vs. usual care or intradialytic exercise interventions, on physical performance and QoL in patients on dialysis. The meta-analysis was performed using fixed effects modeling.

RESULTS

We included 12 unique RCTs involving 791 patients of various ages on maintenance dialysis. Home-based exercise interventions were associated with an improvement of walking speed at the 6 Minutes Walking Test [6MWT; nine RCTs; pooled weighted mean differences (WMD): 33.7 m, 95% confidence interval (CI) 22.8-44.5; P < 0.001; I2 = 0%) and in aerobic capacity as assessed by the peak oxygen consumption (VO2 peak; 3 RCTs; pooled WMD: 2.04 ml/kg/min, 95% CI 0.25-3.83; P = 0.03; I2 = 0%). They were also associated with improved QoL, as assessed by the Short Form (36) Health (SF-36) score. Stratifying the RCTs by control groups, no significant difference was found between home-based exercise and intradialytic exercise interventions. Funnel plots did not reveal any significant publication bias.

CONCLUSIONS

Our systematic review and meta-analysis showed that home-based exercise interventions for 3-6 months were associated with significant improvements in physical performance in patients on maintenance dialysis. However, further RCTs with a longer follow-up should be conducted to assess the safety, adherence, feasibility, and effects on QoL of home-based exercise programs in dialysis patients.

Cardiovascular complications in chronic kidney disease: a review from the European Renal and Cardiovascular Medicine Working Group of the European Renal Association

Chronic kidney disease (CKD) is classified into five stages with kidney failure being the most severe stage (stage G5). CKD conveys a high risk for coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. Cardiovascular complications are the most common causes of death in patients with kidney failure (stage G5) who are maintained on regular dialysis treatment. Because of the high death rate attributable to cardiovascular (CV) disease, most patients with progressive CKD die before reaching kidney failure. Classical risk factors implicated in CV disease are involved in the early stages of CKD. In intermediate and late stages, non-traditional risk factors, including iso-osmotic and non-osmotic sodium retention, volume expansion, anaemia, inflammation, malnutrition, sympathetic overactivity, mineral bone disorders, accumulation of a class of endogenous compounds called 'uremic toxins', and a variety of hormonal disorders are the main factors that accelerate the progression of CV disease in these patients. Arterial disease in CKD patients is characterized by an almost unique propensity to calcification and vascular stiffness. Left ventricular hypertrophy, a major risk factor for heart failure, occurs early in CKD and reaches a prevalence of 70-80% in patients with kidney failure. Recent clinical trials have shown the potential benefits of hypoxia-inducible factor prolyl hydroxylase inhibitors, especially as an oral agent in CKD patients. Likewise, the value of proactively administered intravenous iron for safely treating anaemia in dialysis patients has been shown. Sodium/glucose cotransporter-2 inhibitors are now fully emerged as a class of drugs that substantially reduces the risk for CV complications in patients who are already being treated with adequate doses of inhibitors of the renin-angiotensin system. Concerted efforts are being made by major scientific societies to advance basic and clinical research on CV disease in patients with CKD, a research area that remains insufficiently explored.

Exercise during Hemodialysis in Patients with Chronic Kidney Failure

BACKGROUND: Patients with kidney failure undergoing hemodialysis experience physical deconditioning and multimorbidity. Exercise interventions may mitigate this outcome, but their clinical role is unclear. METHODS: This multicenter, cluster randomized controlled trial evaluated combined endurance and resistance exercise training during hemodialysis versus usual care in chronic kidney failure. It assessed physical functioning, quality of life, hospitalizations, and overall survival. The primary outcome was the change in the 60-second sit-to-stand test (STS60) between baseline and 12 months. RESULTS: A total of 1211 patients underwent randomization, 917 (65.9±14.4 years; 38.9% female) of whom were included in the full analysis (exercise intervention, n=446; usual care, n=471). At 12 months, the STS60 repetitions improved from 16.2±7.6 to 19.2±9.1 in the exercise group but declined from 16.2±7.1 to 14.7±7.9 in the usual care group (group difference, 3.85 repetitions; 95% confidence interval [CI], 2.22 to 5.48; P<0.0001). The timed up-and-go test (−1.1 seconds; 95% CI, −1.9 to −0.3) and the 6-minute walk test (37.5 m; 95% CI, 14.7 to 60.4) also differed in the exercise group versus usual care group. The physical summary score and vitality subscale of the quality of life questionnaire (i.e., the 36-item Short Form Health Survey) differed in the exercise group versus usual care group, but the other subscales did not change. Adverse events during dialysis sessions were similar in both groups. Median days spent in the hospital annually were 2 in the exercise group and 5 in the usual care group. Mortality and dialysis-specific adverse events were not affected. CONCLUSIONS: Twelve months of intradialytic exercise in patients with kidney failure significantly improved the STS60 compared with usual care. (Funded by the Innovation Fund, Federal Joint Committee; ClinicalTrials.gov number, NCT03885102.)

The effect of intradialytic exercise on dialysis patient survival: a randomized controlled trial

BACKGROUND

Patients with kidney failure have a high mortality rate. This study aimed to evaluate the effect of intradialytic exercise on survival in patients receiving hemodialysis (HD).

METHODS

In this randomized controlled trial conducted in a HD center in Iran, adult patients receiving chronic HD were randomized to intradialytic exercise (60 min) in the second hour of thrice weekly dialysis for 6 months (intervention) or no intradialytic exercise (control). The primary outcome was survival rate at 12 months. Secondary outcomes were serum albumin, hemoglobin, hematocrit, red blood cell count, serum calcium, serum phosphorous, parathyroid hormone, physical function (6-min walk test) and nutritional status (Geriatric Nutritional Risk Index) during the first 6 months. The trial follow-up period was 12 months.

RESULTS

The study included 74 participants (44 males) with an age average of 64 ± 12 years old and a dialysis history of 27 ± 12 months, randomized to intervention (n = 37) or control (n = 37). Compared with controls, 1-year survival was higher in the intervention group (94% vs 73%, P = 0.01). The hazard ratio in univariate analysis in intervention group was 0.17 (95% CI 0.04-0.8; P = 0.02) compared to that in control group. During the 6-month intervention period, significant between-group changes were observed in all secondary outcomes between the intervention and control groups.

CONCLUSION

Intradialytic exercise performed for at least 60 min during thrice weekly dialysis sessions improves survival in adult patients receiving HD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04898608. Retrospectively registered on 24/05/2021. Registered trial name: The Effect of Intradialytic Exercise on Dialysis Patients Survival.

Home-Based Exercise in Elderly Patients with Claudication and Chronic Kidney Disease Is Associated with Lower Progressive Renal Function Worsening: A 5-Year Retrospective Study

This observational study aimed to monitor the 5-year trends of kidney function in patients with peripheral artery disease (PAD) and concomitant chronic kidney disease (CKD) enrolled or not enrolled into a rehabilitative exercise program. Sixty-six patients (aged 72 ± 10, males n = 52) at KDOQI stages III-IV and PAD at Rutherford's stage I-III were included in the study, with a group (Exercise, EX; n = 32) receiving a 6-month structured pain-free home-based walking program and a group (Control, CO; n = 34) receiving walking advice and optimal nephrological care. Outcomes included kidney function measured through serum creatinine (sCr) and clinical outcomes, including the rate of advance of CKD stages and admission to dialysis, revascularizations, and hospitalizations. At baseline, the two groups were comparable for age, nephropathy, medications, comorbidities, and PAD severity. Patients in the EX group safely completed the exercise program. SCr values were slightly increased in EX (baseline: 2.35 ± 0.32; 5-year: 2.71 ± 0.39 mg/dL) and progressively worsened in CO (baseline: 2.30 ± 0.31; 5-year 4.22 ± 0.42 mg/dL), with a significant between-group difference (p = 0.002). The control group also showed a higher number of dialysis admissions (5 vs. 0, p = 0.025) and advancing CKD stage as well a higher risks for lower limb revascularization (hazard ratio: 2.59; 95%CI: 1.11-6.02; p = 0.027) and for all-cause hospitalization (hazard ratio: 1.77; 95%CI: 1.05-2.97; p = 0.031). PAD-CKD patients enrolled in a low-moderate intensity home-exercise program showed more favorable long-term trends in kidney function and clinical outcomes than patients with usual care. These preliminary observations need to be confirmed in randomized trials.