Influence of physical activity on cardiorespiratory fitness in children after renal transplantation

Physical activity and its impact on cardiovascular health in pediatric kidney transplant recipients

BACKGROUND

Cardiovascular (CV) morbidity after kidney transplantation (KTx) in childhood is of increasing importance. In light of a high prevalence of CV risk factors, protective measures such as physical activity (PA) come into focus. Our aim was to comprehensively assess PA in pediatric KTx recipients and evaluate its impact on CV health.

METHODS

Forty-eight patients were assessed for frequency, duration, intensity, and setting of PA using the "Motorik-Modul" PA questionnaire. Walking-based activity was measured by accelerometer in a subgroup (n = 23). CV risk factors and subclinical CV organ damage were determined. The impact of PA on CV parameters was analyzed using linear regression models.

RESULTS

Fifty-two percent of pediatric KTx recipients did not reach WHO recommended PA level; 54% did not engage in PA with vigorous intensity (VPA). Twenty-nine percent indicated an extremely inactive lifestyle (< 120 min/week of moderate to vigorous intensity PA, MVPA). Compared to the healthy German KiGGS cohort, KTx recipients specifically lacked engagement in sport activities (KTx: 129 min/week; 95%CI, 97-162 vs. KiGGS, 242 min/week; 95%CI, 230-253). VPA was associated with lower systolic blood pressure (p = 0.024) and resting heart rate (p = 0.005), MVPA with fewer components of the post-transplant metabolic syndrome (p = 0.037), and better left ventricular diastolic function (p = 0.006).

CONCLUSIONS

A considerable lack of PA, especially VPA, exists in young KTx recipients. PA was positively associated with important parameters of CV health. While long-term CV protection through PA seems promising in pediatric KTx recipients, specific educational approaches are most likely needed to increase patients' engagement in sport activities.

Cardiovascular disease risk factors and lifestyle modification strategies after pediatric kidney transplantation: what are we dealing with, and what can we target?

Kidney transplantation in pediatric patients can lead to partial improvement of some of the cardiometabolic parameters that increase the risk for cardiovascular disease (CVD) in patients with chronic kidney disease. However, even after restoration of kidney function, transplant recipients remain at risk for CVD due to the continual presence of traditional and non-traditional risk factors, including the side effects of immunosuppression and chronic inflammation. This educational review describes the prevalence of CVD risk factors in pediatric kidney transplant recipients and presents available evidence for therapeutic lifestyle changes and other non-pharmacologic strategies that can be used to improve traditional and modifiable CVD risk factors. Although trial-grade evidence for interventions that improve CVD in pediatric kidney transplant recipients is limited, potential strategies include lowering dietary sodium and saturated fat intake and increasing physical activity levels. Intensive follow-up may help patients achieve guideline-recommended goals for reducing their overall CVD risk.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

Physical activity and the 'pediatric inactivity triad' in children living with chronic kidney disease: a narrative review

The ‘paediatric inactivity triad’ (PIT) framework consists of three complex inter-related conditions that influence physical inactivity and related health risks. In those living with chronic kidney disease (CKD), a multi-factorial milieu of components likely confound the PIT elements, resulting in a cycle of decreased physical functioning and reduced physical activity. In this review, we explore and summarize previous research on each of the three principal PIT components (exercise deficit disorder, dynapenia, and physical illiteracy) in the pediatric CKD population. We found those living with CKD are significantly physically inactive compared to their peers. Physical inactivity occurs early in the disease process and progressively gets worse as disease burden increases. Although physical activity appears to increase post-transplantation, it remains lower compared to healthy controls. There is limited evidence on interventions to increase physical activity behaviour in this population, and those that have attempted have had negligible effects. Studies reported profound reductions in muscle strength, physical performance, and cardiorespiratory fitness. A small number of exercise-based interventions have shown favourable improvements in physical function and cardiorespiratory fitness, although small sample sizes and methodological issues preclude the generalization of findings. Physical activity must be adapted and individualized to the needs and goals of the children, particularly those with acute and chronic medical needs as is the case in CKD, and further work is needed to define optimal interventions across the life course in this population if we aim to prevent physical activity declining further.

Longitudinal Follow-Up on Cardiopulmonary Exercise Capacity Related to Cardio-Metabolic Risk Factors in Children With Renal Transplants

Background: Children with chronic kidney disease, including those treated with kidney transplantation (KT), have an increased risk of cardiovascular disease. The aim of this study was to examine the cardiopulmonary exercise capacity after KT compared to matched controls, to relate the results to physical activity, blood pressure and biochemical findings and to follow exercise capacity over time.

Methods: Patients with KT (n = 38, age 7.7–18 years), with a mean time from transplantation of 3.7 years (0.9–13.0) and mean time in dialysis 0.8 years, were examined at inclusion and annually for up to three years. Healthy controls (n = 17, age 7.3–18.6 years) were examined once. All subjects underwent a cardiopulmonary exercise test, resting blood pressure measurement, anthropometry and activity assessment. Patients also underwent echocardiography, dual-energy X-ray absorptiometry (DXA), 24-h ambulatory BP measurements (ABPM), assessment of glomerular filtration rate (GFR) and blood sampling annually.

Results: As compared to healthy controls, KT patients showed decreased exercise capacity measured both as VO_2peak (34.5 vs. 43.9 ml/kg/min, p < 0.001) and maximal load (2.6 vs. 3.5 W/kg, p < 0.0001), similarly as when results were converted to z-scores. No significant difference was found in weight, but the KT patients were shorter and had higher BMI z-score than controls, as well as increased resting SBP and DBP z-scores. The patient or parent reported physical activity was significantly lower in the KT group compared to controls (p < 0.001) In the combined group, the major determinants for exercise capacity z-scores were activity score and BMI z-score (β = 0.79, p < 0.0001 and β = −0.38, p = 0.007, respectively). Within the KT group, low exercise capacity was associated with high fat mass index (FMI), low activity score, low GFR and high blood lipids. In the multivariate analysis FMI and low GFR remained predictors of low exercise capacity. The longitudinal data for the KT patients showed no change in exercise capacity z-scores over time.

Conclusion: Patients with KT showed decreased exercise capacity and increased BP as compared to healthy controls. Exercise capacity was associated to GFR, physical activity, FMI and blood lipids. It did not improve during follow-up.

School and sports participation post-transplant

Pediatric recipients of life-saving organ transplants are living longer, with improved graft and overall survivals. After successful transplant, children are encouraged to return to "normal life," with school attendance and participation in age-appropriate physical activities. This transition may cause stress to the recipients, parents, teachers, and other participating caregivers and staff. Planning for school reentry and assuring education for and open lines of communication with the school staff can help alleviate some of this discomfort and ease the process for the patient and the family. Cardiovascular disease has emerged as the leading cause of death in survivors of pediatric transplantation and is contributed to by modifiable risk factors such as obesity, hypertension, and the MS. Physical activity is a proven tool in decreasing surrogate markers of this risk. Sports participation is an important way to promote an enjoyment of physical activity that can ideally persist into adulthood, but conflicting advice and opinions exist regarding type and participation in physical activity. Moreover, specific recommendations are likely not applicable to all recipients, as certain degrees of rehabilitation may be needed depending on degree and length of illness. In general, a program of rehabilitation and increased physical activity has been shown to be safe and effective for most pediatric transplant recipients. Focusing on optimizing the "normal" childhood activities of going to school and participating in sports can improve the physical, social, cognitive, and mental health outcomes of this population after transplant and should be prioritized.

Physical activity in elderly kidney transplant patients with multiple renal arteries

INTRODUCTION

Kidney transplantation (KT) is the gold standard for treatment of patients with end- stage-renal disease. To expand the donor reserve, it is necessary to use marginal/suboptimal kidneys.

METHODS

We retrospectively evaluated the short/long-term outcome of 34 KT elderly patients who received allografts with vascular abnormalities (MRA group), in comparison with 34 KT patients who received a kidney with a single renal artery (SRA group) pair-matched by age, length of time on dialysis, comorbidity and donor age.

RESULTS

All participants completed the International Physical Activity Questionnaire at KT, and then 4, 8, and 12 weeks after transplantation. Our data indicate that kidney with vascular anatomical variants may be successfully transplanted, since the overall rate of surgical complications was 20.6% in the SRA group and 17.6% in the MRA group and that the 5-year survival rate after KT was 100% in both groups.

CONCLUSIONS

The data also underline that individualized physical activity programs induced similar excellent results in both groups, improving physical capacities, arterial pressure, lipid metabolism, insulin sensitivity, quality of life and physical and mental status.

Physical fitness and health-related quality of life in pediatric renal transplant recipients: An interventional trial with active video gaming

BACKGROUND

Pediatric renal transplant recipients are at increased risk for cardiovascular diseases, one contributing factor is reduced cardiorespiratory fitness. The purpose was to evaluate cardiorespiratory fitness, motor coordination, muscle strength, daily physical activity, and health-related quality of life and to find out, if active video gaming is effective for improving these items in this patient population.

METHODS

Twenty renal transplant recipients (13.5 ± 3.4 years) and 33 matched healthy controls (13.1 ± 3.2 years) performed a spiroergometry, a motor coordination test, and a maximal handgrip strength test. Quality of life was determined with a validated questionnaire, and daily physical activity was recorded with a physical activity monitor. Thirteen patients (12.9 ± 3.4 years) participated in a 6-week home-based exergaming intervention (3×/week for 30 minutes) and repeated all tests after that.

RESULTS

The renal transplant recipients exhibited a substantial impairment compared with the controls in peak oxygen consumption (-31%, P < .001), motor competence (-44%, P < .001), daily physical activity (-33%, P = .001), and quality of life (-12%, P = .017). Handgrip strength was similar in both groups. Despite of low compliance in the intervention group, steps per hour were significantly increased after 6 weeks of exergaming (+31%, P = .043); however, all other measures remained unchanged.

CONCLUSION

Cardiorespiratory fitness, motor competence, and quality of life are reduced in pediatric renal transplant recipients. Home-based exergaming is not appropriate to improve these items, probably due to a substantially impaired motor competence. However, it provided a stimulus for an increased daily physical activity.

Small effort, high impact: Focus on physical activity improves oxygen uptake (VO2peak ), quality of life, and mental health after pediatric renal transplantation

This study estimates the effects on peak oxygen uptake (VO2 peak ), QoL, and mental health after the introduction of an adjusted post-transplant follow-up program, that is, early physiotherapy and focus on the importance of physical activity. VO2 peak was measured by a treadmill exercise test in 20 renal-transplanted children on the adjusted post-transplant follow-up and compared with a group of 22 patients investigated in a previously, before the implementation of our new follow-up routines. PedsQL and The Strengths and Difficulties Questionnaire (SDQ) were used to assess QoL and mental health in 45 patients on the new as compared to 32 patients on the previous follow-up strategy. The patients exposed to early physiotherapy and a higher focus on physical activity had significantly higher VO2 peak (44.3 vs 33.5 mL kg-1  min-1 , P = .031) in addition to improved QoL (P = .003) and mental health scores (P = .012). The cardiovascular risk profile was similar in both groups aside from significantly higher triglycerides in the present cohort. Small efforts as early physiotherapy and increased focus on physical activity after pediatric renal transplantation have significant impact on cardiorespiratory fitness, QoL, and mental health. The importance of physical activity should therefore be emphasized in follow-up programs.

Evolution of blood pressure in children with congenital and acquired solitary functioning kidney

Background

It is not yet clear if blood pressure and renal function changes evolve differently in children with a congenital or acquired solitary functioning kidney. This study aims to assess if there are any differences between these two types of solitary kidney patients.

Methods

Current research is a retrospective study assessing the evolution of glomerular filtration rate, proteinuria, and blood pressure in clinical records of 55 children with a solitary functioning kidney (37 congenital and 18 acquired). We used the medical records of children who had been assisted, in our unit of pediatric nephrology, for a period of 14 years (168 months), from the time of diagnosis, between January/1997 and December/2015.

Results

During the study period, glomerular filtration rate (T0 128.89 ± 32.24 vs T14 118.51 ± 34.45 ml/min/1.73 m², p NS) and proteinuria (T0 85.14 ± 83.13 vs T14 159.03 ± 234.66 mg/m²/die, p NS) demonstrated no significant change. However, after 14 years of follow-up 76.4% of patients had increased levels of arterial hypertension with values over the 90th percentile for gender, age, and height. Specifically, children with an acquired solitary functioning kidney mainly developed hypertension [T0 2/17 (12%) vs T14 9/17 (52.9%) p < 0.025], whereas children with a congenital solitary functioning kidney mainly developed pre-hypertension [T0 3/38 (7.9%) vs T14 17/38 (44.7%) p < 0.0005].

Conclusions

The renal function of children with solitary functioning kidneys remains stable during a follow-up of 14 years. However, these children should be carefully monitored for their tendency to develop arterial blood pressure greater than the 90th percentile for gender, age, and height.

Physical Activity and Kidney Injury in Pediatric and Young Adult Kidney Transplant Recipients

OBJECTIVES

To quantify physical activity and grip strength in pediatric kidney transplant recipients and describe attitudes about exercise and exercise counseling given concerns about allograft injury.

STUDY DESIGN

This was a cross-sectional analysis of 101 kidney transplant recipients (7-21 years old) >6 months post-transplant. Patients completed the Physical Activity Questionnaire (PAQ). Grip strength was measured with a dynamometer. We asked about activity limitations and provider counseling. Univariate analysis and multiple linear regression were used to determine independent predictors of PAQ score and grip strength z score.

RESULTS

We enrolled 101 of 122 eligible patients. Median PAQ score was 2.2 (range 0-5) and was lower compared with controls (P < .001). The average grip strength z score was -1.1 and -0.7 in the right and left hand, respectively. Predictors of lower grip strength were younger age (P = .036), non-African American race (P = .029), lower height z score (P = .010), and longer percentage of lifetime with kidney disease (P = .029). Although 49% and 67% limited exercise before and after transplant, respectively, 67% reported increased activity after transplant. By parent report, provider counseling included limiting certain activities (71%) and encouraging regular exercise (45%).

CONCLUSION

Physical activity and grip strength are low after kidney transplant. Patients perceive an emphasis on exercise limitations rather than the benefits of regular exercise. Interventions that encourage physical activity may be beneficial.

Cardiorespiratory fitness: a comparison between children with renal transplantation and children with congenital solitary functioning kidney

Children with end-stage renal disease are known to have a cardiorespiratory fitness significantly reduced. This is considered to be an independent index predictive of mortality mainly due to cardiovascular accidents. The effects of renal transplantation on cardiorespiratory fitness are incompletely known. We compared the maximal oxygen uptake (VO2 max) of children with a functioning renal transplant with that of children with congenital solitary functioning kidney, taking into consideration also the amount of weekly sport activity.

Cardiorespiratory fitness and sports activities in children and adolescents with solitary functioning kidney

BACKGROUND

An increasing number of children with chronic disease require a complete medical examination to be able to practice physical activity. Particularly children with solitary functioning kidney (SFK) need an accurate functional evaluation to perform sports activities safely. The aim of our study was to evaluate the influence of regular physical activity on the cardiorespiratory function of children with solitary functioning kidney.

METHOD

Twenty-nine patients with congenital SFK, mean age 13.9 ± 5.0 years, and 36 controls (C), mean age 13.8 ± 3.7 years, underwent a cardiorespiratory assessment with spirometry and maximal cardiopulmonary exercise testing. All subjects were divided in two groups: sedentary (S) and trained (T) patients, by means of a standardized questionnaire about their weekly physical activity.

RESULTS

We found that mean values of maximal oxygen consumption (VO2max) and exercise time (ET) were higher in T subjects than in S subjects. Particularly SFK-T presented mean values of VO2max similar to C-T and significantly higher than C-S (SFK-T: 44.7 ± 6.3 vs C-S: 37.8 ± 3.7 ml/min/kg; p < 0.0008). We also found significantly higher mean values of ET (minutes) in minutes in SFK-T than C-S subjects (SFK-T: 12.9 ± 1.6 vs C-S: 10.8 ± 2.5 min; p <0.02).

CONCLUSION

Our study showed that regular moderate/high level of physical activity improve aerobic capacity (VO2max) and exercise tolerance in congenital SFK patients without increasing the risks for cardiovascular accidents and accordingly sports activities should be strongly encouraged in SFK patients to maximize health benefits.

Physical activity and renal transplantation

Renal transplantation is burdened by high cardiovascular risk because of increased prevalence of traditional and disease-specific cardiovascular risk factors and, consequently, patients are affected by greater morbidity and mortality. In renal transplanted patients, healthy lifestyle and physical activity are recommended to improve overall morbidity and cardiovascular outcomes. According to METs (Metabolic Equivalent Task; i.e. the amount of energy consumed while sitting at rest), physical activities are classified as sedentary (<3.0 METs), of moderate-(3.0 to 5.9 METs) or vigorous-intensity (≥ 6.0 METs). Guidelines suggest for patients with chronic kidney disease an amount of physical activity of at least 30 minutes of moderate-intensity activity five times per week (min 450 MET-minutes/week). Data on physical activity in renal transplanted patients, however, are limited and have been mainly obtained by mean of non-objective methods. Available data suggest that physical activity is low either at the start or during renal transplantation and this may be associated with poor patient and graft outcomes. Therefore, in renal transplanted patients more data on physical activity obtained with objective, accelerometer-based methods are needed. In the meanwhile, physical activity have to be considered as an essential part of the medical care for renal transplanted recipients.

Exercise test in pediatric renal transplant recipients and its relationship with their cardiac function

Pediatric kidney transplant recipients are at increased risk of CVD. Exercise test is a good method to evaluate exercise capacity, cardiorespiratory fitness, and risk of potential CVDs. The aim of this study was to assess the exercise capacity in this population and determine its relationship with their cardiac function using conventional and tissue Doppler echocardiography. Exercise test, conventional and tissue Doppler echocardiography were performed on 44 kidney transplant children (age ranging 11-20, 59% male) with acceptable renal function, and the results were compared with their normal healthy counterparts. Our transplant patients achieved significantly lower maximal heart rate, maximal heart rate ratio, total energy expenditure during the exercise, and maximal O2 consumption (Max VO2 ) than the normal group (p < 0.05). No correlation was found between hemoglobin (Hb) level, dialysis duration, kidney function, and the exercise test parameters. Kidney transplant patients had preserved systolic despite diminished diastolic cardiac function compared to the normal children. Our pediatric renal transplant recipients had severely impaired diastolic dysfunction and significantly reduced MaxVO2 compared with their healthy counterparts. No correlation was found between MaxVO2 and measured indices of systolic and diastolic cardiac function.

Metabolic syndrome in children with chronic kidney disease and after renal transplantation

Visceral obesity and metabolic abnormalities typical for metabolic syndrome (MS) are the new epidemic in adolescence. MS is not only the risk factor for cardiovascular disease but also for chronic kidney disease (CKD). Thus, there are some reasons to recognize MS as a new challenge for pediatric nephrologists. First, hypertensive and diabetic nephropathy, the main causes of CKD in adults, both share the same pathophysiological abnormalities associated with visceral obesity and insulin resistance and have their origins in childhood. Secondly, as the obesity epidemic also affects children with CKD, MS emerges as the risk factor for progression of CKD. Thirdly, metabolic abnormalities typical for MS may pose additional risk for cardiovascular morbidity and mortality in children with CKD. Finally, although the renal transplantation reverses uremic abnormalities it is associated with an exposure to new metabolic risk factors typical for MS and MS has been found to be the risk factor for graft loss and cardiovascular morbidity after renal transplantation. MS is the result of imbalance between dietary energy intake and expenditure inducing disproportionate fat accumulation. Thus, the best prevention and treatment of MS is physical activity and maintenance of proper relationship between lean and fat mass.