Accelerometry-based physical activity and exercise capacity in pediatric kidney transplant patients

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.

Let's get physical: Aerobic capacity, muscle strength, and muscle endurance after pediatric heart transplantation

BACKGROUND

Pediatric heart (HTx) and kidney transplant (KTx) recipients may have lower physical fitness than healthy children. This study sought to quantify fitness levels in transplant recipients, investigate associations to clinical factors and quality of life, and identify whether a quick, simple wall-sit test is feasible as a surrogate for overall fitness for longitudinal assessment.

METHODS

Aerobic capacity (6-min walk test, 6MWT), normalized muscle strength, muscle endurance, physical activity questionnaire (PAQ), and quality of life (PedsQL™) were prospectively assessed in transplanted children and matched healthy controls.

RESULTS

Twenty-two HTx were compared to 20 controls and 6 KTx. 6MWT %predicted was shorter in HTx (87.2 [69.9-118.6] %) than controls (99.9 [80.4-120] %), but similar to KTx (90.3 [78.6-115] %). Muscle strength was lower in HTx deltoids (6.15 [4.35-11.3] kg/m2) and KTx quadriceps (9.27 [8.65-19.1] kg/m2) versus controls. Similarly, muscle endurance was lower in HTx push-ups (28.6 [0-250] %predicted), KTx push-ups (8.35 [0-150] %predicted), HTx curl-ups (115 [0-450] %predicted), and KTx wall-sit time (18.5 [10.0-54.0] s) than controls. In contrast to HTx with only 9%, all KTx were receiving steroid therapy. The wall-sit test significantly correlated with other fitness parameters (normalized quadriceps strength R = .31, #push-ups R = .39, and #curl-ups R = .43) and PedsQL™ (R = .36).

CONCLUSIONS

Compared to controls, pediatric HTx and KTx have similarly lower aerobic capacity, but different deficits in muscle strength, likely related to steroid therapy in KTx. The convenient wall-sit test correlates with fitness and reported quality of life, and thus could be a useful easy routine for longitudinal assessment.

Reduced peripheral and respiratory muscle strength in pediatric patients after kidney transplantation

INTRODUCTION

Reduced muscle strength and low-exercise capacity are well documented in adults, but there are few studies examining those impairments in children and adolescents after kidney transplantation. The objective of this study was to evaluate peripheral and respiratory muscle strength and the association with submaximal exercise capacity in children and adolescents after kidney transplant.

METHODS

Forty-seven patients between six and 18 years of age clinically stable after transplantation were included. Peripheral muscle strength (isokinetic and hand-grip dynamometry), respiratory muscle strength (maximal inspiratory and expiratory pressure), and submaximal exercise capacity (six-minute walk test - 6MWT) were assessed.

RESULTS

Patients had a mean age of 13.1 ± 2.7 years and an average of 34 months had elapsed since the transplantation. Flexors of the knee showed a significant reduction in muscle strength (77.3% of predicted) and knee extensors had normal values (105.4% of predicted). Hand-grip strength and maximal respiratory pressures (inspiratory and expiratory) also were significantly lower than expected (p < 0.001). Although distance walked in the 6MWT was significantly lower than predicted (p < 0.001), no significant correlation was found with peripheral and respiratory muscle strength.

CONCLUSION

Children and adolescents after kidney transplantation have reduced peripheral muscle strength of knee flexors, hand-grip, and maximal respiratory pressures. No associations were found between peripheral and respiratory muscle strength and submaximal exercise capacity.

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.

Physical performance after pediatric solid organ transplantation

INTRODUCTION

Low physical activity is a well-recognized problem in pediatric solid organ transplant recipients; however, little is known about the differences between transplant groups. Physical performance testing was performed in a cohort of pediatric kidney, liver, and heart transplant recipients.

METHODS

Fifty-one patients (54.9% boys), including 17 liver, 20 kidney, 2 combined liver-kidney, and 12 heart transplant recipients, were tested at the median age of 11.5 (7.5-14.9) years. The results were compared with a control group, which consisted of 425 healthy schoolchildren. The physical performance test included six different tests of endurance, strength, flexibility, and speed.

RESULTS

The transplant recipients performed worse on most tests when compared with the control subjects (leg-lift test 42.0 vs. 44.9 repetitions, p = .002; repeated squatting 21.6 vs. 23.9 repetitions, p < .001; sit-up test 9 vs. 17 vs. 9 repetitions, p < .001, back extension 20 vs. 35 repetitions, p < .001; and shuttle run test 26.5 vs. 23.7 seconds, p < .001). None of the test results differed statistically significantly between the transplant groups.

CONCLUSION

The physical performance of pediatric solid organ transplant recipients is lower than that of their healthy peers but do not differ between different transplant groups. More systematic rehabilitation programs and follow-up are needed.

Organ Transplant Recipients' Experiences of Physical Activity: Health, Self-Care, and Transliminality

Physical activity (PA) is an important lifestyle component of long-term health management for organ transplant recipients, yet little is known about recipients' experiences of PA. The purpose of this study was to shed light on this experience and to investigate the possible implications of PA in the context of what is a complex patient journey. Phenomenological analysis was used to examine interviews with 13 organ transplant recipients who had taken part in sporting opportunities posttransplantation. Findings illuminate how participants' experiences of PA were commonly shaped by the transliminal nature of being an organ transplant recipient as well as a sense of duty to enact health, self-care, and donor-directed gratitude. This analysis underlines the potential role of PA in supporting organ transplant recipients' attempts to live well following transplantation and makes novel connections between PA and our existing knowledge about challenges related to identity, survivorship, obligation, and patient empowerment.

Physical activity and its correlates in a pediatric solid-organ transplant population

PA has been shown to have benefits in SOT patients. Studies assessing physical activity levels and its correlates in a pediatric solid-organ transplant population are limited. The aim of this study was to assess PA levels and identify baseline and contemporaneous factors that contribute to PA in a pediatric SOT population. A retrospective cross-sectional review was performed on 58 pediatric transplant patients (16 heart, 29 kidney, and 13 liver transplant). PA was measured by PAQ-C or PAQ-A. Demographics, baseline, and contemporaneous factors were collected. There were no significant differences in baseline and contemporaneous characteristics between heart, kidney, and liver transplant recipients. SOT recipients were 15.2 [12.3-17.3] years old at time of completing the PAQ. Median PAQ score was 2.2 [1.7-2.9]. There were no significant differences in PAQ scores between organ transplant type or between genders. Lower PAQ score was associated with sensory disability (9 vs 49 without disability; P = <.01) and age at time of completing the PAQ (r = -.50, P = <.01). These results suggest that older age at time of completing the PAQ and presence of sensory disability may influence PA levels in the pediatric SOT population.

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.

Physical activity and its correlates in children and adolescents post-liver transplant

The health benefits of PA are well established for healthy and chronically ill children. This study objectively measures physical fitness and PA levels in children PLT and explores potential correlates and perceived barriers impacting their PA. A total of 23 children (16 females, mean 14.01 ± 2.49 yrs) >1 yr PLT were assessed for peak oxygen consumption (VO2 peak), muscle strength, endurance, and flexibility. MVPA and steps/day were determined with accelerometry. Additionally, SE, perceived fatigue, and barriers and benefits of PA were examined. VO2 peak (mean 33. 2 ± 7.61 mL/kg/min; 77.0 ± 15.6% predicted) and PA (average 6841 ± 2299 steps/day) were below healthy norms. MVPA (31.6 ± 16.1 min/day) was lower than national guidelines. Six participants (30%) attained criterion standards for abdominal strength and one participant (5%) for push-ups. Fatigue and SE were lower than reported levels in healthy children. A commonly perceived barrier to PA was "I am tired." A positive correlation was shown between SE and MVPA (r = 0.57, p = 0.007), SE and fatigue (r = 0.54, p = 0.01), and PELD score and fatigue (r = 0.66, p = 0.007). Children PLT demonstrate below normal levels of PA and aerobic capacity. SE is a modifiable correlate of their PA. Further investigation of the impact of PA correlates can guide the development of future innovative PA intervention strategies in children PLT.

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.