Fitness testing of pediatric liver transplant recipients

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.

Motor development in children 0-2 years pre- and post-LTX, a prospective study

To determine prospectively gross and fine motor development of children <2 years of age, who undergo LTX. In this prospective study, children aged <2 years who undergo LTX were tested using the motor scale of the Bayley Scales of infant and toddler development, 3rd edition Dutch version. Testing was done during screening pre- and post-LTX: at the time of hospital discharge (2-6 weeks), at 3 months, 6 months, and 1 year. Z-scores were calculated. Twenty-nine children participated in this study, 14 boys, median age 6 months, at screening for LTX. Gross motor skills were delayed pre-LTX (Z-score -1.3). Fine motor skills were normal (Z-score 0.3). Immediately post-LTX, both skills reduced, and at 1 year post-LTX, gross motor skills Z-score was -1.0 and fine motor skills Z-score 0.0. Both gross and fine motor skills Z-scores decline post-LTX and tend to recover after 1 year, gross motor skills to low normal and fine motor skills to normal levels. Monitoring of gross motor development and attention on stimulating gross motor development post-LTX remains important, to enable participation in physical activity and sport for health benefits later in life.

Physical activity and aerobic fitness in children after liver transplantation

To determine physical activity (PA), aerobic fitness, muscle strength, health-related quality of life (HRQOL), fatigue, and participation in children after liver transplantation. Children, 6-12 years, at least one year after liver transplantation, participated in this cross-sectional study. Measurements: Time spent in moderate to vigorous PA (MVPA) was measured using an accelerometer, and aerobic fitness (VO_{2 peak} ) was measured by cardiopulmonary exercise testing. Muscle strength was measured by hand-held dynamometry. Fatigue was measured using the multidimensional fatigue scale, and HRQOL with the Pediatric Quality of life Core scales and leisure activities was measured using the Children's Assessment of Participation and Enjoyment. Outcomes (medians and interquartile range (IQR)) were compared to norm values. Twenty-six children participated in this study (14 boys, age 9.7 years, IQR 7.7;11.4). Children spent 0.8 hours/d (IQR 0.6;1.1) on MVPA. One child met the recommendation of at least 1 hour of MVPA every day of the week. Aerobic fitness was similar to norms (VO_{2 peak} 1.4 _L/min , IQR 1.1;1.7, Z-score -0.3). Z-scores of muscle strength ranged between -1.4 and -0.4 and HRQOL and fatigue between -2.3 and -0.4. Participation was similar to published norms (Z-scores between -0.6 and 0.6). Young children after liver transplantation have similar MVPA patterns and aerobic fitness compared to published norms. Despite lower HRQOL, more fatigue, and less muscle strength, these children have similar participation in daily activities. Although children do well, it remains important to stimulate PA in children after liver transplantation in the context of long-term management.

Diet and Exercise in Pediatric Liver Transplant Recipients: Behaviors and Association With Metabolic Syndrome

OBJECTIVE

The aim of the study is to analyze the impact of physical activity and eating behaviors on precursors of cardiovascular disease-including overweight/obesity, hypertension, low high-density lipoprotein, and impaired glucose tolerance-in pediatric liver transplant (LT) recipients and matched controls.

METHOD

Cross-sectional study of pediatric LT recipients 8 to 30 years, matched to controls from the National Health and Nutrition Examination Survey. Dietary intake assessed with 24-hour recall. Physical activity assessed by standardized questionnaires. LT recipients ≥12 years completed a confidential survey on alcohol consumption.

RESULTS

LT recipients (n = 90) were 0.9 to 24.7 years post-transplant. LT recipients and controls were equally likely to consume excess carbohydrates (32% vs 34%) and sugar, per age- and gender-specific recommended dietary intake guidelines. LT recipients spent more hours sedentary or on the computer daily and fewer days each week physically active for >60 minutes than controls. More overweight/obese LT recipients spent 3+ hours at the computer than non-overweight LT recipients (49% vs 27%; P = 0.02). Normal weight LT recipients spent more days doing vigorous activity each week (median 5 days, interquartile range 2-6) than did the overweight/obese LT recipients (median 3 days, interquartile range 2-4; P = 0.01). Among LT recipients, neither dietary intake nor physical activity were consistently associated with measures of hypertension, glucose intolerance, or dyslipidemia. Among LT adolescents and young adults (n = 38), 36% reported ever consuming alcohol; 38% of these reported significant alcohol consumption by frequency or quantity.

CONCLUSIONS

Additional counseling during routine post-LT care on the importance of physical activity and healthy diet may be useful. However, it is unlikely that these factors alone explain the increased prevalence of metabolic syndrome components in pediatric LT recipients.

Physical activity experiences in children post-liver transplant: Developing a foundation for rehabilitation interventions

Physical Activity (PA) plays an important role in the physical and psychosocial health of children and is beneficial in the treatment and prevention of comorbidities associated with transplantation. Despite this, PA participation in pediatric liver transplant recipients remains low compared to healthy peers. This qualitative-focused mixed-methods study explored the PA experiences and parental perception of these experiences, including perceived facilitators and barriers to PA in children post-liver transplant. Eighteen participants (9 children [median age 10.8 years] and 9 parents) took part in semi-structured interviews and completed the PedsQL Multidimensional Fatigue Scale and PAQ. Most children reported they were physically active (PAQ median 3.08 [IQR] 2.60-3.51), participating in PA for its enjoyment, regardless of their level of motor proficiency. Levels of fatigue (median 65.28 [IQR] 56.25-90.97) were higher than healthy norms and impacted PA participation in some children. Children and parents perceived PA as central to post-transplant recovery and valued its social and mental health benefits; however, parents struggled with ongoing uncertainty and perceived physical vulnerability of their child. This study indicates the need for continuing PA support and education and provides valuable information for family-centered interventions to increase PA and improve health outcomes in children post-transplant.

Impaired physical function following pediatric LT

The purpose of this article is to investigate the spectrum of physical function of pediatric liver transplantation (LT) recipients 12-24 months after LT. Review data were collected through the functional outcomes group, an ancillary study of the Studies of Pediatric Liver Transplantation registry. Patients were eligible if they had survived LT by 12-24 months. Children ≥ 8 years and parents completed the Pediatric Quality of Life Inventory™ 4.0 generic core scales, which includes 8 questions assessing physical function. Scores were compared to a matched healthy child population (n = 1658) and between survivors with optimal versus nonoptimal health. A total of 263 patients were included. Median age at transplant and survey was 4.8 years (interquartile range [IQR], 1.3-11.4 years) and 5.9 years (IQR, 2.6-13.1 years), respectively. The mean physical functioning score on child and parent reports were 81.2 ± 17.3 and 77.1 ± 23.7, respectively. Compared to a matched healthy population, transplant survivors and their parents reported lower physical function scores (P < 0.001); 32.9% of patients and 35.0% of parents reported a physical function score <75, which is > 1 standard deviation below the mean of a healthy population. Physical functioning scores were significantly higher in survivors with optimal health than those with nonoptimal health (P < 0.01). There was a significant relationship between emotional functioning and physical functioning scores for LT recipients (r = 0.69; P < 0.001). In multivariate analysis, primary disease, height z score < -1.64 at longterm follow-up (LTF) visit,  > 4 days of hospitalization since LTF visit, and not being listed as status 1 were predictors of poor physical function. In conclusion, pediatric LT recipients 1-2 years after LT and their parents report lower physical function than a healthy population. Findings suggest practitioners need to routinely assess physical function, and the development of rehabilitation programs may be important.

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.

The World Transplant Games: an incentive to improve physical fitness and habitual activity in pediatric solid organ transplant recipients

This prospective, interventional study examined the impact of training for the WTG on levels of health-related physical fitness and habitual activity in a cohort of pediatric SOT recipients. Physical fitness (FitnessGram(®) ) and habitual activity (HAES) measures were performed on participants (n = 19) in the WTG and compared to non-participant controls (n = 14) prior to and following the WTG. Pre-WTG exercise training was provided to participants. Participants demonstrated a statistically significant improvement in their habitual weekday (6.1 ± 1.7 to 8.5 ± 1.9 h; p = 0.002) and weekend (6.3 ± 2.6 to 8.4 ± 2.5 h; p = 0.01) activity over the training period, while controls improved weekday activity only (6.3 ± 2.0 to 8.3 ± 2.1 h; p = 0.05. Weekend activity: 7.7 ± 2.7 to 8.3 ± 2.3 h; p = 0.68). Participants demonstrated a non-statistical improvement in select physical fitness parameters; however, a greater number of participants achieved healthy criterion standards for cardiovascular fitness (2 vs. 1), abdominal strength (5 vs. 3), and upper body strength (7 vs. 3) following training and participating in the WTG. The WTG can provide a positive incentive for greater levels of physical activity and promote improvements in physical fitness levels. Further study is needed to examine long-term impact on lifestyle changes and health outcomes.

Functional capacity after pediatric liver transplantation: a pilot study

The prospective cross-sectional study investigated the 6MWT performance in pediatric group of liver transplant recipients (6-17 yr, median post-transplantation time of 22 months) and compared to the normal values obtained in healthy children as well as evaluated the reproducibility of the 6MWT. We analyzed the relationship between walked distance and the 6MWw, distance walked × body weight) with the anthropometric, clinical, and pulmonary functions. In post-transplanted group, the average walked distance was significantly shorter compared with control (687 ± 80 m vs. 511 ± 72 m, p < 0.001). The calculated ICC coefficient confirmed the reproducibility among tests. The Pearson correlation revealed that only walked distance in the 6MWT was moderately correlated with tidal volume. Conversely, the 6MWw was significantly correlated with age, weight, height, BMI, FVC, PEF rate, and volume expiratory. According to multiple regression analysis, age, VE and FVC factors explained 80% of the variance in the 6MWw. In conclusion, the pediatric liver transplant recipients' performance in the 6MWT is significantly lower than the values for healthy children of the same age. Notably, the 6MWw may provide relevant information, constituting an additional parameter in the determination of functional capacity.

Child and family adjustment following pediatric solid organ transplantation: factors to consider during the early years post-transplant

Adjusting to life after transplant can be challenging to pediatric solid organ transplant recipients and their families. In this review, we discuss a number of important factors to consider during the first 2-3 yr after transplant (defined as the "early years"), including transitioning from hospital to home, returning to physical activity, feeding and nutrition, school reentry, potential cognitive effects of transplant, family functioning, and QOL. We highlight steps that providers can take to optimize child and family adjustment during this period.

Waiting for transplant: physical, psychosocial, and nutritional status considerations for pediatric candidates and implications for care

The waiting period for an organ transplant has been described as a time of tremendous uncertainty and vulnerability, posing unique challenges and stressors for pediatric transplant candidates and their families. It has been identified as the most stressful stage of the transplant journey, yet little attention has been given to the physical, psychological, or social impact of the waiting period in the literature. In this review, we discuss the physical, nutritional, and psychosocial implications of the waiting period for child and adolescent transplant candidates and the impact on their parents and siblings. We identify areas for future research and provide recommendations for clinical practice to support children, adolescents, and families during the waiting period.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

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

BACKGROUND

Low physical activity (PA) is increasingly recognized as a risk factor for children with chronic conditions. A few published studies have measured the exercise capacity of solid organ transplant patients; however, no studies have examined the PA intensity of pediatric kidney transplant patients (PTx) using accelerometry. Therefore, our objective was to complement a gold standard exercise capacity protocol with an objective measure to quantify PA intensity levels of PTx.

METHODS

Sixteen PTx (nine girls), 4.9 ± 2.9 years posttransplant, mean age 13.1 ± 4.0 years, participated. Mean diethylenetriamine pentaacetic acid glomerular filtration rate (DTPA GFR) = 76.7 ± 18.0 ml/min/1.73 m(2). Laboratory data included assessment of cardiopulmonary functioning [peak oxygen uptake (VO(2peak))] from cycle ergometry and body composition [dual-energy X-ray absorptiometry (DEXA)]. PA was quantified by triaxial accelerometry (3 days). Field testing (FITNESSGRAM) included progressive aerobic cardiovascular endurance run (PACER), curlups, and sit/reach tests. Sex- and age-based criterion standards were used as reference.

RESULTS

Below normative values for VO(2peak) was found in eight children (mean = 27.4 ± 3.3). Accelerometry data identified only three children who fulfilled daily recommended moderate-vigorous PA level; 58.5% of their time was spent in sedentary activity.

CONCLUSION

Accelerometry data highlights that not only are PTx patients inactive, the activity they do perform is overall of low intensity. PTx also show compromised exercise capacity and physical fitness. Our results suggest the need to assess PA barriers among PTx. Further research is needed to determine appropriate PA recommendations for children posttransplant.

Cross-sectional analysis of health-related quality of life in pediatric liver transplant recipients

OBJECTIVE

To investigate the distribution of health-related quality of life in pediatric liver transplant recipients compared with a normative population.

STUDY DESIGN

This cross-sectional, multicenter study was conducted at select centers. Patients between 2 and 18 years of age, surviving liver transplantation by at least 12 months, were eligible. Parent/guardian fluency in English or Spanish was required. Children > or =8 years and parents of all children completed the age-appropriate versions of the PedsQL 4.0 (Mapi Research Institute, Lyon, France). Scores were compared with a sample of healthy children (n = 3911) matched by age group, sex, and race/ethnicity and with a sample of pediatric patients with cancer receiving chemotherapy and/or radiation.

RESULTS

Participants included 65% (873/1339) of eligible patients. Mean age was 8.17 +/- 4.43 years, and 55% were female. The total and subscale scores of PedsQL 4.0 were lower than in healthy children (P < .001), with effect sizes for self-report ranging from -0.25 for Emotional Functioning to -0.68 for School Functioning. Patients and their parents reported better physical functioning than patients with cancer but similar social and school functioning. Correlations between parent and self-reports were in the moderate agreement range.

CONCLUSIONS

Pediatric liver transplant recipients and their parents report lower health-related quality of life than control subjects with some domains equal to children receiving cancer therapy.

Health-related fitness and trainability in children with cystic fibrosis

The objective of this study was to examine the effects of a supervised exercise training program performed during an in patient rehabilitation course on various attributes of health-related fitness, e.g., flexibility, balance and coordination. 286 patients with CF, age range 6-18 years (11.8 +/- 3.4 years), mean forced expiratory volume in 1 sec (FEV1 82.7 +/- 22.3% predicted) were included. Patients performed the modified Munich fitness test (mMFT) to assess flexibility, balance, strength and coordination. To assess aerobic capacity a 6-min walk-test (6MWT) was performed. In addition, some of the patients performed an incremental exercise test on a bicycle ergometer using the Godfrey protocol before and after the exercise training program. The supervised training program consisted of 4-6 weeks of different sports activities 5 times per week. After training, pulmonary function showed a significant (P < 0.05) increase. All test items of the mMFT improved significantly (P < 0.05). Compared to healthy children test scores achieved from children with CF in the mMFT were lower but within a normal range. Our children with CF had a lower walk distance in 6MWT (P < 0.05) compared to healthy. Our findings clearly demonstrated benefits of a systematic exercise training program on components of physical fitness in patients with CF, with improvements of test-tasks to predicted normal in some cases. The results from our study suggested that an exercise training program in CF should be focused on several aspects of physical fitness including all components of physical fitness, e.g. aerobic endurance, flexibility, balance and motor skills.

Exercise capacity and physical fitness in pediatric dialysis and kidney transplant patients

Studies of exercise capacity in children with chronic kidney disease (CKD) are limited. We tested 25 pediatric kidney transplant (TX) recipients and 15 pediatric dialysis (DX) patients. Nine children in the DX group received kidney transplants and were retested 3 months following surgery (pre/post). Testing involved treadmill testing with measurement of peak oxygen uptake (VO(2peak)), muscle strength, body composition (percent fat), and "field" tests of physical fitness using the FITNESSGRAM, which included the PACER test. Values obtained were compared with gender- and age-based criterion-referenced standards [healthy fitness zone (HFZ)]. The previous day physical activity recall (PDPAR) was used to assess physical activity participation. There were no differences between TX and DX subjects for VO(2peak) and muscle strength measurements, and all values were below the normative values. The TX group achieved significantly higher PACER scores, but only one TX and no DX subjects achieved the HFZ for the PACER test. No improvement in any measures were observed from pre- to post-TX in the nine subjects tested, except for a significant increase in percent fat, which negatively affected the change in muscle strength and VO(2peak). All subjects were physically inactive, with less than 10% of nonschool time being physical activity participation. Pediatric patients with CKD had low exercise capacity, were physically inactive, and gained significant fat weight following TX. Counseling and encouragement for more physical activity is warranted as a part of routine medical care in these children.

Physical fitness, fatigue, and quality of life after liver transplantation

Fatigue is often experienced after liver transplantation. The aims of this cross-sectional study were to assess physical fitness (cardiorespiratory fitness, neuromuscular fitness, body composition) in liver transplant recipients and to explore whether physical fitness is related to severity of fatigue. In addition, we explored the relationship between physical fitness and health-related quality of life. Included were 18 patients 1-5 years after transplantation (aged 48.0 +/- 11.8 years) with varying severity of fatigue. Peak oxygen uptake during cycle ergometry, 6-min walk distance, isokinetic muscle strength of the knee extensors, body mass index, waist circumference, skinfold thickness, severity of fatigue, and health-related quality of life were measured. Cardiorespiratory fitness in the liver transplant recipients was on average 16-34% lower than normative values (P Collapse

Key Words

• liver transplantation
• fatigue
• peak oxygen uptake
• isokinetic muscle strength
• body composition

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MESH Headings

• Adult
• Body Composition/physiology
• Cardiovascular Physiological Phenomena
• Cross-Sectional Studies
• Fatigue/physiopathology
• Female
• Humans
• Liver Transplantation/physiology
• Male
• Middle Aged
• Muscle Strength/physiology
• Oxygen Consumption/physiology
• Physical Fitness/physiology
• Quality of Life
• Respiratory Physiological Phenomena
• Severity of Illness Index

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Affiliation(s)

Berbke T J van Ginneken Department of Rehabilitation Medicine, Erasmus University Medical Center Rotterdam, The Netherlands.
Rita J G van den Berg-Emons
Geert Kazemier
Herold J Metselaar
Hugo W Tilanus
Henk J Stam

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The comprehensive assessment of physical fitness in children following kidney and liver transplantation

BACKGROUND

Pediatric organ transplant recipients may have elevated cardiovascular (CV) risk. Low cardiorespiratory fitness (CRF) may contribute to CV risk; however, studies of CRF in children following kidney transplantation (KTx) and liver transplantation (LTx) are limited.

METHODS

Laboratory testing included assessment of CRF (VO2peak), muscle strength, and body composition (%fat). Field testing (FITNESSGRAM) included the PACER, curl-up, and sit-and-reach tests. Values obtained were compared to sex- and age-based criterion-referenced standards (Healthy Fitness Zone, HFZ). The Previous Day Physical Activity Recall was used to assess after-school physical activity (PA) participation. Independent t tests were used to compare groups.

RESULTS

Twenty-five KTx and 11 LTx recipients were tested. The groups were similar in all measures. Both groups demonstrated below normative values for VO2peak and muscle strength. Only 4% of the KTx and 9% of the LTx recipients achieved the HFZ for the PACER and 24% of the KTx and 45% of the LTx attained the HFZ for the curl-up test. Approximately 44% of both groups had percent fat greater than the upper criterion value of the HFZ. Both groups reported spending only 8% of their after-school time participating in physical activity.

CONCLUSIONS

Pediatric KTx and LTx recipients have significantly reduced CRF, muscle strength, and physical activity. Routine counseling and encouragement for increased physical activity is recommended as a part of routine care. A randomized clinical exercise intervention trial after pediatric solid organ transplantation is warranted to determine the impact of such lifestyle intervention on improving physical fitness and cardiovascular health.

Transition of care between paediatric and adult gastroenterology. Liver transplantation

With the increasing success of liver transplantation in children, a growing number of children are reaching an age when it is no longer appropriate for them to be followed by paediatricians. Clinicians looking after these liver allograft recipients need to be aware of the additional problems and needs in this group of young patients. While life after transplantation is usually near normal, a proportion of adolescents suffer from physical and psychological stresses that may result in social and behavioural problems. Non-compliance can have a major adverse impact on graft function. Immunosuppression needs to be adjusted to maintain good graft function, but also to keep to a minimum the adverse effects including renal failure and malignancy. The adverse cosmetic effects of some immunosuppressive drugs can be particularly troublesome at this stage in life. Overall, adolescent liver allograft recipients can have an excellent quality of life. Health care professionals need to be aware of the additional problems that this group of patients may have and they will need to adapt the follow-up in response to these issues.