Overweight, central obesity, and cardiometabolic risk factors in pediatric liver transplantation

Physical function in children and adolescents pre- and 1-year post-liver transplant

BACKGROUND

Several studies describe poorer motor developmental motor outcomes post-liver transplant (LT) in younger children. Limited studies examine physical function in older children and adolescents pre- and post-LT.

METHODS

Retrospective review of standard of care physical function outcome measures pre- and 1-year post-LT in children ≥6 years at LT. Measures include: 6-minute walk test (6MWT), grip strength, Bruininks-Oseretsky Test of Motor Proficiency-2 (BOT-2) components, Physical Activity Questionnaire (PAQ), and Paediatric Quality of Life Multidimensional Fatigue Scale. Association of medical variables with outcomes was explored.

RESULTS

The study cohort included 23 (8 male, median (interquartile range) age 11.67 (8.25, 13.92) years at LT) participants. Top two primary diagnoses included biliary atresia (30.4%) and fulminant hepatic failure (21.7%). At 1-year post-LT, over one-third (36%) were overweight or obese. Compared with healthy norms, children had significantly lower pre-LT PAQ scores (p = .002), pre- and post-6MWT scores (p < .001) and post-LT BOT-2 strength and agility scores (p < .001). Pre-LT, lower balance scores were associated with abdominal distention/ascites (p = .009) and splenomegaly (p = .017). Lower pre-LT platelet count correlated with poorer balance (r = .532, p = .017) and lower strength and agility scores (r = .446, p = .043). Significant moderate inverse correlations were found between weight/body mass index z-scores and BOT-2 components. Post-LT children continue to demonstrate decreased levels of motor proficiency and functional capacity but report less fatigue and increased physical activity.

CONCLUSIONS

Older children and adolescents undergoing LT are at risk of decreased physical function, highlighting the need for pre- and post-LT rehabilitation to optimize long term outcomes.

Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia

Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.

Incidence and Risk Factors of Obesity in Childhood Solid-Organ Transplant Recipients

BACKGROUND

Obesity is a significant public health concern; however, the incidence post solid-organ transplantation is not well reported.

METHODS

This study determined the incidence and risk factors of obesity among pediatric solid-organ transplant recipients (heart, lung, liver, kidney, multiorgan) at The Hospital for Sick Children (2002-2011), excluding prevalent obesity. Follow-up occurred from transplantation until development of obesity, last follow-up, or end of study. Incidence of obesity was determined overall, by baseline body mass index, and organ group. Risk factors were assessed using Cox proportional-hazards regression.

RESULTS

Among 410 (55% male) children, median transplant age was 8.9 (interquartile range [IQR]: 1.0-14.5) years. Median follow-up time was 3.6 (IQR: 1.5-6.4) years. Incidence of obesity was 65.2 (95% confidence interval [CI]: 52.7-80.4) per 1000 person-years. Overweight recipients had a higher incidence, 190.4 (95% CI: 114.8-315.8) per 1000 person-years, than nonoverweight recipients, 56.1 (95% CI: 44.3-71.1). Cumulative incidence of obesity 5-years posttransplant was 24.1%. Kidney relative to heart recipients had the highest risk (3.13 adjusted hazard ratio [aHR]; 95% CI: 1.53-6.40) for obesity. Lung and liver recipients had similar rates to heart recipients. Those with higher baseline body mass index (z-score; 1.72 aHR; 95% CI: 1.39-2.14), overweight status (2.63 HR; 95% CI: 1.71-4.04), and younger transplant age (y; 1.18 aHR; 95% CI: 1.12-1.25) were at highest risk of obesity. Higher cumulative steroid dosage (per 10 mg/kg) was associated with increased risk of obesity after adjustment.

CONCLUSIONS

Among all transplanted children at The Hospital for Sick Children, 25% developed obesity within 5-years posttransplant. Kidney recipients, younger children, those overweight at transplant, and those with higher cumulative steroid use (per 10 mg/kg) were at greatest risk. Early screening and intervention for obesity are important preventative strategies.

Nutrition Support of Children With Chronic Liver Diseases: A Joint Position Paper of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

Chronic liver disease places patients at increased risk of malnutrition that can be challenging to identify clinically and treat. Nutrition support is a key aspect of the management of these patients as it has an impact on their quality of life, morbidity, and mortality. There are significant gaps in the literature regarding the optimal nutrition support for patients with different types of liver diseases and the impact of these interventions on long-term outcomes. This Position Paper summarizes the available literature on the nutritional aspects of the care of patients with chronic liver diseases. Specifically, the challenges associated with the nutritional assessment of these subjects are discussed, and recently investigated approaches to determining the patients' nutritional status are reviewed. Furthermore, the pathophysiology of the malnutrition seen in the context of chronic liver disease is summarized and monitoring, as well as treatment, recommendations are provided. Lastly, suggestions for future research studies are described.

Healthy Body Weights With Corticosteroid-free Immunosuppression Is the Best Predictor of Cardiovascular Health in Children After Liver Transplantation

INTRODUCTION

Cardiometabolic dysregulation (CMD) influences morbidity and mortality risk in adults post-liver transplantation (LTx). CMD is reported in 10% to 25% of pediatric LTx recipients, but no information regarding the longitudinal expression of CMD is available. The study objective was to examine the longitudinal expression of CMD and associations with body composition and growth in children post-LTx.

METHODS

A retrospective review was conducted in youth (34 F/30 M) who underwent LTx between 1994 and 2015 at the Stollery Children's Hospital. Primary outcomes included serum markers of CMD (insulin, glucose, hemoglobin A1C [A1C], homeostasis model assessment for insulin resistance [abnormal >3], lipid panel triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol) and systolic/diastolic blood pressure (BP: absolute/z scores).

RESULTS

Mean (±SD) age, weight z, height z, body mass index z was 9.7 ± 3.4 years (3.5-17.9), 0.26 ± 1.03, 0.017 ± 1.2, and 0.41 ± 1.05, respectively. The majority of children had percentage fat mass, percentage fat-free mass within normal reference ranges. Systolic/diastolic BP was within healthy references ranges in 83.1% and 93.5% of children, respectively. Serum insulin (83.4%) and high-density lipoprotein-cholesterol (43.9%) concentrations were low, with abnormal findings of other laboratory markers found in <5% of participants. Abnormal findings for metabolic parameters were independent of weight z, body mass index z, fat mass, and corticosteroids but were positively related to child's age (>9.7 years) and fat-free mass (total, arms). Insulin levels decreased significantly in the first 4 years post-LTx, but no changes in lipid panel, A1C and glucose were noted over 10 years.

CONCLUSIONS

Pediatric LTx recipients with healthy body weights and corticosteroid-free immunosuppression have a low expression of CMD over 10 years.

Center variation in screening for and management of metabolic syndrome in pediatric liver transplant recipients: A survey of SPLIT centers

INTRODUCTION

PTMS-a clustering of hypertension, dyslipidemia, glucose intolerance/diabetes, and obesity-is increasingly recognized as a contributor to long-term morbidity after transplant. We sought to describe pediatric liver transplant center protocols and provider practices in screening for and managing these conditions.

METHODS

Cross-sectional survey of pediatric liver transplant providers from centers that participate in Studies of Liver Transplantation (SPLIT).

RESULTS

Of 49 survey respondents from 39 centers, 64% were hepatologists or surgeons, 18% nurses/NPs/PAs, 12% coordinators, and 4% other. All providers felt that pediatric liver transplant recipients should be routinely screened for PTMS components. For each condition, at least 70% felt that the liver transplant team should be primarily responsible for routine screening. For each condition, at least 30% of providers reported that their center had no standardized protocol for screening. For diagnostic evaluation and initial management, >60% of providers reported that their center had no standardized protocol for glucose intolerance/diabetes, dyslipidemia, or obesity. Almost 40% had no standardized workup or initial management protocol for hypertension or chronic kidney disease. Of centers that did have screening or workup protocols, most were based on existing center practice, provider consensus, or informal review of published evidence. Screening tools, treatment steps, and thresholds for referral to another specialist varied widely.

CONCLUSIONS

Transplant providers intend to screen for and initiate management of PTMS components in these children, but protocols and practices vary substantially. This highlights opportunities for multi-center collaboration on protocols or interventions to improve screening and management.

Cardiovascular Risk Assessment in Pediatric Liver Transplant Patients

OBJECTIVES

Cardiovascular (CV) diseases play a leading role in the mortality of adult liver transplant (LT) recipients. However, data regarding CV risk factors in children after LT remain sparse. The present study assessed the presence of CV risk factors and signs of CV impairment in LT children.

METHODS

A total of 42 LT recipients (21 men, age 9.93 ± 3.57 years) were studied. Body composition [body mass index standard deviation score, percentage of body fat (by bioimpedance analysis)], lipid profiles, glycemic control, blood pressure, and arterial stiffness [assessed by aortic pulse wave velocity (PWV)] were evaluated. The effect of different treatment modalities [tacrolimus (TAC) (n = 30) or cyclosporine (CyA) (n = 11)] was also analyzed.

RESULTS

Almost 18% of children were overweight or obese. Patients on TAC had a significantly higher body fat mass and percentage of body fat compared with the CyA group (P < 0.02). Borderline to high lipid values were present in 40% of patients. Children on CyA had higher serum cholesterol levels compared to TAC (P < 0.004). Nineteen percent of patients had hypertension. Half of the patients had glomerular filtration rate values <90 mL/min/1.73 m, whereas PWV values were above the 95th percentile in 12%.

CONCLUSIONS

Increased body fat, chronic kidney disease, high lipid content, hypertension, and increased arterial stiffness are already present and are in part related to the type of immunosuppression regimen in LT children >5 years following transplantation. Long-term follow-up is needed to evaluate their impact on CV health and survival.

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.

Risk markers for later cardiovascular diseases in liver-transplanted children and adolescents

BACKGROUND

Increased risk of cardiovascular diseases is well described after adult liver transplantation, whereas the risk in the pediatric population still is discussed. The aim of this study was to investigate the prevalence of metabolic syndrome in pediatric liver transplant recipients and whether measurements of carotid intima media thickness and pulse wave velocity were increased compared to healthy controls.

METHODS

We included 42 pediatric liver transplantation recipients and examined them for markers of metabolic syndrome, liver fibrosis measured by shear wave velocity, body fat measured by DXA scans and carotid intima-media thickness, and pulse wave velocity (n = 41 for the carotid scans). The ultrasound measurements of carotid intima-media thickness and pulse wave velocity were also conducted on 82 healthy children and adolescents matched on height and age, respectively.

RESULTS

Participants had a median age of 13.03 years, and median time since transplantation was 8.54 years. Compared to healthy controls, liver-transplanted patients had significantly increased intima-media thickness measurements in both control groups whereas there was no significant difference with regard to pulse wave velocity. Two patients (6.25%) were diagnosed with metabolic syndrome. Within the group of liver-transplanted pediatric patients, only elevated body mass index was associated with elevated carotid intima-media thickness measurement. Elevated pulse wave velocity was only associated with abdominal obesity. Factors not significantly correlated with either were age, sex, metabolic syndrome, hyperglycemia, triglycerides, years since transplantation, fibrosis of the liver, body fat content, smoking habits, HDL cholesterol levels, hypertension, and mono-drug versus multi-drug therapies.

CONCLUSION

Pediatric liver transplant recipients do have an increased risk of increased carotid intima-media thickness.

Effects of Liver Transplantation on Lipids and Cardiovascular Disease in Children With Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare, inherited, life-threatening, metabolic disorder of low-density lipoprotein (LDL) receptor function characterized by elevated serum LDL cholesterol (LDL-C) and rapidly progressive atherosclerotic cardiovascular disease (ACVD). Since LDL receptors are predominantly found on hepatocytes, orthotopic liver transplantation (OLT) has emerged as a viable intervention for HoFH because LDL receptor activity is restored. This study assessed the effects of OLT on ACVD and ACVD risk factors in pediatric patients with HoFH. We analyzed lipids, lipoproteins, body mass index, glucose, blood pressure, and cardiovascular imaging in 8 pediatric patients who underwent OLT for HoFH. Total serum cholesterol, LDL-C, lipoprotein (a), and apolipoprotein B/apolipoprotein A1 ratio decreased to normal values in all subjects (p values <0.001) at 1 month after OLT and were maintained for the length of follow-up (2 to 6 years). There were few complications related to surgery or immunosuppressive therapy. Two patients developed mild hypertension. In the first 4 subjects monitored for 4 to 6 years after OLT, coronary artery disease did not develop or progress except in 1 minor artery in 1 subject and actually regressed in 2 subjects with >50% stenosis. However, aortic valve stenosis progressed in 2 of 4 subjects. In conclusion, OLT is an effective therapeutic option for patients with HoFH with coronary artery disease and persistently elevated serum LDL-C despite maximum medical therapy. Aortic valvular disease may progress. Long-term data are needed to evaluate the true risk-benefit ratio of this surgical approach.

Metabolic Syndrome Components After Pediatric Liver Transplantation: Prevalence and the Impact of Obesity and Immunosuppression

Metabolic syndrome is associated with long-term morbidity and mortality after adult liver transplantation (LT). Whether pediatric LT recipients have a higher prevalence of metabolic syndrome remains controversial. In a cross-sectional study, we evaluated pediatric LT recipients aged 8-30 years using National Health and Nutrition Examination Survey (NHANES) protocols. LT recipients were matched by gender, race/ethnicity, and age with controls from NHANES. Pediatric LT recipients (n = 83), after adjusting for overweight/obesity and glucocorticoid use, had increased prevalence of prehypertension and hypertension, impaired glucose tolerance (IGT; 2-h glucose after oral glucose tolerance test ≥140 mg/dL), and low high-density lipoprotein compared to matched NHANES controls (n = 235) despite a lower prevalence of overweight/obesity. Among LT recipients, the adjusted odds of IGT doubled for every 7.5 years taking calcineurin inhibitors (odds ratio = 2.10, 95% confidence interval 1.06-4.17 per 7.5 years taking calcineurin inhibitors, p = 0.03). Among all subjects with IGT, LT recipients had a lower prevalence of overweight/obesity and less insulin resistance (homeostatic model assessment of insulin resistance) than did controls with IGT. Among normal weight subjects, LT recipients were significantly more likely than controls to have prehypertension/hypertension, IGT, low high-density lipoprotein, and metabolic syndrome. Pediatric LT recipients have unique metabolic syndrome profiles and risk factors and will require tailored screening and management protocols.

Subclinical cardiovascular changes in pediatric solid organ transplant recipients: A systematic review and meta-analysis

CV disease is a major cause of morbidity and mortality following solid organ transplantation in adults. While the prevalence of multiple cardiometabolic risk factors is increased in pediatric solid organ transplant recipients, it is not clear whether they have subclinical CV changes. cIMT, central pWV, and CAC are indicative of subclinical CV disease, and, in adults, predict future CV events. The objective of this systematic review and meta-analysis was to investigate the prevalence of subclinical CV changes, as measured by cIMT, pWV, and CAC among pediatric solid organ transplant recipients. We searched MEDLINE(®) and EMBASE and conducted meta-analysis for studies that evaluated cIMT, central pWV, and CAC among pediatric solid organ transplant recipients (kidney, lung, intestine and liver). The search identified nine eligible studies that included a total of 259 patients and 685 healthy controls. Eight studies reported on kidney transplant recipients and one study on a combined cohort of kidney and liver transplant recipients. The mean cIMT of transplant recipients was significantly higher than that of healthy controls (mean difference = 0.05 mm, 95% CI 0.02-0.07; p < 0.0001) with an estimated pooled prevalence of elevated cIMT of 56.0% (95% CI 17.0-95.0). The one study that assessed pWV showed increased vascular stiffness in transplant recipients compared to healthy controls. No studies assessing for CAC were found. There were limited data regarding subclinical CV disease following pediatric solid organ transplantation. In conclusion, kidney transplantation in childhood is associated with a higher prevalence of subclinical CV changes compared to healthy children. Longitudinal studies are needed to determine whether children have increased CV morbidity and mortality after transplantation.