Growth hormone treatment in short children with chronic kidney disease

Clearance and nutrition in neonatal continuous kidney replacement therapy using the Carpediem™ system

BACKGROUND

Infants with kidney failure (KF) demonstrate poor growth partly due to obligate fluid and protein restrictions. Delivery of liberalized nutrition on continuous kidney replacement therapy (CKRT) is impacted by clinical instability, technical dialysis challenges, solute clearance, and nitrogen balance. We analyzed delivered nutrition and growth in infants receiving CKRT with the Cardio-Renal, Pediatric Dialysis Emergency Machine (Carpediem™).

METHODS

Single-center observational study of infants receiving CKRT with the Carpediem™ between June 1 and December 31, 2021. We collected prospective circuit characteristics, delivered nutrition, anthropometric measurements, and illness severity Score for Neonatal Acute Physiology-II. As a surrogate to normalized protein catabolic rate in maintenance hemodialysis, we calculated normalized protein nitrogen appearance (nPNA) using the Randerson II continuous dialysis model. Descriptive statistics, Spearman correlation coefficient, Mann Whitney, Wilcoxon signed rank, receiver operating characteristic curves, and Kruskal-Wallis analysis were performed using SAS version 9.4.

RESULTS

Eight infants received 31.9 (22.0, 49.7) days of CKRT using mostly (90%) regional citrate anticoagulation. Delivered nutritional volume, protein, total calories, enteral calories, nPNA, and nitrogen balance increased on CKRT. Using parenteral nutrition, 90 ml/kg/day should meet caloric and protein needs. Following initial weight loss of likely fluid overload, exploratory sensitivity analysis suggests weight gain occurred after 14 days of CKRT. Despite adequate nutritional delivery, goal weight (z-score = 0) and growth velocity were not achieved until 6 months after CKRT start. Most (5 infants, 62.5%) survived and transitioned to peritoneal dialysis (PD).

CONCLUSIONS

Carpediem™ is a safe and efficacious bridge to PD in neonatal KF. Growth velocity of infants on CKRT appears delayed despite delivery of adequate calories and protein.

Evaluation of malnutrition and screening tools in hospitalized children

BACKGROUND & AIMS

Detecting malnutrition and its related risk factors are crucial, in hospitalized children. Anthropometric z scores are used to assess malnutrition. Screening tools also aim to detect the presence of malnutrition and the developing risk of malnutrition in hospitalized children to determine who may benefit from nutritional support. Therefore, the aims of the study are to detect malnutrition and its related demographic and clinical risk factors in hospitalized children and determining the sensitivity of Screening Tool for the Assessment of Malnutrition in Pediatrics (STAMP) and Pediatric Yorkhill Malnutrition Score (PYMS) screening tools.

METHODS

A total of 130 hospitalized children aged between 0 and 18 years were included in to study. A survey including demographic and clinical characteristics, STAMP and PYMS were applied to parents of the children. Patients were classified into nutritional risk groups through screening tools. Anthropometric measurements (body weight, length/height, and middle upper arm circumference (MUAC) of the children were taken. Body mass index-for-age and height-for-age z scores were calculated to assess acute and chronic malnutrition prevalence. MUAC-for-age z scores were calculated as well. To detect independent risk factors for acute and chronic malnutrition multivariable logistic regression models were constructed.

RESULTS

A total of 14.6% of hospitalized children had acute malnutrition, 21.5% of children had chronic malnutrition and 27.7% of them had low MUAC standard deviation score (SDS) (less than -2). The independent risk factors for acute malnutrition were younger maternal age at birth and long length of stay (p < 0.05). The independent risk factors for chronic malnutrition were being female, younger maternal age at birth, longer illness duration and having urological or allergy and immunological diseases (p < 0.05). However, MUAC for age SDS groups were not related to any demographic and clinical factors, in children of all ages (p > 0.05). Regarding the screening tools, PYMS displayed 100% sensitivity against acute malnutrition. While PYMS displayed better sensitivity to identify acute malnutrition than STAMP, STAMP was more sensitive than PYMS to detect chronic malnutrition and low MUAC SDS.

CONCLUSIONS

Low MUAC for age SDS was not related to any demographic and clinical factors, in hospitalized children of all ages, unlike acute and chronic malnutrition, in this study. Pediatric screening tools mainly PYMS did not have high sensitivity to detect chronic malnutrition and low MUAC SDS, in hospitalized children. Therefore, the tools have to be used along with z scores of anthropometric parameters.

Pediatric CKD-MBD: existing and emerging treatment approaches

The effects of bone and mineral metabolism on skeletal formation, as well as vascular and soft tissue calcifications, define chronic kidney disease-metabolic bone disease (CKD-MBD). Treatment recommendations center on establishing adequate vitamin D status, phosphate control through diet restriction and phosphate binders, and the use of vitamin D analogs for specific indications. Several emerging bone-promoting therapies have now been studied in adults with CKD, including bisphosphonates and denosumab. These approaches are associated with improved bone mass and, in some cases, decreased fracture rates in adults with CKD-MBD and are of potential interest for some children with CKD-MBD. In children with CKD and immobilization and/or muscle weakness, bisphosphonates appear to be an effective treatment to increase bone mass; baseline assessment and careful monitoring of bone density and/or bone biopsy findings are important in consideration of any new bone therapies for children with CKD-MBD.

Growth Hormone and Insulin-Like Growth Factor Dysregulation in Pediatric Chronic Kidney Disease

Poor growth is a common finding in children with chronic kidney disease (CKD) that has been associated with poor long-term outcomes. The etiology of poor growth in this population is multifactorial and includes dysregulation of the growth hormone (GH) and insulin-like growth factor (IGF) axis. In this review, we describe the data on GH resistance or insensitivity and inappropriate levels or reduced bioactivity of IGF proposed as contributing factors of growth impairment in children with CKD. Additionally, we describe the theorized negative effect of metabolic acidosis, another frequent finding in pediatric CKD, on the GH/IGF axis and growth. Last, we present the current and potential therapies for the treatment of short stature in pediatric CKD that target the GH/IGF hormonal axis.

The Role of Growth Hormone in Chronic Kidney Disease

Growth hormone (GH) has become a critical therapy for treating growth delay and failure in pediatric chronic kidney disease. Recombinant human GH treatment is safe and significantly improves height and height velocity in these growing patients and improved growth outcomes are associated with decreased morbidity and mortality as well as improved quality of life. However, the utility of recombinant human GH in adults with chronic kidney disease and end-stage renal disease for optimization of body habitus and reducing frailty remains uncertain. Semin Nephrol 41:x-xx © 2021 Elsevier Inc. All rights reserved.

Strategies for Optimizing Growth in Children With Chronic Kidney Disease

Growth failure is a hallmark in children with chronic kidney disease (CKD). Therefore, early diagnosis and adequate management of growth failure is of utmost importance in these patients. The risk of severe growth retardation is the higher the younger the child is, which places an additional burden on patients and their families and hampers the psychosocial integration of these children. Careful monitoring of growth, and effective interventions are mandatory to prevent and treat growth failure in children with CKD at all ages and all stages of kidney failure. Early intervention is critical, as all therapeutic interventions are much more effective if they are started prior to the initiation of dialysis. Prevention and treatment of growth failure focuses on: (i) preservation of renal function, e.g., normalization of blood pressure and proteinuria by use of inhibitors of the renin-angiotensin aldosterone system, (ii) adequate energy intake, including tube feeding or gastrostomy in case of persisting malnutrition, (iii) substitution of water and electrolytes, especially in children with renal malformation, (iv) correction of metabolic acidosis, (v) control of parathyroid hormone levels within the CKD-dependent target range, (vi) use of recombinant human growth hormone in cases of persistent growth failure, and, (vii) early/preemptive kidney transplantation using steroid-minimizing immunosuppressive protocols in children with end-stage CKD. This review discusses these measures based on recent guidelines.

Vigier R, Zustin J, Haffner D. Management of bone disease in cystinosis: Statement from an international conference

Cystinosis is an autosomal recessive storage disease due to impaired transport of cystine out of lysosomes. Since the accumulation of intracellular cystine affects all organs and tissues, the management of cystinosis requires a specialized multidisciplinary team consisting of pediatricians, nephrologists, nutritionists, ophthalmologists, endocrinologists, neurologists' geneticists, and orthopedic surgeons. Treatment with cysteamine can delay or prevent most clinical manifestations of cystinosis, except the renal Fanconi syndrome. Virtually all individuals with classical, nephropathic cystinosis suffer from cystinosis metabolic bone disease (CMBD), related to the renal Fanconi syndrome in infancy and progressive chronic kidney disease (CKD) later in life. Manifestations of CMBD include hypophosphatemic rickets in infancy, and renal osteodystrophy associated with CKD resulting in bone deformities, osteomalacia, osteoporosis, fractures, and short stature. Assessment of CMBD involves monitoring growth, leg deformities, blood levels of phosphate, electrolytes, bicarbonate, calcium, and alkaline phosphatase, periodically obtaining bone radiographs, determining levels of critical hormones and vitamins, such as thyroid hormone, parathyroid hormone, 25(OH) vitamin D, and testosterone in males, and surveillance for nonrenal complications of cystinosis such as myopathy. Treatment includes replacement of urinary losses, cystine depletion with oral cysteamine, vitamin D, hormone replacement, physical therapy, and corrective orthopedic surgery. The recommendations in this article came from an expert meeting on CMBD that took place in Salzburg, Austria, in December 2016.

Identification of growth patterns of preterm and small-for-gestational age children from birth to 4 years - do they catch up?

Background A legitimate indication for growth hormone (GH) therapy in children born too light or short at birth [small-for-gestational age (SGA)] exists in Germany and the European Union only if special criteria are met. Methods We conducted a longitudinal, multi-centered study on full-term appropriate-for-gestational age (AGA, n=1496) and pre-term born SGA (n=173) and full-term SGA children (n=891) in Germany from 2006 to 2010. We analyzed height, weight, body mass index (BMI) and head circumference. Results Pre-term or full-term born SGA children were shorter, lighter and had a lower BMI from birth until 3 years of age than full-term AGA children. The growth velocity of the analyzed anthropometric measurements was significantly higher in pre-term and full-term SGA children exclusively in the first 2 years of life than in AGA children. The criteria for GH treatment were fulfilled by 12.1% of pre-term SGA children compared to only 1.3% of full-term SGA children. Conclusion For children that do not catch up growth within the first 2 years of life, an earlier start of GH treatment should be considered, because a catch-up growth later than 2 years of life does not exist. Pre-term SGA-born children more frequently fulfill the criteria for GH treatment than full-term SGA children.

Growth and Nutrition in Pediatric Chronic Kidney Disease

Children with chronic kidney disease (CKD) feature significant challenges to the maintenance of adequate nutrition and linear growth. Moreover, the impaired nutritional state contributes directly to poor growth. Therefore, it is necessary to consider nutritional status in the assessment of etiology and treatment of sub-optimal linear growth. The major causes of poor linear growth including dysregulation of the growth hormone/insulin-like growth factor-I (IGF-I) axis, nutritional deficiency, metabolic acidosis, anemia, renal osteodystrophy/bone mineral disease, and inflammation. This review summarizes the causes and assessment tools of growth and nutrition while providing a summary of state of the art therapies for these co-morbidities of pediatric CKD.

Near-adult height in male kidney transplant recipients started on growth hormone treatment in late puberty

BACKGROUND

Growth retardation and its impact on adult height is considered to be one of the most common complications in patients with chronic kidney disease (CKD). Treatment with recombinant human growth hormone (rhGH) has been effective in improving growth in kidney transplantation (KTx) patients, but little data are available on adult height in patients who began rhGh treatment in late puberty.

METHODS

Near-adult height was evaluated in 13 KTx patients treated with rhGH [growth hormone group (GHGr); dose 9.33 mg/m² per week] for a period of at least 18 months. At initiation of rhGH treatment, testicular volume was >8 ml and serum testosterone was >1 ng/ml compared with the control group (CGr) of ten KTx patients who did not receive rHGH. All subjects were of similar chronological age and bone age and had similar creatinine clearance (CrCl) levels, cumulative corticoid dose, height standard deviation score (SDS), target height SDS, and target height:initial height at the beginning of the study.

RESULTS

Near-adult height was significantly greater in the GHGr than in the CGr (-1.8 ± 0.8 vs. -2.9 ± 1.1; p = 0.018). The difference between initial height and near-adult height in the GHGr revealed a significant height gain (initial height -3.1 ± 1.1; near-adult height -1.8 ± 0.8 SDS, respectively; delta 1.2 ± 0.3; p = 0.021). The CrCl level was not significantly different between the GHGr and CGr at either at study initiation or when attaining near-adult height (p = 0.74 and p = 0.23, respectively).

CONCLUSIONS

Treatment with rhGH was effective in improving adult height in KTx patients who began treatment in late puberty, without any effect on renal function.

Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1.

Effects of Growth Hormone on Bone

PURPOSE

Describe the effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) on the skeleton.

FINDINGS

The GH and IGF-1 axis has pleiotropic effects on the skeleton throughout the lifespan by influencing bone formation and resorption. GH deficiency leads to decreased bone turnover, delayed statural growth in children, low bone mass, and increased fracture risk in adults. GH replacement improves adult stature in GH deficient children, increases bone mineral density (BMD) in adults, and helps to optimize peak bone acquisition in patients, during the transition from adolescence to adulthood, who have persistent GH deficiency. Observational studies suggest that GH replacement may mitigate the excessive fracture risk associated with GH deficiency. Acromegaly, a state of GH and IGF-1 excess, is associated with increased bone turnover and decreased BMD in the lumbar spine observed in some studies, particularly in patients with hypogonadism. In addition, patients with acromegaly appear to be at an increased risk of morphometric-vertebral fractures, especially in the presence of active disease or concurrent hypogonadism. GH therapy also has beneficial effects on statural growth in several conditions characterized by GH insensitivity, including chronic renal failure, Turner syndrome, Prader-Willi syndrome, postnatal growth delay in patients with intrauterine growth retardation who do not demonstrate catchup growth, idiopathic short stature, short stature homeobox-containing (SHOX) gene mutations, and Noonan syndrome.

SUMMARY

GH and IGF-1 have important roles in skeletal physiology, and GH has an important therapeutic role in both GH deficiency and insensitivity states.

Growth hormone treatment in non-growth hormone-deficient children

Until 1985 growth hormone (GH) was obtained from pituitary extracts, and was available in limited amounts only to treat severe growth hormone deficiency (GHD). With the availability of unlimited quantities of GH obtained from recombinant DNA technology, researchers started to explore new modalities to treat GHD children, as well as to treat a number of other non-GHD conditions. Although with some differences between different countries, GH treatment is indicated in children with Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, deletions/mutations of the SHOX gene, as well as in short children born small for gestational age and with idiopathic short stature. Available data from controlled trials indicate that GH treatment increases adult height in patients with Turner syndrome, in patients with chronic renal insufficiency, and in short children born small for gestational age. Patients with SHOX deficiency seem to respond to treatment similarly to Turner syndrome. GH treatment in children with idiopathic short stature produces a modest mean increase in adult height but the response in the individual patient is unpredictable. Uncontrolled studies indicate that GH treatment may be beneficial also in children with Noonan syndrome. In patients with Prader-Willi syndrome GH treatment normalizes growth and improves body composition and cognitive function. In any indication the response to GH seems correlated to the dose and the duration of treatment. GH treatment is generally safe with no major adverse effects being recorded in any condition.

A patient with CKD and poor nutritional status

Protein energy wasting is common in patients with CKD and ESRD and is associated with adverse clinical outcomes, such as increased rates of hospitalization and death, in these patients. A multitude of factors can affect the nutritional and metabolic status of patients with CKD, including decreased dietary nutrient intake, catabolic effects of renal replacement therapy, systemic inflammation, metabolic and hormonal derangements, and comorbid conditions (such as diabetes and depression). Unique aspects of CKD also confound reliable assessment of nutritional status, further complicating management of this comorbid condition. In patients in whom preventive measures and oral dietary intake from regular meals cannot help them maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is effective in replenishing protein and energy stores. The advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic steroids and exercise, with nutritional supplementation or alone, improve protein stores and represent potential additional approaches for the treatment of PEW. There are several emerging novel therapies, such as appetite stimulants, anti-inflammatory interventions, and anabolic agents.

Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism

Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

Changes in bone matrix mineralization after growth hormone treatment in children and adolescents with chronic kidney failure treated by dialysis: a paired biopsy study

BACKGROUND

Patients with chronic kidney disease (CKD) develop renal osteodystrophy with alterations in bone turnover, mineralization, and volume (TMV). A specific skeletal complication in children is growth impairment, which currently is treated by recombinant human growth hormone (rhGH). The effects on bone material properties are poorly understood. This study assesses the effects of rhGH treatment on bone matrix mineralization.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

18 short children and adolescents (aged 3.6-16 years) with CKD on dialysis therapy.

PREDICTOR

rhGH treatment for 1 year.

OUTCOMES

Tetracycline-labeled bone biopsy classified according to the TMV system.

MEASUREMENTS

Bone mineralization density distribution (BMDD) was evaluated by quantitative backscattered electron imaging in trabecular and cortical compartments. Additional data for patients' height and biochemical bone serum parameters were obtained.

RESULTS

Prior to rhGH treatment, our cohort showed low bone turnover and high mineralization densities versus reference data: Ca(mean) (weighted mean calcium content) in cancellous bone, +3.3% (P = 0.04); Ca(mean) in cortical bone, +6.7% (P < 0.001); Ca(peak) (mode of the BMDD) in cancellous bone, +5.0% (P < 0.001); Ca(peak) in cortical bone, +8.2% (P < 0.001); Ca(width) (heterogeneity in mineralization), no significant difference for cancellous (P = 0.2) and cortical (P = 0.1) bone; Ca(high) (portion of fully mineralized bone) in cancellous bone, 5-fold greater (P < 0.001); Ca(high) in cortical bone, 14-fold greater (P < 0.001); Ca(low) (portion of low mineralized bone) in cancellous bone, +23.9% (P = 0.02); Ca(low) in cortical bone, -22.2% (P = 0.05). After rhGH treatment, height increased by 9.1 cm (P < 0.001) and bone turnover indices to normal values or beyond. Matrix mineralization was lesser and more heterogeneous compared to baseline: Ca(width) for cancellous bone, +15.3% (P < 0.001); Ca(width) for cortical bone, +34.1% (P < 0.001). Ca(mean), Ca(peak), and Ca(high) for cancellous bone and Ca(mean) and Ca(peak) for cortical bone were no longer significantly different from reference data. Ca(high) for cortical bone dramatically decreased after treatment but was still substantially greater than reference data.

LIMITATIONS

Low case number per TMV subgroup, no measurements of fibroblast growth factor 23.

CONCLUSIONS

Children and adolescents with CKD and growth deficiency are at risk of having low bone turnover. rhGH treatment improves height and concomitantly bone modeling/remodeling, which appears beneficial for bone matrix mineralization.

Total pubertal growth in patients with juvenile idiopathic arthritis treated with growth hormone: analysis of a single center

OBJECTIVES

Growth failure is a permanent sequelae in juvenile idiopathic arthritis (JIA). The aim of the study was to compare pubertal growth in control and growth hormone (GH) treated JIA subjects.

DESIGN

64 children with JIA at a mean age of 10.38 ± 2.80 years were enrolled and followed until final height (measured in standard deviation (SD) scores). 39 children (20 m) received GH therapy and 24 (9 m) served as controls. GH dose was 0.33 mg/kg/week. Linear regression analysis was performed to identify factors influencing total pubertal growth.

RESULTS

Mean total pubertal growth was 21.1 ± 1.3 cm (mean ± SD) in GH treated JIA patients and 13.8 ± 1.5 cm in controls. Final height was significantly higher with GH treatment (-1.67 ± 1.20 SD) compared to controls (-3.20 ± 1.84 SD). Linear regression model identified age at onset of puberty (ß=-4.2,CI: -5.9, -2.6 in controls and ß=-2.3,CI: -3.6, -1.1 in GH treated) as the main factor for total pubertal growth. Final height SDS was determined by the difference to target height at onset of puberty (ß=-0.59;CI: -0.80, -0.37 in controls and ß=-0.30,CI: -0.52, -0.08 in GH treated), age at onset of puberty (ß=0.47;CI:0.02,0.93 in controls and 0.23;CI: -0.00,0.46 in GH treated) and height gain during puberty (ß=0.13;CI:0.05,0.21 in controls and ß=0.11;CI:0.07,0.16 in GH treated).

CONCLUSION

Total pubertal growth in JIA patients treated with GH was increased by a factor of 1.5 greater in comparison to controls leading to a significantly better final height. To maximize final height GH treatment should be initiated early to reduce the height deficit at onset of puberty.

Functional and total IGFBP3 for the assessment of disorders of the GH/IGF1 axis in children with chronic kidney disease, GH deficiency, or short stature after SGA status at birth

OBJECTIVE

IGFBP3 immunoreactivity may appear elevated in patients with chronic kidney disease (CKD), in part due to accumulation of low molecular fragments. The importance of these IGFBP3 variants for binding and inactivation of IGF1 and their relevance for the impaired growth of uremic children are unclear. Nevertheless, IGFBP3, measured as total (t-)IGFBP3, is frequently used as a diagnostic parameter in pediatric CKD patients. A new assay for functional (f-)IGFBP3 exclusively detects IGFBP3 capable of IGF binding. The aim of the study was to evaluate the significance of f-IGFBP3 measurements for the assessment of uremic abnormalities of the GH/IGF1 axis.

DESIGN

Prospective cross-sectional study.

METHODS

t-IGFBP3, f-IGFBP3, and IGF1 were measured in pediatric CKD patients, including patients with CKD stage 3-4 not on dialysis (CKD, n=33), on dialysis treatment (DT, n=26), patients after renal transplantation (RTx, n=89), healthy children (n=29), children with GH deficiency (GHD, n=42), and small for gestational age (SGA) children (SGA, n=34).

RESULTS

Mean t-IGFBP3 SDS was elevated in CKD, DT, and RTx children compared with controls and GHD patients (P≤0.0004). Highest values were reached in DT (P<0.0001 vs all groups). In contrast, mean f-IGFBP3 was similar in all groups (P=0.30).

CONCLUSIONS

Pediatric CKD patients displayed elevated serum concentrations of t-IGFBP3 but not f-IGFBP3, supporting the hypothesis that IGFBP3 fragments not binding IGF1 accumulate during uremia. f-IGFBP3 is an indicator of IGFBP3 fragmentation and seems to reflect IGF1 binding in CKD better than t-IGFBP3. However, the role of f-IGFBP3 for the diagnosis of disturbances of the GH/IGF hormonal axis appears to be limited.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

Validation of The Health Improvement Network (THIN) database for epidemiologic studies of chronic kidney disease

PURPOSE

Chronic kidney disease (CKD) is a prevalent and important outcome and covariate in pharmacoepidemiology. The Health Improvement Network (THIN) in the UK represents a unique resource for population-based studies of CKD. We compiled a valid list of Read codes to identify subjects with moderate to advanced CKD.

METHODS

A cross-sectional validation study was performed to identify codes that best define CKD Stages 3-5. All subjects with at least one non-zero measure of serum creatinine after 1 January 2002 were included. Estimated glomerular filtration rate (eGFR) was calculated according to the Schwartz formula for subjects aged < 18 years and the Modification of Diet in Renal Disease formula for subjects aged ≥ 18 years. CKD was defined as an eGFR <60 mL/minute/1.73 m² on at least two occasions, more than 90 days apart.

RESULTS

The laboratory definition identified 230,426 subjects with CKD, for a period prevalence in 2008 of 4.56% (95%CI, 4.54-4.58). A list of 45 Read codes was compiled, which yielded a positive predictive value of 88.9% (95%CI, 88.7-89.1), sensitivity of 48.8%, negative predictive value of 86.5%, and specificity of 98.2%. Of the 11.1% of subjects with a code who did not meet the laboratory definition, 83.6% had at least one eGFR <60. The most commonly used code was for CKD Stage 3.

CONCLUSIONS

The proposed list of codes can be used to accurately identify CKD when serum creatinine data are limited. The most sensitive approach for the detection of CKD is to use this list to supplement creatinine measures.

The growth hormone receptor: mechanism of activation and clinical implications

Growth hormone is widely used clinically to promote growth and anabolism and for other purposes. Its actions are mediated via the growth hormone receptor, both directly by tyrosine kinase activation and indirectly by induction of insulin-like growth factor 1 (IGF-1). Insensitivity to growth hormone (Laron syndrome) can result from mutations in the growth hormone receptor and can be treated with IGF-1. This treatment is, however, not fully effective owing to the loss of the direct actions of growth hormone and altered availability of exogenous IGF-1. Excessive activation of the growth hormone receptor by circulating growth hormone results in gigantism and acromegaly, whereas cell transformation and cancer can occur in response to autocrine activation of the receptor. Advances in understanding the mechanism of receptor activation have led to a model in which the growth hormone receptor exists as a constitutive dimer. Binding of the hormone realigns the subunits by rotation and closer apposition, resulting in juxtaposition of the catalytic domains of the associated tyrosine-protein kinase JAK2 below the cell membrane. This change results in activation of JAK2 by transphosphorylation, then phosphorylation of receptor tyrosines in the cytoplasmic domain, which enables binding of adaptor proteins, as well as direct phosphorylation of target proteins. This model is discussed in the light of salient information from closely related class 1 cytokine receptors, such as the erythropoietin, prolactin and thrombopoietin receptors.

Growth hormone: the expansion of available products and indications

Growth hormone is a widely used hormone. This article describes its historical use, current indications and studies for possible future uses.

Growth hormone treatment of renal growth failure during infancy and early childhood

Despite major progress in dialysis, nutrition and drug treatment in the past 20 years, growth of infants and toddlers with chronic kidney disease (CKD) remains a major challenge in paediatric nephrology. Our hypothesis is that early growth deficit is one of the most important factors for impaired final height in children with CKD, and we conclude that early implementation of recombinant human growth hormone (rhGH) therapy should be offered to infants with growth failure. Infants with delayed growth, adequate caloric intake and stable parameters of bone metabolism are candidates for rhGH therapy. One predictive factor for the selection of infants for rhGH treatment may be growth retardation at birth. Our conclusion from the limited published data is that the use of rhGH in young children with CKD is effective and safe. Compared with its use in older children, the early use of growth hormone requires lower absolute dosages of rhGH, which therefore reduce the annual treatment costs and allow earlier renal transplantation. Furthermore, an early start on rhGH improves the psychosocial situation later in childhood and may lead to a further improvement in adult height. A multi-centre randomised controlled study should be initiated to analyse the short-term and long-term effects of early rhGH therapy on infants with CKD.