Proposed diagnostic criteria for the diagnosis of hypophosphatasia in children and adolescents: results from the HPP International Working Group.

Hypophosphatasia (HPP) is a rare inborn error of metabolism that presents variably in both age of onset and severity. HPP is caused by pathogenic variants in the ALPL gene, resulting in low activity of tissue nonspecific alkaline phosphatase (TNSALP). Patients with HPP tend have a similar pattern of elevation of natural substrates that can be used to aid in diagnosis. No formal diagnostic guidelines currently exist for the diagnosis of this condition in children, adolescents, or adults. The International HPP Working Group is a comprised of a multidisciplinary team of experts from Europe and North America who have expertise in the diagnosis and management of patients with HPP. This group reviewed 93 papers through a Medline, Medline In-Process, and Embase search for the terms "HPP" and "hypophosphatasia" between 2005 and 2020 and that explicitly address either the diagnosis of HPP in children, clinical manifestations of HPP in children, or both. Two reviewers independently evaluated each full-text publication for eligibility and studies were included if they were narrative reviews or case series/reports that concerned diagnosis of pediatric HPP or included clinical aspects of patients diagnosed with HPP. This review focused on 15 initial clinical manifestations that were selected by a group of clinical experts.The highest agreement in included literature was for pathogenic or likely pathogenic ALPL variant, elevation of natural substrates, and early loss of primary teeth. The highest prevalence was similar, including these same three parameters and including decreased bone mineral density. Additional parameters had less agreement and were less prevalent. These were organized into three major and six minor criteria, with diagnosis of HPP being made when two major or one major and two minor criteria are present.

The challenge of hypophosphatasia diagnosis in adults: results from the HPP International Working Group Literature Surveillance.

Hypophosphatasia (HPP) is an inborn error of metabolism caused by reduced or absent activity of the tissue non-specific alkaline phosphatase (TNSALP) enzyme, resulting from pathogenic variants in the ALPL gene. Clinical presentation of HPP is highly variable, including lethal and severe forms in neonates and infants, a benign perinatal form, mild forms manifesting in adulthood, and odonto-HPP. Diagnosis of HPP remains a challenge in adults, as signs and symptoms may be mild and non-specific. Disease presentation varies widely; there are no universal signs or symptoms, and the disease often remains underdiagnosed or misdiagnosed, particularly by clinicians who are not familiar with this rare disorder. The absence of diagnosis or a delayed diagnosis may prevent optimal management for patients with this condition. Formal guidelines for the diagnosis of adults with HPP do not exist, complicating efforts for consistent diagnosis. To address this issue, the HPP International Working Group selected 119 papers that explicitly address the diagnosis of HPP in adults through a Medline, Medline In-Process, and Embase search for the terms "hypophosphatasia" and "HPP," and evaluated the pooled prevalence of 17 diagnostic characteristics, initially selected by a group of HPP clinical experts, in eligible studies and in patients included in these studies. Six diagnostic findings showed a pooled prevalence value over 50% and were considered for inclusion as major diagnostic criteria. Based on these results and according to discussion and consideration among members of the Working Group, we finally defined four major diagnostic criteria and five minor diagnostic criteria for HPP in adults. Authors suggested the integrated use of the identified major and minor diagnostic criteria, which either includes two major criteria, or one major criterion and two minor criteria, for the diagnosis of HPP in adults.

Hypophosphatasia diagnosis: current state of the art and proposed diagnostic criteria for children and adults.

BACKGROUND: This manuscript provides a summary of the current evidence to support the criteria for diagnosing a child or adult with hypophosphatasia (HPP). The diagnosis of HPP is made on the basis of integrating clinical features, laboratory profile, radiographic features of the condition, and DNA analysis identifying the presence of a pathogenic variant of the tissue nonspecific alkaline phosphatase gene (ALPL). Often, the diagnosis of HPP is significantly delayed in both adults and children, and updated diagnostic criteria are required to keep pace with our evolving understanding regarding the relationship between ALPL genotype and associated HPP clinical features. METHODS: An International Working Group (IWG) on HPP was formed, comprised of a multidisciplinary team of experts from Europe and North America with expertise in the diagnosis and management of patients with HPP. Methodologists (Romina Brignardello-Petersen and Gordon Guyatt) and their team supported the IWG and conducted systematic reviews following the GRADE methodology, and this provided the basis for the recommendations. RESULTS: The IWG completed systematic reviews of the literature, including case reports and expert opinion papers describing the phenotype of patients with HPP. The published data are largely retrospective and include a relatively small number of patients with this rare condition. It is anticipated that further knowledge will lead to improvement in the quality of genotype-phenotype reporting in this condition. CONCLUSION: Following consensus meetings, agreement was reached regarding the major and minor criteria that can assist in establishing a clinical diagnosis of HPP in adults and children.

Patient-Reported Outcomes from a Randomized, Active-Controlled, Open-Label, Phase 3 Trial of Burosumab Versus Conventional Therapy in Children with X-Linked Hypophosphatemia.

Changing to burosumab, a monoclonal antibody targeting fibroblast growth factor 23, significantly improved phosphorus homeostasis, rickets, lower-extremity deformities, mobility, and growth versus continuing oral phosphate and active vitamin D (conventional therapy) in a randomized, open-label, phase 3 trial involving children aged 1-12 years with X-linked hypophosphatemia. Patients were randomized (1:1) to subcutaneous burosumab or to continue conventional therapy. We present patient-reported outcomes (PROs) from this trial for children aged ≥ 5 years at screening (n = 35), using a Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaire and SF-10 Health Survey for Children. PROMIS pain interference, physical function mobility, and fatigue scores improved from baseline with burosumab at weeks 40 and 64, but changed little with continued conventional therapy. Pain interference scores differed significantly between groups at week 40 (- 5.02, 95% CI - 9.29 to - 0.75; p = 0.0212) but not at week 64. Between-group differences were not significant at either week for physical function mobility or fatigue. Reductions in PROMIS pain interference and fatigue scores from baseline were clinically meaningful with burosumab at weeks 40 and 64 but not with conventional therapy. SF-10 physical health scores (PHS-10) improved significantly with burosumab at week 40 (least-squares mean [standard error] + 5.98 [1.79]; p = 0.0008) and week 64 (+ 5.93 [1.88]; p = 0.0016) but not with conventional therapy (between-treatment differences were nonsignificant). In conclusion, changing to burosumab improved PRO measures, with statistically significant differences in PROMIS pain interference at week 40 versus continuing with conventional therapy and in PHS-10 at weeks 40 and 64 versus baseline.Trial registration: ClinicalTrials.gov NCT02915705.

Pilot Trial of a Sleep-Promoting Intervention for Children With Type 1 Diabetes.

OBJECTIVE: To assess the feasibility and acceptability of an educational sleep-promoting intervention (Sleep Coach Jr.) for school-aged children (ages 5-9) with type 1 diabetes (T1D) and their parents. METHODS: Parents and children (N = 39 dyads, mean child age = 8 years, 64% girls,) were randomized to either the Sleep Coach Jr. intervention, consisting of educational materials and three individual phone calls (N = 20), or the Standard Care condition (N = 19). Data were collected at enrollment and 3 months later. Children and parents wore actigraphy devices to obtain an objective measure of sleep characteristics, and parents completed questionnaire measures of sleep quality and psychosocial outcomes. Clinical data (i.e., hemoglobin A1c, glucose data) were obtained from children's medical records. RESULTS: Feasibility and acceptability of the study were demonstrated to be high; all three sessions were completed by 80% of parents randomized to the Sleep Coach Jr. intervention, and 90% of parents completed follow-up data at 3 months. Parents reported high levels of satisfaction with the study and identified barriers to participation. No changes were observed in children's sleep or diabetes outcomes, but parental sleep quality and well-being improved. CONCLUSIONS: A brief, behavioral sleep-promoting intervention is feasible and acceptable for school-aged children with T1D and their parents. A larger trial is needed to evaluate efficacy of the intervention.

Burosumab versus conventional therapy in children with X-linked hypophosphataemia: a randomised, active-controlled, open-label, phase 3 trial.

BACKGROUND: X-linked hypophosphataemia in children is characterised by elevated serum concentrations of fibroblast growth factor 23 (FGF23), hypophosphataemia, rickets, lower extremity bowing, and growth impairment. We compared the efficacy and safety of continuing conventional therapy, consisting of oral phosphate and active vitamin D, versus switching to burosumab, a fully human monoclonal antibody against FGF23, in paediatric X-linked hypophosphataemia. METHODS: In this randomised, active-controlled, open-label, phase 3 trial at 16 clinical sites, we enrolled children with X-linked hypophosphataemia aged 1-12 years. Key eligibility criteria were a total Thacher rickets severity score of at least 2·0, fasting serum phosphorus lower than 0·97 mmol/L (3·0 mg/dL), confirmed PHEX (phosphate-regulating endopeptidase homolog, X-linked) mutation or variant of unknown significance in the patient or a family member with appropriate X-linked dominant inheritance, and receipt of conventional therapy for at least 6 consecutive months for children younger than 3 years or at least 12 consecutive months for children older than 3 years. Eligible patients were randomly assigned (1:1) to receive either subcutaneous burosumab starting at 0·8 mg/kg every 2 weeks (burosumab group) or conventional therapy prescribed by investigators (conventional therapy group). Both interventions lasted 64 weeks. The primary endpoint was change in rickets severity at week 40, assessed by the Radiographic Global Impression of Change global score. All patients who received at least one dose of treatment were included in the primary and safety analyses. The trial is registered with ClinicalTrials.gov, number NCT02915705. FINDINGS: Recruitment took place between Aug 3, 2016, and May 8, 2017. Of 122 patients assessed, 61 were enrolled. Of these, 32 (18 girls, 14 boys) were randomly assigned to continue receiving conventional therapy and 29 (16 girls, 13 boys) to receive burosumab. For the primary endpoint at week 40, patients in the burosumab group had significantly greater improvement in Radiographic Global Impression of Change global score than did patients in the conventional therapy group (least squares mean +1·9 [SE 0·1] with burosumab vs +0·8 [0·1] with conventional therapy; difference 1·1, 95% CI 0·8-1·5; p<0·0001). Treatment-emergent adverse events considered possibly, probably, or definitely related to treatment by the investigator occurred more frequently with burosumab (17 [59%] of 29 patients in the burosumab group vs seven [22%] of 32 patients in the conventional therapy group). Three serious adverse events occurred in each group, all considered unrelated to treatment and resolved. INTERPRETATION: Significantly greater clinical improvements were shown in rickets severity, growth, and biochemistries among children with X-linked hypophosphataemia treated with burosumab compared with those continuing conventional therapy. FUNDING: Ultragenyx Pharmaceutical and Kyowa Kirin International.

Sleep coach intervention for teens with type 1 diabetes: Randomized pilot study.

BACKGROUND: Teens with type 1 diabetes (T1D) experience increased sleep disturbances, which have been linked to problems with adherence and glycemic control. As such, sleep represents a novel target to improve outcomes in teens. OBJECTIVE: To evaluate the feasibility, acceptability, and preliminary efficacy of a sleep-promoting intervention in teens with T1D. RESEARCH DESIGN AND METHODS: Teens aged 13 to 17 with T1D (n = 39) completed measures of sleep quality and diabetes management and wore actigraphs to obtain an objective measure of sleep. Hemoglobin A1C (HbA1c) was collected from medical records. Teens were randomized to Usual Care (n = 19) or the Sleep Coach intervention (n = 20). Teens in the Sleep Coach group received educational materials on healthy sleep habits and completed three individual telephone sessions. Follow-up data were collected at 3 months, including exit interviews with teens and parents. RESULTS: Feasibility of the study was excellent; 80% of teens in the Sleep Coach group completed all three sessions, and retention was high (90%). Based on actigraphy data, a significant improvement in sleep efficiency and sleep duration was observed (48-minute increase) among teens randomized to the Sleep Coach intervention, and teens in the control group were 7.5 times more likely to report poor sleep quality after 3 months than intervention participants. No change in HbA1c was observed. CONCLUSIONS: The Sleep Coach intervention for teens with T1D is a feasible and acceptable program that increased sleep duration and improved sleep quality for this high-risk population.

Effect of Continuous Glucose Monitoring on Glycemic Control in Adolescents and Young Adults With Type 1 Diabetes: A Randomized Clinical Trial.

Importance: Adolescents and young adults with type 1 diabetes exhibit the worst glycemic control among individuals with type 1 diabetes across the lifespan. Although continuous glucose monitoring (CGM) has been shown to improve glycemic control in adults, its benefit in adolescents and young adults has not been demonstrated. Objective: To determine the effect of CGM on glycemic control in adolescents and young adults with type 1 diabetes. Design, Setting, and Participants: Randomized clinical trial conducted between January 2018 and May 2019 at 14 endocrinology practices in the US including 153 individuals aged 14 to 24 years with type 1 diabetes and screening hemoglobin A1c (HbA1c) of 7.5% to 10.9%. Interventions: Participants were randomized 1:1 to undergo CGM (CGM group; n = 74) or usual care using a blood glucose meter for glucose monitoring (blood glucose monitoring [BGM] group; n = 79). Main Outcomes and Measures: The primary outcome was change in HbA1c from baseline to 26 weeks. There were 20 secondary outcomes, including additional HbA1c outcomes, CGM glucose metrics, and patient-reported outcomes with adjustment for multiple comparisons to control for the false discovery rate. Results: Among the 153 participants (mean [SD] age, 17 [3] years; 76 [50%] were female; mean [SD] diabetes duration, 9 [5] years), 142 (93%) completed the study. In the CGM group, 68% of participants used CGM at least 5 days per week in month 6. Mean HbA1c was 8.9% at baseline and 8.5% at 26 weeks in the CGM group and 8.9% at both baseline and 26 weeks in the BGM group (adjusted between-group difference, -0.37% [95% CI, -0.66% to -0.08%]; P = .01). Of 20 prespecified secondary outcomes, there were statistically significant differences in 3 of 7 binary HbA1c outcomes, 8 of 9 CGM metrics, and 1 of 4 patient-reported outcomes. The most commonly reported adverse events in the CGM and BGM groups were severe hypoglycemia (3 participants with an event in the CGM group and 2 in the BGM group), hyperglycemia/ketosis (1 participant with an event in CGM group and 4 in the BGM group), and diabetic ketoacidosis (3 participants with an event in the CGM group and 1 in the BGM group). Conclusions and Relevance: Among adolescents and young adults with type 1 diabetes, continuous glucose monitoring compared with standard blood glucose monitoring resulted in a small but statistically significant improvement in glycemic control over 26 weeks. Further research is needed to understand the clinical importance of the findings. Trial Registration: ClinicalTrials.gov Identifier: NCT03263494.

Sex- and age-dependent effects of celiac disease on growth and weight gain in children with type 1 diabetes: Analysis of the type 1 diabetes Exchange Clinic Registry.

BACKGROUND: Celiac disease (CD) is common in patients with type 1 diabetes (T1D) and effects of CD on growth in children with T1D remain unclear. METHODS: We analyzed heights, weights, and body mass index (BMI) in 215 matched pediatric CD/control pairs in the T1D Exchange Clinic Registry. CD was defined by a clinic-reported diagnosis and positive celiac serology (n = 80) and/or positive small bowel biopsy (n = 135). Cases and controls were matched by age (mean: 14 years), diabetes duration (median: 7 years), sex (57% female), and clinic site. There were 5569 height/weight measurements. RESULTS: Gluten was restricted for varying periods of time in 61% of females and 51% of males with CD. Females with CD were shorter than female controls at all ages (P = 0.01). Weight z-scores were initially lower in preschool females with CD but similar to controls by middle childhood. Males with CD were initially shorter but adult heights were similar. Height in both sexes and weight in males were lower in CD participants diagnosed at younger age. Growth in T1D children with biopsy-proven CD, 76% of them were gluten-restricted, was comparable to that of T1D controls. CONCLUSION: Concurrent CD impairs linear growth in T1D females at all stages of development and in young T1D males. Young females with CD have lower weights, but both sexes have similar weights by middle childhood. Children younger at CD onset remain shorter throughout childhood; males younger at CD onset have persistently lower weights. Long-term gluten restriction may restore weight gain and linear growth in children with CD and T1D.

Cyclic bisphosphonate therapy reduces pain and improves physical functioning in children with osteogenesis imperfecta.

BACKGROUND: Children with osteogenesis imperfecta (OI) experience pain and impaired physical functioning. The longitudinal effect of cyclic bisphosphonate treatment on these symptoms has not been described. We serially evaluated pain and functioning in pediatric patients with OI treated with intravenous bisphosphonate therapy. METHODS: Pain and physical functioning were assessed at multiple time-points over two infusion cycles in 22 OI patients (median age 10 years [range 2-21 years]; 8 girls) receiving cyclic intravenous bisphosphonate therapy. Pain was assessed using the FACES® visual analogue scale; physical functioning, including self-care, was assessed using the PedsQL™ Generic Core inventory. RESULTS: Pain scores decreased significantly immediately following infusion and remained reduced at 4 weeks post-infusion, increasing before and decreasing again after subsequent infusion (F = 25.00, p < 0.001). Physical functioning scaled scores improved 4 weeks after infusion and declined before subsequent infusion across patients (F = 10.87, p = 0.007). Exploratory analyses indicated significantly different effects between mild and moderate-severe OI types for pain, but not for physical functioning. No fractures occurred during the study. CONCLUSION: In children with OI, cyclic intravenous bisphosphonate therapy transiently reduces pain and improves functional abilities. Pain relief occurs immediately following infusion with functional improvements observed 4 weeks later. Both pain and physical functioning return to pretreatment levels by the subsequent infusion.

Enzyme-replacement therapy in life-threatening hypophosphatasia.

BACKGROUND: Hypophosphatasia results from mutations in the gene for the tissue-nonspecific isozyme of alkaline phosphatase (TNSALP). Inorganic pyrophosphate accumulates extracellularly, leading to rickets or osteomalacia. Severely affected babies often die from respiratory insufficiency due to progressive chest deformity or have persistent bone disease. There is no approved medical therapy. ENB-0040 is a bone-targeted, recombinant human TNSALP that prevents the manifestations of hypophosphatasia in Tnsalp knockout mice. METHODS: We enrolled infants and young children with life-threatening or debilitating perinatal or infantile hypophosphatasia in a multinational, open-label study of treatment with ENB-0040. The primary objective was the healing of rickets, as assessed by means of radiographic scales. Motor and cognitive development, respiratory function, and safety were evaluated, as well as the pharmacokinetics and pharmacodynamics of ENB-0040. RESULTS: Of the 11 patients recruited, 10 completed 6 months of therapy; 9 completed 1 year. Healing of rickets at 6 months in 9 patients was accompanied by improvement in developmental milestones and pulmonary function. Elevated plasma levels of the TNSALP substrates inorganic pyrophosphate and pyridoxal 5'-phosphate diminished. Increases in serum parathyroid hormone accompanied skeletal healing, often necessitating dietary calcium supplementation. There was no evidence of hypocalcemia, ectopic calcification, or definite drug-related serious adverse events. Low titers of anti-ENB-0040 antibodies developed in four patients, with no evident clinical, biochemical, or autoimmune abnormalities at 48 weeks of treatment. CONCLUSIONS: ENB-0040, an enzyme-replacement therapy, was associated with improved findings on skeletal radiographs and improved pulmonary and physical function in infants and young children with life-threatening hypophosphatasia. (Funded by Enobia Pharma and Shriners Hospitals for Children; ClinicalTrials.gov number, NCT00744042.).

Knowledge of diagnosis, treatment history, and risk of late effects among childhood cancer survivors and parents: The impact of a survivorship clinic.

BACKGROUND: Childhood cancer survivors are at risk for treatment-related adverse health outcomes, known as late effects. Through matched and longitudinal cohorts, we assessed the impact of survivorship care on patient and parent knowledge of treatment history and associated health risks. PROCEDURE: Childhood cancer survivors were recruited from a single-institution survivorship clinic and matched with survivors receiving routine follow-up care (controls) on diagnosis, age, and time off therapy. One hundred seventy-four participants completed telephone interviews assessing knowledge of diagnosis, treatment history, and risk of late effects. Additionally, 48 new survivorship patients were followed longitudinally with serial interviews for 18 months. RESULTS: In the case-control study, survivorship participants were more likely than controls to correctly report their diagnosis (98% vs. 90%, P = 0.039) and indicate a previous discussion of risk of late effects (99% vs. 62%, P<0.0001). Compared to controls, survivorship participants were 13% more sensitive reporting chemotherapeutics (95%CI 2.8-23.7%, P = 0.013) and 12% more sensitive reporting late effect risk (95%CI 7.3-16.6%, P<0.0001). In the longitudinal cohort, participants were 7% more sensitive reporting chemotherapeutics (95%CI 5.4-10.8%, P < 0.001) and 9% more sensitive reporting late effect risk (95%CI 5.6-23.8%, P<0.001) at 3 months compared to baseline. In regression analysis, baseline knowledge correlated with subsequent interview performance, and time since survivorship visit correlated with decreased knowledge of late effects, but not diagnosis or treatment history. CONCLUSIONS: Survivorship care was associated with increased knowledge of diagnosis, treatment history, and risk of late effects in both cohorts. Knowledge of late effects decreases with time, suggesting the need for additional educational strategies.

Effect of Metformin Added to Insulin on Glycemic Control Among Overweight/Obese Adolescents With Type 1 Diabetes: A Randomized Clinical Trial.

IMPORTANCE: Previous studies assessing the effect of metformin on glycemic control in adolescents with type 1 diabetes have produced inconclusive results. OBJECTIVE: To assess the efficacy and safety of metformin as an adjunct to insulin in treating overweight adolescents with type 1 diabetes. DESIGN, SETTING, AND PARTICIPANTS: Multicenter (26 pediatric endocrinology clinics), double-blind, placebo-controlled randomized clinical trial involving 140 adolescents aged 12.1 to 19.6 years (mean [SD] 15.3 [1.7] years) with mean type 1 diabetes duration 7.0 (3.3) years, mean body mass index (BMI) 94th (4) percentile, mean total daily insulin 1.1 (0.2) U/kg, and mean HbA1c 8.8% (0.7%). INTERVENTIONS: Randomization to receive metformin (n = 71) (≤2000 mg/d) or placebo (n = 69). MAIN OUTCOMES AND MEASURES: Primary outcome was change in HbA1c from baseline to 26 weeks adjusted for baseline HbA1c. Secondary outcomes included change in blinded continuous glucose monitor indices, total daily insulin, BMI, waist circumference, body composition, blood pressure, and lipids. RESULTS: Between October 2013 and February 2014, 140 participants were enrolled. Baseline HbA1c was 8.8% in each group. At 13-week follow-up, reduction in HbA1c was greater with metformin (-0.2%) than placebo (0.1%; mean difference, -0.3% [95% CI, -0.6% to 0.0%]; P = .02). However, this differential effect was not sustained at 26-week follow up when mean change in HbA1c from baseline was 0.2% in each group (mean difference, 0% [95% CI, -0.3% to 0.3%]; P = .92). At 26-week follow-up, total daily insulin per kg of body weight was reduced by at least 25% from baseline among 23% (16) of participants in the metformin group vs 1% (1) of participants in the placebo group (mean difference, 21% [95% CI, 11% to 32%]; P = .003), and 24% (17) of participants in the metformin group and 7% (5) of participants in the placebo group had a reduction in BMI z score of 10% or greater from baseline to 26 weeks (mean difference, 17% [95% CI, 5% to 29%]; P = .01). Gastrointestinal adverse events were reported by more participants in the metformin group than in the placebo group (mean difference, 36% [95% CI, 19% to 51%]; P < .001). CONCLUSIONS AND RELEVANCE: Among overweight adolescents with type 1 diabetes, the addition of metformin to insulin did not improve glycemic control after 6 months. Of multiple secondary end points, findings favored metformin only for insulin dose and measures of adiposity; conversely, use of metformin resulted in an increased risk for gastrointestinal adverse events. These results do not support prescribing metformin to overweight adolescents with type 1 diabetes to improve glycemic control. TRIAL REGISTRATION: clinicaltrials.org Identifier: NCT01881828.

Insulin pump use in young children in the T1D Exchange clinic registry is associated with lower hemoglobin A1c levels than injection therapy.

Insulin delivery via injection and continuous subcutaneous insulin infusion (CSII) via insulin pump were compared in a cross-sectional study (n = 669) and retrospective longitudinal study (n = 1904) of young children (<6 yr) with type 1 diabetes (T1D) participating in the T1D Exchange clinic registry. Use of CSII correlated with longer T1D duration (p < 0.001), higher parental education (p < 0.001), and annual household income (p < 0.006) but not with race/ethnicity. Wide variation in pump use was observed among T1D Exchange centers even after adjusting for these factors, suggesting that prescriber preference is a substantial determinant of CSII use. Hemoglobin A1c (HbA1c) was lower in pump vs. injection users (7.9 vs. 8.5%, adjusted p < 0.001) in the cross-sectional study. In the longitudinal study, HbA1c decreased after initiation of CSII by 0.2%, on average (p < 0.001). Frequency of a severe hypoglycemia (SH) event did not differ in pump vs. injection users (p = 0.2). Frequency of ≥1 parent-reported diabetic ketoacidosis (DKA) event in the prior year was greater in pump users than injection users (10 vs. 8%, p = 0.04). No differences between pump and injection users were observed for clinic-reported DKA events. Children below 6 yr have many unique metabolic characteristics, feeding behaviors, and care needs compared with older children and adolescents. These data support the use of insulin pumps in this youngest age group, and suggest that metabolic control may be improved without increasing the frequency of SH, but care should be taken as to the possibly increased risk of DKA.

Screening for vitamin D insufficiency in pediatric cancer survivors.

BACKGROUND: Corticosteroids increase risk for decreased bone mineral density, which can be worsened by vitamin D insufficiency (VDI) or deficiency (VDD). PROCEDURE: In the Vanderbilt cancer survivorship clinic, we obtained screening total 25-hydroxy vitamin D levels (VDL) in 171 cancer survivors <23 years old who were treated with prolonged corticosteroids for their cancer, and compared this group to a control group of 97 healthy pediatric patients. RESULTS: VDD was diagnosed in 15.8% and VDI in 34.5% of cancer survivors and VDD/VDI combined was associated with body mass index (BMI) >85th percentile (Odds ratio [OR] = 5.4; P < 0.001), older age (OR = 2.2; P = 0.012), non-Caucasian or Hispanic race (OR = 4.5; P = 0.008) and summer versus winter season (OR = 0.12; P < 0.001). In multivariable analysis, VDI/VDD prevalence did not differ from the control group (VDI/VDD (43.3%)). In the combined survivor/control group multivariable analysis, cancer diagnosis did not increase VDI/VDD risk, but significant associations persisted with elevated BMI (P < 0.001), age (P = 0.004), non-Caucasian or Hispanic race (P < 0.001), and seasonality (P < 0.001). CONCLUSION: VDD/VDI is equally common in pediatric cancer survivors treated with corticosteroids and healthy children. The impact of VDD/VDI in cancer survivors may be greater due to risk for impaired bone health superimposed on that conferred from corticosteroid exposure. Thus, screening VDLs should be obtained in pediatric cancer survivors treated with corticosteroids, particularly in those with elevated BMI, older age, or non-Caucasian race. Prospective studies evaluating the impact of interventions to minimize VDD/VDI on long-term bone health in survivors are required.

A polygenic score for height identifies an unmeasured genetic predisposition among pediatric patients with idiopathic short stature.

Background A subset of children with short stature do not have an identified clinical explanation and are assigned a diagnosis of idiopathic short stature (ISS). We hypothesized that a polygenic score for height (PGS height ) could identify children with ISS who have an unrecognized heritable predisposition to shorter height. Methods We examined 534 pediatric participants in an EHR-linked DNA biobank (BioVU) who had undergone an evaluation for short stature by an endocrinologist. We used a previously validated PGS height and standardized it to a standard deviation (SDS) of 1. PGS height differences between short stature subtypes was estimated using Tukey's HSD. The PGS height and mid-parental height (MPH) were then used to predict adult heights for each participant and these predictions were compared using Cohen's d stratifying by short stature subtype. The ability of the PGS height to discriminate between ISS and short stature due to underlying disease was evaluated using logistic regression models with area under the ROC curve (AUC) analyses and testing the incremental benefit (ΔAUC) of adding the PGS height to prediction models. Results Among the 534 participants, 22.1% had ISS (median [IQR] PGS height SDS = -1.31 [-2.15 to -0.47]), 6.6% had familial (genetic) short stature (FSS) (-1.62 [-2.13 to -0.54]), and 45.1% had short stature due to underlying pathology (-0.74 [-1.23 to -0.19]). Children with ISS had similar PGS height values as those with FSS (ΔPGS height [95% CI] = 0.19 [-0.31 to 0.70], p = 0.75), but predicted heights generated by the PGS height were lower than the MPH estimate for children with ISS ( d = -0.64; p = 4.0×10 - 18 ) but not FSS ( d = 0.05; p = 0.46), suggesting that MPH underestimates height in the ISS group. Children with ISS had lower PGS height values than children with pathology (ΔPGS height = -0.60 SDS [-0.89 to -0.31], p < 0.001), suggesting children with ISS have a larger predisposition to shorter height. In addition, the PGS height improved model discrimination between ISS and pathologic short stature (ΔAUC, + 0.07 [95% CI, 0.01 to 0.11]). Conclusions Some children with ISS have a clinically unrecognized polygenic predisposition to shorter height that is comparable to children with FSS and larger than those with underlying pathology. A PGS height could help clinicians identify children who have a benign predisposition to shorter height.

Burosumab vs conventional therapy in children with X-linked hypophosphatemia: results of the open-label, phase 3 extension period.

In a randomized, open-label phase 3 study of 61 children aged 1-12 years old with X-linked hypophosphatemia (XLH) previously treated with conventional therapy, changing to burosumab every 2 weeks (Q2W) for 64 weeks improved the phosphate metabolism, radiographic rickets, and growth compared with conventional therapy. In this open-label extension period (weeks 64-88), 21 children continued burosumab Q2W at the previous dose or crossed over from conventional therapy to burosumab starting at 0.8 mg/kg Q2W with continued clinical radiographic assessments through week 88. Efficacy endpoints and safety observations were summarized descriptively for both groups (burosumab continuation, n = 6; crossover, n = 15). At week 88 compared with baseline, improvements in the following outcomes were observed in the burosumab continuation and crossover groups, respectively: mean (SD) RGI-C rickets total score (primary outcome), +2.11 (0.27) and +1.89 (0.35); mean (SD) RGI-C lower limb deformity score, +1.61 (0.91) and +0.73 (0.82); and mean (SD) height Z-score + 0.41 (0.50) and +0.08 (0.34). Phosphate metabolism normalized rapidly in the crossover group and persisted in the continuation group. Mean (SD) serum alkaline phosphatase decreased from 169% (43%) of the upper limit of normal (ULN) at baseline to 126% (51%) at week 88 in the continuation group and from 157% (33%) of the ULN at baseline to 111% (23%) at week 88 in the crossover group. During the extension period, treatment-emergent adverse events (AEs) were reported in all 6 children in the burosumab continuation group and 14/15 children in the crossover group. The AE profiles in the randomized and extension periods were similar, with no new safety signals identified. Improvements from baseline in radiographic rickets continued in the extension period among children with XLH who remained on burosumab. Children who crossed over from conventional therapy to burosumab demonstrated a rapid improvement in phosphate metabolism and improved rickets healing over the ensuing 22 weeks.

Obesity and insulin resistance in pediatric acute lymphoblastic leukemia worsens during maintenance therapy.

BACKGROUND: Pediatric acute lymphoblastic leukemia (ALL) survivors are at increased risk for the metabolic syndrome (MS). To establish the trajectory of development during active treatment, we followed patients longitudinally over the first year of maintenance therapy. PROCEDURE: In a prospective cohort of 34 pediatric ALL patients, followed over the first 12 months of ALL maintenance, we evaluated changes in body mass index (BMI), blood pressure, fasting insulin and glucose, lipids, Homeostatic Metabolic Assessment (HOMA), leptin, and adiponectin. RESULTS: Over the study time period, the median BMI z-score increased from 0.29 to 0.66 (P = 0.001), median fasting insulin levels increased from 2.9 to 3.1 µU/ml (P = 0.023), and the proportion of patients with insulin resistance by HOMA (>3.15) increased from 3% to 24% (P = 0.016). Median leptin increased from 2.5 to 3.5 ng/ml (P = 0.001), with levels correlated with BMI z-score. Median adiponectin level decreased from 18.0 to 14.0 µg/ml (P = 0.009), with levels inversely correlated to BMI z-score. No change in median total cholesterol and LDL levels was observed. Median triglycerides decreased (P < 0.001) and there was a trend to increase in HDL (P = 0.058). Blood pressure did not significantly change, although overall prevalence of systolic and diastolic hypertension was high (23.5% and 26.4%, respectively). CONCLUSIONS: Following patients over the first year of ALL maintenance therapy demonstrated that components of the MS significantly worsen over time. Preventive interventions limiting increases in BMI and insulin resistance during maintenance therapy should be targeted during this time period to avoid long-term morbidity associated with the MS in long-term survivors.

Burosumab vs Phosphate/Active Vitamin D in Pediatric X-Linked Hypophosphatemia: A Subgroup Analysis by Dose Level.

CONTEXT: In an open-label, randomized, controlled, phase 3 trial in 61 children aged 1 to 12 years with X-linked hypophosphatemia (XLH), burosumab improved rickets vs continuing conventional therapy with active vitamin D and phosphate. OBJECTIVE: We conducted an analysis to determine whether skeletal responses differed when switching to burosumab vs continuing higher or lower doses of conventional therapy. METHODS: Conventional therapy dose groups were defined as higher-dose phosphate [greater than 40 mg/kg] (HPi), lower-dose phosphate [40 mg/kg or less] (LPi), higher-dose alfacalcidol [greater than 60 ng/kg] or calcitriol [greater than 30 ng/kg] (HD), and lower-dose alfacalcidol [60 ng/kg or less] or calcitriol [30 ng/kg or less] (LD). RESULTS: At week 64, the Radiographic Global Impression of Change (RGI-C) for rickets was higher (better) in children randomly assigned to burosumab vs conventional therapy for all prebaseline dose groups: HPi (+1.72 vs +0.67), LPi (+2.14 vs +1.08), HD (+1.90 vs +0.94), LD (+2.11 vs +1.06). At week 64, the RGI-C for rickets was also higher in children randomly assigned to burosumab (+2.06) vs conventional therapy for all on-study dose groups: HPi (+1.03), LPi (+1.05), HD (+1.45), LD (+0.72). Serum alkaline phosphatase (ALP) also decreased in the burosumab-treated patients more than in the conventional therapy group, regardless of on-study phosphate and active vitamin D doses. CONCLUSION: Prior phosphate or active vitamin D doses did not influence treatment response after switching to burosumab among children with XLH and active radiographic rickets. Switching from conventional therapy to burosumab improved rickets and serum ALP more than continuing either higher or lower doses of phosphate or active vitamin D.