Vertebral Body Reshaping after Fractures: An Important Index of Recovery in Glucocorticoid-Treated Children.

PURPOSE: In this 6-year study we identified factors associated with spontaneous vertebral body reshaping in glucocorticoid (GC)-treated children with leukemia, rheumatic disorders, and nephrotic syndrome. METHODS: Subjects were 79 children (mean age 7.4 years) who had vertebral fracture (VF) evaluation on lateral spine radiographs at least 1 year after VF detection. VF were graded using the modified Genant semiquantitative method and fracture burden for individuals was quantified using the spinal deformity index (SDI; sum of grades from T4 to L4). RESULTS: Sixty-five children (82.3%) underwent complete vertebral body reshaping (median time from VF detection to complete reshaping 1.3 years by Cox proportional hazard modeling). Of 237 VF, the majority (83.1%) ultimately reshaped, with 87.2% reshaping in the thoracic region vs 70.7% in the lumbar region (P = .004). Cox models showed that (1) every g/m2 increase in GC exposure in the first year after VF detection was associated with a 19% decline in the probability of reshaping; (2) each unit increase in the SDI at the time of VF detection was associated with a 19% decline in the probability of reshaping [hazard ratio (HR) = 0.81; 95% confidence interval (CI) = 0.71, 0.92; P = .001]; (3) each additional VF present at the time of VF detection reduced reshaping by 25% (HR = 0.75; 95% CI = 0.62, 0.90; P = .002); and (4) each higher grade of VF severity decreased reshaping by 65% (HR = 0.35; 95% CI = 0.21, 0.57; P < .001). CONCLUSION: After experiencing a VF, children with higher GC exposure, higher SDI, more severe fractures, or lumbar VF were at increased risk for persistent vertebral deformity.

Reductions in Bone Mineral Density Are Apparent Early in Children With Prevalent Osteonecrosis Lesions Following Leukemia Therapy.

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multisite magnetic resonance imaging (MRI) more than 1 year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the Steroid Associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1 ± 1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (35%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09 ± 1.53 versus -1.27 ± 1.25, p = 0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31 ± 1.02) but not in those without (0.13 ± 0.82, p = 0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77 ± 1.22) compared to those without (-1.03 ± 1.07, p = 0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98 ± 0.95 versus -0.28 ± 1.06, p = 0.010; TB -1.36 ± 1.10 versus -0.48 ± 1.50, p = 0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p = 0.841. In multivariable models, older age at diagnosis (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.15-2.13; p = 0.004), and hip BMD Z-score at MRI (OR 2.23; 95% CI, 1.02-4.87; p = 0.046) were independently associated with ON. Overall, one-third of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first 1 and 2 years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Risk factors associated with prevalent vertebral fractures in Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) have a high fracture burden due to progressive myopathy and steroid-induced osteoporosis. This study in males with DMD showed that markers of systemic glucocorticoid exposure including shorter stature, greater bone age delay, and lower lumbar spine bone mineral density were associated with spine fragility. INTRODUCTION: Fragility  fractures are frequent in DMD. The purpose of this study was to identify clinical factors associated with prevalent vertebral fractures (VF) in boys, teens/young adults with Duchenne muscular dystrophy (DMD). METHODS: This was a cross-sectional study of males aged 4-25 years with DMD. VF were evaluated using the modified Genant semi-quantitative method on T4-L4 lateral spine radiographs. Areal bone mineral density (aBMD) was measured at the lumbar spine (LS) and used to estimate volumetric BMD (vBMD). Clinical factors were analyzed for their association with the Spinal Deformity Index (SDI, the sum of the Genant grades). RESULTS: Sixty participants were enrolled (mean age 11.5 years, range 5.4-19.5). Nineteen participants (32%) had a total of 67 VF; 23/67 VF (34%) were moderate or severe. Participants with VF were shorter (mean height Z-score ± standard deviation: - 3.1 ± 1.4 vs. - 1.8 ± 1.4, p = 0.001), had longer glucocorticoid exposure (mean duration 6.0 ± 3.3 vs. 3.9 ± 3.3 years, p = 0.027), greater bone age (BA) delay (mean BA to chronological age difference - 3.2 ± 3.4 vs. - 1.3 ± 1.2 years, p = 0.035), and lower LSaBMD Z-scores (mean - 3.0 ± 1.0 vs. - 2.2 ± 1.2, p = 0.023). There was no difference in LSvBMD Z-scores. Multivariable Poisson regression showed that every 0.1 mg/kg/day increment in average glucocorticoid daily dose was associated with a 1.4-fold SDI increase (95% confidence interval: 1.1-1.7, p = 0.013). Greater BA delay (p < 0.001), higher weight Z-score (p = 0.004), decreased height Z-score (p = 0.025), and lower LSvBMD Z-score (p = 0.025) were also associated with SDI increase. CONCLUSION: Readily measurable clinical variables were associated with prevalent VF in males with glucocorticoid-treated DMD. These variables may be useful to identify candidates for primary osteoporosis prevention after glucocorticoid initiation.

Aetiologies of low alkaline phosphatase in a Canadian Paediatric Tertiary Care Centre.

Objectives: Increasingly, laboratories flag low serum alkaline phosphatase (sALP) that are age-and sex-specific in paediatrics. The aim of this study was to report clinical manifestations of paediatric patients with age-and sex-specific low sALP, thereby increasing awareness of its potential aetiologies. Methods: This retrospective Canadian tertiary care paediatric hospital study assessed all sALP of ambulatory patients aged less than 18 years from 2015 to 2017. The hospital used a Beckman Coulter AU assay to measure sALP and compared values to the Canadian age-and sex-specific reference intervals from CALIPER. All children who had at least one subnormal age-and sex-specific sALP were evaluated. A review of medical charts of included patients was performed and demographic characteristics, medical history and diagnosis were collected, and categorized under groups of medical disorders. Results: Of 11,874 included patients, 1,001 patients (9.2%) had low sALP. Of those, 48% (485/1,001) had transient low sALP activity and 9.6% (96/1,001) had persistently low sALP. Prolonged immobilization and inflammatory bowel disease represented the main aetiologies for persistently low sALP. Interestingly, 13.5% (13/96) of patients with persistently low sALP had no apparent aetiology. Conclusions: Our results report aetiologies of low sALP in a Canadian paediatric population using age-and sex-specific Canadian reference ranges. This study highlights that healthcare providers should be aware that a low sALP may have clinical significance and should be repeated if warranted based on further clinical assessment.

Zoledronic Acid vs Placebo in Pediatric Glucocorticoid-induced Osteoporosis: A Randomized, Double-blind, Phase 3 Trial.

CONTEXT: Glucocorticoids (GCs) prescribed for chronic pediatric illnesses are associated with osteoporotic fractures. OBJECTIVE: This study aims to determine the efficacy and safety of intravenous (IV) zoledronic acid (ZA) compared with placebo to treat pediatric GC-induced osteoporosis (GIO). METHODS: Children aged 5 to 17 years with GIO were enrolled in this multinational, randomized, double-blind, placebo-controlled phase 3 trial (ClinicalTrials.gov NCT00799266). Eligible children were randomly assigned 1:1 to 6 monthly IV ZA 0.05 mg/kg or IV placebo. The primary end point was the change in lumbar spine bone mineral density z score (LSBMDZ) from baseline to month 12. Incident fractures and safety were assessed. RESULTS: Thirty-four children were enrolled (mean age 12.6 ±â€…3.4 years [18 on ZA, 16 on placebo]), all with low-trauma vertebral fractures (VFs). LSBMDZ increased from -2.13 ±â€…0.79 to -1.49 ±â€…1.05 on ZA, compared with -2.38 ±â€…0.90 to -2.27 ±â€…1.03 on placebo (least squares means difference 0.41 [95% CI, 0.02-0.81; P = .04]); when corrected for height z score, the least squares means difference in LBMDZ was 0.75 [95% CI, 0.27-1.22; P = .004]. Two children on placebo had new low-trauma VF vs none on ZA. Adverse events (AEs) were reported in 15 of 18 children (83%) on ZA, and in 12 of 16 (75%) on placebo, most frequently within 10 days after the first infusion. There were no deaths or treatment discontinuations due to treatment-emergent AEs. CONCLUSION: LSBMDZ increased significantly on ZA compared with placebo over 1 year in children with GIO. Most AEs occurred after the first infusion.

Osteoporotic Fractures and Vertebral Body Reshaping in Children With Glucocorticoid-treated Rheumatic Disorders.

CONTEXT: Osteoporotic fractures are an important cause of morbidity in children with glucocorticoid-treated rheumatic disorders. OBJECTIVE: This work aims to evaluate the incidence and predictors of osteoporotic fractures and potential for recovery over six years following glucocorticoid (GC) initiation in children with rheumatic disorders. METHODS: Children with GC-treated rheumatic disorders were evaluated through a prospective inception cohort study led by the Canadian STeroid-induced Osteoporosis in the Pediatric Population (STOPP) Consortium. Clinical outcomes included lumbar spine bone mineral density (LS BMD), vertebral fractures (VF), non-VF, and vertebral body reshaping. RESULTS: A total of 136 children with GC-treated rheumatic disorders were enrolled (mean age 9.9 years, SD 4.4). The 6-year cumulative fracture incidence was 16.3% for VF, and 10.1% for non-VF. GC exposure was highest in the first 6 months, and 24 of 38 VF (63%) occurred in the first 2 years. Following VF, 16 of 19 children (84%) had complete vertebral body reshaping. Increases in disease activity and body mass index z scores in the first year and declines in LS BMD z scores in the first 6 months predicted incident VF over the 6 years, while higher average daily GC doses predicted both incident VF and non-VF. LS BMD z scores were lowest at 6 months (mean -0.9, SD 1.2) and remained low by 6 years even when adjusted for height z scores (-0.6, SD 0.9). CONCLUSION: VF occurred early and were more common than non-VF in children with GC-treated rheumatic disorders. Eighty-four percent of children with VF underwent complete vertebral body reshaping, whereas vertebral deformity persisted in the remainder of children. On average, LS BMD z scores remained low at 6 years, consistent with incomplete recovery.

Use of bisphosphonates in a retrospective case series of children and adolescents with complex regional pain syndrome.

BACKGROUND: There is increasing evidence for the use of bisphosphonates to treat Complex Regional Pain Syndrome in adults. However, there are scarce data for their use in children with Complex Regional Pain Syndrome. AIM: This retrospective case series aimed to analyze the effects of intravenous bisphosphonate use in children and adolescents with Complex Regional Pain Syndrome enrolled in a multidimensional pain treatment program. METHODS: We analyzed the data of 16 patients (15 females and 1 male, mean age 14 ± 3 years) who received infusions of zoledronic acid (0.015 ± 0.0044mg/kg), pamidronate (0.72 ± 0.17mg/kg), or both depending on their initial response between October 2014 and December 2019. The primary endpoint of the study was the patient's global impression of change. Secondary outcomes included pain intensity, physical function, role function (school attendance), need for pain medications, and adverse effects. RESULTS: Nine of 16 patients reported meaningful improvements (global impressions of change of 84% or higher) at a median follow-up time of 16 (8-21) months after their last infusion of bisphosphonates. There were also meaningful reductions in pain intensity and the need for pain medications. There was an increase in the proportion of patients with minimal or without physical disability, and almost all patients normalized their school activities. Thirteen patients (81%) reported adverse effects, mostly flu-like symptoms, for a few days after the infusion. CONCLUSION: The use of bisphosphonate infusions may represent an effective treatment option for children with Complex Regional Pain Syndrome, not responding to multidisciplinary pain treatment programs.

Evaluating Curricular Modules in the Care of Children With Medical Complexity: A Mixed-Methods Randomized Controlled Trial.

OBJECTIVE: Children with medical complexity (CMC) are a growing population, yet training in complex care varies across pediatric residency programs. The purpose of this study was 1) to evaluate the effectiveness of a curriculum for pediatric residents in improving performance in a simulated clinical scenario, and 2) to explore residents' perceived self-efficacy in caring for CMC. METHODS: A randomized controlled trial was conducted supplemented by qualitative inquiry. Pediatric residents from 2 residency programs were randomly assigned to participate in interactive modules on: 1) clinical assessment, care planning, and technological dependency or 2) noncomplex care topics. The primary outcome was mean score on an Observed Structured Clinical Examination (OSCE) of tracheostomy care. Semistructured interviews were conducted postintervention and analyzed using qualitative content analysis. RESULTS: Ninety-four eligible residents were randomized. Residents who attended all modules and the OSCE and consented to participate (intervention [n = 20] and control [n=24]) were included in the final analysis. At baseline, few (9%) reported being comfortable caring for CMC. There was no significant difference in mean OSCE score between intervention and control groups (39.0 ± 1.1 vs 38.0 ± 1.0, P = .48). Qualitative analysis revealed 3 emerging themes related to resident self-efficacy: building a system of care, navigating uncertainty, and professional identity formation. CONCLUSIONS: A standardized complex care curriculum delivered in a classroom setting did not lead to improved performance in an OSCE station despite increased resident-reported self-efficacy in approaching care for CMC. These findings highlight the need for multidimensional educational interventions and assessments in complex care.

Impact of Vertebral Fractures and Glucocorticoid Exposure on Height Deficits in Children During Treatment of Leukemia.

Objective: To assess the effect of vertebral fractures (VF) and glucocorticoid (GC) exposure on height deficits in children during treatment of acute lymphoblastic leukemia (ALL). Methods: Children with ALL treated without cranial radiation therapy (n = 160; median age, 5.1 years; 58.1% male) were followed prospectively for 6 years. Spinal deformity index (SDI) was used to quantify VF status. Results: Baseline height z score ± SD was 0.3 ± 1.2. It fell by 0.5 ± 0.4 in the first 6 months for boys and by 0.4 ± 0.4 in the first 12 months for girls (P < 0.01 for both) and then subsequently recovered. The prevalence of VF peaked at 1 year (17.6%). Among those with VF, median SDI rose from 2 [interquartile range (IQR): 1, 7] at baseline to 8 (IQR: 1, 8) at 1 year. A mixed model for repeated measures showed that height z score declined by 0.13 (95% CI: 0.02 to 0.24; P = 0.02) for each 5-unit increase in SDI during the previous 12 months. Every 10 mg/m2 increase in average daily GC dose (prednisone equivalent) in the previous 12 months was associated with a height z score decrement of 0.26 (95% CI: 0.20 to 0.32; P < 0.01). Conclusions: GC likely plays a major role in the observed height decline during therapy for ALL. Because only a minority of children had VF, fractures could not have contributed significantly to the height deficit in the entire cohort but may have been important among the subset with VF.

Bone Morbidity and Recovery in Children With Acute Lymphoblastic Leukemia: Results of a Six-Year Prospective Cohort Study.

Osteoporotic fractures are a significant cause of morbidity in acute lymphoblastic leukemia (ALL). Our objective was to determine the incidence and predictors of fractures and recovery from osteoporosis in pediatric ALL over 6 years following glucocorticoid initiation. Vertebral fractures (VF) and vertebral body reshaping were assessed on annual spine radiographs, low-trauma non-VF were recorded at regular intervals and spine bone mineral density (BMD) was captured every 6 months for 4 years and then annually. A total of 186 children with ALL were enrolled (median age 5.3 years; range, 1.3 to 17.0 years). The cumulative fracture incidence was 32.5% for VF and 23.0% for non-VF; 39.0% of children with VF were asymptomatic. No fractures occurred in the sixth year and 71.3% of incident fractures occurred in the first 2 years. Baseline VF, cumulative glucocorticoid dose, and baseline lumbar spine (LS) BMD Z-score predicted both VF and non-VF. Vertebral body reshaping following VF was incomplete or absent in 22.7% of children. Those with residual vertebral deformity following VF were older compared to those without (median age 8.0 years at baseline [interquartile range {IQR}, 5.5 to 9.4] versus 4.8 years [IQR, 3.6 to 6.2], p = 0.04) and had more severe vertebral collapse (median maximum spinal deformity index 3.5 [IQR, 1.0 to 8.0] versus 0.5 [IQR, 0.0 to 1.0], p = 0.01). VF and low LS BMD Z-score at baseline as well as glucocorticoid exposure predicted incident VF and non-VF. Nearly 25% of children had persistent vertebral deformity following VF, more frequent in older children, and in those with more severe collapse. These results suggest the need for trials addressing interventions in the first 2 years of chemotherapy, targeting older children and children with more severe vertebral collapse, because these children are at greatest risk for incident VF and subsequent residual vertebral deformity. © 2018 American Society for Bone and Mineral Research.

Approach to Clinical Assessment of Children With Medical Complexity.

Introduction: General pediatricians have a major role in the care of children with medical complexity (CMC) in hospital and community settings. CMC are often affected by chronic multisystem diseases and functional limitations and may use a wheelchair or other aids for mobility. Dedicated training opportunities to perform comprehensive clinical assessments for this specialized population are lacking. Methods: We developed a module focused on special considerations for CMC history taking and physical examination that was piloted in a pediatric residency program. The 60-minute session included a video of a clinical assessment of a child in a wheelchair. The module offered suggestions for incorporating patients or standardized patients as optional activities. Target learners answered formative pre- and posttest questions to check understanding and completed a 1-minute paper to convey lessons learned. Qualitative content analysis identified themes in written responses. Results: Fifteen pediatrics residents in a single program participated in the module. Most had not received any formal training in complex care. Themes in learner knowledge of steps in a clinical encounter included defining family goals and providing anticipatory guidance. Themes from responses about anticipated changes in clinical practice included systematic and comprehensive approach to history taking, thorough examination, and importance of safe transfers. Discussion: Developed as part of a national initiative in complex care curriculum development, this module can be adapted for interprofessional learners who provide care for CMC, with the goal of enabling future members of health care teams to provide high-quality clinical assessments for CMC.

Understanding the Needs of Children With Medical Complexity.

Introduction: Children with medical complexity (CMC) are characterized by chronic conditions, functional limitations, technology dependence, and high health care utilization. There are limited formal training opportunities in the provision of complex care for pediatric residents. Methods: We developed a module to enable target learners to understand unique needs of CMC and the general pediatrician's role in creating a medical home. The module was piloted in a single pediatric residency program. The 60-minute session incorporated small-group activities and didactic instruction. Learners were given formative pre- and posttest questions to check understanding and completed a 1-minute paper to summarize anticipated changes in practice. Qualitative content analysis was used to identify themes in written responses. Results: Fifteen pediatrics residents participated in the module at a single children's hospital. Most residents had not had a complex care clinical rotation. Themes in learner knowledge of CMC included recognizing functional limitations and recurrent health care utilization. Themes from anticipated changes in practice included having less fear/anxiety when approaching care for CMC and asking about diverse areas of need, including nonmedical. Discussion: This core module was developed as part of a national systematic approach to complex care curriculum development. It has the potential to be adapted to frame a broader complex care curriculum and to be implemented with other learners in the health professions who care for this vulnerable patient population. The pilot study informed implementation in multiple residency programs, with the goal of enabling future pediatricians to provide high-quality care within a medical home for CMC.

Complex care core curriculum for pediatric post-graduate trainees: Results of a North American needs assessment.

PURPOSE: There are increasing numbers of children with chronic, complex conditions requiring comprehensive care, however post-graduate training in this field is limited. Lack of training may contribute to reticence in engaging with their care. Although children with medical complexity (CMC) are heterogeneous, their care needs are similar. We aimed to address a lack of explicit training via a standardized curriculum. As an initial step, a collaborative needs assessment of key content was developed. METHODS: An on-line survey with drafted learning objectives was sent to professionals skilled in complex care. Participants indicated if an objective should be obtained by the end of Junior residency (PGY2), Senior residency (PGY4), or not at all. RESULTS: Eighty-two Canadian and US professionals participated; 60.3% practiced in a University Health Centre and 60% cared for CMC and participated in pediatric postgraduate education. Over 80% felt that the medical home concept should be understood by the end of PGY2, and that trainees should develop a care plan by the end of PGY4. CONCLUSION: This needs assessment supported the learning objectives and provided information on the expected competency time line for knowledge and skill acquisition. Additional comments will be used to revise the objectives.

Common normal variants of pediatric vertebral development that mimic fractures: a pictorial review from a national longitudinal bone health study.

Children with glucocorticoid-treated illnesses are at risk for osteoporotic vertebral fractures, and growing awareness of this has led to increased monitoring for these fractures. However scant literature describes developmental changes in vertebral morphology that can mimic fractures. The goal of this paper is to aid in distinguishing between normal variants and fractures. We illustrate differences using lateral spine radiographs obtained annually from children recruited to the Canada-wide STeroid-Associated Osteoporosis in the Pediatric Population (STOPP) observational study, in which 400 children with glucocorticoid-treated leukemia, rheumatic disorders, and nephrotic syndrome were enrolled near glucocorticoid initiation and followed prospectively for 6 years. Normal variants mimicking fractures exist in all regions of the spine and fall into two groups. The first group comprises variants mimicking pathological vertebral height loss, including not-yet-ossified vertebral apophyses superiorly and inferiorly, which can lead to a vertebral shape easily over-interpreted as anterior wedge fracture, physiological beaking, or spondylolisthesis associated with shortened posterior vertebral height. The second group includes variants mimicking other radiologic signs of fractures: anterior vertebral artery groove resembling an anterior buckle fracture, Cupid's bow balloon disk morphology, Schmorl nodes mimicking concave endplate fractures, and parallax artifact resembling endplate interruption or biconcavity. If an unexpected vertebral body contour is detected, careful attention to its location, detailed morphology, and (if available) serial changes over time may clarify whether it is a fracture requiring change in management or simply a normal variant. Awareness of the variants described in this paper can improve accuracy in the diagnosis of pediatric vertebral fractures.

Incident Vertebral Fractures and Risk Factors in the First Three Years Following Glucocorticoid Initiation Among Pediatric Patients With Rheumatic Disorders.

Vertebral fractures are an important yet underrecognized manifestation of osteoporosis in children with chronic, glucocorticoid-treated illnesses. Our goal was to determine the incidence and clinical predictors of vertebral fractures in the 3 years following glucocorticoid initiation among pediatric patients with rheumatic disorders. Incident vertebral fractures were evaluated according to the Genant semiquantitative method on lateral radiographs at baseline and then annually in the 3 years following glucocorticoid initiation. Extended Cox models were used to assess the association between vertebral fractures and clinical risk predictors. A total of 134 children with rheumatic disorders were enrolled in the study (mean ± standard deviation (SD) age 9.9 ± 4.4 years; 65% girls). The unadjusted vertebral fracture incidence rate was 4.4 per 100 person-years, with a 3-year incidence proportion of 12.4%. The highest annual incidence occurred in the first year (6.0%; 95% confidence interval (CI) 2.9% to 11.7%). Almost one-half of the patients with fractures were asymptomatic. Every 0.5 mg/kg increase in average daily glucocorticoid (prednisone equivalents) dose was associated with a twofold increased fracture risk (hazard ratio (HR) 2.0; 95% CI 1.1 to 3.5). Other predictors of increased vertebral fracture risk included: (1) increases in disease severity scores between baseline and 12 months; (2) increases in body mass index Z-scores in the first 6 months of each 12-month period preceding the annual fracture assessment; and (3) decreases in lumbar spine bone mineral density Z-scores in the first 6 months of glucocorticoid therapy. As such, we observed that a clinically significant number of children with rheumatic disorders developed incident vertebral fractures in the 3 years following glucocorticoid initiation. Almost one-half of the children were asymptomatic and thereby would have been undiagnosed in the absence of radiographic monitoring. In addition, discrete clinical predictors of incident vertebral fractures were evident early in the course of glucocorticoid therapy.

The choice of normative pediatric reference database changes spine bone mineral density Z-scores but not the relationship between bone mineral density and prevalent vertebral fractures.

OBJECTIVES: Our objectives were to assess the magnitude of the disparity in lumbar spine bone mineral density (LSBMD) Z-scores generated by different reference databases and to evaluate whether the relationship between LSBMD Z-scores and vertebral fractures (VF) varies by choice of database. PATIENTS AND DESIGN: Children with leukemia underwent LSBMD by cross-calibrated dual-energy x-ray absorptiometry, with Z-scores generated according to Hologic and Lunar databases. VF were assessed by the Genant method on spine radiographs. Logistic regression was used to assess the association between fractures and LSBMD Z-scores. Net reclassification improvement and area under the receiver operating characteristic curve were calculated to assess the predictive accuracy of LSBMD Z-scores for VF. RESULTS: For the 186 children from 0 to 18 years of age, 6 different age ranges were studied. The Z-scores generated for the 0 to 18 group were highly correlated (r ≥ 0.90), but the proportion of children with LSBMD Z-scores ≤-2.0 among those with VF varied substantially (from 38-66%). Odds ratios (OR) for the association between LSBMD Z-score and VF were similar regardless of database (OR = 1.92, 95% confidence interval 1.44, 2.56 to OR = 2.70, 95% confidence interval 1.70, 4.28). Area under the receiver operating characteristic curve and net reclassification improvement ranged from 0.71 to 0.75 and -0.15 to 0.07, respectively. CONCLUSIONS: Although the use of a LSBMD Z-score threshold as part of the definition of osteoporosis in a child with VF does not appear valid, the study of relationships between BMD and VF is valid regardless of the BMD database that is used.

Vertebral fractures despite normal spine bone mineral density in a boy with nephrotic syndrome.

Glucocorticoids (GCs) are associated with fragility fractures in children with various chronic illnesses. The impact of GCs on bone health in children with nephrotic syndrome (NS) is less well understood. Here we report skeletal findings in a 10-year-old boy with steroid-sensitive NS who presented with back pain due to vertebral fractures 5 years after NS diagnosis. Spine radiographs showed a Genant grade 2 fracture at T7 and a grade 1 fracture at T8. Dual-energy X-ray absorptiometry (DXA) revealed a lumbar spine areal bone mineral density (BMD) Z-score of -0.5 and a total body areal BMD Z-score of -0.4. Quantitative transiliac bone histomorphometry revealed low trabecular bone volume and cortical width but no osteomalacia. Our findings show the potential for significant bone morbidity due to osteoporosis in steroid-sensitive NS treated with intermittent GC therapy and emphasize that vertebral fractures may be an underrecognized complication. Furthermore, our report highlights that vertebral fractures can be associated with normal spine areal BMD in this context, suggesting that DXA-based, anteroposterior areal BMD should not be relied upon exclusively for assessing bone health and disease in children with steroid-sensitive NS.

Osteosclerosis in two brothers with autosomal dominant pseudohypoparathyroidism type 1b: bone histomorphometric analysis.

OBJECTIVE: Pseudohypoparathyroidism (PHP) is a heterogeneous disorder characterized by hypocalcemia and hyperphosphatemia resulting from selective renal resistance to parathyroid hormone (PTH). One autosomal dominant form of PHP type 1b (PHP-Ib) is most frequently caused by a maternally inherited 3-kb deletion within STX16, the gene encoding syntaxin 16. To date, increased bone mineral density (BMD) has been described only in PHP type 1a, and there is a lack of detailed information on bone histomorphometry in PHP-Ib. The objective of this report was to present trans-iliac static and dynamic histomorphometry in two brothers with the 3-kb deletion in the STX16 region and elevated BMD. DESIGN: Observational study of two brothers (age 18.0 and 22.7 years) with the 3-kb STX16 deletion and increased BMD. RESULTS: The brothers had elevated PTH (146 pg/ml (15.6 pmol/l) and 102 pg/ml (10.9 pmol/l); normal: 10-64 pg/ml (1.1-6.8 pmol/l)) and striking osteosclerosis (lumbar spine areal BMD Z-scores: +5.4 and +4.9). Bone histomorphometry showed marked elevations in cortical width for both brothers (241 and 209% of the mean result expected for age), with elevations in the bone formation rate on the endocortical (119 and 260% of the healthy mean) and trabecular (220 and 190% of mean) surfaces. CONCLUSION: Our findings suggest that PTH in this PHP-Ib genotype can increase cortical thickness due to its anabolic effect on endocortical bone, and underscore the heterogeneity in the skeletal phenotype among patients with PHP-Ib.

Zoledronic acid for the treatment of osteopenia in pediatric Crohn's disease.

BACKGROUND: Pediatric patients with Crohn's disease often have low bone mass (osteopenia) for age. No randomized, placebo-controlled trials using zoledronic acid have ever been performed in this population. The objective of this study was to assess the efficacy of zoledronic acid in children with Crohn's disease and osteopenia. METHODS: A double-blind, randomized, placebo-controlled design was used. Thirteen adolescents received either a single intravenous dose of zoledronic acid (0.066 mg/kg, max 4 mg, n= 7) or saline placebo (n= 6). The primary outcome was change in lumbar spine bone mineral density (LSBMD) z-score at 6 months. Secondary outcomes included bone markers and adverse events. RESULTS: At 6 months, the change in LSBMD z-score was significantly higher in the zoledronic acid group compared to placebo (0.7 vs 0.1, P < 0.001). Volumetrically adjusted LSBMD z-score also significantly increased in the treated group. This significant difference persisted until 12 months. With zoledronic acid, urinary C-telopeptide excretion decreased by 50% at 6 months and remained suppressed at 12 months (P= 0.02), but no changes were observed with placebo. Both groups had similar adverse events which included transient fever, arthralgias, and nausea (3/7 treated, 2/6 placebo, P= NS). CONCLUSIONS: In this study, zoledronic acid demonstrated a significant increase in LSBMD at 6 and 12 months following a well-tolerated infusion.