Nazih Shenouda

Advanced Vertebral Fracture among Newly Diagnosed Children with Acute Lymphoblastic Leukemia: Results of the Canadian STeroid-associated Osteoporosis in the Pediatric Population (STOPP) Research Program

Vertebral compression is a serious complication of childhood acute lymphoblastic leukemia (ALL). The prevalence and pattern of vertebral fractures, as well as their relationship to BMD and other clinical indices, have not been systematically studied. We evaluated spine health in 186 newly diagnosed children (median age, 5.3 yr; 108 boys) with ALL (precursor B cell: N = 167; T cell: N = 19) who were enrolled in a national bone health research program. Patients were assessed within 30 days of diagnosis by lateral thoraco‐lumbar spine radiograph, bone age (also used for metacarpal morphometry), and BMD. Vertebral morphometry was carried out by the Genant semiquantitative method. Twenty‐nine patients (16%) had a total of 75 grade 1 or higher prevalent vertebral compression fractures (53 thoracic, 71%; 22 lumbar). Grade 1 fractures as the worst grade were present in 14 children (48%), 9 patients (31%) had grade 2 fractures, and 6 children (21%) had grade 3 fractures. The distribution of spine fracture was bimodal, with most occurring in the midthoracic and thoraco‐lumbar regions. Children with grade 1 or higher vertebral compression had reduced lumbar spine (LS) areal BMD Z‐scores compared with those without (mean ± SD, −2.1 ± 1.5 versus −1.1 ± 1.2; p < 0.001). LS BMD Z‐score, second metacarpal percent cortical area Z‐score, and back pain were associated with increased odds for fracture. For every 1 SD reduction in LS BMD Z‐score, the odds for fracture increased by 80% (95% CI: 10–193%); the presence of back pain had an OR of 4.7 (95% CI: 1.5–14.5). These results show that vertebral compression is an under‐recognized complication of newly diagnosed ALL. Whether the fractures will resolve through bone growth during or after leukemia chemotherapy remains to be determined.

Prevalent Vertebral Fractures among Children Initiating Glucocorticoid Therapy for the Treatment of Rheumatic Disorders

Vertebral fractures are an under‐recognized problem in children with inflammatory disorders. We studied spine health among 134 children (87 girls) with rheumatic conditions (median age 10 years) within 30 days of initiating glucocorticoid therapy.

Incident vertebral fractures among children with rheumatic disorders 12 months after glucocorticoid initiation: a national observational study.

To determine the frequency of incident vertebral fractures (IVF) 12 months after glucocorticoid (GC) initiation in children with rheumatic diseases and to identify children at higher risk.

High Incidence of Vertebral Fractures in Children With Acute Lymphoblastic Leukemia 12 Months After the Initiation of Therapy

PURPOSE Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported. PATIENT AND METHODS We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures. RESULTS Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006). CONCLUSION Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features.

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.

Incident Vertebral Fractures in Children With Leukemia During the Four Years Following Diagnosis

OBJECTIVES The purpose of this article was to determine the incidence and predictors of vertebral fractures (VF) during the 4 years after diagnosis in pediatric acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS Children were enrolled within 30 days of chemotherapy initiation, with incident VF assessed annually on lateral spine radiographs according to the Genant method. Extended Cox models were used to assess the association between incident VF and clinical predictors. RESULTS A total of 186 children with ALL completed the baseline evaluation (median age, 5.3 years; interquartile range, 3.4-9.7 years; 58% boys). The VF incidence rate was 8.7 per 100 person-years, with a 4-year cumulative incidence of 26.4%. The highest annual incidence occurred at 12 months (16.1%; 95% confidence interval [CI], 11.2-22.7), falling to 2.9% at 4 years (95% CI, 1.1-7.3). Half of the children with incident VF had a moderate or severe VF, and 39% of those with incident VF were asymptomatic. Every 10 mg/m(2) increase in average daily glucocorticoid dose (prednisone equivalents) was associated with a 5.9-fold increased VF risk (95% CI, 3.0-11.8; P < .01). Other predictors of increased VF risk included VF at diagnosis, younger age, and lower spine bone mineral density Z-scores at baseline and each annual assessment. CONCLUSIONS One quarter of children with ALL developed incident VF in the 4 years after diagnosis; most of the VF burden was in the first year. Over one third of children with incident VF were asymptomatic. Discrete clinical predictors of a VF were evident early in the patients clinical course, including a VF at diagnosis.

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.

Observer agreement in pediatric semiquantitative vertebral fracture diagnosis.

BackgroundThe Genant semiquantitative (GSQ) method has been a standard procedure for diagnosis of vertebral fractures in adults but has only recently been shown to be of clinical utility in children. Observer agreement using the GSQ method in this age group has not been described.ObjectiveTo evaluate observer agreement on vertebral readability and vertebral fracture diagnosis using the GSQ method in pediatric vertebral morphometry.Materials and methodsSpine radiographs of 186 children with acute lymphoblastic leukemia were evaluated independently by three radiologists using the same GSQ methodology as in adults. A subset of 100 radiographs was evaluated on two occasions.ResultsAn average of 4.7% of vertebrae were unreadable for the three radiologists. Intraobserver Cohen’s kappa (κ) on readability ranged from 0.434 to 0.648 at the vertebral level and from 0.416 to 0.611 at the patient level, while interobserver κ for readability had a range of 0.330 to 0.504 at the vertebral level and 0.295 to 0.467 at the patient level. Intraobserver κ for the presence of vertebral fracture had a range of 0.529 to 0.726 at the vertebral level and was 0.528 to 0.767 at the patient level. Interobserver κ for fracture at the vertebral level ranged from 0.455 to 0.548 and from 0.433 to 0.486 at the patient level.ConclusionMost κ values for both intra- and interobserver agreement in applying the GSQ method to pediatric spine radiographs were in the moderate to substantial range, comparable to the performance of the technique in adult studies. The GSQ method should be considered for use in pediatric research and clinical practice.

The Radiology of Vertebral Fractures in Childhood Osteoporosis Related to Glucocorticoid Administration

A number of unusual conditions cause decreased bone mass and density in children and these may be associated with low-trauma fractures. However, a series of reports have more recently identified that children with chronic disease sustain vertebral fractures (VFs) much more often than had been suspected. The common denominator involved is glucocorticoid (GC) administration, although other factors such as disease activity come into play. This review will focus on the imaging findings in this form of secondary osteoporosis. Spinal fractures in children have been found to correlate with back pain. At the same time, up to 2/3 of children with VFs in the GC-treated setting are asymptomatic, underscoring the importance of routine surveillance in at-risk children. Other predictors of prevalent and incident VFs include GC exposure (average daily and cumulative dose), declines in lumbar spine bone mineral density Z-scores and increases in body mass index Z-scores, as well as increases in disease activity scores. The imaging diagnosis of osteoporotic VFs in children is made differently from that in adults because immature vertebral bodies continue to ossify during growth. Thus, it is not possible to assess the vertebral end plates or periphery until late, as enchondral ossification extends centripetally within the centrum. Diagnosis, therefore, is much more dependent upon changes in shape than on loss of structural integrity, which may have a more prominent diagnostic role in adults. However, children have a unique ability to model (a growth-dependent process) and thereby reshape previously fractured vertebral bodies. If the underlying disease is successfully treated and the child has sufficient residual growth potential, this means that, on one hand, treatment of the bone disease may be of more limited duration, and, as a last recourse, the diagnosis may be apparent retrospectively.

Impact of vertebral fractures and glucocorticoid exposure on height deficits in children during treatment for 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.