Skeletal findings in the first 12 months following initiation of glucocorticoid therapy for pediatric nephrotic syndrome

• Published in: Osteoporosis international Vol. 25; no. 2; pp. 627 - 637
• Main Authors: Phan, V., Blydt-Hansen, T., Feber, J., Alos, N., Arora, S., Atkinson, S., Bell, L., Clarson, C., Couch, R., Cummings, E. A., Filler, G., Grant, R. M., Grimmer, J., Hebert, D., Lentle, B., Ma, J., Matzinger, M., Midgley, J., Pinsk, M., Rodd, C., Shenouda, N., Stein, R., Stephure, D., Taback, S., Williams, K., Rauch, F., Siminoski, K., Ward, L. M.
• Format: Journal Article
• Language: English
• Published: London Springer London 01-02-2014; Springer Nature B.V
• Subjects: Adolescent; Anthropometry - methods; Bone density; Bone Density - drug effects; Child; Child, Preschool; Childrens health; Dose-Response Relationship, Drug; Endocrinology; Female; Follow-Up Studies; Fractures; Glucocorticoids - administration & dosage; Glucocorticoids - adverse effects; Glucocorticoids - therapeutic use; Humans; Infant; Kidney diseases; Lumbar Vertebrae - physiopathology; Male; Medicine; Medicine & Public Health; Nephrotic Syndrome - drug therapy; Nephrotic Syndrome - physiopathology; Original Article; Orthopedics; Osteoporosis - chemically induced; Osteoporotic Fractures - chemically induced; Osteoporotic Fractures - physiopathology; Rheumatology; Spinal Fractures - chemically induced; Spinal Fractures - physiopathology; Steroids; Vertebrae; Vertebral fracture; Osteoporosis; Bone mineral density; Nephrotic syndrome; Children
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-013-2466-7

Summary
Incident vertebral fractures and lumbar spine bone mineral density (BMD) were assessed in the 12 months following glucocorticoid initiation in 65 children with nephrotic syndrome. The incidence of vertebral fractures was low at 12 months (6 %) and most patients demonstrated recovery in BMD Z-scores by this time point.
Introduction
Vertebral fracture (VF) incidence following glucocorticoid (GC) initiation has not been previously reported in pediatric nephrotic syndrome.
Methods
VF was assessed on radiographs (Genant method); lumbar spine bone mineral density (LS BMD) was evaluated by dual-energy X-ray absorptiometry.
Results
Sixty-five children were followed to 12 months post-GC initiation (median age, 5.4 years; range, 2.3–17.9). Three of 54 children with radiographs (6 %; 95 % confidence interval (CI), 2–15 %) had incident VF at 1 year. The mean LS BMD Z-score was below the healthy average at baseline (mean ± standard deviation (SD), −0.5 ± 1.1;
p
 = 0.001) and at 3 months (−0.6 ± 1.1;
p
 < 0.001), but not at 6 months (−0.3 ± 1.3;
p
 = 0.066) or 12 months (−0.3 ± 1.2;
p
 = 0.066). Mixed effect modeling showed a significant increase in LS BMD Z-scores between 3 and 12 months (0.22 SD; 95 % CI, 0.08 to 0.36;
p
 = 0.003). A subgroup (
N
 = 16; 25 %) had LS BMD Z-scores that were ≤−1.0 at 12 months. In these children, each additional 1,000 mg/m
2
of GC received in the first 3 months was associated with a decrease in LS BMD Z-score by 0.39 at 12 months (95 % CI, −0.71 to −0.07;
p
 = 0.017).
Conclusions
The incidence of VF at 1 year was low and LS BMD Z-scores improved by 12 months in the majority. Twenty-five percent of children had LS BMD Z-scores ≤−1.0 at 12 months. In these children, LS BMD Z-scores were inversely associated with early GC exposure, despite similar GC exposure compared to the rest of the cohort.