Bone mineral density in children wth systemic lupus erythematosus and juvenile rheumatoid arthritis

Evaluation of Bone Mineral Density in Juvenile Systemic Lupus Erythematosus

Objectives

The present study aimed to determine the prevalence of low bone mineral density (BMD) and low bone mineral content (BMC) as chronic complications of juvenile systemic lupus erythematosus (JSLE) and identify the associated variables and patient characteristics to investigate the relationship between BMD and influential factors.

Methods

This cross-sectional study enrolled 54 patients with JSLE, including 38 females and 16 males. The BMD and BMC were assessed by dual-energy X-ray absorptiometry in the hip (femoral neck) and the lumbar spine. Low BMD was considered a Z-score < -2. The study investigated the association of BMC and Z-score with the current daily dose of corticosteroids, the daily dose of corticosteroids at disease onset, the duration of disease, the duration of steroid treatment, the time from the onset of symptoms to diagnosis, and renal involvement.

Results

The prevalence of low BMD in the lumbar spine and the femoral neck was 14.8% and 18.5%, respectively; the reduction of BMD was more significant in the femoral neck compared to the lumbar spine. Osteoporosis was detected in one patient. The multiple linear regression analysis found a significant association between a higher daily corticosteroid dose and lower BMC of the femoral neck and the lumbar spine. In addition, patients receiving higher doses of corticosteroids at disease onset showed better follow-up bone mineral densitometry results.

Conclusion

Based on the findings of this study, JSLE more affects the femoral neck than the lumbar spine. Patients receiving a more robust treatment with higher doses of corticosteroids at disease onset (to control the inflammatory processes) showed better spinal BMC results. A higher dose of daily corticosteroid treatment during assessment was identified as a risk factor for low BMD.

A systematic review and meta-analysis of glucocorticoid-induced osteoporosis in children

OBJECTIVE

To summarize the published effects of systemic glucocorticoid therapy on bone mineral density (BMD) and fractures in children.

METHODS

We performed a systematic review and meta-analysis of existing literature, using Medline, CINAHL, and Cochrane databases to identify studies of BMD or fractures in children ≤18 years taking systemic glucocorticoid therapy. We excluded studies of inhaled glucocorticoids, chemotherapy, and organ transplantation. Two authors reviewed abstracts for inclusion, read full-text articles to extract data, and rated each study using the Downs-Black scale.

RESULTS

A total of 16 studies met eligibility criteria, including 10 BMD (287 children) and six fracture (37,819 children) studies. Spine BMD was significantly lower (-0.18; 95% CI = -0.25; -0.10 g/cm(2)) in children taking glucocorticoid therapy, compared to age- and gender-matched healthy controls. Spine BMD was also lower (-0.14; 95% CI = -0.27; 0.00 g/cm(2)) in children taking glucocorticoids, compared to children with the same disease not taking glucocorticoids. Incident clinical fracture rates varied from 2% to 33%. Morphometric vertebral fracture incidence ranged from 6% to 10%, and prevalence was 29-45%.

CONCLUSION

Published data suggest that children treated with glucocorticoid therapy have lower spine BMD compared to healthy children. Whether children receiving glucocorticoid therapy have lower spine BMD compared to children with milder disease not requiring such therapy is not certain. Clinical and morphometric vertebral fractures are common, although only one study assessed fracture rates in healthy controls. Additional well-designed, prospective studies are needed to evaluate the skeletal effects of glucocorticoid therapy in children.

Prevalent vertebral fractures among children initiating glucocorticoid therapy for the treatment of rheumatic disorders

OBJECTIVE

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.

METHODS

Children were categorized as follows: juvenile dermatomyositis (n = 30), juvenile idiopathic arthritis (n = 28), systemic lupus erythematosus and related conditions (n = 26), systemic arthritis (n = 22), systemic vasculitis (n = 16), and other conditions (n = 12). Thoracolumbar spine radiograph and dual x-ray absorptiometry for lumbar spine (L-spine) areal bone mineral density (BMD) were performed within 30 days of glucocorticoid initiation. Genant semiquantitative grading was used for vertebral morphometry. Second metacarpal morphometry was carried out on a hand radiograph. Clinical factors including disease and physical activity, calcium and vitamin D intake, cumulative glucocorticoid dose, underlying diagnosis, L-spine BMD Z score, and back pain were analyzed for association with vertebral fracture.

RESULTS

Thirteen vertebral fractures were noted in 9 children (7%). Of these, 6 patients had a single vertebral fracture and 3 had 2-3 fractures. Fractures were clustered in the mid-thoracic region (69%). Three vertebral fractures (23%) were moderate (grade 2); the others were mild (grade 1). For the entire cohort, mean +/- SD L-spine BMD Z score was significantly different from zero (-0.55 +/- 1.2, P < 0.001) despite a mean height Z score that was similar to the healthy average (0.02 +/- 1.0, P = 0.825). Back pain was highly associated with increased odds for fracture (odds ratio 10.6 [95% confidence interval 2.1-53.8], P = 0.004).

CONCLUSION

In pediatric rheumatic conditions, vertebral fractures can be present prior to prolonged glucocorticoid exposure.

Glucocorticoid-induced osteoporosis in rheumatic diseases

The aim of this article is to review rheumatological diseases that are associated with glucocorticoid-induced osteoporosis or fractures and to perform a critical analysis of the current guidelines and treatment regimens. The electronic database MEDLINE was searched using the date range of July 1986 to June 2009 and the following search terms: osteoporosis, bone mineral density, fractures, systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, vasculitis, juvenile rheumatoid arthritis, juvenile idiopathic arthritis and juvenile dermatomyositis. Osteopenia and osteoporosis respectively account for 1.4 to 68.7% and 5.0 to 61.9% of adult rheumatological diseases. Among juvenile rheumatological disorders, the frequency of low bone mass ranges from 38.7 to 70%. In general, fracture rates vary from 0 to 25%. Although glucocorticoid-induced osteoporosis has a high rate of prevalence among rheumatic diseases, a relatively low number of patients on continuous glucocorticoid treatment receive adequate diagnostic evaluation or preventive therapy. This deficit in patient care may result from a lack of clear understanding of the attributed risks by the patients and physicians, the high complexity of the treatment guidelines and poor patient compliance.