A clinically significant number of children with rheumatic disorders develop vertebral fractures in the three years following glucocorticoid initiation, Canadian researchers have found.

Writing in the Journal of Bone and Mineral Health the researchers say their findings highlight the need for a bone health assessment in at-risk patients that includes not only a DXA-based BMD but also a lateral thoracolumbar spine radiograph.

The prospective study of 134 children with rheumatic disorders found an unadjusted vertebral fracture incidence rate of 4.4 per 100-person years, with a three-year incidence of 12.4%.

Every 0.5mg/kg increase in average daily glucocorticoid dose was associated with a two-fold increased fracture risk, reported the authors led by Claire LeBlanc from McGill University in Montreal, Canada.

Other factors predicting an increased vertebral fracture risk included increases in disease activity scores, from baseline to 12 months, increases in body mass index Z scores in the first 6 months of therapy, and decreases in lumbar spine bone mineral density Z-scores from baseline to 6 months.

The peak annual VF incidence occurred at 12 months, a finding that the authors said was not surprising given that GC exposure was highest in the first year of therapy.

An important finding was that almost one-half of the children were asymptomatic and would have been undiagnosed in the absence of radiographic monitoring, the study authors noted.

“It seems reasonable to recommend baseline spine radiograph at the time of GC initiation for any child anticipated to be on GC therapy for 3 months or more” they wrote.

“In addition, a follow-up radiograph at 12 months also appears justified given this is the time point of the highest annual VF incidence,” they added.