Bone Abstracts

Autoimmune hepatitis (AIH) is an immune-mediated chronic inflammatory disease of the liver of unknown origin, that suddenly appears in previously healthy, normally growing children. Standard therapy is long-term prednisone, aimed at avoiding progression to cirrhosis. Considering the inflammatory origin of the disease and the long-term steroid therapy, negative consequences for bone health can be expected, but no data on this complication have been published until now.

We measured lumbar spine bone mineral density in 17 children (8 F, 9 M) affected by AIH and treated with steroids. Two DXA scans were performed, at the time of diagnosis (liver biopsy) and after 12 months of steroid therapy. The bone mineral apparent density (BMAD) Z-score was −1.8±1.3 (calculated with respect to a healthy age- and sex-matched Italian population). In particular, 12 children had a lower-than-normal Z-score (−1.2 to −3.8), and the lower values were observed in pubertal (Z-score −1.9±1.7) rather than in pre-pubertal children (Z-score −1±1.2).

After 1 year of steroids, even with adequate calcium intake and vitamin D supplementation, BMAD showed a further decrease (Z-score −2.5±1.4): 13 children (76.4%) showed a mean Z-score reduction of −0.95±.5. Three children sustained a fragility fracture in the first months of steroid treatment (vertebral fractures in two cases).

The BMAD Z-score values were correlated to age at onset of AIH (r=−0.31, P<0.02) and cumulative steroid dose (r=−0.30, P<0.02).

In conclusion, these data call attention upon a problem that has been neglected until now. In AIH, bone mineral density may be reduced at a very early time, even before starting steroid therapy, particularly in pubertal children. The risk of vertebral fractures strongly recommends an evaluation of bone density with DXA as soon as possible after a diagnosis of AIH. The required immunosuppressive therapy must be carefully and individually tailored to minimize further negative effects on bone.