A Patient With Autoimmune Liver Disease on Steroids: Screening and Treatment of Bone Disease

A 38-year-old woman presented with clinical and biochemical features of acute hepatitis. A tentative diagnosis of type 1 autoimmune hepatitis was made on the basis of positive autoantibodies (antinuclear and anti-smooth muscle), hypergammaglobulinemia, and hypocomplementemia. She was started on oral prednisone 40 mg/day, tapered over the subsequent 12 weeks to a maintenance dose of 7.5 mg/day. Azathioprine 100 mg/day then was introduced for its steroid-sparing effect, and she was started on vitamin D and calcium supplements. Her bone density (after 18 months of treatment) revealed a spine Z-score of −1.2 and a hip Z-score of −.8. She has never broken any bones, does not smoke, takes oral contraceptives, and has no other major risk factors for osteoporosis. What is the interpretation of the bone density Z-scores? How can this patient’s fracture risk be minimized, and how should she be monitored?