Objectives: Diminished bone mineral density (BMD) is a recognized complication of Crohn's disease (CD). The mechanisms underlying bone loss are unclear but may include a direct effect of inflammatory cytokines related to disease activity. Because tumor necrosis factor alpha (TNF-alpha) plays a central role in the pathogenesis of CD inflammation, we evaluated the effect on BMD of maintenance treatment with infliximab in patients with CD.
Methods: BMD of the lumbar spine (L2-L4) and proximal left femur (neck and trochanter) were measured at baseline and 1 yr in 46 CD patients treated with infliximab (5 mg/kg) at 6-8 wk intervals for 1 yr. Thirteen patients received concurrent prednisone at a mean dose of 10 mg/day (range: 5-15).
Results: At baseline, reduced BMD (T-score <or= 1) occurred in 43% of patients at the lumbar spine and 46% at the left femur. Between baseline and 1 yr, mean BMD increased at the lumbar spine by 2.4%+/- 0.7% (p= 0.002), at the femoral trochanter by 2.8%+/- 1.2% (p= 0.03), and at the femoral neck by 2.6%+/- 0.7% (p= 0.001). BMD gain at the lumbar spine and the left femur between the groups without and with osteopenia were not different. Changes in BMD were not correlated with concurrent corticosteroid therapy, calcium supplementation, or changes in C-reactive protein (CRP).
Conclusions: Maintenance treatment with infliximab improves BMD in patients with CD and this effect is independent of corticosteroid administration. The BMD response after infliximab suggests that TNF-alpha plays a role in the bone loss associated with CD.