Osteoporosis and vertebral fractures in ankylosing spondylitis

Abstract

To review the recent literature on the prevalence of osteoporosis, risk of vertebral fractures, and the recent advances in the treatment of osteoporosis in patients with ankylosing spondylitis (AS). Newer data suggest that the prevalence of osteoporosis is 25% and vertebral fractures is 10% in patients with AS. New advances in the field of osteoimmunology help explain the trabecular bone loss and generalized osteoporosis linked to increased expression of receptor activator of nuclear factor kappa B ligand (RANK-L) due to pro-inflammatory cytokines, and the simultaneous new bone formation (e.g. syndesmophytes) in areas of previous inflammation through suppressed Dickkopf-related protein 1 levels and increased WNT (wingless) signaling. Osteoporosis is a common problem for patients with AS. We recommend screening within 10 years of diagnosis. Suspecting and promptly recognizing vertebral fractures in patients with AS could prevent serious neurological complications. Although bisphosphonates and tumor necrosis factor-α inhibitors look promising, further prospective trials on the treatment of osteoporosis in AS are needed.