Beek KJ, et al. - In 135 patients with Ankylosing Spondylitis (AS), researchers investigated how Bone Mineral Density (BMD) and the incidence of Vertebral Fractures (VFx) could be affected over long-term by treatment with TNF-inhibitors (TNFi). This study included consecutive patients who received a TNFi treatment for up to 4 years and had active AS, with available DXA scans and spine X-rays. At baseline and 4 years of TNFi treatment, they assessed BMD (classified according to the WHO criteria for osteoporosis) of hip and lumbar spine, the VFx (classified as a Genant-score > 1/> 20% height loss) and radiological progression (modified stoke ankylosing spondylitis spinal score; mSASSS) scores. In AS patients with a long disease duration, new VFx, increase in severity in the number and grade of VFx and radiographic progression were found during 4 years of treatment with TNFi despite the observed improvement of BMD and well-known reduction in disease activity.