THU0399 Effects of 12-Month Etanercept Therapy on Disease Activity, Bone Turnover Markers and Peripheral QCT Bone Mineral Density in Patients with Ankylosing Spondylitis

Background Ankylosing spondylitis (AS) is a chronic inflammatory disease with elevated risk of vertebral fractures. Several factors play role in fracture rate in these patients including age, body mass index, immobility, spinal inflammation and high disease activity. Objectives The aim of our study was to investigate the relationship of bone mineral density (BMD) with some measures ofdisease activity and functional ability. In addition, we wished to determine the effects of 12-month etanercept (ETN) therapy on disease activity, bone markers, as well as bone density assessed by DEXA and peripheral qCT. Methods We assessed 17 AS patients (14 males, 3 females) with a mean age of 42.6 years and a mean disease duration of 7.2 years. 50mg weekly ETN therapy was administered and patients were assessed at baseline and after 3, 6 and 12 months of treatment. Disease activity was determined by BASDAI. BMD was evaluated by DEXA and by radius pQCT, a method capable of total, trabecular and cortical density assessment. In addition, serum osteocalcin, CTX, 25-hydroxy-D3 vitamin (25-OH-D3) and P1NP levels were also determined. Results BASDAI values improved significantly during the one-year anti-TNFα therapy (6.14, 2.26, 1.82 and 1.25 mean BASDAI at baseline and after 3, 6 and 12 months, respectively). DEXA and most bone markers showed no significant changes in BMD at the lumbar spine or femur region. However, peripheral qCT revealed increased total (852 mg/cm3) and trabecular density (279 mg/cm3) after 12 months of anti-TNF therapy in comparison to baseline values (773 mg/cm3 and 256 mg/cm3, respectively). In addition, 25-OH-D3 levels increased from 60 to 73 nmol/l (normal value: >75 nmol/l) upon one-year ETN treatment. Conclusions One-year ETNtherapy may prevent further bone loss in AS. Biologic treatment may have beneficial effects on the trabecular bone. ETN therapy may also restore 25-OH-D3 levels. Disclosure of Interest None Declared