AB0480 INFLUENCE OF ANTI TNF THERAPIES AND HYPERHOMOCYSTEINEMIA ON BONE MINERAL DENSITY IN ANKILOSING SPONDYLITIS PATIENTS
Authors: D. Anghel, E. M. Hoinoiu, M. M. Negru, O. G. Petrache, N. O. Costache, V. Iachim, R. A. Bursuc, A. Ghiatau, A. Manolache, V. V. Smedescu, C. F. Plesa
Journal: Annals of the Rheumatic Diseases (2021)

Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease associated with an important risk factor of osteoporosis. A high serum level of Homocysteine (Hcy) has been recently recognized as a risk factor for osteoporosis and osteoporotic fractures. Treatment with TNF-α blockers might influence bone metabolism and prevent structural bone damage in AS. Objectives: The aim of the study was to evaluate the influence of anti-TNF therapies and hyperhomocysteinemia on bone mineral density in AS patients. Methods: In our retrospective study were enrolled 73 AS patients with anti TNF-α therapies (29 Adalimumab 40mg/2weeks, 24 Etanerceptum50mg/week, 20 Infliximabum5 mg/kg/8 weeks) and 45 AS patients non anti TNF-α therapies. All patients included in this study met the modified New York criteria. The current medications used by the non anti TNF-α therapies patients were nonsteroidal anti-inflammatory drugs. We used Dual energy x ray absorptiometry (DXA) method for measuring bone mineral density (BMD). Osteoporosis is defined as a T score of ≤ −2.5 SD, according to the WHO criteria. BMD of the hip and lumbar spine (L1-L4) was determined at baseline and after 6 months. Hcy concentrations were measured by using a chemiluminescence immunoassay method. The normal serum Hcy level is considered to be below 15mmol/L. In both group we followed the activities disease (C reactive protein-CRP, eritrocytes sedimentation rate-ESR, Bath ankylosing spondylitis disease activity index-BASDAI score) and determined vitamin D3 level. All parameters were determined at baseline and after 6 months. Results: The mean age of study group1 was 47.4±11.1 years and 42±9,8year in group2. The mean disease duration was 11.9 ± 6.1 years. 83,5% of patients were HLA-B27 positive in group1 and 71,1% in group2. BMD measurements revealed more severe osteoporosis in patients with positive HLA-B27 in both groups at baseline. After 6 months in group1 BMD increased by 0.4% at lumbar spine and 0.1% in the hip and in group2 decreased by 0.9% and 0.6% in the same sites. No significant differences between type of anti-TNF therapies and BMD. In group 1, HLA-B27 positive status was positive correlated with decrease BMD(p=0.001) after 6 months. Hcy levels were found significantly increased (14.8 ± 3.8 mg/mL vs. 12.4 ± 4.2 mg/mL; P &lt; 0.001) at baseline in both groups. Serum levels of Hcy were inversely correlated to lumbar spine BMD ( p &lt; 0.005) and femur neck BMD(p=0,001) after 6 months in group1. At baseline the mean level of 25-hydroxyvitamin D 3 was 22.8 ± 14.1 ng/mL in group1 and 26.6 ± 12.5 ng/mL in group2. In anti TNF patients group, we found a positive correlation between decrease BMD, low level of 25-hydroxyvitamin D 3 and high level of Hcy(p=0,001) after six months. No correlation was found between BMD and BASDAI score and inflammatory parameters (ESR, CRP). Conclusion: Bone mineral density measurements revealed more severe osteoporosis in positive HLA-B27 AS patients and hyperhomocysteinemia. Association of low level of 25-hydroxyvitamin D3 and hiperhomocysteinemia is correlated with high-risk fracture in positive HLA-B27 patients. Anti TNF therapies reduce this risk. References: [1]Kim JI, Moon JH, Chung HW, Kong MH, Kim HJ. Association between homocysteine and bone mineral density according to age and sex in healthy adults. J Bone Metab 2016; 23:129-34. [2]Fratoni V, Brandi ML. B Vitamins, homocysteine and bone health. Nutrients 2015; 7:2176-92. [3]Jahn O, Wex T, Klose S, Kropf S, Adolf D, Piatek S, et al. Cathepsin K in treatment monitoring following intravenous zoledronic acid. Biomed Rep 2014; 2:915-7. Disclosure of Interests: None declared.