DOES BONE MINERAL DENSITY CHANGE IN EARLY AXIAL SPONDYLOARTHRITIS?

The rate of osteoporosis (OP) and the mechanism  of its development in patients with ankylosing spondylitis (AS) and other spondyloarthrititides (SpA) have not been sufficiently investigated. Steady-state  inflammatory disease activity is anticipated  to be the leading factor of OP in AS.

Objective: to investigate lumbar spine (LS) and femoral neck (FN)  bone mineral density (BMD)  in patients with early axial SpA (axSpA) and to reveal its association with inflammatory disease activity.

Subjects and methods. A total of 150 patients (59 men and 91 women) aged 18 to 45 years with inflammatory back pain for ≥3 months and ≤5 years were examined. The diagnosis of axSpA was established in accordance  with the 2009 ASAS criteria. BASDAI and ASDAS-CRP were used to assess activity and functional status was evaluated with BASFI. The examination  included determination of HLA-B27, X-ray of the pelvis and LS, magnetic resonance imaging (MRI)  of the sacroiliac joints, LS, and hip joints (in the presence of clinical signs of their involvement),  and densitometry of LS (LI–IV)  and FN. By taking into account the patients’ young age, the Z score was used to estimate BMD. The Z-score -2 SD or lower in at the least one of the regions examined is considered to be diminished BMD. Results and discussion. The median Z-score was -0.7 [-1.3; -0.2] SD for FN and -0.9 [-1.6; -0.6] SD for LS. Reduced BMD in at the least one of the regions examined was diagnosed in 27 (18.0%) patients. There was lower BMD in LS in 21 (14.0%) patients and in FN in 8 (5.3%). Two (1.3%) patients were diagnosed as having osteopenia in the two examined regions. There was no association between diminished BMD and age, gender, disease activity assessed with BASDAI, ASDAS-СRP, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). An association was found between inflammatory LS changes, as evidenced by MRI (MRI spondylitis), and reduced BMD in at least one of the examined regions. MRI spondylitis was detected in 27 (18.0%) patients. Decreased BMD in any of the examined skeletal regions was seen in 9 (33.3%) of the 27 patients having MRI spondylitis; the remaining 18 (66.7%) patients had normal BMD values. In the absence of MRI spondylitis, osteopenia was identified in 18 (14.6%) patients; normal BMD values were noted in 105 (85.4%); p = 0.03).

There was also a relationship  between the presence of MRI spondylitis and diminished  BMD in the same region. LS osteopenia  was found in 7 (25.9%) patients with MRI spondylitis and LS BMD remained  within the normal range in 20 (74.1%). In the absence of MRI spondylitis, LS osteopenia  was observed in 14 (11.4%) patients and LS BMD was normal in 109 (88.6%) (p < 0.05).

Conclusion. There was an association between inflammatory LS changes, as evidenced by MRI,  and reduced BMD in the same region. Our findings confirm the hypothesis that bone mass loss in the vertebral bodies in early axSpA results from local inflammation.

1. Лесняк ОМ, Беневоленская ЛИ, редакторы. Остеопороз. Диагностика, профилактика и лечение. 2-е изд. Москва: ГЭОТАР-Медиа; 2009. 270 с. [Lesnyak OM, Benevolenskaya LI, editors. Osteoporoz. Diagnostika, profilaktika i lechenie [Osteoporosis. Diagnosis, prevention and treatment]. 2nd ed. Moscow: GEOTAR-Media; 2009. 270 p.].

2. Toussirot E, Michel F, Wendling D. Bone density, ultrasound measurements and body composition in early ankylosing spondylitis. Rheumatology (Oxford). 2001;40:882-8. doi: 10.1093/rheumatology/40.8.882

3. Briot K, Durnez A, Paternotte S, et al. Bone oedema on MRI is highly associated with low bone mineral density in patients with early inflammatory back pain: results from the DESIR cohort. Ann Rheum Dis. 2013;72(12):1914-9. doi: 10.1136/annrheumdis-2012-201845

4. Haugeberg G, Bennett AN, McGonagle D, et al. Bone loss in very early inflammatory back pain in undifferentiated spondyloarthropathy: a 1-year observational study. Ann Rheum Dis. 2010;69:1364-6. doi: 10.1136/ard.2009.124982

5. Bessant R, Keat A. How shoud clinicians manage osteoporosis in ankylosing spondylitis? J Rheumatol. 2002;29:1511-9.

6. Sarikaya S, Basaran A, Tekin Y, et al. Is osteoporosis generalized or localized to central skeleton in ankylosing spondylitis? J Clin Rheumatol. 2007;13:20-4. doi: 10.1097/01.rhu.0000255688.83037.42

7. Ghozlani I, Ghazi M, Nouijai A, et al. Prevalence and risk factors of osteoporosis and vertebral fractures in patients with ankylosing spondylitis. Bone. 2009;44:772-6. doi: 10.1016/j.bone.2008.12.028

8. Kim H-R, Kim H-Y, Lee S-H. Elevated serum levels of soluble receptor activator of nuclear factors-κB ligand (sRANKL) and reduced bone mineral density in patients with ankylosing spondylitis (AS). Rheumatology. 2006;45:1197-200. doi: 10.1093/rheumatology/kel072

9. Klingberg E. Clinical study on osteoporosis in ankylosing spondylitis. Dissertation. Gothenburg: Centre for Bone and Arthritis Research Department of Rheumatology and Inflammation Research Sahlgrenska Academy at University of Gothenburg; 2013.

10. Mei Y, Pan F, Gao J, et al. Increased serum IL-17 and IL-23 in the patient with ankylosing spondylitis. Clin Rheum. 2011;30(2):269-73. doi: 10.1007/s10067-010-1647-4

11. Maillefert JF, Aho LS, Maghraoui A, et al. Changes in bone density in patients with ankylosing spondylitis: a two-year follow-up study. Osteoporos Int. 2001;12:605-9. doi: 10.1007/s001980170084

12. Gratacos J, Collado A, Pons F, et al. Significant loss of bone mass in patients with early, active ankylosing spondylitis: a followup study. Arthritis Rheum. 1999;42:2319-24. doi:10.1002/1529-0131(199911)42:11<2319::AID-ANR9>3.0.CO;2-G

13. Rudwaleit M, Landewe R, van der Heijde D, et al. The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part I): classification of paper patients by expert opinion including uncertainty appraisal. Ann Rheum Dis. 2009;68(6):770-6. doi: 10.1136/ard.2009.108217

14. Sieper J, Ruadwaleit M, Baraliakos X, et al. The Assesment of Spondyloarthritis international Society (ASAS) Handbook: a guide to assess spondyloarthritis. Ann Rheum Dis. 2009;68 Suppl. II:ii1ii44. doi: 10.1136/ard.2008.104018

15. Official Positions of the International Society for Clinical Densitometry, Copyright ISCD, October 2007, Supersedes all prior «Official Positions» publications.