The Correlation of Bone Bridge and Low Bone Mineral Density Measured by Quantitative Computed Tomography in Patients with Ankylosing Spondylitis

So-Yun Lee¹, Sang Wan Chung ¹, Ran Song ², Hyung-In Yang ¹ and Sang-Hoon Lee ¹, ¹School of Medicine, Kyung Hee University, seoul, Republic of Korea, ²School of Medicine, Kyung Hee University, seoul

Meeting: 2019 ACR/ARP Annual Meeting

Keywords: Ankylosing spondylitis (AS) and osteoporosis

Session Information

Date: Sunday, November 10, 2019

Title: Spondyloarthritis Including Psoriatic Arthritis – Clinical Poster I: Axial Spondyloarthritis, Clinical Features

Session Type: Poster Session (Sunday)

Session Time: 9:00AM-11:00AM

Background/Purpose: Chronic inflammation of the spine leads not only to new bone formation in axial joints and vertebral spaces, but also to bone resorption leading to osteoporosis, which is increased in ankylosing spondylitis . We planned this study to know whether the formation of bone bridge correlate with low bone mineral density measured by quantitative computed tomography in patients with ankylosing spondylitis.

Methods: The patient’s BMD and medical records were analyzed retroactively through chart review. BMD of the lower thoracic and lumbar spine was assessed using QCT. Vertebrae from T11 to L4 were scanned in the supine position. For the BMD of spinal trabecular bone, thresholds of 120 mg/cm³ for osteopenia (equivalent to a DXA T-score of −1.0 SD) and 80 mg/cm³ for osteoporosis (equivalent to a DXA T-score of −2.5 SD) were suggested by the International Society for Clinical Densitometry in 2007 and by the American College of Radiology in 2008. We analyzed the near total or total bone bridge on X-rays at the thoracic and lumbar spine (T11-L5 level). R software packages was used for statistical analysis.

Results: Total 52 AS patients were enrolled : 78% male, mean age 47.3 years, mean disease duration 8.2 years, mean ESR 20.6 mm/h, mean CRP 0.7 mg/dL, all patients fulfil modified New York criteria. The trabecular BMD of the lower thoracic and lumbar spine (T11-L5) ranged from 29.1 to 178.8 mg/cm3 (mean 104.8 ± 34.1 mg/cm3), and lumbar spine (L1-L5) ranged from 22.5 to 177.7 mg/cm3 (mean 102.7 ± 35.5 mg/cm3) as measured by QCT. The lumbar BMD measurements showed that 15 (28.8%) had osteoporosis and 19 (36.5%) had osteopenia. Bone bridge formation showed negative correlation with BMD. Low BMD was significantly correlated with bone bridge of lateral side in vertebral body (p< 0.05), but not with bone bridge of anterior side in vertebral body. In particular, the correlation was found to be higher in the lumbar spine than the lower thoracic spine (p< 0.05).

Conclusion: The reducing mobility of vertebrae due to bone bridge formation affects low BMD in ankylosing spondylitis patients.

Disclosure: S. Lee, None; S. Chung, None; R. Song, None; H. Yang, None; S. Lee, None.

To cite this abstract in AMA style:

Lee S, Chung S, Song R, Yang H, Lee S. The Correlation of Bone Bridge and Low Bone Mineral Density Measured by Quantitative Computed Tomography in Patients with Ankylosing Spondylitis [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/the-correlation-of-bone-bridge-and-low-bone-mineral-density-measured-by-quantitative-computed-tomography-in-patients-with-ankylosing-spondylitis/. Accessed .

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