Mark Sapsford1, Gregory D Gamble1, Opetaia Aati1, Julie Knight1, Anne Horne1, Anthony J Doyle2, Nicola Dalbeth3. 1. Bone and Joint Research Group, Department of Medicine. 2. Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand. 3. Bone and Joint Research Group, Department of Medicine n.dalbeth@auckland.ac.nz.
Abstract
OBJECTIVES: Imaging and pathology studies have established a close relationship between tophus and bone erosion in gout. The tophus is an organized structure consisting of urate crystals and chronic inflammatory tissue. The aim of this work was to examine the relationship between bone erosion and each component of the tophus. METHODS: Plain radiographs and dual energy CT scans of the feet were prospectively obtained from 92 people with tophaceous gout. The 10 MTP joints were scored for erosion score, tophus urate and soft tissue volume. Data were analysed using generalized estimating equations and mediation analysis. RESULTS: Tophus was visualized in 80.2% of all joints with radiographic (XR) erosion [odds ratio (OR) = 7.1 (95% CI: 4.8, 10.6)] and urate was visualized in 78.6% of all joints with XR erosion [OR = 6.6 (95% CI: 4.7, 9.3)]. In mediation analysis, tophus urate volume and soft tissue volume were directly associated with XR erosion score. About a third of the association of the tophus urate volume with XR erosion score was indirectly mediated through the strong association between tophus urate volume and tophus soft tissue volume. CONCLUSION: Urate and soft tissue components of the tophus are strongly and independently associated with bone erosion in gout.
OBJECTIVES: Imaging and pathology studies have established a close relationship between tophus and bone erosion in gout. The tophus is an organized structure consisting of urate crystals and chronic inflammatory tissue. The aim of this work was to examine the relationship between bone erosion and each component of the tophus. METHODS: Plain radiographs and dual energy CT scans of the feet were prospectively obtained from 92 people with tophaceous gout. The 10 MTP joints were scored for erosion score, tophus urate and soft tissue volume. Data were analysed using generalized estimating equations and mediation analysis. RESULTS: Tophus was visualized in 80.2% of all joints with radiographic (XR) erosion [odds ratio (OR) = 7.1 (95% CI: 4.8, 10.6)] and urate was visualized in 78.6% of all joints with XR erosion [OR = 6.6 (95% CI: 4.7, 9.3)]. In mediation analysis, tophus urate volume and soft tissue volume were directly associated with XR erosion score. About a third of the association of the tophus urate volume with XR erosion score was indirectly mediated through the strong association between tophus urate volume and tophus soft tissue volume. CONCLUSION:Urate and soft tissue components of the tophus are strongly and independently associated with bone erosion in gout.
Authors: Chang-Nam Son; Ken Cai; Sarah Stewart; John Ferrier; Karen Billington; Yun-Jung Jack Tsai; Thomas Bardin; Anne Horne; Lisa K Stamp; Anthony Doyle; Nicola Dalbeth Journal: Arthritis Res Ther Date: 2021-12-08 Impact factor: 5.156