Background/aims Radiographic damage is frequently observed in patients with longstanding gout. The aim of this prospective observational study was to determine factors associated with change in radiographic damage scores in gout.
Methods People with gout and disease duration <10 years were recruited into this prospective observational study. At the baseline visit, structured assessment was undertaken in 290 participants including detailed clinical examination and plain radiographs (XR) of the hands and feet. Participants were invited to attend a further study visit with repeat XR 3 years after the baseline visit. XR were scored for erosion and joint space narrowing according to the gout-modified Sharp/van der Heijde XR damage score.
Results Age, subcutaneous tophus count and tender joint count were independently associated with XR damage score at the baseline visit. Paired serial XR were available for 140 participants. In stepwise linear regression analysis, change in total damage score over 3 years was positively associated with change in subcutaneous tophus count and baseline XR damage score, and inversely associated with baseline subcutaneous tophus count (model R2=0.39, p<0.001). Change in subcutaneous tophus count contributed most to the change in erosion score (partial R2 change=0.31, p<0.001), and baseline XR damage score contributed most to the change in narrowing score (partial R2 change=0.31, p<0.001).
Conclusions Development of new subcutaneous tophi and baseline radiographic damage are associated with progressive joint damage scores in people with gout. These data provide further evidence that the tophus plays a central role in bone erosion in gout.
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Handling editor Tore K Kvien
Contributors ND (the guarantor) accepts full responsibility for the work and the conduct of the study, had access to the data and controlled the decision to publish. AE scored the radiographs and completed the first draft of the manuscript. MEH coordinated the study. ZV, JK and PT assisted with data management and study coordination. AH provided oversight of study coordination, recruitment and data management. GDG assisted with data analysis. AJD contributed to study design and data interpretation. WJT designed the study, led the study at the Wellington site and interpreted the data. ND designed the study, led the study at the Auckland site, scored the radiographs, analysed the data, interpreted the data and assisted with completion of the first draft of the manuscript. All authors revised and approved the final manuscript.
Funding This study was funded by Arthritis New Zealand, the University of Auckland and Henry Cotton Charitable Trust.
Competing interests ND has received consulting fees, grants or speaker fees from Takeda, Crealta, Menarini, AstraZeneca, Ardea, Pfizer, Cymabay and Fonterra, outside the submitted work. WJT has received consulting fees from AstraZeneca and Pfizer, outside the submitted work.
Patient consent Obtained.
Ethics approval The New Zealand Multiregional Ethics Committee approved the study (MEC/06/10/114).
Provenance and peer review Not commissioned; externally peer reviewed.
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