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Abstract
Objectives The dynamics of monosodium urate (MSU) crystal changes across a range of serum urate concentrations in people with gout are unknown. This study aimed to systematically examine the relationship between serum urate and changes in dual-energy CT (DECT) urate volume in people with gout and stable serum urate concentrations.
Methods Individual participant data were analysed from three studies of people with gout. The time periods for the analysis were selected to identify study participants with serial DECT scans of both feet over a 12-month epoch of stable urate-lowering therapy and serum urate concentrations. Data from 251 study participants were analysed using a mixed models analysis of covariance approach according to mean serum urate cut-points and mean serum urate bands.
Results For all mean serum urate cut-points assessed (0.24, 0.30, 0.36, 0.42 and 0.48 mmol/L), reductions in DECT urate volumes were observed below the cut-point. Increased DECT urate volumes were observed at or above the 0.48 mmol/L mean serum urate cut-point. Differences in the change in DECT volume were observed for the 0.42 mmol/L cut-point (p=0.0044) and the 0.48 mmol/L cut-point (p<0.0001). Significantly reduced DECT urate volumes were observed for the mean serum urate bands<0.24 mmol/L and 0.24–0.29 mmol/L and increased DECT urate volume was observed for the mean serum urate band≥0.48 mmol/L.
Conclusions Over 1 year, MSU crystal dissolution, as measured by DECT, occurs with mean serum urate bands of<0.24 mmol/L and 0.24–0.29 mmol/L while MSU crystal formation occurs with mean serum urate≥0.48 mmol/L.
- Gout
- Crystal arthropathies
- Arthritis
- Therapeutics
- Epidemiology
Data availability statement
Data are available upon reasonable request. Analysed data may be made available upon reasonable request following review by the principal investigators with appropriate acknowledgements.
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Data availability statement
Data are available upon reasonable request. Analysed data may be made available upon reasonable request following review by the principal investigators with appropriate acknowledgements.
Footnotes
Handling editor Josef S Smolen
Contributors BK: Study conception, drafting the work. GDG: Study conception and design, statistical analysis, drafting the work. AH: Participant recruitment and data management, revising the work for important intellectual content. AJD: Study design, radiology oversight, revising the work for important intellectual content. JD: Participant recruitment and data management, revising the work for important intellectual content. OA: Dual-energy CT scoring, revising the work for important intellectual content. C-NS: Dual-energy CT scoring, revising the work for important intellectual content. RK: Dual-energy CT scoring, revising the work for important intellectual content. KL: Participant recruitment and data management, dual-energy CT scoring, revising the work for important intellectual content. LS: Study conception and design, interpretation of data, revising the work for important intellectual content. ND: Study conception and design, dual-energy CT scoring, interpretation of data, drafting the work. All authors agreed for the manuscript to be published. The guarantor of the study is ND, who accepts full responsibility for the finished work and/or the conduct of the study, had access to the data and controlled the decision to publish.
Funding Health Research Council of New Zealand (grant numbers 09-111D, 11-203, 15-576 and 19-232).
Competing interests ND has received consulting fees, speaker fees or grants from AstraZeneca, Novartis, Horizon, Selecta, Arthrosi, JW Pharmaceutical Corporation, PK Med, LG Chem, JPI, PTC Therapeutics, Protalix, Unlocked Labs, Hikma, Dexcel Pharma, Shanton Pharma, Sobi, Avalo outside the submitted work. The other authors have no disclosures.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
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