T. Pascart 1,2, A. Ramon 3, S. Ottaviani 4, J. Legrand 5, V. Ducoulombier 1, E. Houvenagel 1, L. Norberciak 6, P. Richette 7,8, F. Becce 9, P. Ornetti 3, JF. Budzik 2,5

1. Department of Rheumatology, Lille Catholic Hospitals, University Of Lille, F-59160 Lomme, France 2. Ea 4490, Pmoi, Physiopathologie des Maladies Osseuses Inflammatoires, University of Lille, Lille, France 3. Department of Rheumatology, Dijon University Hospital, University of Bourgogne, Dijon, France 4. Department of Rheumatology, Hôpital Bichat, Ap-Hp, Paris, France 5. Department of Diagnostic and Interventional Radiology, Lille Catholic Hospitals, University Of Lille, Lomme, France 6. Department of Medical Research, Biostatistics, Lille Catholic Hospitals, University Of Lille, Lomme, France 7. Department of Rheumatology, Hôpital Lariboisière, Ap-Hp, Paris, France 8. Inserm U1132, Université Paris Diderot, Paris, France 9. Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland


Context: The reasons explaining why some patients exhibit higher monosodium urate (MSU) crystal burdens than others remain largely unknown. While MSU crystal formation is enhanced by certain factors in vitro such as pH, temperature, and other ion concentrations, it is currently unknown whether comorbidities and clinical features are associated with increased MSU deposition in vivo.

Objectives: To determine which factors are associated with the burden of MSU crystal deposition quantified by dual-energy CT (DECT) in urate lowering therapy (ULT)-naive gout patients.

Methods: In this multicenter cross-sectional study, DECT scans of knees and feet were prospectively obtained from ULT-naive, or not taking any ULT for more than a year, gout patients. Demographic, clinical (including gout history and comorbidities), and biological data were collected, and their association with DECT MSU crystal volume was analyzed using bivariate and multivariate analyses. A second bivariate analysis was performed by splitting the dataset depending on an arbitrary threshold of DECT MSU volume (1 cm3).

Results: A total of 125 gout patients were included, of whom 91 underwent both DECT scans of knees and feet. In bivariate analysis, age (p=0.03), symptom duration (p=0.003), subcutaneous tophi (p=0.004), hypertension (p=0.02), diabetes mellitus (p=0.05), and chronic heart failure (p=0.03) were associated with the total DECT volume of MSU crystal deposition. In multivariate analysis, factors associated with DECT MSU volumes ≥1 cm3 were gout duration (OR for each 10-year increase 3.15 [1.60;7.63]), diabetes mellitus (OR 4.75 [1.58;15.63]), and chronic heart failure (OR 7.82 [2.29;31.38]). The model performance was good with an AUC of 0.816.

Conclusions: Specific comorbidities, particularly chronic heart failure, diabetes mellitus, and hypertension, are more strongly associated with increased MSU crystal deposition in knees and feet than gout duration, regardless of serum urate level.