A Correlational Study of Monosodium Urate Crystal Volume in Different Joints and Clinical Characteristics of Gout Patients: A Dual-Energy CT Study

Abstract

Background: The spatial pattern of monosodium urate (MSU) crystal deposition is a hallmark of gout progression and contributes to the pathogenesis of associated comorbidities. However, the correlations between MSU crystal volume in the feet/ankle, knee, and hand/wrist joint sites and clinical features in gout patients remain unclear. Objectives: This study aims to explore the spatial pattern of MSU crystal deposition and its potential relationship with associated comorbidities. Additionally, it evaluates the correlation between MSU crystal volume detected by dual-energy computed tomography (DECT) in different joints and clinical characteristics, including serum uric acid (sUA), glomerular filtration rate (GFR), and disease duration. Patients and Methods: In this single-center study conducted from October 2017 to August 2023, 527 patients (mean age 49.0 ± 23.0 years) diagnosed with gout and confirmed MSU deposition via DECT were included. Spearman's rank correlation coefficient was used to assess relationships between sUA, gout duration, GFR, and MSU volumes in the foot/ankle, knee, and hand/wrist. Results: Among the 527 patients, the median gout duration was 6.0 years. MSU crystals were most commonly found in the feet/ankles (84.8%), followed by knees (63.6%) and hands/wrists (28.8%). Gout duration positively correlated with MSU crystal volumes (r = 0.32, P < 0.01). MSU volumes in the feet/ankle and knee showed negative correlations with GFR (r = -0.18, P < 0.01; r = -0.16, P = 0.03, respectively), while no significant correlation was observed in hand/wrist volume (r = -0.06, P = 0.55). No significant associations were found between MSU volumes and sUA levels across all groups. Conclusion: The MSU crystal burden negatively correlates with GFR but not with sUA levels. The volumes of MSU crystals in the ankle/foot and knee joints, along with the total volume of MSU crystals in the ankle/foot, hands/wrists, and knee joints, show a negative correlation with GFR and a positive correlation with disease duration. This indicates a need for further research on the relationship between MSU deposition and renal dysfunction in gout patients.