Lower Serum Urate Target Enhances Crystal Dissolution in DECT-Measured MSU Crystal Deposition

According to a study in RMD Open, “In patients with DECT [dual-energy computed tomography]-measured MSU [monosodium urate] crystal deposition, reaching the <5.0 mg/dL SU [serum urate] target provides more extensive and rapid crystal dissolution than reaching the <6.0 mg/dL SU target.”

Investigators examined 62 patients diagnosed with gout who underwent baseline DECT scans of their knees and feet to measure MSU crystal volumes of at least 0.1 cm³. These patients also had at least 1 follow-up DECT scan conducted at 6, 12, 18, or 24 months. The primary objective was to examine the relationship between the change in MSU crystal volume and SU levels. The researchers utilized Spearman’s correlation coefficient and linear mixed models to assess these associations.

Investigators found that the achievement of SU target levels played a significant role in the kinetics of MSU crystal dissolution. A strong correlation was observed between SU levels and the percentage change in MSU crystal volume, highlighting the importance of SU reduction as a therapeutic strategy.

Furthermore, the data revealed that patients who reached the lower SU target of <5.0 mg/dL exhibited more extensive and rapid crystal dissolution compared with those who achieved <6.0 mg/dL. At the 12-month mark, the median decrease in MSU crystal volume for patients achieving <5.0 mg/dL was a remarkable ‒85%, whereas it was ‒40% for those reaching ≥5.0 mg/dL to <6.0 mg/dL levels.

In a multivariable analysis, 3 key factors were identified as significantly associated with MSU crystal volume change: time from the baseline DECT scans, hypertension, and SU level <5.0 mg/dL.

Time (assessed in days) was inversely associated with crystal dissolution, with shorter time periods associated with more rapid dissolution. Patients with hypertension exhibit slower crystal dissolution. Finally, achieving an SU level of <5.0 mg/dL had a substantial negative coefficient, reinforcing its importance as a target in gout management.