Crystal deposition measured with Dual-Energy Computed Tomography: association with mortality and cardiovascular risks in gout.

Objectives To determine whether the volume of monosodium urate (MSU) crystal deposition measured with dual-energy computed tomography (DECT) is predictive of short-term mortality and development of cardiovascular comorbidities and diabetes mellitus. Methods Patients with a diagnosis of gout having had baseline DECT scans of their knees and feet to measure the volume of MSU crystals deposition were included to undergo a follow-up visit. Risk factors for mortality and a composite variable (onset of any cardio-metabolic event) were examined using multivariable Cox models. Results A total of 128 patients aged 66.1 (±14.0) years with gout durations of 11.4 (±10.4) years were included, most were naive of urate lowering therapy (ULT) (61.7%), with a follow-up visit at 24 [12; 36] months. Baseline serum urate (SU) levels were 7.44 (±2.29) mg/dl and DECT volumes of MSU crystals were 0.2 [0; 0.9] cm3. A total of 14 patients died during follow-up and for 6/14 from a cardiovascular cause, and 17 patients presented a new cardio-metabolic comorbidity. Factors associated with mortality risk were baseline DECT volume of MSU crystals (HR 1.02, 95% CI 1.002-1.03) and baseline SU level (HR 1.04, 95% CI 1.003-1.06). DECT volume of MSU crystals was the only factor associated with the onset of cardio-metabolic comorbidities with an HR of 1.014 (95% CI 1.001-1.03). Conclusions Volume of MSU crystal measured with DECT is a biomarker for the risk of developing new cardio-metabolic diseases and for all-cause mortality.