Analysis Explores Clinical Significance of Negative DECT Scans in Gout

Credit: Adobe Stock/jittawit.21

A new investigation provided updated insight into the predictive value of two thresholds of negative dual-energy computed tomography (DECT) for monosodium urate crystal deposition among patients with gout.¹

Results from this new analysis revealed the 0.1cm³ threshold of positive for DECT detection of MSU crystal deposition was better correlated to clinical presentation and evolution compared with 0.01 cm³ among the population with gout.

“Patients with gout with negative DECTs exhibit milder disease and a lower comorbidity burden,” wrote the investigative team led by Victor Laurent, department of rheumatology, Hôpital Saint-Philibert, Université Catholique de Lille.

Recent evidence has supported the predictive connection between DECT-detected MSU crystal deposition and the short-term development of comorbidities among patients with gout. These data showed the volume of MSU crystals measured with DECT is a biomarker for the risk of developing new onset cardiometabolic diseases and for all-cause mortality.

In this analysis, Laurent and colleagues selected patients with the CRYSTALILLE cohort with a diagnosis of gout naive to urate-lowering therapy (ULT) with baseline DECT scans of knees and feet. The goal of the analysis was to determine clinical associations and predictive value of the two thresholds of negative DECT for MSU crystal deposition in patients with gout initiating ULT, and to examine the clinical relevance of each threshold.

For the analysis, the two thresholds of positivity for DECT detection of MSU crystal deposition were <0.01cm³ and <0.1cm³. Baseline characteristics and the prediction of key outcomes after initiation of ULT, including serum urate levels <6.0 and 5.0 mg/dL and occurrence of flares (at 6, 12, and 24 months), associated with both thresholds of negative DECTs were compared with patients showing positive DECT scans.

A total of 211 patients aged 66.2 years with a symptom duration of 3 years were included in the study. Of this population, 38 (18%) and 90 (43%) patients had negative DECT scans for the 0.01 and 0.1 cm³ thresholds, respectively. Laurent and colleagues noted the factors associated with negative DECT scans included younger age, shorter symptom duration, and absence of cardiovascular disease for both volume thresholds.

Among those with <0.1cm³ MSU crystals, 9 of 39 (23.1%), 3 of 26 (11.5%), and 1 of 18 (5.6%) exhibited flares at 6, 12, and 24 months, respectively. In comparison, those with ≥0.1cm³ MSU crystals, 18 of 25 (40.0%), 9 of 36 (25.0%), and 2 of 18 (11.1%) exhibited flares at 6, 12, and 24 months, respectively (P >.05).

Altogether, Laurent and colleagues found 95 patients (68.3%) reached serum urate levels <6.0 mg/dL, and 68 (48.9%) reached levels <5.0 mg/dL, without any difference between positive and negative DECTS. They noted the ULT dosages trended lower in patients with negative DECT.

Overall, the investigative team indicated the 0.1 cm3 threshold appeared to be better correlated to clinical presentation and evolution than 0.01 cm³. Those with gout and negative DECTs exhibited milder disease and lower comorbidities—despite the presence of hyperuricemia, they also exhibited a lower flare risk.

“They do not exhibit particularly easy-to-treat hyperuricemia, but may have a lower risk of flares,” Laurent and colleagues wrote.

References

1. _{Victor Laurent, Charlotte Jauffret, Vincent Ducoulombier, Aurore Pacaud, Julie Legrand, Stéphane Verdun, Laurène Norberciak, Jean-François Budzik, Tristan Pascart, Are patients with gout with negative dual-energy computed tomography for monosodium urate crystal deposition easy-to-treat?, Rheumatology, 2024;, keae061, https://doi.org/10.1093/rheumatology/keae061}
2. _{Anne Marty-Ané, Laurène Norberciak, Mariano Andrès, Eric Houvenagel, Vincent Ducoulombier, Julie Legrand, Jean-François Budzik, Tristan Pascart, Crystal deposition measured with dual-energy computed tomography: association with mortality and cardiovascular risks in gout, Rheumatology, Volume 60, Issue 10, October 2021, Pages 4855–4860, https://doi.org/10.1093/rheumatology/keaa920}