Crystal Deposition in Patients Meeting Provisional Gout Remission Criteria

Crystal deposition may still be present in patients with gout who fulfill the provisional gout remission criteria, according to research results published in Arthritis Research and Therapy.

Using dual-energy computed tomography (CT), researchers performed an analysis that tested the concurrent validity of provisional remission criteria through an examination of the association of individual remission domains and the full remission criteria set in gout. Data from a large, multicenter dual-energy CT study were used.

The study cohort included 152 patients with gout taking ≥300 mg allopurinol daily for at least 3 months. Researchers determined that the serum urate remission domain was met in 50.7% of patients, the tophus domain was met in 68.4%, the flare domain in 46.1%, the pain domain in 68.4%, and the patient global assessment domain in 55.2% of patients. In total, 15.1% of participants fulfilled all 5 remission domains.

The highest rate of overlap was noted between the pain and patient global assessment domains (50.7%), followed by the pain and tophus domains (48.0%). Conversely, the lowest overlap was noted between the serum urate and flare domains (20.4%).

Dual-energy CT urate crystal deposition was found in 44% of patients fulfilling the provisional remission criteria compared with 73.6% of those not fulfilling the provisional criteria (odds ratio [OR], 0.28; P =.004). The median dual-energy CT urate crystal volume was 0.00 cm³ (range 0.00-0.46 cm³) for patients who fulfilled the remission criteria, compared with 0.08 cm³ (range 0.00-19.53 cm³) for those who did not fulfill the criteria (P =.002).

In results of a regression analysis that ranked dual-energy CT crystal volumes, dual-energy CT urate crystal volume was independently associated with the serum urate, tophus, and global assessment domains (P =.036, P =.001, and P =.043, respectively).

Among participants with serum urate <5 mg/dL (27%), 60.9% fulfilled provisional remission criteria; 20.9% did not. Dual-energy CT urate crystal deposition was present in 56% of participants with serum urate <5 mg/dL, compared with 73.9% of participants with serum urate ≥5 mg/dL (OR, 0.45; 95% CI, 0.21-0.95).

Limitations of this research included minor deviations from published provisional remission criteria due to the design of the study, and a lack of generalizability to patients outside of the study population.

“While this study provides some support for the validity of the provisional gout remission criteria, it has demonstrated that crystal deposition may still be present in some people achieving these criteria,” the researchers of the study concluded.

Disclosure: The clinical study was funded by AstraZeneca. This analysis was an investigator-initiated project, with independent statistical work funded by Ironwood Pharmaceuticals. Drs Dalbeth, Fung, Baumgartner, and Choi disclosed affiliations with pharmaceutical companies. For a complete list of disclosures, please see the reference.

Reference

Dalbeth N, Frampton C, Fung M, Baumgartner S, Nicolaou S, Choi HK. Concurrent validity of provisional remission criteria for gout: a dual-energy CT study. Arthritis Res Ther. 2019;21:150