Treat-to-target approach significantly reduces urate deposits in gout
Among patients with gout, ultrasound scoring for crystal deposits demonstrates that treat-to-target with urate-lowering therapy results in significant reductions in all depositions, according to data published in the Annals of the Rheumatic Diseases.
“The Outcome Measures in Rheumatology (OMERACT) ultrasound group has defined three specific types of depositions (elementary lesions): double contour (DC), tophi and aggregates,” Hilde Berner Hammer, MD, PhD, of the University of Oslo, in Norway, and colleagues wrote. “A few, mostly small, longitudinal studies have shown that ultrasound detected crystal depositions gradually decrease in size and often disappear during ULT, and DC appeared to be most sensitive to change.”
To examine the most frequent locations for depositions, the extent of erosions in the first metatarsophalangeal joints, and the resolution of various forms of ultrasound-detected monosodium urate in patients with gout receiving urate-lowering therapy in a treat-to-target approach, Hammer and colleagues conducted a prospective, single-center, observational study. A total of 209 consecutive patients with a recent gout flare were enrolled and began management with a treat-to-target approach.
All participants were assessed using bilateral ultrasound examinations of joints, tendons, entheses of hands, elbows, knees, ankles and feet at baseline, as well as at 3, 6 and 12 months. The researchers then applied a new semiquantitative scoring system of 0–3 of elementary lesions — double contour, tophi and aggregate — to analyze the amount of depositions in follow-up.
According to the researchers, serum urate levels decreased from a mean of 500 µmol/L at baseline to 312 µmol/L at 12 months, (P < .001). The first metatarsophalangeal joint was the most common location for all the elementary lesions, and erosions were associated with higher amounts of crystal deposits. Mean sum scores from baseline to 12 months decreased for double contour, from 4.3 to 1.3; tophi, from 6.5 to 3.8; and aggregates, from 9.3 to 6.7 (P < .001 for all). Double contour was the most sensitive to change.
“This is the largest longitudinal study using ultrasound to assess MSU crystal depositions by use of a new semiquantitative scoring system,” Hammer and colleagues wrote. “We found that during a treat-to-target approach with ULT all the different forms of ultrasound detected depositions decreased, with DC having the most extensive reduction. MTP1 was found to be most frequently involved, and the score of MTP1 erosion was at joint level associated with the score of the elementary lesions.
“Presence of an ultrasound detected index tophus was highly associated with sum scores of all the elementary lesions both at baseline and after 12 months,” they added. “The present study gives important results by showing that patients in clinical practice who are followed by a treat-to-target approach regarding ULT reduced their burden of MSU crystals as measured by ultrasound.”