ALICANTE, Spain—Keeping serum uric acid (SUA) levels below 360 µmol/L can clear urate crystals from the synovial fluid in patients with long-standing, untreated disease gout, but this process may require nearly 3 years of treatment. Eliseo Pascual, MD, and Francisca Sivera, MD, both from the rheumatology department at the Hospital General Universitario de Alicante, in Spain, used arthrocentesis to monitor the numbers of monosodium urate (MSU) crystals in the synovial fluid of previously inflamed joints in 18 patients with MSU-crystal proven gout during hypouricemic treatment and report the results in Annals of the Rheumatic Diseases.¹

"MSU crystals disappeared from the synovial fluid of all 18 joints after reduction of SUA to normal levels. The time required for disappearance ranged from 3 to 33 months; disappearance time correlated with the duration of gout," Dr. Pascual writes.

The patients were recruited to the study after their initial diagnosis using arthrocentesis at a knee or first metatarsophalangeal (MTP) joint. The researchers emphasize that all patients were thus aware of the discomfort associated with the repeat arthrocentesis that would be done in the study. Twenty-six patients were initially enrolled, but eight withdrew before their synovial fluid samples were free of crystals. The remaining patients were all men and had disease duration ranging from 2 months to 40 years (median 7 years).

All patients were asymptomatic at the time they entered the study, which excluded those with tophaceous gout. Median baseline SUA level was 550 µmol/L.

Patients were treated with benzbromarone (n = 15) or combined benzbromarone and allopurinol (n = 3) along with prophylactic colchicine (1 mg/day). Benzbromarone was widely used in Spain at the time of this study but was subsequently withdrawn from general and is now allowed for only restricted use.

After the initial visit, patients were tested every 3 months and a semiquantitative crystal count was done for each synovial fluid sample.

Within the first 3 months of treatment, SUA dropped from 550 µmol/L to 290 µmol/L and remained stable for the rest of the study. MUA crystals eventually disappeared from the synovial fluid of all 18 patients. In those with gout duration <10 years, nine of 10 patients were free of crystals after 1 year of treatment, and all were free of crystals after 18 months of treatment. "The time required for crystal disappearance...showed a good correlation with the time since the initial episode of gout [r = 0.71, P <.01]," Dr. Pascual says.

The investigators warn, however, that disappearance of MSU crystals from the synovial fluid samples does not necessarily mean that there are none left in the joint or in the synovial fluid, but they conclude that "the results presented strongly suggest that the presence of MSU crystal deposits in the joints can be reversed."

They add, "Finally, despite the good understanding that we have of the mechanisms of gout and the reversibility of MSU crystal deposits, standards of gout management on both sides of the Atlantic remain poor. In this report we show that by achieving proper control of serum urate levels, gouty joints can be freed of MSU crystals. This direct evidence may help to stimulate a much-needed upgrading of the management of gout by the medical community."

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