For a study, researchers wanted to determine if lowering serum uric acid (SUA) concentrations below 6 mg/dl or lowering SUA for a more extended period will result in urate crystal depletion in the knee joints and prevent recurrent gout attacks. At the Philadelphia VA Medical Center, prospective research was started 10 years ago to determine if SUA levels in patients with crystal confirmed gout could be kept below 6.0 mg/dl. All 57 patients who were available in 1,999 were recalled. Patients were separated into two groups: Group A, who had an SUA of more than 6 mg/dl, and Group B, who had an SUA of less than or equal to 6 mg/dl. All asymptomatic Group B patients and many in Group A were asked to take a knee joint aspirate. The crystals in the aspirates were identified using polarized light microscopy. There were no variations in age, sex, gout duration, or serum creatinine between the groups. For the previous year, Group A (n=38) experienced an average of 6 gout bouts, with those with tophi having the most frequent attacks. Monosodium urate (MSU) crystals were identified in 14 of the 16 patients in this group who agreed to knee aspiration, even though they were asymptomatic at the time. For more than a year, 19 individuals in Group B maintained blood urate levels of less than or equal to 6 mg/dl. Nearly half of them had not experienced a gout attack in 2 years or more, with a mean of 1 episode in the previous year for the entire sample. 3 of the individuals who had tophi did not have significant gout flare-ups in the last year. A total of 16 asymptomatic patients had their knee joints aspirated. MSU crystals were still present in 7 (44%) of the knees. Patients in this group who took preventive colchicine exhibited no differences in synovial fluid character from those who had stopped taking it for up to several years, while those who continued colchicine had fewer attacks. When SUA levels were held at or below 6 mg/dl for several years, the majority of patients were able to deplete urate crystal reserves in their knee joint fluids. The processes underlying the persistence of crystals in some patients are unknown, as is whether such crystals have therapeutic relevance. To avoid additional episodes, patients with chronic gout must keep their serum urate concentrations low.
Link:www.jrheum.org/content/28/3/577.short
