Clinical Question

Is a baseline serum urate level in adults with a history of acute gout accurate for predicting the risk of subsequent gout flare-ups?

Bottom Line

In patients with a history of gout, higher serum urate levels at baseline are associated with an increased risk of subsequent gout flare-ups and rates of hospitalization for recurrent gout. (Level of Evidence = 2b)

Synopsis

The investigators analyzed data from multiple registries in the United Kingdom from 2006 to 2010 that linked adults (n = 3,613) with a history of gout and baseline serum urate levels to the subsequent risk of recurrent gout flare-ups. Recurrent gout flare-ups included hospitalization with gout or a diagnosis of new acute gout episodes in primary care with a prescription issued on the same day for corticosteroids, colchicine, or nonsteroidal anti-inflammatory drugs. Over a mean follow-up of 8.3 years, 1,773 new episodes of gout were treated in primary care or during hospitalization. More than 95% of recurrent gout flare-ups occurred in patients with baseline serum urate levels of 6 mg per dL (0.36 mmol per L) or greater. Baseline serum urate levels were associated with recurrent acute gout in a graded manner. Rates of acute gout flare-ups per 1,000 person-years were 10.6 for patients with baseline urate levels of less than 6 mg per dL; 40.1 for levels of 6.0 to 6.9 mg per dL (0.36 to 0.41 mmol per L); 82.0 for levels of 7.0 to 7.9 mg per dL (0.42 to 0.47 mmol per L); 101.3 for levels of 8.0 to 8.9 mg per dL (0.48 to 0.53 mmol per L); 125.3 for levels of 9.0 to 9.9 mg per dL (0.54 to 0.59 mmol per L); and 132.8 for levels of 10 mg per dL (0.59 mmol per L) or greater. Rates of hospitalization were similarly related in a graded manner to baseline serum urate levels.