Background/Purpose: Gout is a common inflammatory arthritis, and its worldwide prevalence is increasing. EULAR and ACR guidelines recommend a target serum urate (sUA) ≤6 mg/dL. We describe US and EU physician, patient, and treatment characteristics in patients treated with xanthine oxidase inhibitor (XOI) therapy who achieve sUA ≤6 mg/dL yet have 2 or more physician-confirmed gout flares per year.

Methods: A large survey of more than 500 physicians across the US and EU was conducted. Data was confirmed through in-depth chart audits, which assessed diagnosis, comorbid conditions, disease severity, and laboratory results of the last 5 patients with gout that they treated. Disease severity was measured using a physician global assessment (mild, moderate, or severe), flare counts, joint damage, and presence of tophi. Type and dose of XOI, length of current treatment, compliance, physician type, and patient sociodemographic factors were identified. Comorbidities were captured using chart review and analyzed as present or absent. Descriptive and multivariate statistics described patients having 2 or more flares per year (excluding treatment initiation flares) in patients achieving sUA ≤6 mg/dL.

*p<0.05.

Results: In total, 251 rheumatologists and 250 primary care physicians were interviewed. Of 2505 patients with gout, 82% were male and the average age was 58 (SD=12) years; 1826 (73%) patients were treated with a XOI. Of these, 811 (44%) had at least one assessment of sUA ≤6 mg/dL and 305 (38%) reported 2 or more flares in the last 12 months (Table). A backward stepwise multivariate model predicting patients classified as controlled (sUA ≤6 mg/dL) and continuing to flare (2 or more flares in the last year) found physician-reported and chart-documented coexisting comorbidities, including chronic kidney disease (OR 2.8; p<0.01), alcoholism (OR 3.6; p<0.01), and diabetes mellitus (OR 1.9; p<0.05). There was no difference by XOI or physician type. Results were similar for patients with single or multiple sUA assessments ≤6 mg/dL during the study period.

Conclusion: Less than 50% of patients treated with a XOI alone achieved sUA target. Of the patients achieving a sUA level of ≤6 mg/dL, more than one-third reported 2 or more flares in a 12-month period despite being treated with the same ULT for more than 3 years. Frequent flares and greater tophaceous burden requires treatment to an even lower urate target than 6.0 mg/dL.