Toward a valid definition of gout flare: results of consensus exercises using Delphi methodology and cognitive mapping.

OBJECTIVE: To identify, in people known to have gout, the testable, key components of a standard definition of gout flare for use in clinical research.

METHODS: Consensus methodology was used to identify key elements of a gout flare. Two Delphi exercises were conducted among different groups of rheumatologists. A cognitive mapping technique among 9 gout experts with hierarchical cluster analysis provided a framework to guide the panel discussion, which identified the final set of items that should be tested empirically.

RESULTS: From the Delphi exercises, 21 items were presented to the expert panel. Cluster analysis and multidimensional scaling showed that these items clustered into 5 concepts (joint inflammation, severity of symptoms, stereotypical nature, pain, and gout archetype) distributed along 2 dimensions (objective to subjective features and general features to specific features of gout). Using this analysis, expert panel discussion generated a short list of potential features: joint swelling, joint tenderness, joint warmth, severity of pain, patient global assessment, time to maximum pain, time to complete resolution of pain, an acute-phase marker, and functional impact of the episode.

CONCLUSION: A short list of features has been identified and now requires validation against a patient- and physician-defined gout flare in order to determine the best combination of features.