Assessment of outcome in clinical trials of gout--a review of current measures.

There has been renewed interest in the treatment of gout with recent reported intervention studies of new agents such as etoricoxib, febuxostat and pegylated-uricase. However, these studies have highlighted the relative paucity of validated outcome measures with which to judge efficacy. This review outlines the published information regarding which endpoints have been measured in randomized clinical trials, what should be measured, what tools or instruments are available for this and the technical properties of such instruments. It highlights recent work that validates measures of tophi, radiographic damage and patient-reported outcomes. The absence of a valid definition of gout-flare or how flare reduction defines response is problematic; this forms the basis for a current ACR-EULAR sponsored project.