Definition of gout flare that requires fulfillment of at least 3 of 4 patient-reported criteria is now validated to be sensitive, specific, and accurate for gout flares, as demonstrated using an independent large international patient sample in a study published in the journal 'Arthritis and Rheumatology'

Flares (also known as attacks) are the defining characteristic of gout. Despite their importance as an outcome measure, an appropriated way to define flares in research is lacking. The definitions published were based on a “number of criteria” rule with peak diagnostic accuracy when 3 or more out of the 4 criteria were present. To develop a gout response criterion, two definitions for gout flares based entirely on patient-reported measures were previously published. These two definitions were considered provisional since the small sample size used to derive these definitions did not allow for a validation exercise.

Therefore, the current study was conducted by Gaffo AL et al . to validate the previously published provisional definitions for gout flare by determining their accuracy and diagnostic properties in a diverse and independent, international patient sample. In this study, the authors included the total of 509 patients with gout from 17 international sites. Data were collected to classify patients as experiencing or not experiencing a gout flare, according to a provisional definition. An expert rheumatologist evaluated the final independent adjudication of gout flare status. Sensitivity, specificity, predictive values, and receiver operating characteristic (ROC) curves were used to determine the diagnostic performance of gout flare definitions.

The findings stated that the definition requiring fulfillment of at least 3 of 4 criteria was 85% sensitive and 95% specific in confirming the presence of a gout flare, with an accuracy of 92%. The ROC area under the curve was 0.97. The definition based on a classification and regression tree algorithm (entry point, pain at rest score >3, followed by patient-defined flare "yes") were 73% sensitive and 96% specific.