Validation of a definition of flare in patients with established gout

Flares (also known as attacks) are a defining characteristic of gout. Despite their recognized importance as an outcome measure, a validated way to define flares in research is lacking. Therefore the present study demonstrated that 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.

To execute the external validity of a provisional definition of disease flare among gout patients.

A total of 590 subjects gout patients were selected and data were assembled as per provisional definition to categorize patients as experiencing or not experiencing a gout flare. A local expert rheumatologist executed the final individualistic adjudication of gout flare state. The diagnostic performance of gout flare definitions was identified using predictive values, specificity, sensitivity, and receiver operating characteristic (ROC) curves.

The patients' mean ± SD age during the analysis was 57.5 ± 13.9 years. The definition demanding accomplishment of at least 3 of the four criteria was 95% specific and 85% sensitive in affirming the presence of a gout flare, with 92% accuracy. The ROC area under the curve noticed to be 0.97. The definition on the basis of classification and regression tree algorithm was 96% specific and 73% sensitive.

The definition of gout flare that needs accomplishment of at least 3 of 4 patient-reported criteria is now justified to be specific, accurate, and sensitive for gout flares, as revealed using a self-sustaining large international patient sample. The ascertainment of an important clinical outcome in studies of gout will be improved by the presence of validated gout flare definition.