Presence of four criteria provides 96 percent specificity, 85 percent positive predictive value
FRIDAY, Nov. 18 (HealthDay News) -- Gout flare is best defined using a "number of criteria" approach that includes the presence of four patient-reported features associated with flare, according to a study published online Nov. 14 in Arthritis & Rheumatism.
Angelo L. Gaffo, M.D., M.S.P.H., from the Veterans Affairs Medical Center in Birmingham, Ala., and colleagues sought to develop an empirical definition for gout flare based on patient-reported features. Potential gout flare criteria were evaluated against the gold standard of expert rheumatologist definition by using data from 210 patients with gout (mean age, 56.3 years; 98 percent men). The number of criteria independently correlating with flare, and classification and regression tree approaches were used to define flare.
The investigators found that 26 percent of the participants had gout flares. The study gold standard showed independent associations with the presence of any patient-reported warm or swollen joint, pain at rest (>3 on a 0 to 10 scale), and patient-reported flare. The presence of at least three of the four criteria had the greatest discriminating power (sensitivity 91 percent, specificity 82 percent), whereas the presence of all four features was associated with the highest specificity (96 percent) and positive predictive value (85 percent). A classification tree approach revealed that the rule associated with the gold standard was pain at rest >3, followed by patient self-reported flare (sensitivity 83 percent, specificity 90 percent).
"A gout flare definition using the 'number of criteria' approach that required the presence of all four features had the highest positive predictive value and lowest number of false positives," the authors write.
Several of the study authors disclosed financial ties to the pharmaceutical industry.
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