Table 2.

Relationship between MDA-5 and other indices of low disease activity. The established MDA criteria (MDA-5) serve as the reference, or “gold standard.” The performance of the other measures listed in column 1 is tested against this standard. The performance statistics are represented by sensitivity, specificity, overall accuracy, PPV, NPV, Youden index, and bias-adjusted κ statistic. Values are % unless otherwise specified.

VariablesSensitivitySpecificityOverall AccuracyPPVNPVYouden Indexκ*
  • * κ: prevalence adjusted, bias adjusted κ. MDA: minimal disease activity; MDA-5: MDA criteria with 5 items required; PPV: positive predictive value; NPV: negative predictive value; MDA-joints: MDA criteria mandating the articular items; PASDAS: Psoriatic Arthritis Disease Activity Score; CPDAI: Composite Psoriatic Disease Activity Index; CPDAI-4: CPDAI score with 4 as cutoff; CPDAI-3: CPDAI score with 3 as cutoff.