Table 3.

Cross-tabulation of various assessments of low disease activity compared to (1) MDA as judged by the treating physician (MDAphys) and (2) disease control as reported by the patient (DWCpatient). MDAphys and DWCpatient serve as the reference, or “gold standard.” The performance of the other measures listed were 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.

VariablesCutoff for Low Disease ActivitySensitivitySpecificityOverall AccuracyPPVNPVYouden Indexκ*
  • * κ: prevalence adjusted, bias adjusted κ. MDA: minimal disease activity; PPV: positive predictive value; NPV: negative predictive value; MDA-5: MDA criteria with 5 items required; MDA-6: MDA criteria with 6 items required; MDA-7: MDA criteria with 7 items required; 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.