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.

Variables	Cutoff for Low Disease Activity	Sensitivity	Specificity	Overall Accuracy	PPV	NPV	Youden Index	κ^*
MDAphys
MDA-5	5	46	93	74	81	72	39	0.48
MDA-6	6	29	99	71	94	68	28	0.42
MDA-7	7	15	100	66	96	64	15	0.32
MDA-joints	5	35	97	72	87	69	32	0.44
PASDAS	3.2	64	93	82	85	80	57	0.63
CPDAI-4	4	69	76	73	67	78	45	0.46
CPDAI-3	3	58	88	75	77	75	46	0.51
DWC
MDA-5	5	40	98	65	96	55	38	0.30
MDA-6	6	25	100	57	100	50	25	0.14
MDA-7	7	13	100	50	100	46	13	0.01
MDA-joints	5	29	99	59	99	51	28	0.18
PASDAS	3.2	52	98	72	97	61	50	0.44
CPDAI-4	4	63	82	71	83	62	45	0.43
CPDAI-3	3	51	94	69	92	58	45	0.38

↵* 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.