Table 4.

Biomarker concentration thresholds differentiating disease groups, using receiver operating characteristic analyses

	Maximum accuracy(proportion of cases correctly classified)		Minimum value forsensitivity ≥ 0.95
	PsC vs. PsA	HC vs. PsA	PsC vs. PsA	HC vs. PsA
	MMP-3
Threshold (ng/mL)	14.51	7.21	8.22	8.32
Sensitivity	0.76	0.99	0.96	0.95
Specificity	0.60	0.12	0.16	0.20
AUC (95% CI)	0.70 (0.65, 0.75)	0.66 (0.59, 0.74)	0.70 (0.65, 0.75)	0.66 (0.59, 0.74)
	M-CSF
Threshold (ng/mL)	0.05	0.02	0.10	0.02
Sensitivity	0.99	1.00	0.95	1.00
Specificity	0.01	0.00	0.02	0.00
AUC (95% CI)	0.34 (0.29, 0.40)	0.24 (0.17, 0.31)	0.34 (0.29, 0.40)	0.24 (0.17, 0.31)
	PsA cases: Non-RAD vs. RAD		PsA cases: Non-RAD vs. RAD
	Dkk-1
Threshold (ng/mL)	4.96		0.91
Sensitivity	0.15		0.96
Specificity	0.94		0.05
AUC (95% CI)	0.56 (0.44, 0.67)		0.56 (0.44, 0.67)
	OPG
Threshold (ng/mL)	3.88		0.08
Sensitivity	0.00		0.95
Specificity	0.99		0.08
AUC (95% CI)	0.47 (0.39, 0.56)		0.47 (0.39, 0.56)

AUC area under the curve, 95CI 95% confidence interval, Dkk-1 Dickkopf 1, M-CSF Macrophage colony stimulating factor, MMP-3 Matrix metalloproteinase 3, OPG osteoprotegerin, PsA psoriatic arthritis, PsC psoriasis without arthritis, HC healthy control, RAD radiographic axial disease