Table 3:

Diagnostic accuracy of serum S100A8/A9 and S100A12 levels at the time of anti-TNF withdrawal regarding the prediction of flare within 30 days, 60 days, 90 days or 8 months.

	S100A8/A9 (cut-off 690 ng/ml)				S100A12 (cut-off 120 ng/ml)
	30 days	60 days	90 days	8 months	30 days	60 days	90 days	8 months
Sensitivity	67%	38%	40%	66%	56%	54%	53%	33%
Specificity	42%	58%	58%	45%	70%	70%	71%	68%
Positive likelihood ratio	1.16	0.91	0.95	1.20	1.85	1.84	1.86	1.05
Youden index	0.09	−0.04	−0.02	0.11	0.25	0.24	0.25	0.02
Hazard ratio*(95% CI), P	0.68 (0.18–2.58), 0.57	0.83 (0.28–2.52), 0.75	0.89 (0.32–2.49), 0.82	0.72 (0.36–1.42), 0.34	2.83 (0.70; 11.49), 0.15	2.63 (0.82; 8.43), 0.10	2.59 (0.87; 7.67), 0.09	1.13 (0.55; 2.33), 0.74
AUC (95% CI)	0.51 (0.31; 0.70)	0.51 (0.33; 0.69)	0.51 (0.34; 0.67)	0.56 (0.44; 0.67)	0.64 (0.50; 0.77)	0.66 (0.54; 0.79)	0.64 (0.51; 0.77)	0.51 (0.39; 0.62)

^*hazard ratio for the occurrence of disease flare if level is above threshold

AUC, area under the receiver operating characteristic curve; CI, confidence interval

The Youden index is calculated as follows: sensitivity + specificity - 1