Table 3

The 12 ASAS-selected preliminary draft definitions of flare with their performances in the vignette exercise

Instrument	AUC	Flare definition	Se	Spe	PPV	NPV
Pain (0–10)	0.86	Δ pain ≥2 AND final value ≥4	0.99	0.30	0.76	0.97
		Δ pain ≥3	0.95	0.69	0.83	0.88
		If observed value is ≥4: Δ pain ≥2 points, otherwise: Δ pain ≥3 points	0.97	0.56	0.79	0.92
BASDAI (0–10)	0.86	Δ BASDAI ≥2 points	0.99	0.40	0.78	0.94
		Δ BASDAI ≥2 points AND final value ≥4	0.99	0.32	0.81	0.92
		Δ BASDAI ≥3 points	0.92	0.70	0.87	0.80
		Δ BASDAI ≥3 points AND final value ≥4	0.94	0.63	0.88	0.79
		If observed value is ≥4, Δ BASDAI ≥2 points, otherwise: Δ BASDAI ≥3 points	0.94	0.54	0.81	0.80
ASDAS-CRP	0.89	Δ ASDAS ≥0.6	0.97	0.65	0.75	0.96
		Δ ASDAS ≥0.9	0.85	0.87	0.87	0.85
		Δ ASDAS ≥1.1	0.60	0.94	0.93	0.69
		Δ ASDAS ≥0.6 AND observed ASDAS ≥1.3	0.97	0.59	0.78	0.93

ASAS, Assessment of Spondyloarthritis; ASDAS, Ankylosing Spondylitis Disease Activity Score; AUC: area under the receiver-operating characteristic curve; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; PPV and NPV, positive and negative predictive values; Se: sensitivity; Spe: specificity; Δ: change.