Table 7 Discriminatory ability (OASIS database): standardised mean difference between a high (>6/10 on a visual analogue scale) and a low level of patient global disease activity (<4/10)

	Patient global >6/10 (n = 31) Mean (SD)	Patient global <4/10 (n = 87) Mean (SD)	Standardised mean difference
ASDAS A	3.97 (0.83)	2.14 (0.81)	2.24
ASDAS B	3.32 (0.81)	1.63 (0.69)	2.35
ASDAS C	3.89 (0.76)	2.00 (0.88)	2.22
ASDAS D	3.82 (0.91)	2.42 (0.93)	1.51
BASDAI	5.47 (1.76)	2.48 (1.64)	1.79
Ln (CRP+1)	2.73 (0.99)	2.01 (1.06)	0.69
CRP (mg/l)*, median (range)	14 (0–92)	6 (0–124)
√(ESR)	3.91 (2.10)	2.94 (1.36)	0.63
ESR*, median (range)	14 (0–74)	8 (0–47)
Ln (swollen joint count+1)	0.45 (0.64)	0.12 (0.35)	0.78
Swollen joint count*, median (range)	0 (0–7)	0 (0–6)
BASFI	5.00 (2.67)	2.74 (2.32)	0.94
BASDAI question 1 (fatigue)	6.14 (2.60)	3.71 (2.75)	0.90
BASDAI question 2 (back pain)	6.59 (2.48)	3.06 (2.15)	1.58
BASDAI question 3 (peripheral pain/swelling)	4.22 (3.49)	1.50 (2.10)	1.10
BASDAI question 6 (duration of morning stiffness)	5.39 (3.32)	3.01 (2.71)	0.82

*For information purposes only, actual values are presented.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; OASIS, Outcome in Ankylosing Spondylitis International Study.