Comparison of non-radiographic axial spondyloarthritis and ankylosing spondylitis patients – baseline characteristics, treatment adherence, and development of clinical variables during three years of anti-TNF therapy in clinical practice

Table 1 Patient characteristics at initiation of anti-TNF therapy

Baseline characteristics	nr-axSpA, n = 86	AS, n = 238	P value^a
Male sex, n (%)	53 (62)	180 (76)	0.013
Age, years	38 (13)	43 (12)	<0.001
Disease duration, years	9 (9)	16 (12)	<0.001
Peripheral arthritis, n (%)	39 (45)	118 (50)	0.501
VAS global, mm	60 (19)	61 (22)	0.313
VAS pain, mm	60 (22)	62 (22)	0.292
Evaluator’s global, score 0–4	1.7 (0.6)	2.0 (0.7)	0.001
BASDAI score	5.3 (1.7)	5.4 (1.9)	0.727
BASFI score	4.1 (2.3)	4.3 (2.1)	0.503
ESR, mm/h	23 (21)	28 (23)	0.026
CRP, mg/l	10 (13)	23 (26)	<0.001
Elevated CRP, n (%)^b	47 (58)	177 (81)	<0.001
EQ-5D (UK)			0.381
Mean (SD)	0.43 (0.32)	0.45 (0.33)
Median (IQR; range)	0.59 (0.64; –0.22 to 0.80)	0.62 (1.3; –0.48 to 0.80)
Concomitant DMARD (%)	29 (34)	150 (63)	<0.001
Previous DMARDs (n)	0.8 (0.9)	1.5 (1.0)	<0.001
First anti-TNF agent used, n (%)			<0.001^c
Infliximab	19 (22)	112 (47)
Etanercept	37 (43)	89 (37)
Adalimumab	20 (23)	37 (16)
Golimumab	7 (8)	0 (0)
Certolizumab pegol	3 (4)	0 (0)

Mean (SD) if not otherwise stated. Missing data in the non-radiographic axial spondyloarthritis (nr-axSpA)/ankylosing spondylitis (AS) groups, n (%) as follows: Disease duration 1(1)/0(0); visual analog scale (VAS) global 7(8)/24(10); VAS pain 7(8)/24(10); Evaluator’s global 2(2)/18(8); Bath ankylosing spondylitis disease activity index (BASDAI) 36(42)/105(44); Bath ankylosing spondylitis functional index (BASFI) 35(41)/108(45); erythrocyte sedimentation rate (ESR) 4(5)/19(8); C-reactive protein (CRP) 5(6)/20(8); EuroQ ol 5-Dimensions (EQ-5D) 40(47)/60(25); Concomitant disease-modifying anti-rheumatic drug (DMARD) 1(1)/1(0.4). ^aχ2 for categorical and Mann–Whitney U test for continuous variables. ^bCRP >3.0 mg/l. ^cFisher’s exact test

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