Table 1: Demographics and disease characteristics of mild- and severe-AS patients*.

Mild-AS (n = 171) Severe-AS (n = 64) P value
Male, n (%) 83 (48.5) 55 (85.9) <0.001
Age, years 38.7±9.4 51.2±9.8 <0.001
Disease duration, years 14.1±4.8 23.0±8.5 <0.001
Ever-smoked n (%) 42 (24.6) 24 (37.5) 0.049
HLA-B27 positivity, n (%) 95 (55.6) 47 (73.4) 0.013
Enthesitis, n (%) 44 (25.7) 19 (29.7) 0.543
Peripheral arthritis, n (%) 75 (43.9) 31 (48.4) 0.531
Coxofemoral joint involvement, n (%) 35 (20.5) 26 (40.6) 0.002
Uveitis, n (%) 20 (11.7) 17 (26.6) 0.005
TNFi ever-used, n (%) 64 (37.4) 43 (67.2) <0.001
NSAID current users, n (%) 81 (47.4) 27 (42.2) 0.540
ESR, mm/h, median (IQR) 20 (12-34) 30 (15.7-48) 0.005
CRP, mg/L, median (IQR) 5 (3.4-9.2) 9.6 (3.6-20.1) <0.001
mSASSS (0-72) 0 48.5±17.8 <0.001

* Values are presented as mean±SD, unless indicated otherwise.
AS= Ankylosing spondylitis; TNFi= TNF inhibitor; NSAID= Nonsteroidal anti-inflammatory drugs; ESR= Erythrocyte sedimentation rate; CRP= C-reactive protein; mSASSS= modified Stokes AS spinal score.