Table 1

Baseline characteristics

PsA (n=150)SpA (n=76)Control-group (n=226)p Value PsA-group versus control-groupp Value SpA-group versus control-group
Age (years) at inclusion, mean±SD47.0±13.8 n=15037.0±15.0 n=7643.6±15.6 n=2260.03<0.001
Male, N (%)86 (57.3) n=15037 (48.7) n=76118 (52.2) n=2260.330.59
Symptom duration* (weeks) at first visit, mean±SD35.5±58.0 n=13422.8±37.3 n=7022.1±27.9 n=2030.010.87
6.4±9.4 (n=22)
30.3±42.6 (n=48)
HLA-B27 positive, N (%)19 (15.2) n=12529 (47.5) n=6114 (7.7) n=1810.04<0.001
Pos. fam. history SpA, N (%)133 (88.7) n=15036 (47.4) n=7618 (8.0) n=226<0.001<0.001
IBP, N (%)13 (8.7) n=15022 (28.9) n=7639 (17.3) n=2260.020.03
Psoriasis, N (%)141 (94.0) n=1504 (5.3) n=7613 (5.8) n=226<0.0010.87
Dactylitis, N (%)55 (36.7) n=1505 (6.6) n=495 (2.2) n=200<0.0010.07
Enthesitis, N (%)17 (11.3) n=15013 (17.1) n=7611 (4.9) n=2260.02<0.001
Uveitis, N (%)1 (0.7) n=1507 (9.2) n=761 (0.4) n=2260.83<0.001
IBD, N (%)1 (0.7) n=15011 (14.5) n=764 (1.8) n=2260.36<0.001
Preceding infection, N (%)10 (6.7) n=15028 (36.8) n=7611 (4.9) n=2260.46<0.001
RF negative, N (%)133 (91.7) n=14567 (91.8) n=73155 (72.4) n=214<0.0010.001
CRP (mg/l), mean±SD19.2±24.6 n=13340.7±49.5 n=6929.2±43.9 n=2110.010.07
ESR (mm/h), mean±SD29.2±27.3 n=14341.4±32.5 n=7531.6±27.6 n=2150.410.01
Good response to NSAIDs0 (0.0) n=1507 (9.2) n=7620 (8.8) n=226<0.0010.92
Asymmetric lower limb arthritis32 (21.3) n=15032 (42.1) n=7641 (18.1) n=2260.44<0.001
Sacroiliitis X-ray, N (%)3 (9.4) n=329 (34.6) n=260 (0.0) n=350.24<0.001
Juxta-articular new bone formations, N (%)19 (12.7) n=1500 (0.0) n=760 (0.0) n=226<0.001
  • * Patient reported.

  • Patients with preceding infection.

  • Patients without preceding infection (preceding infection can be balinitis, urethritis, cervicitis and/or acute diarrhea).

  • age, age at baseline; delay, duration between first complaints and first visit outpatient clinic rheumatology; CRP, C reactive protein; ESR, erythrocyte sedimentation rate; HLA-B27, human leucocyte antigen; IBD, inflammatory bowel disease; IBP, inflammatory back pain; NSAID, non-steroidal anti-inflammatory drug; PsA, psoriatic arthritis; RF, rheumatoid factor; SpA, spondyloarthritis.