Table 1

Sociodemographics and clinical characteristics, disease activity and disease burden with regard to the diagnosis

axSpA
N=2719
pSpA
N=433
PsA
N=1033
ReA+IBD-SpA
N=168
Juv-SpA+others
N=112
Age, mean (SD)42.0 (13.0)44.2 (14.4)51.8 (13.0)44.8 (14.5)37.5 (16.6)
Gender (men)68.3%46.9%48.5%55.4%61.6%
Region
Latin America10.2%8.1%17.0%14.9%23.2%
Europe and North America37.2%23.5%47.3%23.8%30.4%
Asia22.4%31.9%16.0%20.2%25.0%
Middle East and North Africa30.2%36.5%19.7%41.1%21.4%
BMI (kg/m2), mean (SD)25.9 (5.1)26.3 (5.4)28.0 (5.9)25.2 (4.9)24.1 (4.8)
Ever smoker1185/2717 (43.6%)128/432 (29.6%)494/1032 (47.9%)36.9%27.7%
Ever alcohol1089/2718 (40.1%)179/432 (41.4%)451/1032 (43.7%)36.3%28.6%
University education1178/2717 (43.4%)45.5%320/1032 (31.0%)44.0%41.1%
Fibromyalgia (rheumatologist’s opinion)212/2717 (7.8%)11.1%11.6%9.5%3.6%
Fibromyalgia (FiRST)427/2482 (17.2%)69/391 (17.6%)245/982 (24.9%)25/165 (15.2%)9/107 (8.4%)
Symptom duration (years), mean (SD)14.4 (11.1)10.1 (9.5)16.8 (12.3)12.7 (10.7)10.7 (8.8)
Diagnosis delay (years), mean (SD)5.8 (7.7)4.3 (6.6)9.1 (11.1)6.9 (8.5)4.0 (6.6)
HLA-B27 positive1709/2168 (78.8%)197/316 (62.3%)86/474 (18.2%)27/85 (31.8%)47/77 (61.0%)
First-degree or second-degree relatives of SpA*35.5%28.9%36.3%22.0%27.7%
Axial involvement (according to the rheumatologist)97.5%55.0%35.5%58.3%66.1%
Sacroiliitis on X-ray75.1%33.7%20.5%37.5%48.2%
Uveitis ever21.6%17.3%2.6%16.1%18.8%
IBD ever (confirmed by endoscopy)4.7%4.4%0.5%64.3%1.8%
Psoriasis ever (confirmed by a dermatologist)154/2718 (5.7%)12.2%86.5%3.0%8.9%
csDMARDs ever51.6%88.7%92.8%92.9%76.8%
bDMARDs ever59.3%51.5%64.7%53.0%48.2%
Current csDMARDs23.1%53.1%59.6%52.4%49.1%
Current bDMARDs47.5%37.0%51.6%38.1%33.9%
NSAIDs alone30.5%15.0%10.8%12.5%23.2%
CRP mg/L, mean (SD)11.7 (26.6)13.9 (25.4)11.4 (28.6)13.1 (22.5)12.8 (20.3)
CRP ≥6 mg/L1142/2295 (49.8%)48.0%412/1028 (40.1%)42.9%46.4%
ASDAS-CRP, mean (SD)2.5 (1.1)2.6 (1.2)2.6 (1.1)2.5 (1.1)2.5 (1.1)
ASDAS-CRP <1.3457/2682 (17.0%)67/428 (15.7%)147/1015 (14.5%)30/167 (18.0%)20/110 (18.2%)
ASDAS-CRP <2.11088/2682 (40.6%)153/428 (35.7%)379/1015 (37.3%)64/167 (38.3%)41/110 (37.3%)
PGA, mean (SD)4.3 (2.7)4.5 (2.7)4.6 (2.7)4.3 (2.7)4.4 (2.8)
BASDAI, mean (SD)3.7 (2.4)4.0 (2.4)4.3 (2.5)3.8 (2.4)3.7 (2.5)
BASFI, mean (SD)3.0 (2.6)2.8 (2.6)3.1 (2.8)2.8 (2.6)3.0 (2.7)
ASAS-HI, mean (SD)6.3 (4.5)6.6 (4.4)7.2 (4.7)6.2 (4.2)7.4 (4.7)
Peripheral manifestations
Peripheral joint disease in the past36.0%94.7%90.8%77.4%75.9%
Peripheral joint disease in the past confirmed by specific investigations30.2%88.9%85.7%72.6%72.3%
Root joints involvement in the past33.9%44.3%26.7%32.7%52.7%
Midfoot arthritis (tarsitis) in the past5.2%13.6%10.3%9.5%18.8%
Midfoot arthritis (tarsitis) in the past confirmed by specific investigations1.5%3.7%3.1%3.0%4.5%
Any enthesitis in the past40.9%57.3%45.8%45.8%65.2%
Any enthesitis in the past confirmed by specific investigations12.9%25.9%23.3%18.5%27.7%
Dactylitis in the past6.0%23.1%37.0%12.5%16.1%
Number of current swollen joints, mean (SD)0.3 (2.0)1.2 (2.9)1.9 (4.8)0.7 (1.7)1.1 (6.3)
Any current swollen joint281/2716 (10.3%)41.6%410/1032 (39.7%)23.8%24.1%
Number of current tender joints, mean (SD)1.5 (4.4)3.3 (6.2)4.8 (8.7)2.7 (5.5)2.1 (5.2)
Any current tender joint928/2716 (34.2%)271/433 (62.6%)651/1032 (63.1%)53.0%50.9%
Current MEI score, mean (SD)2.2 (5.5.)2.4 (5.7)2.9 (7.6)3.0 (6.3)2.1 (4.4)
Number of current enthesitis according to the MEI†, mean (SD)0.6 (1.8)0.6 (2.1)0.8 (2.7)0.8 (1.9)0.7 (1.7)
Any current enthesitis according to the MEI†455/2716 (16.8%)18.2%191/1032 (18.5%)25.6%20.5%
Any current enthesitis according to the SPARCC Enthesitis Index221/2716 (8.1%)15.2%143/1032 (13.9%)16.1%10.7%
Any current enthesitis according to the LEI174/2716 (6.4%)12.2%106/1032 (10.3%)10.1%9.8%
  • All results are presented as mean and SD and percentages for continuous and categorical variables, respectively.

  • *First-degree or second-degree relatives with ankylosing spondylitis, psoriasis, uveitis, reactive arthritis or IBD.

  • †Enthesis with a score >1 according to the MEI.

  • ASAS-HI, ASAS Health Index; ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score; AxSpA, axial spondyloarthritis; BASDAI, Bath Ankylosing Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; bDMARDs, biological disease-modifying antirheumatic drugs; BMI, body mass index; CRP, C reactive protein; csDMARDs, conventional synthetic disease-modifying antirheumatic drugs; FiRST, Fibromyalgia Rapid Screening Tool; IBD, inflammatory bowel disease; IBD-SpA, inflammatory bowel disease-associated spondyloarthritis; SPARCC Enthesitis Index, Spondyloarthritis Research Consortium of Canada Enthesitis Index; Juv-SpA, juvenile spondyloarthritis; LEI, Leeds Enthesitis Index; MEI, Mander Enthesitis Index; PGA, Patient’s Global Assessment; PsA, psoriatic arthritis; pSpA, peripheral spondyloarthritis; ReA, reactive arthritis.;