Category | Cluster 1 n=16 | Cluster 2 n=20 | Cluster 3 n=22 | Cluster 4 n=20 | P value |
WPI | 2.7±1.9 | 3.1±2.2 | 3.5±2.8 | 1±1.2 | 0.03 |
PD | 8.6±2.9 | 6±3.9 | 8.8±5.6 | 0.7±1.9 | <0.001 |
Female sex | 9 (56.2%) | 5 (25%) | 9 (40.9%) | 2 (10%) | 0.02 |
Age (years) | 37.4±8.5 | 43.5±11.7 | 43.1±10.2 | 36.2±9.4 | 0.58 |
BMI (kg/m²) | 26.9±5.7 | 26.3±4 | 27±4.9 | 24.7±4.5 | 0.24 |
HLA-B27 positivity | 15 (93.8%) | 20 (100%) | 19 (86.4%) | 18 (90%) | 0.4 |
Symptom duration (years) | 14.3±9.2 | 20.1±12.9 | 16.5±9.5 | 10.7±7.6 | 0.14 |
ASDAS at follow-up | 2.1±0.8 | 1.8±0.8 | 1.8±0.7 | 1.1±0.5 | <0.001 |
CRP at baseline (mg/l) | 8.4±6.4 | 19.9±19.2 | 11.7±13.4 | 13.1±17.1 | 0.87 |
CRP at follow-up (mg/l) | 4.4±5.1 | 4.6±5.7 | 3.4±3.8 | 2.6±2.8 | 0.14 |
Current NSAID intake | 6 (37.5%) | 6 (30%) | 14 (63.6%) | 4 (20%) | 0.03 |
Continuous variables are expressed as mean±SD and categorial variables as n (%). P values were calculated using χ2 for categorial variables and Analysis of Variance for continous variables.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BMI, body mass index; CRP, C reactive protein; HLA, human leucocyte antigen; NSAID, non-steroidal anti-inflammatory drugs; PD, PainDETECT; WPI, Widespread Pain Index.