Table 1

 Baseline characteristics of 68 patients with chronic inflammatory low back pain

CharacteristicAll patients (n = 68)
*45 of the 47 patients who were asked about night pain.
AS, ankylosing spondylitis; ESSG, European Spondylarthropathy Study Group; IBD, inflammatory bowel disease; IQR, interquartile range.
Sex (% male)38
Age (years) (mean (SD))34.9 (10.3)
Symptom duration (months) (median (IQR))18.0 (12.0 to 24.0)
Criteria for inflammatory low back pain:
    3 criteria present56%
    4 criteria present41%
    5 criteria present3%
Night pain present96%*
HLA-B27 present46%
History of IBD present15%
History of uveitis present15%
History of psoriasis present24%
Family history of AS present37%
Fulfilling ESSG criteria84%
Fulfilling Amor criteria71%
Fulfilling both ESSG and Amor criteria63%