Table 3

Association between mSASSS change rate and covariates

Independent variableUnivariate modelMultivariable model
Beta estimate*95% CIP valueBeta estimate*95% CIP value
Lower boundUpper boundLower boundUpper bound
Age at diagnosis0.0170.0050.0280.0040.012−0.0020.0250.085
Sex (female)−0.415−0.714−0.1170.006−0.561−0.883−0.2390.001
HLA-B27 positivity0.5870.0501.1230.032
Eye involvement0.4320.1420.7210.0030.4200.1240.7170.005
Peripheral joint involvement−0.215−0.5110.0810.155−0.181−0.4810.1190.237
ESR at the start of the interval (log)0.1280.0500.2060.0010.1990.0930.305<0.001
CRP at the start of the interval (log)0.006−0.0450.0580.811
BASDAI at the start of the interval (square root)−0.100−0.2450.0440.173−0.225−0.406−0.0430.015
mSASSS at the start of the interval−0.001−0.0140.0120.920
cDMARDs†−0.335−0.538−0.1330.001−0.241−0.4940.0130.063
NSAIDs†−0.079−0.2090.0510.235
Glucocorticoids†0.134−0.2830.5520.529
TNFis−0.054−0.099−0.0090.017−0.054−0.101−0.0080.022
  • *Unstandardised regression coefficient.

  • †Number of intervals prescribed with drugs for >50% of the interval period.

  • BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; cDMARDs, conventional disease-modifying anti-rheumatic drugs; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; HLA, human leucocyte antigen; mSASSS, modified Stoke Ankylosing Spondylitis Spinal Score; NSAIDs, non-steroidal anti-inflammatory drugs; TNFis, tumour necrosis factor inhibitors.