Table 1

BSRBR-AS study: baseline characteristics of biological and non-biological cohorts

Biological cohort
Non-biological cohort (n=416)Difference*95% CI
Age, mean years42.447.0−4.6−6.6 to 2.5
Male, %64.667.3−2.7−11.3 to 5.9
Disease duration, mean years7.712.3−4.6−6.5 to 2.7
Current smokers, %21.311.010.23.9 to 16.5
BASDAI5. to 2.9
BASFI5. to 3.2
BAS-G§ to 3.9
CRP (mg/dL)−0.8 to 1.6
ASDAS3. to 1.3
Physical job, %44.851.0−6.2−3.1 to 15.5
WPAI measures (in the last 7 days)
 Absenteeism, % to 11.4
 Presenteeism, %41.020.620.415.9 to 24.9
 work impairment, %
42.321.420.916.2 to 25.7
 Overall activity impairment, % to 31.4
  • *Difference=biological – non-biologic cohort.

  • ASDAS, Ankylosing Spondylitis Disease Activity Scale; BAS-FI, Bath Ankylosing Spondylitis Functional Index; BAS-G, Bath Ankylosing Spondylitis Global Disease Status; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BSRBR-AS, British Society of Rheumatology Biologics register in Axial Spondyloarthritis; CRP, C reactive protein; WPAI, Work Productivity and Activity Impairment.