Table 2

Demographic, clinical, PRO and WPAI–axSpA characteristics of the full study population and the ≤47 and >47 years age subgroups

CharacteristicsFull study population
≤47 years group
>47 years group
P value
General demographics
 Male, % (n)61.6 (474)64.6 (248)58.5 (226)0.085
 Age (years), mean±SD47.1±12.5 (19–81)36.6±6.9 (19–47)57.5±6.8 (18–81)<0.001
 BMI (kg/m2)28.0±11.926.9±10.929.0±12.10.012
 University or college degree, % (n)27.0 (208)29.7 (114)24.4 (94)0.096
Clinical characteristics
 Time of diagnosis (years), mean±SD13.4±11.99.6±9.117.3±13.0<0.001
 BASDAI score (range 0–10), mean±SD3.9±2.23.6±2.34.2±2.0<0.001
 BASFI score (range 0–10), mean±SD3.4±2.52.6±2.34.2±2.4<0.001
 ASAS-HI score (range 0–17), mean±SD6.6±3.85.9±3.97.3±3.7<0.001
WPAI-axSpA (n=590)
  Employed, % (n)
  Impairments in daily activity (0–10, n=695), mean (Numerical Rating Scale)±SD
76.6 (590)
88.5 (340)
64.8 (250)
 Missed hours from work because of axSpA during the past 7 days, mean±SD3.8±10.33.8±10.83.8±9.50.980
 Missed hours from work during the past 7 days because of any other reason, such as vacation, holidays, time off to participate in this study, mean±SD6.0±12.75.9±12.56.1±13.00.836
 Hours actually worked during the past 7 days, mean±SD28.9±17.129.8±16.627.7±17.60.143
 Presenteeism during the past 7 days, mean±SD32.6%±25.6%29.3±25.4%37.0±25.4%<0.001
 Absenteeism during the past 7 days, mean±SD10.6%±26.2%9.2%±24.8%12.5%±28.0%0.004
 0 (no absenteeism), % (n)81.9 (483)85.0 (289)77.6 (194)0.021
 Total impairment calculated as absenteeism score/(1−absenteeism score)×presenteeism score) resulting in a range from 0% to 100% with higher percentages indicating higher impairment, mean±SD36.6%±29.6%33.9%±29.3%41.7%±29.5%0.003
  • *Results of the WPAI–axSpA are only presented for employed patients (n=590) unless otherwise noted.

  • ASAS-HI, Assessment of SpondyloArthritis International Society–Health Index; axSpA, axial spondyloarthritis; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BMI, body mass index; BMI, body mass index; PRO, patient-reported outcome; WPAI, Work Productivity and Activity Impairment Questionnaire.