Jones et al developed the Bath Ankylosing Spondylitis Global Score (BAS-G) to monitoring well-being of patients with ankylosing spondylitis. The authors are from the Royal National Hospital for Rheumatic Diseases in Bath and the University of Southhampton in England.
Parameters:
(1) 10 cm VAS for effect of ankylosing spondylitis on well-being during the past week
(2) 10 cm VAS for effect of ankylosing spondylitis on well-being during the past 6 months
Anchors for VAS scale:
(1) none at 0 cm
(2) very severe (most extreme imaginable) at 10 cm
The 1 week measure can be compared to short-term measures of disease activity such as the BASDAI and BASFI.
The 6 month measure is based on the usual interval between consultations.
Symptoms likely to change with the BAS-G:
(1) spinal pain
(2) fatigue
(3) morning stiffness
(4) entheses
(5) peripheral joint pain
difference in scores =
= (previous score) - (current score)
Interpretation:
• minimum difference: -10
• maximum difference: + 10
• A negative difference indicates deterioration.
• A positive difference indicates improvement.
Performance:
• The BAS-G is sensitive to changes in disease activity and correlates with changes in the BASDAI and BASFI.
• The score is considered reliable and meets validity criteria (face, construct, predictive).
