The Ankylosing Spondylitis Working Group (ASWG) developed criteria for describing the patient's response to therapy for ankylosing spondylitis. This can be used to monitor the response to therapy over time. The authors are from multiple university hospitals in France, The Netherlands, and Massachusetts.
Domains evaluated:
(1) pain
(2) function
(3) inflammation
(4) global assessment of the patient
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Domain
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Measure
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pain
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VAS scaled from 0 to 100
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function
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BASFI (functional index) scaled from 0 to 100
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inflammation
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mean of (a) severity of morning stiffness from 0 to 100 and (b) duration of morning stiffness with 120 minutes scored 100, or points equal (5 / 6 * minutes) up to 100 maximum
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global assessment
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overall status scaled from 0 to 100
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where:
• Scales are 0 to 100 with 0 absent and 100 very severe (extreme, worst imaginable).
• Scaling pain can be done in 3 ways - (a) anchored at equal intervals for mild, moderate, severe and extreme, (b) anchored at increasing intervals reflecting the greater impact of greater pain, (c) logarithmic (linear but exponential significance).
net improvement =
= ((measure before treatment) - (measure after treatment))
percent fraction improvement =
= ((measure before treatment) - (measure after treatment)) / (measure before treatment) * 100%
net deterioration = negative of net improvement =
= ((measure after treatment) - (measure before treatment))
percent fraction deterioration = negative of percent fraction improvement =
= ((measure after treatment) - (measure before treatment)) / (measure before treatment) * 100%
Criteria for response - one of the following:
(1) all 4 domains show:
(1a) a percent fraction improvement >= 20%
(1b) an absolute net improvement >= 10 points
(2) 3 domains improve and the fourth does not deteriorate:
(2a) 3 show a percent fraction improvement >= 20%
(2b) 3 show an absolute net improvement >= 10 points
(2c) the fourth domain does not show a percent fraction deterioration >= 20%
(2d) the fourth domain does not show a absolute net deterioration >= 10 points
