Fibromyalgia is not axial spondyloarthritis: Towards an appropriate use of the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA
Ankylosing Spondylitis Disease Activity Score (ASDAS): defining cut-off values for disease activity states and improvement scores
The ASDAS formulae:
ASDAS-CRP (the preferred version):
0.12 × Back Pain + 0.06 × Duration of Morning Stiffness + 0.11 × Patient Global + 0.07 × Peripheral Pain/Swelling + 0.58×Ln(CRP+1)
ASDAS-ESR (the alternative version):
0.08 × Back Pain + 0.07 × Duration of Morning Stiffness + 0.11 × Patient Global + 0.09 × Peripheral Pain/Swelling+0.29 × √(ESR)
CRP is in mg/litre, ESR is in mm/h; the range of other variables is from 0 to 10; Ln represents the natural logarithm; √ represents the square root.
"Four disease activity states were chosen by consensus: inactive disease, moderate, high and very high disease activity. The three cut-offs selected to separate these states were: 1.3, 2.1 and 3.5 units. Selected cut-offs for improvement were: change ≥1.1 units for clinically important improvement and change ≥2.0 units for major improvement."
An ASAS-endorsed definition of clinically important worsening in axial spondyloarthritis based on ASDAS
"Sensitivity and specificity for an increase of at least 0.6, 0.9 and 1.1 ASDAS points to detect patient-reported worsening were 0.55 (Se) and 0.91 (Sp), 0.38 (Se) and 0.96 (Sp), and 0.33 (Se) and 0.98 (Sp), respectively. The ASAS consensus was to define clinically important worsening as an increase in ASDAS of at least 0.9 points."
Measurement and Treatment of Radiographic Progression in Ankylosing Spondylitis: Lessons Learned from Observational Studies and Clinical Trials
"Given its higher sensitivity to detect change, the mSASSS has been used in clinical studies to evaluate the effectiveness of treatments to slow radiographic progression.
The anterior corners of the cervical and lumbar vertebrae are scored for erosions, sclerosis, squaring (scored as 1), syndesmophytes (scored as 2), or bridged syndesmophytes (scored as 3), with a possible range of 0 (normal) to 72 (complete bridging of both the cervical and lumbar spine).
Group mean mSASSS of the historical OASIS (Outcome Assessments in Ankylosing Spondylitis International Study) cohort increased approximately 1 unit per year."
Scoring radiographic progression in ankylosing spondylitis: should we use the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) or the Radiographic Ankylosing Spondylitis Spinal Score (RASSS)?
"Exclusive progression of the thoracic segment occurred in only 5% of the cases. The contribution of thoracic vertebral corners in the RASSS method is negligible, and does not justify the additional scoring efforts."