| Name of the Instrument/Tool | Ankylosing Spondylitis Disease Activity Score (ASDAS) |
| First Description |
Lukas C, Landewé R, Sieper J, Dougados M, Davis J, Braun J, van der Linden S, van der Heijde D; Assessment of SpondyloArthritis international Society. Development of an ASAS-endorsed disease activity score (ASDAS) in patients with ankylosing spondylitis. Ann Rheum Dis. 2009 Jan;68(1):18-24. doi: 10.1136/ard.2008.094870. Epub 2008 Jul 14. PMID: 18625618. |
| Year | 2009 |
| Domains | |
| Concept of constructs | Disease activity |
| Population/Disease | Disease specific |
| Originally developed for | Axial Spondyloarthritis |
| Other rheumatic diseases where can be applied (only if validated) |
--- |
| Additional population with no rheumatic diseases |
No |
| Language: Originally published in | --- |
| Available in Language | English |
| REFERENCE IDENTIFICATION | |
| Author/s | Lukas C, |
| Title | Assessment of SpondyloArthritis international Society. Development of an ASAS-endorsed disease activity score (ASDAS) in patients with ankylosing spondylitis. |
| Journal | Ann Rheum Dis. |
| Year | 2009 |
| Vol | 68 |
| Num | 1 |
| Pages | 18-24. |
| Country | International Study (ASAS group) |
| Language | English |
| Other references of interest | |
| Link | https://www.ncbi.nlm.nih.gov/pubmed/29453216 |
| Brief Description |
Ankylosing Spondylitis Disease Activity Score (ASDAS): 2018 update of the nomenclature for disease activity states. |
| Link | http://www.ncbi.nlm.nih.gov/pubmed/19060001 |
| Brief Description |
ASDAS, a highly discriminatory ASAS-endorsed disease activity score in patients with ankylosing spondylitis. |
| Link | http://www.ncbi.nlm.nih.gov/pubmed/22772319 |
| Brief Description |
Extensive data about sensitivity and discriminatory ability of the ASDAS in patients treated with etanercept or sulphasalazine in the ASCEND trial. |
| Instrument/Tool Translations References | |
| No other References. | |
| DEVELOPER CONTACT INFORMATION | |
| Correspondence to | Professor Robert Landewé |
| --- | |
| Address | Department of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1100 DD Amsterdam |
| Website | --- |
| Available | --- |
| Links | |
| DESCRIPTION OF THE INSTRUMENT | |
| Type Of Measure | Composite Index |
| Brief Description |
ASDAS is a composite index with continuous measurement properties. The Assessment of SpondyloArthritis international Society (ASAS) membership has selected the ASDAS containing C-reactive protein (CRP) as acute phase reactant as the preferred version, and the one with erythrocyte sedimentation rate (ESR) as the alternative version. Apart from the value of CRP or ESR, the four additional self-reported items included in this index are back pain (BASDAI question 2), duration of morning stiffness (BASDAI question 6), peripheral pain/swelling (BASDAI question 3) and patient global assessment of disease activity. |
| Number of Items | 5 |
| Range | 0 - ≈7 (arithmetically there is no upper limit) |
| Responses options/scale |
Yes peripheral pain/swelling (BASDAI question 3) and patient global assessment of disease activity. Back pain and peripheral pain/swelling are anchored from 0 (none) to 10 (very severe) and patient global assessment is also anchored from 0 (not active) to 10 (very active). Duration of morning stiffness (BASDAI question 6) is anchored by a time scale (0–2 or more hours). The fifth item is the value of one of the acute phase reactants: CRP (in mg/L) or ESR (in mm/h). Items are mathematically combined to give a continuous score - the ASDAS. |
| Developed for | Both |
| PRACTICAL APPLICATION | |
| Method of administration | Self-administered |
| Recommendations to score |
The formula for ASDAS-CRP (preferred version) is: 0.12 x Back Pain + 0.06 x Duration of Morning Stiffness + 0.11 x Patient
The formula for ASDAS-ESR (alternative version) is: 0.08 x Back Pain + 0.07 x Duration of Morning Stiffness + 0.11 x Patient
The score is most easily calculated using an online calculator or a hand-held calculator, although it is possible to calculate longhand or using a quick ASDAS calculation form available online. Also, the ASAS group has a mobile application that can be used to calcuulate the score. |
| Score Interpretation | Ranges from 0 (no disease activity) to ≈7 (maximal disease activity), although arithmetically there is no upper limit for ASDAS (upper end of the scale being determined by the level of the CRP or ESR). |
| Cut-off points | 1.3 "inactive" from "low disease activity"; 2.1 "moderate" from "high disease activity"; 3.5 "high" from "very high disease activity" |
| Cut-off points applied to | Both |
| Smallest detectable change if described | 0.41 to 1.06 depending on the method. "clinically important improvement" a change >=1.1 units & "major improvement" a change >=2.0 units |
| Smallest detectable change applied to | Both |
| Completion time by the patient | less than 1 minute minutes |
| Scoring time by the assessor | quick assessment forms (both available at http://www.asas-group.org/research.php?id=01) and hand-held calculator but is unwieldy without such a tool. minutes |
| Training to score | Not necessary |
| Strengths | Useful in clinical practice & research, Easy to use |
| Limitations | Complex scoring |
| OTHER COMMENTS | |
| Other Comments |
The ASDAS has been validated in several observational cohorts and trial populations and is now being used regularly in clinical trials, including longitudinal studies of patients with SpA receiving TNFi. The ASDAS has been endorsed by the ASAS and by Outcome Measures in Rheumatology. ASDAS is emerging as the best measure of disease activity in AS/axial SpA on the basis of including both patient-generated items and objective measures of inflammation and on having, to date, equivalent or often superior psychometric performance when compared to the BASDAI. |