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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/2789

Title: Comparison of statistically derived ASAS improvement criteria for ankylosing spondylitis with clinically relevant improvement according to an expert panel
Authors: van Tubergen, A
VAN DER HEIJDE, Desiree
Landewe, R
Dougados, M
Braun, J
Bellamy, N.
Udrea, G
van der Linden, S
Issue Date: 2003
Publisher: BRITISH MED JOURNAL PUBL GROUP
Citation: ANNALS OF THE RHEUMATIC DISEASES, 62(3). p. 215-221
Abstract: Objective: To investigate whether the recently developed (statistically derived) "ASsessment in Ankylosing Spondylitis Working Group" improvement criteria (ASAS-IC) for ankylosing spondylitis (AS) reflect clinically relevant improvement according to the opinion of an expert panel. Methods: The ASAS-IC consist of four domains: physical function, spinal pain, patient global assessment, and inflammation. Scores on these four domains of 55 patients with AS, who had participated in a non-steroidal anti-inflammatory drug efficacy trial, were presented to an international expert panel (consisting of patients with AS and members of the ASAS Working Group) in a three round Delphi exercise. The number of (non-) responders according to the ASAS-IC was compared with the final-consensus of the experts. The most important domains in the opinion of the experts were identified, and also selected with discriminant analysis. A number of provisional criteria sets that best represented the consensus of the experts were defined. Using other datasets, these clinically derived criteria sets as well as the statistically derived ASAS-IC were then tested for discriminative properties and for agreement with the end of trial efficacy by patient and doctor. Results: Forty experts completed the three Delphi rounds. The experts considered twice as many patients to be responders than the ASAS-IC (42 v 21). Overall agreement between experts and ASAS-IC was 62%. Spinal pain was considered the most important domain by most experts and was also selected as such by discriminant analysis. Provisional criteria sets with an agreement of greater than or equal to 80% compared with the consensus of the experts showed high placebo response rates (27-42%), in contrast with the ASAS-IC with a predefined placebo response rate of 25%. All criteria sets and the ASAS-IC discriminated well between active and placebo treatment (chi(2) = 36-45; p < 0.001). Compared with the end of trial efficacy assessment, the provisional criteria sets showed an agreement of 71-82%, sensitivity of 67-83%, and specificity of 81-88%. The ASAS-IC showed an agreement of 70%, sensitivity of 62%, and specificity of 89%. Conclusion: The ASAS-IC are strict in defining response, are highly specific, and consequently show lower sensitivity than the clinically derived criteria sets. However, those patients who are considered as responders by applying the ASAS-IC are acknowledged as such by the expert panel as well as by. patients' and doctors' judgments, and are therefore likely to be true responders.
Notes: Univ Hosp Maastricht, Dept Internal Med, Div Rheumatol, NL-6202 AZ Maastricht, Netherlands. Limburgs Univ Ctr, Diepenbeek, Belgium. Boston Univ, Med Ctr, Dept Med, Clin Epidemiol Res & Training Unit, Boston, MA USA. Hop Cochin, Dept Rheumatol, Paris, France. Rheumazentrum Ruhrgebiet, Dept Rheumatol, Herne, Germany. Ctr Natl Res Disabil & Rehabil Med CONROD, Brisbane, Qld, Australia. Dr Ioan Cantacuzino Hosp, Dept Rheumatol, Bucharest, Romania.van der Heijde, D, Univ Hosp Maastricht, Dept Internal Med, Div Rheumatol, POB 5800, NL-6202 AZ Maastricht, Netherlands.
URI: http://hdl.handle.net/1942/2789
DOI: 10.1136/ard.62.3.215
ISI #: 000181257500005
ISSN: 0003-4967
Category: A1
Type: Journal Contribution
Validation: ecoom, 2004
Appears in Collections: Research publications

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