OBJECTIVE: To investigate whether the recently developed (statistically derived) "ASsessment in @entity1691 Working Group" improvement criteria (ASAS-IC) for @entity1691 ( @entity1691 ) reflect clinically relevant improvement according to the opinion of an expert panel. METHODS: The ASAS-IC consist of four domains: physical function, @entity158 , @entity1 global assessment, and @entity32 . Scores on these four domains of 55 @entity1 with @entity1691 , who had participated in a non-steroidal anti-inflammatory drug efficacy trial, were presented to an international expert panel (consisting of @entity1 with @entity1691 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 @entity1 and doctor. RESULTS: Forty experts completed the three Delphi rounds. The experts considered twice as many @entity1 to be responders than the ASAS-IC (42 v 21). Overall agreement between experts and ASAS-IC was 62%. Spinal @entity158 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 >or=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 @entity1 who are considered as responders by applying the ASAS-IC are acknowledged as such by the expert panel as well as by @entity1 ' and doctors' judgments, and are therefore likely to be true responders.

Comparison of statistically derived ASAS improvement criteria for XXXX with clinically relevant improvement according to an expert panel.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity32 :: ('MESH:D007249', 'Disease') :: ['inflammation'] @entity1691 :: ('MESH:D013167', 'Disease') :: ['ankylosing spondylitis', 'AS', 'Ankylosing Spondylitis'] @entity158 :: ('MESH:D010146', 'Disease') :: ['spinal pain', 'pain']
@entity1691 :: (MESH:D013167,Disease) :: ['ankylosing spondylitis']
