This is supported by the evidence that the ankylosing spondylitis disease activity score (ASDAS)-C reactive protein (CRP), and to a lesser extent the ASDAS-erythrocyte sedimentation rate (ESR), where acute phase reactants are the item with the highest weight, are better discriminators compared to the BASDAI that only includes 10 mm visual analogic scales to be compiled by the patient (41, 44). This evidence concerns the gene CRP and ankylosing spondylitis.