Axial involvement
axial disease, pain
At baseline, axial involvement was determined by investigator judgement (yes or no) based on the totality of available clinical information, such as duration and characteristics of back pain, age of onset, and previous lab investigations and imaging, if available. For these studies, imaging was not required to confirm axial disease. In addition to investigator judgement, a second set of patient-reported outcome (PRO)-based criteria for active axial inflammatory involvement were applied: overall BASDAI score ≥ 4 and BASDAI question 2 (“