Fig. 1

Improvement events in pain. Proportions of patients with ≥ 30% improvement in a total back pain and b nocturnal pain, and ≥ 50% improvement in c total back pain, d nocturnal pain, and e spinal pain (BASDAI Q2) at each study visit. Vertical dotted line indicates week 16, after which all patients received open-label tofacitinib until week 48. The 50th percentile line is to facilitate interpretation of the results. BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BID, twice daily; Q, question