Kaplan-Meier analysis of time to relapse in AS patients after discontinuation of infliximab treatment. (a) Cumulative probability of relapse analyzed according to state of remission as measured by ASAS partial remission criteria at TP1. Patients were (bold line) or were not (thin line) in partial remission at TP1. (b) Cumulative probability of relapse according to state of disease activity at TP1 as indicated by a BASDAI ≥ 3 (high disease activity) (thin line) or <3 (low disease activity) (bold line). (c) Cumulative probability of relapse according to state of disease activity at TP1 as indicated by a CRP ≤ 6 mg/l (bold line; low disease activity) or >6 mg/l (thin line; increased disease activity). AS, ankylosing spondylitis; ASAS, Assessments in Ankylosing Spondylitis [working group]; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; pts., patients; TP1, time point 1 (when infliximab treatment was discontinued).