Do patients with ankylosing spondylitis adapt to their disease? Evidence from a 'then-test' in patients treated with TNF-inhibitors

Objective: To investigate whether patients with ankylosing spondylitis (AS) adapt to their disease, using the 'then-test'. Methods: Data from patients participating in the AS Study for Evaluation of Recombinant Infliximab Therapy (ASSERT) and continuing in the European AS Infliximab Cohort (EASIC) were used. At 5 assessments in EASIC, patients were asked to rerate their global well-being before the start of infliximab in ASSERT. The patients evaluated their past situation by using a 'then-test' ('retrospective patient global'). Initial and retrospective patient global were compared using a paired t test, and mixed linear models investigated whether the retrospective score of well-being was stable at all follow-up assessments in EASIC. Linear regression analysis explored whether treatment response was associated with the difference between the initial and retrospective score ('gap') while adjusting for possible confounders. Results: 86 patients (mean age 39.8 years (SD=10.4), mean disease duration 10.8 years (SD=8.5)) contributed to the current analyses. At the time of starting infliximab, patients judged their global at 7.0 (SD=1.6), and with the 'then-test' at 7.2 (SD=2.3) (p=0.45). Time elapsed did not influence the 'then-test' (p=0.13). Multivariably, the gap was irrespective of treatment response, but associated with initial patient global (p