Effects of tapering tumor necrosis factor inhibitor on the achievement of inactive disease in patients with axial spondyloarthritis: a nationwide cohort study.

OBJECTIVES

To investigate the association between the extent of tapering tumor necrosis factor inhibitor (TNFi) and the likelihood of achieving inactive disease in patients with axial spondyloarthritis (axSpA)

METHODS

We analyzed 1575 1-year follow-up interval data of 776 axSpA patients treated with TNFi for more than 1 year in a nationwide observational cohort. The decision on tapering TNFi was made by patients and their physicians. We quantified TNFi used during interval as a dose quotient (DQ). The intervals were classified into the heavy-tapering (DQ < 50), mild-tapering (DQ 50-99), and control groups (DQ = 100). Outcome variables included achieving Ankylosing Spondylitis Disease Activity Score-inactive disease (ASDAS-ID) and major clinical response of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI50) in the follow-up visit. The effects of TNFi tapering on the outcome were analyzed using the generalized estimating equation.

RESULTS

At the baseline visit, 91.1% of the patients showed a high disease activity (ASDAS-CRP ≥ 2.1). DQ of each interval was significantly influenced by the ASDAS-CRP measure in the prior follow-up (P < 0.001). ASDAS-ID was observed in 42.3% of the intervals. A multivariable analysis showed that the likelihood of outcome achievement was comparable between the control and mild-tapering groups, but significantly decreased in the heavy-tapering group (vs. the control group, adjusted OR = 0.28, [95% CI, 0.08-0.94]). In contrast, the likelihood to achieve BASDAI50 response was not different among the groups. In the subgroup of patients who reached ASDAS-ID 1 year after TNFi treatment (n = 327), ASDAS-ID was observed in 66.1% of the subsequent intervals, and only the mild-tapering group showed a likelihood of target maintenance comparable with that of the control group (adjusted OR = 1.25 [0.41-3.80]). This likelihood decreased with an increase in ASDAS-CRP.

CONCLUSION

Mild tapering of TNFi has efficacy comparable with that of the standard-dose treatment for ASDAS-ID achievement in patients with axSpA.