Different disease activity trajectories in early axial spondyloarthritis lead to significantly different long-term outcomes: a trajectory-based analysis of the DESIR cohort over 10 years.

Introduction: The study aimed to identify and describe disease activity trajectories over 10 years in patients with recent-onset axial spondyloarthritis (axSpA) and determine their impact on long-term outcomes.

Methods: This prospective, multicentre study (Devenir des Spondylarthropathies Indifférenciées Récentes cohort, ClinicalTrials.gov NCT) followed patients with early axSpA for 10 years. Only patients with at least three Axial Spondylitis Disease Activity Score (ASDAS) values were included. Long-term outcomes assessed were TNF inhibitors (TNFi) exposure, structural progression, function (Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index), quality of life (36-items Short Form Survey), sick leave days and cardiovascular (CV) events. ASDAS trajectories were identified using k-means clustering. Multinomial multivariable regression estimated associations between baseline characteristics and trajectories. Long-term outcomes for each trajectory were described.

Results: Among 601 patients, five ASDAS trajectories were identified: persistent low disease activity/remission (tA), clinically important improvement (tD) and persistent moderate (tB), high (tC) or very high (tE) disease activity. Patients in tA were more likely to be male, have a university degree, have white-collar jobs, have positive HLA B27 status and have less fibromyalgia. Trajectory tE was linked to poorer function (BASFI 50/100 vs 7/100 for lower ASDAS trajectory), higher TNFi exposure (74% vs 29%) and more CV events (5.7% vs 0). Structural progression was low but comparable across trajectories, except for higher sacroiliac joint progression in tB.

Conclusion: The k-means method revealed distinct disease activity trajectories in axSpA. Higher disease activity trajectories were associated with a higher prevalence of fibromyalgia and poorer outcomes, except for structural progression, which was comparable across trajectories.