Association Between Adalimumab Dosing Interval and Uveitis Recurrence in Patients with Ankylosing Spondylitis

<b>Background/Objectives</b>: Ankylosing spondylitis (AS) is a chronic inflammatory disease frequently associated with acute uveitis (AU). Adalimumab, a monoclonal tumor necrosis factor (TNF) inhibitor, is widely used to manage AS and AU. While biologic tapering is recommended in stable AS, its impact on uveitis recurrence remains unclear. <b>Methods</b>: This real-world retrospective cohort study analyzed 65 AS patients with a history of AU who received adalimumab for ≥6 months. Time-dependent covariates, including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), erythrocyte sedimentation rate (ESR), and adalimumab dosing interval, were incorporated into a logistic regression model using generalized estimating equations to identify risk factors for uveitis recurrence. Uveitis recurrence rates were compared among different dosing intervals: every 2 weeks (q2w), every 3 weeks (q3w), and every 4 weeks or longer (q4w+). <b>Results</b>: Among the 65 patients, 27 (41.5%) experienced a total of 50 AU flares during adalimumab treatment. Recurrence rates increased with dosing interval extension (1.5% for q2w, 3.6% for q3w, and 4.0% for q4w+; <i>p</i> = 0.036). In adjusted logistic analysis, the odds ratio (OR) for AU recurrence was significantly higher for q3w (OR = 3.766) and q4w+ (OR = 4.916) compared to q2w. Other factors, including age, sex, ESR, and BASDAI, were not significantly associated with uveitis recurrence. <b>Conclusions</b>: Extended dosing intervals of adalimumab in AS patients with prior AU may be associated with a higher prevalence of uveitis recurrence, even when axial symptoms remain controlled. Therefore, adalimumab spacing strategies should be implemented with caution in these patients to minimize the risk of uveitis recurrence.