Distinct clinical outcomes linked to peripheral arthritis and dactylitis in axial spondyloarthritis: findings from a retrospective Irish cohort

Abstract

Introduction: Axial spondyloarthritis (AxSpA) is a chronic inflammatory condition primarily affecting the axial skeleton. Peripheral features such as peripheral arthritis (PA) and dactylitis are common in AxSpA disease. This study aimed to investigate the independent impact of these manifestations on patient presentation and disease outcomes within an Irish AxSpA cohort. Methods: 912 Irish AxSpA patients were analyzed in this study. Disease outcomes in patients with and without peripheral arthritis or dactylitis were compared using univariate and multivariate methods. The prevalence of extra-spinal manifestations was further assessed in relation to AxSpA disease duration. Results: 30.2% of patients reported PA, while 6.6% had dactylitis. PA and dactylitis were strongly linked, with 70% of patients presenting with dactylitis also showing features of PA. Psoriasis was more common in both patients with PA (OR 2.2, P < 0.001) and dactylitis (OR 3.38, P < 0.001). Dactylitis, but not PA was strongly linked to uveitis (OR 2.91, P < 0.001) and inflammatory bowel disease (OR 3.15, P < 0.001), while PA was associated with worse patient functioning and reduced quality of life. PA, but not dactylitis was linked with increased AxSpA disease duration. Discussion: Despite high concurrence of PA and dactylitis in AxSpA patients, each manifestation is independently associated with worse outcomes. While some of these overlapped, several outcomes are specific to either PA or dactylitis. Due to its strong association with uveitis and inflammatory bowel disease, an early presentation of dactylitis may represent a unique subset of patients and serve as a valuable predictive marker for the later onset of these conditions.