Pos0026 Patient and Disease Characteristics Associated With Global Functioning and Health (Asas Hi) in Axial Spondyloarthritis: A Mixed-Effects Model Analysis of Longitudinal Data From the Desir Cohort

Background: The Assessment of SpondyloArthritis international Society Health Index (ASAS HI) is a disease-specific measure of global functioning and health for patients with axial spondyloarthritis (axSpA). Better understanding of the factors that determine ASAS HI scores can contribute to optimize the quality of life of affected patients. Objectives: To explore the role of selected patient- and disease characteristics on predicting ASAS HI over time. Methods: Longitudinal data from the Devenir des Spondyloarthropathies Indifferénciées (DESIR) cohort were used. Patients with a diagnosis of axSpA at their last visit and at least one non-missing value for ASAS HI were included. The study period spanned from the 6th year after inclusion (when ASAS HI was initially collected) to the 10th year, including annual visits throughout this period. A linear mixed-effects model accounting for the inter-dependence of repeated measurements in the same patient was used to analyse factors potentially associated with ASAS HI over time. Among these factors were: socio-demographic variables (age, sex, body mass index, education), disease activity markers (axSpA Disease Activity Score - ASDAS), physical function (Bath Ankylosing Spondylitis (AS) Functional Index - BASFI), spinal and hip mobility (Bath AS Metrology Index - BASMI), 'fibromyalgianess' (Fibromyalgia Rapid Screening Tool – FiRST; with a cut-off score of ⩾5/6), extra-musculoskeletal manifestations, and drug treatments. Using an analysis with a multilevel structure (mixed-effects) allows for heterogeneity among patients and enables predictions at the population level, as well as predictions for each individual patient. Model estimates, namely regression coefficients as well as standardized coefficients (to allow a comparison on the effect of the different predictors) are presented with 95% confidence intervals. Results: In total, 1805 visits of 460 patients were analysed. The mean ASAS HI, which was 5.8 at year 6, remained largely unchanged over the study period. BASFI and female sex were most important in predicting ASAS HI (according to standardized coefficients, Table 1). A one-unit higher BASFI was associated with 0.80 units higher average ASAS HI scores. Being female was associated with a 1.08-units higher ASAS HI than being male. Moreover, higher ASDAS values, having a history of an expert diagnosis of chronic inflammatory bowel disease (IBD) and a high FiRST (≥5/6) were independently associated with worse ASAS HI values, whereas time (visit) was not associated with ASAS HI (Table 1). Conclusion: In patients with axSpA, the ASAS HI remained rather stable over a study period of 5 years. Physical function and female sex were the main determinants of ASAS HI, followed by disease activity, a history of IBD, and having widespread pain. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: Imke Redeker: None declared, Robert Landewé: None declared, Désirée van der Heijde received consulting fees from AbbVie, Argenx, BMS, Galapagos, Glaxo-Smith-Kline, Janssen, Lilly, Novartis, Pfizer, Takeda UCB Pharma. Director of Imaging Rheumatology bv, Sofia Ramiro received research grants and/or consulting fees from AbbVie, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Pfizer, UCB, Sanofi, Annelies Boonen received research grants from Abbvie and honoraria for lectures or consulting fees from Pfizer, Novartis, UCB, Abbvie and Galapagos; all to her department, Maxime Dougados: None declared, Juergen Braun: None declared, Uta Kiltz received grant and research support and consultancy fees from AbbVie, Amgen, Biocad, Biogen, Chugai, Eli Lilly, Fresenius, Gilead, Grünenthal, GSK, Hexal, Janssen, MSD, Novartis, onkowissen.de, Pfizer, Roche, UCB and Viatris.