Pos0499 Impaired Dietary Intake in Patients With Radiographic Axial Spondyloarthritis and Its Relation to Disease Activity and Physical Function: A Multi-Regional Cross-Sectional Study

Background: Radiographic axial spondyloarthritis (r-axSpA) is one of the most common chronic inflammatory rheumatic diseases, affecting about 0.2 % of the population. As of today, there is no specific dietary guideline for managing r-axSpA patients, and no RCT-studies on diet intervention have been published. We previously reported an impaired dietary quality in patients with r-axSpA 1, but there is a lack of data on the relevance of dietary intake on disease outcomes in r-axSpA patients. Objectives: The aim of this study was to assess the relationship between dietary nutrient intake in r-axSpA patients and disease outcomes. Methods: Patients with r-axSpA (modified NY criteria) at the rheumatology clinic in Umeå University Hospital, northern Sweden, as well as patients in south-western Sweden (Sahlgrenska University Hospital, Södra Älvsborgs Hospital and Alingsås Hospital), were recruited. In total 296 patients were included, study protocols have been described elsewhere 2, 3. Dietary nutrient intake was assessed by a semi-quantitative food frequency questionnaire 4. Nutrients that differed significantly, and where the mean intake differed >20% compared to controls, were examined in linear regression models in relation to Ankylosing Spondylitis Disease Activity Score C-reactive protein (ASDAS), Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index (BASMI). BASFI score was transformed by square root to fit model assumptions. In addition, Vitamin-D was included on a hypothetical basis. The analyses were adjusted for age, sex, country of birth, educational level, single household, weight, smoking status and energy intake. Results: Data on dietary intake was available for 295 patients. Age range was 25-84 years, 63% were male and symptom duration ranged from 3 to 60 years (Table 1). A lower intake of the omega-3 fatty acids Docosapentaenoic and Eicosapentaenoic acid correlated to higher ASDAS, BASFI and BASMI scores (Figure 1). Higher intake of Vitamin-D was related to a lowered ASDAS. Likewise, a higher intake of Selenium and Vitamin-K was related to a lower BASMI score. Conclusion: Dietary intake is impaired in patients with r-axSpA and relates to higher disease activity and worse physical function. Further exploration of the relationship between dietary intake and disease outcomes in patients in other regions, and an assessment of the impact of a health promoting dietary intervention in this patient group is warranted. REFERENCES: 1 Hulander E et al. Patients with radiographic axial spondylarthritis have an impaired dietary intake-a cross-sectional study with matched controls from northern Sweden. Arthritis research 25(1):142. 2 Forsblad-d'Elia H et al. Biomechanical Properties of Common Carotid Arteries Assessed by Circumferential 2D Strain and β Stiffness Index in Patients With Ankylosing Spondylitis. The Journal of rheumatology. 2021;48(3):352-60. 3 Klingberg E et al. Osteoporosis in ankylosing spondylitis - prevalence, risk factors and methods of assessment. Arthritis research 14(3):R108. 4 Christensen SE et al. Two New Meal- and Web-Based Interactive Food Frequency Questionnaires: Validation of Energy and Macronutrient Intake. J Med Internet Res. 2013;15(6):e109. Acknowledgements: We would like to thank research nurse Viktoria von Zweigbergk for her work with the Backbone study. Disclosure of Interests: None declared.