POS1475-HPR PHYSICAL FUNCTION AND REGULAR PHYSICAL EXERCISE IS IMPORTANT FOR HEALTH-RELATED QUALITY OF LIFE IN PATIENTS WITH RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS
Authors: C. Feldthusen, M. Hallström, A. Deminger, E. Hulander, H. Forsblad-D’elia
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Radiographic axial SpondyloArthritis (r-axSpA) is a chronic, rheumatic disease that results in long-lasting pain and stiffness in the back, with negative impact on physical function and health-related quality of life (HRQoL). Physical activity is a cornerstone in the treatment of r-axSpA. The connection between physical activity and HRQoL is not well understood in r-axSpA and needs to be further clarified to better develop and provide appropriate rehabilitation interventions for patients with r-axSpA. <h3>Objectives:</h3> To evaluate physical function, spinal mobility, muscle strength and physical activity compared to normal values and recommendations and to investigate if these factors are associated with HRQoL in patients with long-standing r-axSpA. <h3>Methods:</h3> A cross-sectional study from the Long-term Outcome Ankylosing Spondylitis (LOAS), 13 years follow-up program. HRQoL was assessed by Assessment of SpondyloArthritis international Society Health Index (ASAS-HI) [1] and Short Form Survey Instrument 36-Item (SF36) Physical and Mental Component Summary score (PCS, MCS). Demographic data, disease activity assessed by ASDAS, physical function by Bath Ankylosing Spondylitis Functional Index (BASFI), spinal mobility by modified Bath Ankylosing Spondylitis Metrology Index (BASMI), muscle strength by Timed Stands Test (TST) [2] for leg strength and Grippit [3] for handgrip force, and physical activity by time spent on regular physical exercise, daily activities, and sedentary behavior were recorded. BASFI was compared according to values discriminating patients from healthy controls (1.5 for 30-50 years; 2.5 for &gt;50 years) [4], BASMI according to age specific reference intervals (&lt;quartile 3) [5], and TST and Grippit according to reference values for age and sex [2,3]. Models were developed to analyse associations between the dependent variables ASAS-HI, SF36 MSC, and PCS and the independent variables BASFI, BASMI, TST, Grippit, physical exercise, daily activity, and sedentary behavior in addition to age and sex using stepwise multivariable linear regression. <h3>Results:</h3> Results are shown in Table 1. For physical function (BASFI), 55% scored within the values for healthy controls and 45% displayed spinal mobility (BASMI) within normal range. Regarding muscle strength, 82% performed within normal range for leg strength (TST), and 91% for handgrip force (Grippit). Concerning physical activity, 75% reached the recommendations for health enhancing physical activity by WHO, Figure 1. Regression analysis displayed that BASFI and physical exercise were able to significantly explain the variation in ASAS-HI (adjusted R<sup>2</sup>=0.51). Regarding SF36, BASFI, physical exercise and TST significantly explained the variation in SF36 PCS (adjusted R<sup>2</sup>=0.48), and BASFI, age and physical exercise the variation in SF36 MCS (adjusted R<sup>2</sup>=0.22). <h3>Conclusion:</h3> Approximately half of the participants displayed physical function and spinal mobility within normal range. The majority had normal muscle function and reached the recommended level of health enhancing physical activity. Physical function and regular physical exercise had great importance for HRQoL and were able to explain 22-51% of its variation. <h3>REFERENCES:</h3> [1] Csuka M, et al. Simple method for measurement of lower extremity muscle strength. Am J Med. 1985;78:77-81. [2] Nordenskiold UM, et al. Grip force in patients with rheumatoid arthritis and fibromyalgia and in healthy subjects. A study with the Grippit instrument. Scand J Rheumatol. 1993;22:14-9. [3] Feldthusen C, et al. The ASAS Health Index and Environmental Factors Item Set: validity and reliability of the Swedish translations in Swedish patients with ankylosing spondylitis. Scand J Rheumatol. 2023:1-8. [4] Wariaghli G, et al. Normative values for the Bath Ankylosing Spondylitis Functional Index in the general population compared with ankylosing spondylitis patients in Morocco. BMC Musculoskelet Disord. 2012;13:40. [5] Ramiro S, et al. Reference intervals of spinal mobility measures in normal individuals: the MOBILITY study. Ann Rheum Dis. 2015;74:1218-24.<b>Table 1.</b> Characteristics of the patients with radiographic axial spondyloarthritis (r-axSpA) <h3>Figure 1. Physical activity behavior in terms of the distribution of regular physical exercise (running, gymnastics, sports, etc.), daily activity (brisk walks, gardening, bicycling, etc.), and sedentary behavior apart from sleep (i.e., sitting). Acknowledgements:</h3> The clinical rheumatology research center (KRF) at the Rheumatology Clinic at Sahlgrenska University Hospital. <h3>Disclosure of Interests:</h3> <b>None declared.</b>