THU0358 NEGATIVE CHANGES OF BODY COMPOSITION IN MYOSITIS PATIENTS AND THEIR ASSOCIATION WITH DISEASE SPECIFIC CHARACTERISTICS, PHYSICAL ACTIVITY AND NUTRITIONAL STATUS.
Authors: S. Oreska, M. Špiritović, P. Česák, O. Marecek, H. Štorkánová, B. Heřmánková, K. Kubinova, M. Klein, L. Vernerová, O. Růžičková, K. Pavelka, L. Šenolt, H. Mann, J. Vencovský, M. Tomčík
Journal: Annals of the Rheumatic Diseases (2020)

Background: Skeletal muscle, pulmonary and articular involvement in idiopathic inflammatory myopathies (IIM) limit the mobility/self-sufficiency of patients, and can have a negative impact on body composition. Objectives: The aim was to assess body composition and physical activity of IIM patients and healthy controls (HC) and the association with selected inflammatory cytokines/chemokines and laboratory markers of nutrition and lipid metabolism. Methods: 54 patients with IIM (45 females; mean age 57.7; disease duration 5.8 years; polymyositis (PM, 22) / dermatomyositis (DM, 25) / necrotizing myopathy (IMNM, 7)) and 54 age-/sex-matched HC (45 females, mean age 57.7) without rheumatic/tumor diseases were included. PM/DM patients fulfilled Bohan/Peter criteria for PM/DM. We assessed body composition (densitometry: iDXA Lunar, bioelectric impedance: BIA2000-M), physical activity (Human Activity Profile, HAP questionnaire), serum levels of 27 cytokines/chemokines (commercial multiplex ELISA kit, Bio-Rad Laboratories) and serum levels of selected parameters of nutrition and lipidogram. Disease activity (MITAX and MYOACT activity score) and muscle involvement (manual muscle testing, MMT-8, and functional index 2, FI2) were evaluated. Data are presented as mean±SD. Results: Compared to HC, patients with IIM had a trend towards significantly increased body fat % (BF%; iDXA: 39.9±7.1 vs. 42.4±7.1 %, p=0.077), but significantly decreased lean body mass (LBM; iDXA: 45.6±8.1 vs. 40.6±7.2 kg, p=0.001; BIA: 52.6±8.8 vs. 48.7±9.0 kg, p=0.023), increased extracellular mass/body cell mass (ECM/BCM) ratio (1.06±0.15 vs. 1.44±0.42, p&lt;0.001), reflecting deteriorated nutritional status and predisposition for physical activity, and significantly lower bone mineral density (BMD: 1.2±0.1 vs. 1.1±0.1 g/cm 2 , p&lt;0.001). Disease duration negatively correlated with BMD and LBM-BIA. Disease activity (MITAX, MYOACT) positively correlated with LBM (by BIA and DXA), similarly as with basal metabolic rate (BMR), and fat free mass (FFM). CRP was positively associated with BF% (BIA and DXA). Higher BF%-DEXA was associated with worse physical endurance (FI2) and worse ability to perform physical activity (HAP). MMT-8 score negatively correlated with ECM/BCM ratio. Serum levels of several inflammatory cytokines/chemokines (specifically IL-1ra, MCP, IL-10) and markers of nutrition (specifically albumin, C3-, C4-complement, cholinesterase, amylase, insulin and C-peptide, vitamin-D, orosomucoid), and lipid metabolism (specifically triglycerides, high-density lipoprotein, apolipoprotein A and B, atherogenic index of plasma) were significantly associated with alterations of body composition in IIM patients. (p&lt;0.05 for all correlations) Conclusion: Compared to healthy age-/sex-matched individuals we found significant negative changes in body composition of our IIM patients associated with their disease activity and duration, inflammatory status, skeletal muscle involvement, and physical activity. These data could reflect their impaired nutritional status and predispositions for physical exercise, aerobic fitness and performance. Serum levels of certain inflammatory cytokines/chemokines and markers of nutrition and lipid metabolism were associated with alterations of body composition in IIM patients. This might further support the role of systemic inflammation and nutritional status on the negative changes in body composition of IIM patients. Acknowledgments: Supported by AZV NV18-01-00161A, MHCR 023728, SVV 260373 and GAUK 312218 Disclosure of Interests: Sabina Oreska: None declared, Maja Špiritović: None declared, Petr Česák: None declared, Ondrej Marecek: None declared, Hana Štorkánová: None declared, Barbora Heřmánková: None declared, Kateřina Kubinova: None declared, Martin Klein: None declared, Lucia Vernerová: None declared, Olga Růžičková: None declared, Karel Pavelka Consultant of: Abbvie, MSD, BMS, Egis, Roche, UCB, Medac, Pfizer, Biogen, Speakers bureau: Abbvie, MSD, BMS, Egis, Roche, UCB, Medac, Pfizer, Biogen, Ladislav Šenolt: None declared, Heřman Mann: None declared, Jiří Vencovský: None declared, Michal Tomčík: None declared