POS1328 HAVE THE CHILDREN WITH JUVENILE IDIOPATHIC ARTHRITIS AN EXCESS OF ADIPOSITY?
Authors: G. Diaz-Cordobes, S. Aguado Henche, L. Martín Pedraz, R. Galindo Zavala, N. Mena-Vázquez, E. Núñez Cuadros
Journal: Annals of the Rheumatic Diseases (2021)

Background: In recent years, several studies show contradictory results regarding body composition in juvenile idiopathic arthritis. Adiposity in Rheumatoid Arthritis and Psoriasic Arthritis has been associated to inflammatory activity, but it is not clear what happens in JIA. Objectives: To describe the body composition and anthropometric parameters of patients with JIA compared with healthy controls and analyze associated risk factors in JIA patients. Methods: Observational cross-sectional study in spanish children aged 4-15 years with JIA compared with healthy controls matched for age and sex. We recorded epidemiological variablesanthropometric parameters, clinical data and validated physical activity questionnaires. Body composition was measured using dual-energy x-ray absorptiometry (DXA), and included total mass (kg), fat mass (g), lean mass (g), and lean mass and android and gynoid fat mass. The fat mass index (FMI) was defined as fat mass (kg)/height squared (m 2 ) and fat-free mass index (FFMI) as fat-free mass (kg)/height squared (m 2 ). Descriptive, bivariete and two multivariate models were constructed to identify factors associated with obesity and fat mass in JIA patients. Results: We analyze 160 subjects: 80 patients with JIA and 80 healthy controls.The baseline characteristics of both groups are shown in Table 1. No differences were found between both groups in BMI (p=0.936), fat mass (p = 0.449), lean mass (p = 0.793) and in fat and lean mass of legs, arms and trunk, or in physical activity questionnaire (p = 0.582). The factors associated with obesity in patients with JIA were: time with biological drug (OR [95% CI] = 1.12 [1.01-1.04]; p = 0.042) and sedentary lifestyle (OR [95% CI] = 3.50 [1.18-7.35]; p = 0.023); while the factors associated with the fat mass index were: age (ß [95% CI] = 0.30 [0.16-1.41]; p= 0.014), inflammatory activity (JDAS) (ß [95% CI] = 0.44 [0.16-1.08]; p= 0.009) and physical activity (ß [95% CI] = -0.22 [-0.10,-0.28]; p = 0.031). Table 1. Baseline characteristics of patients with JIA and controls Variable JIA (n=80) Controls (n=80) P-value Sex, girls n (% ) 56 (70.0) 57 (71.3) 0.862 Age, mean (SD ) 10.7 (3.2) 10.2 (3.2) 0.893 Disease duration (years) JIA, mean (SD ) 6.5 (3.7) JIA subtype Systemic, n (% ) 9 (11.3) Oligoarticular persistent, n (% ) 38 (47.5) Oligoarticular extended, n (% ) 13 (16.3) Rheumatoid Factor-positive polyarticular, n (% ) 1 (1.3) Rheumatoid Factor-negative polyarticular, n (% ) 19(23.8) CRP (mg/l), mean (SD ) 4,8 (9,5) ESR (mm/h), mean (SD ) 8.8 (7,3) JADAS27, mean (SD ) 2 (4.0) CHAQ, mean (SD ) 0.17 (0.4) Treatment DMARDs (synthetic), n (% ) 42 (52.5) DMARDs (biological), n (% ) 24 (30.0) Anti IL-1, n (% ) 4 (16.7) Anti IL-6, n (% ) 2 (8.3) Anti TNF-α, n (% ) 18 (75.0) Treatment duration DMARDs synthetic, (months), mean (±SD ) 51 (37.5) DMARDs biological, (months), mean (±SD ) 19.7 (28.4) DMARDs total (months), mean (±SD ) 55.8 (38.0) Cumulative corticoisteroids dose, median (range ) 11.3 (0.12-870) Abreviaturas; JIA: juvenile idhipathic arthritis; SD: standart deviation; CRP: C-reactive protein; VSG:erytrocyte sedimentation rate; JADAS27: Juvenile Arthritis Disease Activity Score; CHAQ: Childhood Health Assessment; DMARD: disease-modifyng anti-rheumatic drug. Conclusion: Children with JIA have adiposity similar to healthy controls. Inflammatory activity measured by JDAS is associated with fat mass but not to anthropometric measurements such as body mass index (BMI). References: [1]Grönlund et al Juvenile idiopathic arthritis patients with low inflammatory activity have increased adiposity. Scand J Rheumatol 2014. [2]Giani et al. The Influence of Overweight and Obesity on Treatment Response in Juvenile Idiopathic Arthritis. Front Pharmacol 2019 [3]Wiech et al. Body composition and phase angle as an indicator of nutritional status in children with juvenile idiopathic arthritis. Pediatric Rheumatology 2018 [4]Alvarez-Nemegyei et al. Association between Overweight/Obesity and Clinical Activity in rheumatoid arthritis. Reumatol Clin 2020 Disclosure of Interests: None declared