Background Adults with rheumatoid arthritis have been shown to have a reduction in lean mass and increased adiposity, despite presenting normal Body Mass Index (BMI). Several studies have shown increased adiposity induces a proinflammatory state which lead to a worse response to treatment. There are few publications about this subject in juvenile idiopathic arthritis (JIA)
Objectives Describing body composition and anthropometric parameters in JIA patients, and evaluating relationship between adiposity and inflammatory in these children.
Methods Observational cross-sectional study, in JIA patients from 4 to 15 years, monitored by a Pediatric Rheumatology Unit. Monoarticular forms were excluded. Anthropometric, clinical and treatment data were recorded. DXA (measuring bone and fat mass) were obtained. Fat Mass Index (FMI) was defined as fat mass (kg)/height (m2) and fat-free mass index (FFMI) as lean mass (kg)/height (m2). JADAS27 index was used to evaluate inflammatoty activity.
Results We analyzed 80 patients, whose characteristics are shown in table 1. The most frequent JIA subtype was oligoarticular (16.3% extended,47.5% persistent) followed by polyarticular (25.1%). Twenty five percent of patients had uveitis. Fifty percent them had inactive disease with treatment, 26% had activity and 23% were inactive without treatment. Regarding the treatment, 52.5% were on methotrexate and 30% on a biological drug (22.5% antiTNFα, 5% antiIL-1, 2.5% antiIL-6). Disease duration average was 6.6 years (± 3.7SD). JADAS27 index mean score was 2 (±4SD), CRP 4.7mg/l (±9,5SD), ESR 8.7mm (±7,2SD) and CHAQ 0.17 (± 0,38SD). Anthropometric parameters are shown in table 1. Mean JADAS27 index score in patients with normal BMIwas lower (1.7±3.6 SD) than mean JADAS27 index score in overweight and obese patients (3.3±6.0SD), although this difference was not significantly (p=0.255). In multiple linear regression, an increase of 0.3 JADAS27 was observed for each unit of FMI increase (p=0.03). This relationship was maintained in the multivariate analysis (B0.015; p0.01) independently of JIA subtype and received treatment.
Conclusions In JIA patients, there is a linear relationship between FMI and disease activity measured by JADAS27, but most patients had a normal BMI. The establishment of this relationship (fat-inflammatory activity) would be transcendental due to the need to optimize the recommendations in the JIA approach.
Alvarez-Nemecye J, Buenfil-Rello FA, Pacheco Pantoja El. Association between body composition and disease activity in rheumatoid arthritis. A sistematic review. Reumatol Clin. 2016;12(4):190–5.
Disclosure of Interest None declared