Obesity Increases Disease Activity of Norwegian Patients with Axial Spondyloarthritis: Results from the European Map of Axial Spondyloarthritis Survey

Current Rheumatology Reports (2020) 22: 43 https://doi.org/10.1007/s11926-020-00917-4 SPONDYLOARTHRITIS (MA KHAN, SECTION EDITOR) Obesity Increases Disease Activity of Norwegian Patients with Axial Spondyloarthritis: Results from the European Map of Axial Spondyloarthritis Survey Christian Bindesbøll 1 & Marco Garrido-Cumbrera 2,3 & Gunnstein Bakland 4 & Hanne Dagfinrud 5 Published online: 23 June 2020 # The Author(s) 2020 Abstract Objective To investigate the prevalence of overweight and obesity, as well as the association between body mass index (BMI) and disease activity in patients with axial spondyloarthritis (axSpA). Methods Norwegian axSpA patients from the European Map of Axial Spondyloarthritis (EMAS) survey were included in this analysis. Sociodemographic, anthropomorphic, and disease-related variables (HLA-B27, comorbidities, BASDAI, and selfreported spinal stiffness) were reported. Patients were categorized into under/normal weight (BMI < 25 kg/m2), overweight (BMI ≥ 25 to < 30 kg/m2), and obese (≥ 30 kg/m2). Results Of the 509 participants in the EMAS survey, 35% were categorized as under/normal weight, 39% overweight, and 26% obese. Compared to under/normal-weight patients, overweight patients had significantly higher degree of spinal stiffness (mean (SD) 7.91 ± 2.02 vs 7.48 (2.15) and number of comorbidities (2.45 ± 2.11, vs 1.94), both p < 0.001. Obese patients had significantly higher disease activity (BASDAI mean (SD) 5.87 ± 1.78 vs 4.99 ± 2.08, p < 0.001), degree of spinal stiffness (8.18 ± 2.03 vs 7.48 ± 2.15, p = 0.006), and number of comorbidities (3.43 ± 2.43 vs 1.94. ± .38, p < 0.001) than under/normal weight patients. After adjusting for gender and age, obesity proved to be independently associated with disease activity. Conclusion Obesity was associated with higher reported BASDAI score, and being overweight or obese was associated with a higher degree of spinal stiffness and number of comorbidities compared to under/normal weight respondents. The results highlight the serious impact of obesity on health status, and obesity should therefore be considered as a modifiable risk factor for disease activity within the disease management of axSpA. Keywords Axial spondyloarthritis . Obesity . Body mass index . Disease activity This article is part of the Topical Collection on Spondyloarthritis Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11926-020-00917-4) contains supplementary material, which is available to authorized users. * Christian Bindesbøll 1 Novartis Pharma AG, Oslo, Norway 2 Health & Territory Research (HTR), Universidad de Sevilla, Seville, Spain 3 Spanish Federation of Spondyloarthritis Associations (CEADE), Madrid, Spain 4 Department of Rheumatology, University Hospital of Northern Norway, Tromsø, Norway 5 National Advisory Unit on Rehabilitation in Rheumatology, Diakonhjemmet Hospital, Oslo, Norway Introduction Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease that primarily affects the axial skeleton [1]. The axSpA diagnosis comprises radiographic axSpA (raxSpA), which corresponds to ankylosing spondylitis (AS), and non-radiographic axial spondyloarthritis (nr-axSpA). The disease is characterized by early onset, as patients experience their first symptoms in their twenties. The most typical clinical features are reduced spinal mobility, stiffness, and inflammatory low back pain [1]. Current treatment recommendations for people with inflammatory arthritis underline the importance of appropriately dosed physical activity to improve cardiorespiratory fitness and muscle strength [2, 3], but still, people with axSpA are shown to be less physically active and have lower physical fitness compared to the general population [4, 5]. 43 Page 2 of 7 Recent evidence from population-based studies points toward a combined effect of physical activity and body weight on mortality and health profile [6]. Increased weight is known to exert general biological stress, and a link between obesity and autoimmunity is suggested [7]. The exact mechanisms are not known, but evidence supports an association between increased levels of pro-inflammatory cytokines and adipokines derived from adipose tissue [7]. Knowledge about how obesity influences disease activity in axSpA patients is, however, limited. A small study reported more functional limitations and higher subjective disease activity and reduced the benefit of exercise in obese compared to normal weight AS patients [8]. Furthermore, obesity is also reported to be associated with impaired clinical outcome and reduced response to treatment with biological medication [9, 10]. Overweight axSpA patients are reported to show significantly lower response to tumor necrosis factor (TNF) inhibitors than normal-weight patients [10–12]. This knowledge adds to the existing large body of evidence of the negative health effects of excessed weight [13]. The aim of this study was to investigate the prevalence of overweight and obesity and to explore the association between body mass index (BMI) and disease activity, in Norwegian patients with axSpA included in the European Map of Axial Spondyloarthritis Survey [14••]. Methods Design of Survey The design and survey development of EMAS was recently reported [14••]. In brief, EMAS was a cross-sectional survey of unselected 2846 patients self-reporting axSpA from 13 different European countries: Austria, Belgium, France, Germany, Italy, the Netherlands, Norway, Russia, Slovenia, Sweden, Switzerland, the UK, and Spain. This analysis was based on data from the 509 Norwegian respondents. A Norwegian Patient Support Group, Spafo, supported recruitment by distributing the survey to its members. The questionnaire was completed via an online platform for survey data collection. The patient questionnaire included information about sociodemographic variables (age, gender, educational level, marital status, employment status, income level, member of a patient association for axSpA), anthropomorphic (BMI), comorbidity, living habits (smoke and alcohol), and diseaserelated variables described below. BMI was classified according to WHO Europe. BASDAI was used to assess patientreported disease activity. BASDAI includes six questions (Q) addressing fatigue/tiredness (Q1), neck, back or hip pain (Q2), pain/swelling in joints other than the neck (Q3), back or hips, discomfort of any areas tender to touch or pressure (Q4), Curr Rheumatol Rep (2020) 22: 43 morning stiffness from time of awakening (Q5), and duration of morning stiffness from time of awakening (up to 120 min) (Q6). Mean values for each of the six questions (Q1–6) and total BASDAI score (sum of Q1–Q4 + mean of Q5 and Q6, divided by 5) were calculated from 0 (no activity) to 10 (maximum activity) [15]. General Stiffness Index This index, developed specifically for EMAS, assessed the self-reported degree of stiffness experienced by pa (...truncated)