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

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 self-reported spinal stiffness) were reported. Patients were categorized into under/normal weight (BMI < 25 kg/m(2)), overweight (BMI >= 25 to < 30 kg/m(2)), and obese (>= 30 kg/m(2)). 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), bothp < 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.