Background Obesity is associated with an increased risk for many disorders, impaired functional capacity, and impaired quality of life (QoL).
Objectives The aim of the present study was to evaluate the prevalence of obesity and the relation to clinical assessments of disease activity, physical function, and QoL in patients with axial spondyloarthritis (SpA).
Methods 465 consecutive patients from the Groningen Leeuwarden Axial SpA (GLAS) cohort who visited the outpatient clinic between January 2011 and December 2012 were included in this cross-sectional analysis. All patients fulfilled the modified New York criteria for ankylosing spondylitis (AS; >90%) or the ASAS criteria for axial SpA. Body mass index (BMI) was calculated and patients were divided into groups according to the WHO criteria: low BMI (BMI <18.5 kg/m2), normal BMI (BMI 18.5-25 kg/m2), overweight (BMI 25-30 kg/m2), and obesity (BMI >30 kg/m2). BMI was compared with the LifeLines cohort, a three generation population-based longitudinal cohort study in the North of the Netherlands.
Disease activity was assessed by Bath AS Disease Activity Index (BASDAI), AS Disease Activity Score (ASDAS), and C-reactive protein (CRP), physical function by Bath AS Functional Index (BASFI), and quality of life by ASQoL questionnaire.
Results Mean age of the 465 patients was 45 years (SD ±13), median symptom duration was 17 years (range 0-61), 65% were male, and median BMI was 26.0 kg/m2 (range 17.0-45.4). In total, 8 (2%) patients had low BMI, 183 (39%) had normal BMI, 174 (37%) were overweight, and 100 (22%) were obese. Of the 100 obese patients, 19 had BMI between 35-40 kg/m2 and 3 had BMI >40 kg/m2. In comparison, the LifeLines population (n=136577) had an estimated prevalence of 1% low BMI, 42% normal BMI, 43% overweight, and 15% obesity.
Obese axial SpA patients were significantly older, had longer disease duration, and more comorbidity than patients with normal BMI. Disease activity of obese patients was significantly higher and physical function and QoL were significantly worse compared to patients with normal BMI (Table 1). These differences remained statistically significant after correcting for age, disease duration, and comorbidity.
Conclusions This cross-sectional analysis shows a high prevalence of obesity in a large cohort of axial SpA patients. The presence of obesity was associated with higher disease activity and worse physical function and QoL.
Acknowledgements The GLAS cohort was supported by an unrestricted grant from Pfizer. Pfizer had no role in the design, conduct, interpretation, or publication of this study.
Disclosure of Interest : None declared