Obesity represents a persisting health issue in axial spondyloarthritis, particularly affecting socially disadvantaged patients.

OBJECTIVE: Obesity is an important comorbidity in axial spondyloarthritis (axSpA). However, the prevalence of obesity in axSpA compared with the general population and associated socioeconomic factors remain unknown.

METHODS: This repeated cross-sectional study compared BMI groups of patients with axSpA to the Swiss population at three time points (2007, 2012 and 2017). BMI categories were compared by different age, sex, and education categories using the Chi-Squared Goodness of Fit test. Unpaired, one-sided t-tests were used to compare the BMI in axSpA patients between the different time points.

RESULTS: Compared to the general population, axSpA patients had a higher proportion of overweight and obese: 18.9% of all axSpA patients were obese, compared to 11.3% of the Swiss population in 2017. Comparison of BMI groups within sex, age and education groups consistently showed a trend towards higher rates of overweight and obesity in axSpA. Furthermore, axSpA patients, especially females, showed a trend of increasing BMI over the studied 10 years. At every time point, overweight and obese patients were significantly more likely to be male, were older and had higher disease activity than patients with normal weight. Obesity was associated with a deprived socioeconomic status as indicated by a higher proportion of patients with manual labor jobs and lower levels of education.

CONCLUSION: The prevalence of obesity was significantly higher among patients with axSpA compared to the Swiss population, with socially disadvantaged individuals being the most affected. There is an urgent need to initiate prevention strategies for obesity in axSpA patients.