Body Composition in Patients with Ankylosing Spondylitis on Anti-Tumor Necrosis Factor Alpha Treatment

Objectives: To examine the body composition (BC) of the Ankylosing spondylitis (AS) patients on anti-TNF therapy and to evaluate the clinical parameters in obese AS patients Design: Cross-sectional case-control study Setting: Department of Physical Medicine and Rehabilitation, Cumhuriyet University, Medical Faculty, Sivas, Turkey Subjects: Thirty-four AS patients and 34 healthy subjects as controls were included in the study between November 2014 and May 2015 Main outcome measures: Waist circumference (WC), body mass index (BMI), percent body fat (PBF), fat mass (FM) and fat free mass (FFM) were measured in patients and control group. In AS group, disease activity, functional status, spinal mobility and life quality were examined by standard AS questionnaires. Results: WC, BMI, PBF, FM, and FFM were comparable in AS patients and controls. There was a positive correlation between the duration of the anti-TNF treatment and BMI (p = 0.02, r = 0.409). In obese AS patients, the duration of the anti-TNF treatment was significantly longer than the normal weight AS patients (for BMI p = 0.02, for PBF p = 0.03). Obese and normal weight AS patients were comparable regarding disease duration, disease activity, functional status, spinal mobility and life quality. Conclusions: The BC of AS patients on anti-TNF treatment was similar to healthy controls. Anti-TNF treatment has comparable effects on disease parameters in both the normal weight and obese AS patients. Long-term treatment with anti-TNF drugs may lead to obesity. Prospective controlled studies with more patients to clarify this probable effect of anti-TNF drugs are required.