Background Previous studies have shown a significant increase in body weight and body composition changes (increase in lean and fat masses) in patients with spondyloarthritis receiving anti-TNF-alpha (anti-TNFa) treatment. SpA is associated with increased cardiovascular risk, due to chronic inflammation. Recent studies indicate that visceral adipose tissue (deposited around the mesentery and omentum) is a recognized cardiometabolic risk factor.

Objectives To evaluate changes in visceral adipose tissue (VAT) area in patients with spondyloarthritis (SpA) receiving anti-TNFa treatment.

Methods 28 patients with axial SpA (9 women, 19 men) according to European Spondyloarthropathy Study Group (ESSG) criteria were included in a two-year prospective open study. Each patient received etanercept (25 mg twice a week), because of persistent active disease despite an optimal non steroidal anti-inflammatory drugs (NSAIDS) treatment. Body weight and body mass index (BMI) were measured at baseline, 6 months, one and two years. We also measured at each visit VAT area and waist circumference (WC) using a new validated software on the whole body composition scan using a dual-energy X ray absorptiometry (DXA) device (Hologic, Waltham, MA, USA). This technique has a very low radiation to the patients compared to computed tomography (CT). Baseline characteristics were assessed, and logistic regression analysis was performed in order to determine predictive factors of visceral fat changes.

Results Mean age of the patients was 40.4±11.7years. They had an active disease: mean BASDAI was 56.7±21.1and mean CRP was 25.1±46.9 mg/l. BMI significantly increased from baseline over 6 months (+0.50 kg/m² [0.14 – 1.19], i.e.3.7%, p<0.05), one year (+0.67 kg/m² [0.16 – 1.46], i.e. 4.1%, p‹0.0001) and two years (+0.65 kg/m² [-0.12– 1.71], i.e. 4.2%, p‹0.0001). Waist circumference significantly increased over 6 months (+2.41 cm [+0.21 – 6.33], i.e.3.6%, p<0.001), one year (+2.55cm [1.51– 5.88], i.e. 4.1%, p‹0.0001) and two years (+2.47 cm [-0.37– 5.37], i.e. 4.2%, p‹0.0001).

There was a significant increase in VAT area after 6 months (+18.60cm² [4.88– 30.59], i.e.21.3%, p<0.001) which remained stable at, one year (+19.06 cm²[10.81– 32.81], i.e. 24.1%, p‹0.0001) and two years (+19.01cm²[9.21– 3.71] i.e. 25.6%, p‹0.0001).

After adjusting for age, gender and baseline CRP, 6-month VAT change was significantly associated with baseline BASDAI [b(SE)= -0.37(0.13), p=0.013] and 6-month BMI change [b(SE)= 11.74(2.39), p=0.002].

Conclusions This study shows for the first time that VAT significantly increases in patients with active SpA receiving anti-TNF-alpha treatment over 2 years. This increase mostly occurs in the first 6-months, and is significantly associated with baseline disease activity. The contribution of VAT changes to cardiovascular risk in SpA patients and the effects of antiTNFα need to be elucidated.

Disclosure of Interest None Declared