E056 Prevalence and risk factors of low bone mineral density in spondyloarthritis Free

Several studies have shown that spondyloarthritis (SpA) by itself may be a risk factor for decreased bone mineral density (BMD). Our study aimed to assess the decline in BMD in patients with SpA and to identify factors associated with this decrease in BMD.

We conducted a cross-sectional study including 112 patients with SpA according to the ASAS criteria. Patients with conditions or treatments that could induce osteoporosis were excluded. Disease activity was assessed using the Ankylosing Spondylitis Disease Activity Score (ASDAS) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Mobility was assessed using the Bath Ankylosing Spondylitis Metrology Index (BASMI). BMD was evaluated using dual-energy X-ray absorptiometry (DXA) at both the femoral and lumbar sites. Osteoporosis as T-score≤2.5DS and osteopenia between -1 and -2.5DS.

Our study included 112 patients. The average age was 46.12±12.16 years, with a male-to-female ratio of 2.29. The median age at diagnosis was 38 years. The average disease duration was 12.16 years. The average body mass index (BMI) was 24.8 ± 4.39 kg/m², with 36.5% of patients being overweight or obese. The mean values for erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were 46.12 ± 12.16 mm and 28.42 ± 39.27 mg/L, respectively. The respective mean scores for BASDAI, ASDAScrp, and BASMI were 3.99 ± 1.93, 2.93 ± 1.27, and 2.63 ± 2.42. The mean BMD was 1.023 ± 0.530g/cm² at the lumbar site and 0.945 ± 0.149g/cm² at the femoral site. Osteoporosis and osteopenia were found in 30.4% and 27.7% of cases, respectively. A decrease in BMD was observed in 48% of cases at the lumbar site and in 35% of cases at the femoral site. Patients with low BMD (osteoporosis and osteopenia) had a lower BMI (23.71vs26.35 kg/m² p = 0.002). BASMI was negatively correlated with femoral BMD (r = -0.363, p = 0.001) and femoral T-score (r=-0.418, p = 0.001). No associations were noted between the decline in BMD and gender (p = 0.8), smoking (p = 0.246).

Our study has shown that a decrease in BMD is common in patients with SpA. Limited axial mobility appears to be associated with the decline in BMD. Additionally, as demonstrated in postmenopausal osteoporosis, a lower BMI was associated with a higher risk of decreased BMD.

M. Slouma: None. M. Dhifallah: None. I. Gharsallah: None.