Risk Factors of Bone Loss in Spondyloarthritis

We aimed to determine the bone mineral status in patients with spondyloarthritis (SA), and to assess the impact of parameters associated with bone loss on bone mineral density (BMD). Seventy-five patients (62 men) with SA fulfilling the modified New York criteria were included in a cross-sectional study during one year. BMD was assessed in all patients using dual-energy X-ray absorptiometry. The patient’s average age was 36.8 years. Sixty-five patients (86.6%) had bone loss. The lumbar spine was the site most affected by osteoporosis (37%). Bone loss was significantly associated with low BMI, peripheral joint involvement, active disease (high ASDASESR and BASDAI), vitamin D insufficiency, elevated erythrocyte sedimentation rate (ESR) and c-reactive protein, as well as high BASRI, high BASMI, and with the use of csDMARDs or anti-TNF alpha therapy. The disease activity, biologic inflammation, low vitamin D level, peripheral joint involvement, and structural damage were the major factors that induce bone loss in SA patients. Multivariate analysis showed that only high ESR level (AOR 19.9, 95% CI) and peripheral arthritis (AOR 14.5, 95% IC) were independent risk factors of bone loss. Our study shows that bone loss was a multifactorial complication of SA.