Assessment of fracture risk in patients with spondyloarthritis using the FRAX scores.

Introduction: Osteoporosis and fractures are known to complicate spondyloarthritis (SA). The Fracture Risk Assessment Tool (FRAX) estimate the 10-year probability of major osteoporotic fracture (MOF) and also hip fracture (FH). It can be useful as risk assessment tools for the purpose of preventing fracture in SA.

Aim: To measure the bone mineral density (BMD), to evaluate the FRAX and to determinate factors associated with high risk of fracture in patients with SA.

Methods: It's a prospective cross-sectional study that included seventy-five patients admitted for SA, in the rheumatology department of Kassab institute in Tunisia. All of them fulfilled the modified New York criteria for SA.

Results: Sixty-two men and thirteen women were enrolled, with mean age of 36.8 ± 11.8 years. The mean age at disease onset was 27.8± 9.9 years. Mean BASDAI and ASDAS CRP were respectively 3.5 ± 2.4 and 3 ± 0.83. The mean BASRI was 8.9 ± 4.2 and the mean mSASSS was 17.6 ± 19.6. Vitamin D insuffiency and deficiency were found in 43 and 30 patients respectively. Osteoporosis (T score ≤ -2,5 SD) were found in 49% of patients and 80 % of them have a reduced BMD (T score ≤ -1 SD). The mean MOF score was 0,36 ± 0,3 [0-0,9] and the mean FH score was 0,3 ± 0 [0-0,5].The MOF was significantly associated with Bone loss (p=0.000). A trend for a significant association was also found with ASDASCRP (p=0.05). The MOF and FH were both significantly associated to the age at the onset of SA (respectively, p=0,003 and p=0,002). The risk of FH was higher when hip BASRI (p=0..036) and ESR were high (p=0,014), it's also associated to age (p=0..002) and vitamin D deficiency (p= 0.043). However, no correlation was found between the MOF and FH and the presence of peripheral arthritis, enthesitis or hip arthritis.

Conclusion: The MOF score, in patient's wih SA, was associated with bone loss, age at disease onset and ASDASCRP. The HF score was associated with age, Vitamine D deficiency, age at disease onset, high hip BASRI and high ESR.