High disease activity influences the presence of vertebral fractures in rheumatoid arthritis

Introduction: It is important to assess the risk of vertebral fractures (VFs) in patients with rheumatoid arthritis (RA), as RA is associated with a high risk of VFs. However, the epidemiology and risk of VFs in patients with RA remain inconclusive. The present study therefore clarified the prevalence and associated factors of VFs in patients with RA. Methods: We included 107 patients (19 men and 88 women) and retrospectively investigated the number and location of VFs, bone mineral density (BMD), RA disease activity score for 28 joints based on C-reactive protein (DAS28-CRP), and history of medication for RA and osteoporosis. Based on the investigated items, we assessed the prevalence of VFs in patients with RA and the association between the clinical parameters of RA patients and VFs. Results: The average age, disease duration, and DAS28-CRP were 67.9 years old, 14.9 years, and 2.2, respectively. We found that the prevalence of VFs in patients with RA was 30.8%, and 84.8% of patients with VFs and 62.2% of those without VFs had been treated for osteoporosis. We further found that the prevalence of VFs in patients with RA with a history of anti-osteoporotic agent use was 37.8%. In univariate analyses, patients with RA with VFs had significantly higher DAS28-CRP values, a higher rate of corticosteroid use, and lower BMD (p = 0.018, p = 0.004, and p < 0.001, respectively) than those without VFs. A multivariable　logistic regression analysis and ordinal logistic analysis revealed that the DAS28-CRP and BMD were independent factors associated with the presence (p = 0.042 and p = 0.011, respectively) and number (p = 0.036 and p = 0.048, respectively) of VFs. Conclusions: The prevalence of VFs was relatively high in patients with RA, regardless of the use of anti-osteoporotic agents. A high disease activity score and low BMD are associated with the presence and number of VFs in patients with RA. Based on these findings, to reduce VFs in RA patients, it is important to tightly control the disease activity of RA in addition to osteoporosis treatment.