Risk factors for vertebral fracture in rheumatoid arthritis patients using biological disease-modifying anti-rheumatic drugs (cases over 5 years): An observational study.

While biological disease-modifying anti-rheumatic drugs (bDMARDs) are considered beneficial for preventing osteoporosis and bone fracture, it is unclear whether bone loss is involved in the development of vertebral fracture, and few reports have examined the factors related to vertebral fracture in rheumatoid arthritis (RA) patients using bDMARDs. This study aims to identify factors influencing vertebral fracture in RA patients treated with bDMARDs. We retrospectively examined the records of 129 RA patients treated with bDMARDs for over 5 years. The lumbar spine and femoral bone mineral density, Disease Activity Score-28-C-Reactive Protein (DAS28-CRP) value, Simplified Disease Activity Index (SDAI), and modified Health Assessment Questionnaire (mHAQ) score were evaluated. The frequency of new vertebral fracture during the study and their risk factors were investigated. A comparison between the fracture group and the nonfracture group was performed. Multivariate analysis was performed using logistic regression analysis to detect risk factors for new vertebral fracture. The number of patients with new vertebral fracture during follow-up was 15 (11.6%) of the 129 patients in the study. Age and mHAQ score were significantly higher and lumbar spine and femoral neck bone mineral density were significantly lower in the fracture group than the nonfracture group. The risk factors for new vertebral fracture during the disease course were older age and higher mHAQ score indicating no remission over the 5 years of follow-up. In this study, there was no significant difference in disease indices such as the DAS28-CRP value and the SDAI between the fracture and nonfracture groups, suggesting an effective control of RA with bDMARDs. However, age and the mHAQ score, an index of RA dysfunction, were significantly higher in the fracture group. These results suggest that improving functional impairment may be important to prevent vertebral fracture in patients using bDMARDs.