Increased risk of vertebral fracture in patients with rheumatoid arthritis

The relationship between rheumatoid arthritis and risk of vertebral fracture has been reported by several observational studies. However, there is no higher-level evidence study, such as meta-analysis, that has investigated the relationship, and its mechanisms are not yet fully clear. This meta-analysis aimed to provide a summary of an observational study of the relationship between rheumatoid arthritis and the risk of vertebral fractures. Relevant studies were identified by searching PubMed and EMBASE databases (up to August 1, 2016). We included published observational studies (cohort or case-control design) evaluating the relationship between rheumatoid arthritis and the risk of vertebral fractures. Two reviewers searched and abstracted the data independently. Relative risks (RRs) with 95% confidence intervals (CIs) were used throughout the whole analysis. Seven observational studies (2 cohort studies, 2 nested case-control studies, and 3 case-control studies) were included in this meta-analysis. The results showed that the pooled RR of vertebral fracture for individuals with rheumatoid arthritis was 2.34 (95% CI 2.05–2.63, I2 = 35.4%, P for heterogeneity = 0.16). Further subgroup analysis by sex showed that the pooled RRs for both women and men, and only women were 2.14 (95% CI 1.47–2.8, I2 = 48.5%, P for heterogeneity = 0.12) and 2.39 (95% CI 2.07–2.70, I2 = 34%, P for heterogeneity = 0.22), respectively. Subgroup analysis by study design showed that the pooled RRs for cohort studies, nested case-control studies, and case-control studies were 2.31 (95% CI 1.95–2.67, I2 = 4.8%, P for heterogeneity = 0.31), 1.89 (95% CI 1.01–2.77, I2 = 72.1%, P for heterogeneity = 0.06), and 2.62 (95% CI 2.04–3.91, I2 = 26.1%, P for heterogeneity = 0.26), respectively. Based on our meta-analysis, rheumatoid arthritis should be regarded as an independent risk factor of vertebral fracture. Further studies are needed to institute prevention and treatment strategies.