Bone Mineral Density and Fracture Risk in Ankylosing Spondylitis: A Meta-Analysis

We conducted a meta-analysis of studies to examine the risk of vertebral and non-vertebral fractures in patients with ankylosing spondylitis (AS). Additionally, we evaluated the risk factors of vertebral fractures in AS. Two authors independently searched Embase and Medline for studies that had assessed the risk of fractures in patients with AS. Twenty-two studies were eligible for the meta-analysis. Patients with AS had high frequency of vertebral fractures [OR (95% CI): 1.96 (1.52-2.51)]. Major risk factors for vertebral fractures in patients with AS include low BMD at the femoral neck and total hip, male gender, longer disease duration, higher BASDAI, higher BASRI, and possibly inflammatory bowel disease. The risk of non-vertebral fractures [OR (95% CI) 1.10 (1.04-1.15)] was 10% higher in AS patients than in controls. The risk of hip fractures in AS patients was not statistically significant [OR (95% CI) 1.17 (0.71-1.92)] in our pooled analysis. We found that patients with AS are at high risk of vertebral fractures. Male sex, duration of AS, mSASSS, BASRI, and low BMD at the hip and distal forearm were associated with the risk of vertebral fractures. Current evidence on the risk of hip fractures in patients with AS is inconsistent. Data about the effect of NSAIDs and TNF inhibitors on fracture risk in AS are limited.