Comparison of bone mineral density in different anatomical locations of ankylosing spondylitis patients and its clinical significance

Objective To compare the bone mineral density(BMD) in different anatomical locations of ankylosing spondylitis(AS) patients. Methods Twenty seven AS patients were included. The BMD was measured by the dual-energy X-ray absorptiometry(DEXA). The Z-scores of BMD in lumbar spine, femoral neck and distal radius were measured and recorded.According to the disease duration, the patients were divided into group A(early stage group, disease duration 10 years) and group B(late stage group, disease duration ≥10 years). Results The Z scores of BMD in lumbar spine were significant different between group A and group B(P 0.05). The Z scores of BMD in femoral neck and distal radius showed no significant difference between the two groups(P 0.05). In group A, the patients had a lower BMD at lumbar spine and it's more sensitive in detecting bone loss in AS patients. In contrast, the lumbar BMD increased in group B, the BMD at the femoral neck was more sensitive in detecting bone loss in AS patients. Conclusion The BMD of the lumbar spine is more accurate in detecting bone loss in the early-stage AS patients, while the BMD of the femoral neck is more precise in the late-stage AS patients.