Evaluation of bone turnover in ankylosing spondylitis patients

Abstract EN

Materials & Methods: This study was performed on 20 ankylosing spondylitis (AS) patients, compared with 10 healthy subjects matching in age and sex as a control group.

Bone formation was quantified by measurement of serum alkaline phosphatase, and osteocalcin.

Bone resorption was assessed by urinary excretion of calcium, pyridinoline and deoxypyri-dinoline in patients and controls.

Also plain X-rays for the dorsal and lumbosacral spine were done and bone mineral density was measured with single energy CT of the lumbar spine in both groups.

Disease activity was assessed with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

Results: AS patients had significantly lower mean serum osteocalcin (p<0.05) and significantly higher mean serum alkaline phosphatase (p<0.05) as compared with controls.

However there was no significant difference in urinary calcium, pyridinoline or deoxypyridinoline between patients and controls.

It was also found that AS patients had reduced bone mineral density of the lumbar spine and the difference was statistically significant as compared with controls (p<0.01).

Of the 20 AS patients, 2 patients (10%) had a vertebral fracture.

It was also found that the biochemical markers of bone formation and resorption correlated well with inflammatory indices of disease activity (acute phase reactants).

Conclusion: Bone mineral density was reduced and bone formation was decreased while bone resorption was within normal limits.

Also disease activity had a role in bone turnover.