Osteoporosis in ankylosing spondylitis

Area of Science:

• Rheumatology
• Endocrinology
• Orthopedics

Background:

• Osteoporosis (OP) is a frequent complication of ankylosing spondylitis (AS), even in early disease stages.
• Elevated biochemical markers of bone turnover, proinflammatory cytokines (e.g., interleukin-6, tumor necrosis factor-alpha), and acute-phase reactants suggest inflammatory involvement in bone loss.
• Multiple factors contribute to bone loss in AS, including genetic factors, hormonal imbalances, and impaired nutrient absorption.

Purpose of the Study:

• To highlight the challenges in assessing bone mineral density (BMD) in AS patients using traditional methods.
• To emphasize the significance of femoral neck BMD for detecting osteopenia and osteoporosis and assessing fracture risk in AS.
• To address the lack of specific guidelines for OP detection and management in AS.

Main Methods:

• Review of existing literature on osteoporosis in ankylosing spondylitis.
• Discussion of limitations of dual x-ray absorptiometry (DXA) for spinal BMD assessment in AS.
• Emphasis on femoral neck BMD as a reliable measure.

Main Results:

• Femoral neck BMD is reduced in AS patients and correlates with an increased risk of vertebral fractures.
• Optimal control of AS disease activity is the primary evidence-based recommendation to prevent bone loss.
• Emerging evidence suggests beneficial effects of therapies like infliximab and bisphosphonates on bone health in AS.

Conclusions:

• Femoral neck BMD measurement is crucial for accurate osteopenia and osteoporosis detection and fracture risk assessment in AS.
• There is an unmet need for established guidelines for OP management in AS patients, particularly young men.
• Controlling AS disease activity and considering specific therapies may help mitigate bone loss.