The state of bone mineral density in men with ankylosing spondylitis and its relationship with the course of the disease

Introduction: The aim of the study was to study the structural and functional state of bone tissue in men with ankylosing spondylitis (AS) and to assess its relationship with the course of the disease. Material and methods: A study was conducted with the participation of 105 men with AS aged from 22 to 59 years (average age was 40.7 +/- 0.8 years) with a duration of the disease of 8.7 +/- 0.5 years and 29 persons of the control group. Disease activity and the degree of functional limitations were determined by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI),Ankylosing Spondylitis Activity Score correlated with C-reactive protein (ASDAS-CRP) and the Bath Ankylosing Spondylitis Functional Index (BASFI). Laboratory examination included determination of C-reactive protein (CRP). Bone mineral density (BMD) of the lumbar spine and femoral neck was determined by the method of dual-energy X-ray absorptiometry on the Hologic Discovery Wi device (S/N 87227). Results: In men with AS, a decrease in BMD (according to the Z -score and T -score) was found in 41.9%, while the percentage of patients with osteoporosis at the level of the femoral neck and lower back was 16.7%. Development of osteoproliferative changes was observed in 42 (40%) patients. Bone mass loss was associated with high activity of the inflammatory process according to ASDAS, BASDAI (r = -0.39, -0.65), and CRP (r = -0.28, -0.38) and low functional capacity according to BASFI (r = -0.27, -0.59), while syndesmophytosis had a reliable association with the age of the patients, the duration of the disease and low functional capacity. Low-energy fractures occurred in 11.4% of men with AS. The presence of fractures was associated with high disease activity (ASDAS, BASDAI, CRP) and was not related to the age of the patients or duration of the disease. Conclusions: A decrease in BMD and the development of fractures were closely associated with high activity of the inflammatory process and low functional capacity, while syndesmophytosis was related to the age of patients and the duration of the disease.