engleski

No association of osteoporosis with peripheral arthritis or enthesitis in patients with ankylosing spondilitis

Objectives. Osteopenia or osteoporosis may develop in patients with ankylosing spondylitis (AS), presumably in patients with more active disease. The purpose of the study was to evaluate the association between bone mineral density (BMD), peripheral arthritis and enthesitis in patients with AS. Materials and Methods. Eighty consecutive patients (46 men and 34 women) with confirmed diagnosis of AS (according to the modified New York criteria) were included in the study. Presence of peripheral arthritis and enthesitis were assessed clinically during the detailed physical examination. Bone mineral density was measured at the lumbar spine (L1-L4) and at the left hip by dual X-ray apsorptiometry (DXA, Hologic, QDR 4500, USA) in a standard manner. Patients were classified as having osteoporosis, osteopenia or normal BMD according to the WHO criteria. Data were analyzed using methods of descriptive statistics, Student's t-test, Chi-square test, one-way ANOVA and Kruskal-Wallis' test. Results were considered to be significant at P0.05. Results. Mean age of the patients was 52.3±10.4 years (range 25-73 years) and mean duration of the disease was 21.8±10.3 years. T-score for lumbar spine was -0.67±2.15, for total hip -0.28±2.34 and for femoral neck -1.51±1.147. Clinical signs of peripheral arthritis were found in 51 patients (63.7%) and enthesitis in 54 patients (67.5%). There was no association between presence of peripheral arthritis with osteoporosis in lumbar region (P=0.274), or in the hip region (P=0, 488). Similar was found for enthesitis and osteoporosis status in lumbar region (P=0.510) and in the hip region (P=0.577). As many patients experience osteoporotic fracture not having truly osteoporotic BMD, patients were also grouped in those having pathological value (T-score less than -1.0 SD) or normal value (-1.0 SD and better), but, again, no significant association was found with peripheral arthritis or enthesitis. Conclusion. As far as we know this is the first study aiming to find the association between presence of peripheral arthritis or enthesitis with osteoporosis status in AS patients. The negative result might be explained with the cross- sectional design of the study and fluctuation of arthritis and enthesitis in patients with AS. For more precise evaluation larger longitudinal studies are needed.

osteoporosis; ankylosing spondylitis; arthritis; enthesitis

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