Bone mineral density and bone turnover in patients with psoriatic arthritis

Psoriasis is a common inflammatory skin disease, and conflicting data have been published about osteoporosis and bone turnover markers in patients with psoriatic arthritis. The aim of this study was to assess bone mineral density (BMD) and bone turnover markers in psoriatic patients with and without peripheral arthritis and to investigate the relationship between clinical parameters and markers of bone turnover. Forty-seven patients (24 women, 23 men) with psoriasis were included to the study. Demographic data and clinical characteristics were recorded. Erythrocyte sedimentation rate and C-reactive protein were assessed as disease activity parameters. BMD was determined for lumbar spine and total hip by dual X-ray absorptiometry (DXA). Serum Ca, P, alkalen phosphatase (ALP), and serum type I collagen cross-linked C telopeptide (CTX) were measured as bone turnover markers in all patients. The patients were divided into two groups according to their peripheral arthritis status. The clinical and laboratory variables, as well as bone mass status of the groups, were compared with each other. Eighteen patients had peripheral arthritis. All the female patients were premenopausal. None of the patients had radiologically assessed axial involvement. There was no significant difference between the BMD levels of psoriatic patients with and without arthropathy. One patient (5%) had osteoporosis, and nine (50%) patients had osteopenia in arthritic group, while eight (27.5%) patients had osteopenia in patients without arthritis. Serum CTX, ALP, Ca, and P levels were not significantly different in arthritic than in non-arthritic patients (p > 0.05). In patients with psoriatic arthritis, the duration of arthritis was negatively correlated with BMD values of lumbar spine and total femur and serum CTX levels, suggesting an association of increased demineralization with the duration of joint disease. In conclusion, psoriatic patients with peripheral arthritis with longer duration of joint disease may be at a risk for osteoporosis, which can require preventative treatment efforts.