Osteoporosis in psoriatic arthritis: is there any?

Although considered as a feature of inflammatory rheumatic diseases, there is a lot of controversy around low bone mass in patients with psoriatic arthritis. The aim of this cross-sectional study was to analyze bone mineral density in patients with psoriatic arthritis, as well as to investigate its possible association with some measures of disease activity and functional capacity.

Sixty-nine patients with established psoriatic arthritis (mean age 56.20 ± 12.23 years) and who have not been treated with specific antiosteoporotic drugs were recruited from the out-patient clinic database. Bone mineral density was measured by dual-energy X-ray absorptiometry at the lumbar spine and at the left hip. Disease activity measures included: duration of morning stiffness, tender and swollen joint count, patient's and physician's global assessment, presence of dactylitis and enthesitis, ESR, CRP and Disease Activity Score 28. Health Assessment Questionnaire was used to assess functional status.

According to WHO definition, spinal osteoporosis was found in 7.2% of patients, total hip osteoporosis in 1.4% of patients and femoral neck osteoporosis in 2.9% of patients. There was no significant association of any of the measures of disease activity with BMD at any site. Higher HAQ scores were associated with lower total hip BMD.

In our sample of patients with psoriatic arthritis we did not find increased prevalence of osteoporosis. There was no association of BMD with indices of disease activity, while negative correlation was found between HAQ and total hip BMD.