Osteoporosis in psoriatic arthritis: a cross-sectional study of an outpatient clinic population

BACKGROUND: The risk of osteoporosis in patients with psoriatic arthritis (PsA) still remains unclear. The aim of this study was to investigate bone mineral density (BMD) at the hip and lumbar spine measured by dual-energy X-ray absorptiometry in patients with PsA. METHODS: From an outpatient clinic in southern Norway, 140 patients with PsA were consecutively recruited and assessed for osteoporosis as part of a prospective study from January 2013 to May 2014. An extensive data collection was performed including demographic data and measures reflecting disease activity and health status. RESULTS: Mean age was 52.4 years and 71 (50.7%) were women. Median disease duration was 7.8 years. The proportion of patients with low BMD (defined as Z score≤−1.0 SD) was comparable to the expected value of 16%, according to the normal distribution of the Z score in the population. Osteoporosis was only found in 6.4% (95% CI3% to 11%) of the patients. No significant associations were found between BMD and disease activity measures. CONCLUSION: The prevalence of PsA patients with osteoporosis or low BMD was low and in the range seen in the reference population. This supports that patients with PsA are not at high risk for osteoporosis compared with the general population. Therefore, clinicians may follow the general population guidelines for monitoring of osteoporosis for patients with PsA.