Patients With Psoriatic Arthritis at Risk for Lower Bone Mineral Density, Osteoporosis

Patients with psoriasis and psoriatic arthritis (PsA) are at a greater risk for osteopenia and osteoporosis, but the risk is not causal. According to new research published in Annals of Rheumatic Diseases, the associate is the result of secondary factors, such as medication.

The researchers used 432,513 samples from the UK Biobank data set and a multivariable linear/logistic regression to estimate the relationship between psoriasis and PsA with bone mineral density (BMD). They also used a weighted Genetic Risk Score to estimate the effect of psoriasis/PsA on estimated BMD.

The authors categorized potential confounders in 3 ways: model0 included age, height, weight, smoking, and drinking; model1 included model0 plus regular physical activity; and model2 included model1 plus medication treatments.

A total of 4904 patients with psoriasis and 847 patients with PsA were included in the analysis. The study also included control participants.

While the data suggest an association between PsA and lower estimated BMD in model0 and model1 compared with controls, the association disappeared with treatment with methotrexate or ciclosporin, suggesting the association was secondary. Patients with psoriasis showed no difference in association of estimated BMD compared with controls.

The authors also found that, according to the weighted Genetic Risk Score, the association between PsA and BMD was not genetically determined.

The researchers concluded that patients with PsA “should be screened for osteopenia and osteoporosis and proper management should be provided to reduce the fracture risk, especially for those who received treatment with methotrexate or ciclosporin.”

Reference

Xia J, Xie SY, Liu KQ, et al. Systemic evaluation of the relationship between psoriasis, psoriatic arthritis and osteoporosis: observational and Mendelian randomisation study. Ann Rheum Dis. Published online July 31, 2020. doi:10.1136/annrheumdis-2020-217892