Do Glucocorticoids Affect Bone Mineral Density Among Patients With RA vs PsA?

Patients with rheumatoid arthritis (RA) have significantly lower bone mineral density (BMD) than patients with psoriatic arthritis (PsA), which is not entirely explained by differences in glucocorticoid doses, relative levels of inflammation, or duration of disease, according to results from a recent study.

The researchers sought to fill a knowledge gap concerning the possible association of glucocorticoid therapy with osteopenia and osteoporosis in patients with rheumatic diseases other than RA.

To determine whether such an association exists, they measured the BMD of 92 patients with PsA and compared these data with those of 92 patients with RA, matched for age and gender.

The study team also factored into their analysis data on the frequency, duration, and dose of glucocorticoid therapy; whether patients had also been treated with conventional synthetic disease-modifying antirheumatic drugs (DMARDS) or biologic DMARDs; various serological measures, including vitamin D and calcium levels and inflammatory markers; and the patients’ functionality as measured by a Health Assessment Questionnaire.

Overall, participants with RA showed significantly lower mean values of BMD than patients with PsA and a corresponding higher frequency of osteopenic BMDs. However, the researchers found no differences in the frequency at which they detected osteoporotic bone densities in the 2 groups.

Participants with PsA reported longer disease duration and higher current dosages of glucocorticoids, the research team reported, while participants with RA reported higher frequency of glucocorticoid intake.

Participants with RA took higher doses of calcium, which can have a protective effect against bone loss. However, the researchers could not attribute the differences in BMD between the 2 cohorts to the participants’ levels of calcium and vitamin D, their cumulative dose of glucocorticoids nor the duration of glucocorticoid therapy. They found no significant difference between the frequency at which the 2 groups received conventional synthetic DMARD therapy, though the participants with PsA did have a higher frequency of biologic DMARD therapy.

“The lower bone density in RA patients seems not to be fully explained by higher [glucocorticoid cumulative dose], disease duration, or higher levels of inflammation,” the researchers concluded. “Additionally, differences in bone density between the two groups could be related to the higher number of [biologic] DMARD therapies in PsA patients, but further investigations like multivariate analyses with higher numbers of patients are necessary. Furthermore, there is more need for research on possible molecular and genetic factors in PsA, which are protecting from low bone density.”

—Rebecca Mashaw

Reference:

Freier D, Wiebe E, Biesen R, et al. AB0767 Patients with rheumatoid arthritis have a lower bone density than patients with psoriatic arthritis. Ann Rheum Dis. 2020;79(Suppl 1):677. https://ard.bmj.com/content/79/Suppl_1/1681.1