Denosumab use reduces risk of rheumatoid arthritis in patients with osteoporosis.

Objectives: To investigate the protective effect of osteoporosis medications on the risk of developing rheumatoid arthritis (RA) in patients with osteoporosis.

Methods: We conducted a retrospective cohort study from 1 January, 2011 to 31 March, 2023. There was a total of 971901 patients from a hospital-based population in Taiwan. In this cohort, there was a total of 17065 osteoporosis patients with or without pathological fracture. In these patients, 7180 patients were osteoporosis medication users, and 9605 patients were non-osteoporosis medication users, after exclusion of previous RA. The risk of RA in the patients with osteoporosis medications was assessed, and stratified by sex and different medications, including bisphosphonates, denosumab, raloxifene and teriparatide.

Results: Patients with osteoporosis medication use had a reduced risk of RA compared with non-osteoporosis medication users [adjusted hazard ratio (aHR)=0.484, 95%CI: 0.270-0.867, p<0.05), after adjusting for age, comorbidites and medications. Specifically, patients with ever use of bisphosphonates (n=2069) or denosumab (n=4510) had a reduced risk of RA (aHR=0.405, 95%CI: 0.173-0.951, p<0.05, and aHR=0.394, 95%CI: 0.192-0.809, p<0.05, respectively). Notably, patients that only used denosumab (n=2938) had a further reduced risk of RA (aHR=0.32, 95%CI: 0.12-0.83, p<0.05), particularly in female patients (aHR=0.26, 95%CI: 0.09-0.74, p<0.05). Patients taking raloxifene or teriparatide did not have a significantly reduced risk of RA.

Conclusions: Denosumab use reduces the risk of RA in patients with osteoporosis. Receptor activator of nuclear factor kappa B ligand (RANKL) mediated osteoclast joint damage may be involved in the pathogenesis of RA during the preclinical stage.