Reduced bone density loss with b/tsDMARDs vs csDMARDs in RA
medwireNews: Patients with rheumatoid arthritis (RA) gain greater long-term protection against bone mineral density (BMD) loss taking biologic or targeted synthetic (b/ts)DMARDs than they do taking conventional synthetic (cs)DMARDS, suggest study results.
Tien-Tsai Cheng (Kaohsiung Chang Gung Memorial Hospital, Taiwan) and colleagues acknowledge that the association between b/tsDMARDs and BMD has previously been investigated but over short-term observation periods. The 3-year follow-up adopted for the current study “seems more adequate to assess BMD changes,” they explain.
The real-world observational study included 276 participants who were recruited from a Taiwanese RA-related osteoporosis and fracture registry, between September 2014 and March 2019. Of these, 92 individuals had received continuous b/tsDMARDs plus csDMARDs for at least a year and they were matched according to propensity scores to 184 patients who had received csDMARDs alone.
The b/tsDMARDs prescribed included tumor necrosis factor inhibitors, tocilizumab, abatacept, rituximab, and the Janus kinase inhibitor tofacitinib. The csDMARDs included methotrexate, sulfasalazine, hydroxychloroquine, azathioprine, and leflunomide.
Over a 3-year follow-up period, Cheng and fellow investigators observed no significant changes in BMD at the femoral neck, hip, and lumbar spine of b/tsDMARD-treated patients.
By comparison, there was significant BMD loss among those given csDMARDs alone, of 0.014 g/cm2 at the femoral neck, 0.015 g/cm2 at the hip, and 0.009 g/cm2 at the lumbar spine.
These findings suggest that “long-term b/tsDMARD therapy can protect against generalized osteoporosis in patients with RA better than csDMARD therapy,” the researchers write in Rheumatology.
They note, however, that anti-osteoporosis therapy (AOT) “plays the most important role in bone loss protection for patients with RA receiving either b/tsDMARD or csDMARD therapy.” AOT protected against bone loss at all skeletal sites for all patients regardless of whether they were taking b/tsDMARDs or csDMARDs. Among participants not taking AOT, there was “clear bone loss at all sites” for patients in the csDMARD treatment group and at all sites bar the hip for those in the b/tsDMARD group.
The researchers therefore acknowledge that “the co-administration of b/tsDMARD and AOT has a better protective effect against generalized bone loss in patients with RA than either b/tsDMARD or AOT alone.”
They say that “the anti-inflammatory character of b/tsDMARD likely played an essential role in protecting against bone loss not only in early RA but also in established RA after 3 years of therapy,” adding: “Whether long-term b/tsDMARDs therapy has a direct inhibitory effect on osteoclastogenesis, which then mediated the bone loss in patients with RA, is not yet known.”
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