Biologics Help Maintain Bone Density in RA

Bone mineral density was preserved over a three-year period in patients with rheumatoid arthritis treated with biological/targeted synthetic disease-modifying antirheumatic drugs (DMARDS) but declined in those who received only conventional-synthetic DMARDs, say researchers recently writing in Rheumatology.

While primarily affecting peripheral joints, rheumatoid arthritis also leads to deteriorated skeletal microarchitecture and bone strength due to the release of proinflammatory cytokines that upset the balance between bone formation by osteoblasts and resorption by osteoclasts. The annual bone loss rate in patients with active rheumatoid has been shown to range from 5.5 percent to 10 percent. Compared with the general population, the prevalence of osteoporosis is around two-fold greater in patients with rheumatoid arthritis, ranging from 7 percent to 26 percent in the hip and 11 percent to 32 percent in the spine.

In recent decades, several cytokines inhibitors, in particular biological/targeted synthetic DMARDs have been developed, with their use resulting in marked clinical symptom alleviation, improved quality of life, and decelerated joint damage in patients with rheumatoid arthritis. The long-term effect of biological/targeted synthetic DMARDs on generalized bone loss in patients with rheumatoid arthritis remains unknown, as previous studies have been limited by short duration, small numbers, and retrospective designs. Meanwhile, medications for the treatment of postmenopausal osteoporosis including denosumab, bisphosphonates and parathyroid hormone have shown efficacy in the prevention of systemic bone loss or in reducing localized bone erosions in rheumatoid arthritis.

“We aimed to investigate the impact of long-term biological/targeted synthetic DMARD therapy on bone mineral density changes in patients with rheumatoid arthritis via a three-year real-world, prospective, cohort and observational study,” wrote the authors, led by Tien-Tsai Cheng, M.D.,  from Chang Gung University College of Medicine in Kaohsiung, Taiwan. “In addition, we explored the synergistic effect of a three-year treatment with biological/targeted synthetic DMARDs and with or without anti-osteoporosis therapy on bone mineral density changes.”

Of the participants (age 57, disease duration 14 years, >80 percent female), 92 were treated with biologics or targeted therapies (group 1) and 184 were given conventional DMARDs (group 2). After three years, bone mineral density remained stable at the femoral neck, hip, and lumbar vertebra (P=0.09, 0.15, 0.87) in group 1. However, bone mineral density decreased significantly in group 2 (P=0.045, <0.001, 0.004) at corresponding sites.

“Long-term biological/targeted synthetic DMARDs benefit rheumatoid arthritis patients not only in ameliorating disease activity but also preserving bone mass,” the authors wrote. “Patients who underwent conventional-synthetic DMARDs, compared to biological/targeted synthetic DMARDs, experienced more substantial bone loss.”

“Participants receiving combined biological/targeted synthetic DMARD and anti-osteoporosis therapy experienced a greater bone mineral density preserving effect than other subgroups,” the authors wrote.

The authors recommended further research to explore the “specific influence of each biologic or target therapy on bone health and metabolism, and future research should focus on better profiling of patients with rheumatoid arthritis, targeting various therapeutic choices and more extended observation periods.”

REFERENCE

Jia-Feng Chen, Chung-Yuan Hsu, Shan-Fu Yu, et al.“The impact of long-term biologics/target therapy on bone mineral density in rheumatoid arthritis: a propensity score-matched analysis.”Rheumatology. January 25, 2020. https://doi.org/10.1093/rheumatology/kez655