リウマチ患者における骨粗鬆症治療の現状

抄録

Objective: In rheumatoid arthritis (RA), synovial inflammation induces cartilage and bone destruction. As a result, glucocorticoids are used as disease modifying treatment. Because of the adverse side effects from glucocorticoid use, the medical treatment for osteoporosis is very important. The treatment rate (TR) for fractures in patients with osteoporosis has been reported to be approximately 13%-25%. However, the TR for patients with RA has not been reported previously. In this study we report the TR for patients with RA and osteoporosis.

Methods: We reviewed 80 patients with RA retrospectively who had an average age of 67.3±10.6 years old. There were 18 males (68.6±9.9 years old), and 62 females (66.8±10.9 years old), respectively. Selected osteoporosis treatments included bisphosphonates, teriparatide (parathyroid hormone derivative) and denosumab. The TR was investigated and compared in aspects of their age, sex, dose of glucocorticoids, duration of rheumatoid arthritis, use of biologic agents, level of estimated glomerular filtration rate (eGFR), level of C-reactive protein (CRP) and Disease Activity Score (DAS) 28-CRP.

Results: The total TR for patients with RA was 47.5%. The TR increased significantly in response to age (<70 years old 37.8%; ≥70 years old 60.0%; P=0.049), dose of glucocorticoids (0 mg/day 16.7%; 0 mg< <5 mg/day 60.9%; 5 mg≥/day 89.5%; P<0.001), duration of RA (<5 years 36.4%; 5 years-15 years 40.7%; >15 years 67.9%; P=0.047), and level of CRP (CRP<0.3 33.3%; 0.3≥CRP 59.1%; P=0.025). There were no significant differences in respect of sex, use of biologic agents, level of eGFR or DAS28-CRP.

Discussion: The TR of osteoporosis in patients with RA was higher compared to patients with fractures. In general, the risk of osteoporotic fractures increases depending on age and sex. The risk of osteoporotic fractures in patients with RA is known to increase with rheumatoid disease activity, glucocorticoid use, and disease duration, etc. In this study, the TR increased with age and factors related to RA. Sex was not associated with the TR.

Conclusion: In patients with RA, treatment for osteoporosis should be strongly considered especially in those individuals with longstanding disease, high disease activity and use of glucocorticoids.