Background/Purpose: Osteoporosis is more prevalent in patients with rheumatoid arthritis (RA) than in the general population. Janus kinase (JAK) inhibitors and tumor necrosis factor (TNF) inhibitors are widely used in RA treatment; these drugs effectively reduce disease activity and prevent joint destruction by suppressing inflammation. However, their effects on bone mineral density (BMD) remain unclear. Thus, this study aims to compare BMD changes in RA patients with osteoporosis treated with JAK inhibitors versus TNF inhibitors, thereby providing insights into their impact on bone metabolism and informing optimal treatment strategies for osteoporosis management in RA

Methods: This retrospective study included RA patients diagnosed with osteoporosis who were treated with either TNF inhibitors or JAK inhibitors at a tertiary referral center between January 2005 and December 2024. Areal BMD (g/cm²) was measured at the lumbar spine, femoral neck, trochanter, and total femur using dual-energy X-ray absorptiometry. The rate of BMD change was expressed as the annualized percentage change between the initial and follow-up measurements

Results: Among RA patients who received biologics (n = 23) and JAK inhibitors (n = 13), 23 (100.0%) and 12 (92.3%) were women, respectively. The mean ages at initial BMD measurement for these patients were 66.0 years (IQR, 62.5–71.0 years) and 59.0 years (IQR, 54.0–65.0 years), respectively (P = 0.14). There was no significant difference in baseline clinical characteristics, including laboratory data and baseline BMD, between the two groups. With osteoporosis treatment, follow-up areal BMD was significantly increased compared with the initial value at the lumbar spine and femur neck in RA patients, regardless of concomitant use of JAK inhibitors or TNF inhibitors. Further, no statistically significant differences were observed in annualized BMD changes between RA patients receiving TNF inhibitors and JAK inhibitors (P = 0.83).

Conclusion: In RA patients receiving osteoporosis treatment, JAK inhibitors did not provide a significant additional effect on bone formation compared with TNF inhibitors.

Table 1. Clinical characteristics of RA patients undergoing osteoporosis treatment: Comparison between JAK inhibitor users and TNF inhibitor users.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/effect-of-jak-inhibitors-on-bone-mineral-density-in-rheumatoid-arthritis-patients-with-osteoporosis-a-comparative-study-with-biologics/