TOPLINE: 

Among patients with rheumatoid arthritis (RA), a decrease in disease activity was noted with the use of biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs); however, bone mineral density (BMD) still declined. BMD decreased in patients who did not receive antiosteoporotic medication, whereas it remained unchanged in those who received the medication.

METHODOLOGY:

• Researchers performed a 5-year follow-up analysis of a prospective observational study in Japan involving 27 institutions to examine the long-term effects of b/tsDMARDs on bone metabolism in patients with active RA.
• They assessed 797 patients who initiated their first b/tsDMARD between August 2013 and July 2022. The various b/tsDMARDs included TNF inhibitors, interleukin-6 receptor inhibitors, JAK inhibitors, and abatacept.
• BMD measurements were obtained at the femoral neck and one-third radius at baseline (week 0), week 26, week 52, and annually thereafter, with total hip BMD derived from femoral neck images through post hoc analysis and T-score, Z-score, and BMD values recorded at each assessment. Osteoporosis was diagnosed according to World Health Organization criteria.
• The primary endpoint was the change in BMD (T-score) from baseline; secondary outcomes included changes in Z-score and BMD and factors associated with T-score changes.
• Participants were divided into two groups: 645 patients (mean age, 59.4 years; 74.1% women) who did not receive antiosteoporotic drugs at enrollment and 152 patients (mean age, 69.8 years; 90.1% women) who received such treatment; the median follow-up duration was 3.1 years.

TAKEAWAY:

• Disease activity improved (mean clinical disease activity index score declined from 25.7 to 6.6; P < .001); however, T-scores decreased at both the femoral neck (from -1.58 to -1.67; P < .001) and radius (from -0.96 to -1.25; P < .001) in the overall cohort; total hip T-scores also declined from -1.14 to -1.21 (P < .001).
• Z-scores increased at the femoral neck (from -0.27 to -0.20; P < .001), and total hip Z-scores decreased (from -0.22 to -0.32; P < .001). The incidence of osteoporosis increased from 31.7% to 34.6% (P < .001); 21 new cases of fragility fractures were noted.
• In patients who did not receive antiosteoporotic medication, T-scores decreased at both the femoral neck (from -1.43 to -1.54; P < .001) and radius (from -0.60 to -0.93; P < .001). In those who received the medication, no change in T-score was observed.
• In multivariate analysis, longer duration of osteoporosis treatment was associated with increased T-scores at both the femoral neck (P < .001) and radius (P < .001), and higher baseline T-scores were associated with subsequent decreases in T-score (P < .001). Notably, duration of b/tsDMARD use and disease activity were not associated with BMD maintenance.

IN PRACTICE:

“Although the decrease in BMD in the group not receiving osteoporosis medication became more ‘age-appropriate,’ managing osteoporosis remains important. Regular evaluation and appropriate interventions for osteoporosis in patients with RA are considered necessary,” the authors wrote.

SOURCE:

The study was led by Takafumi Aritomi, MD, of the University of Occupational and Environmental Health, Kitakyushu, Japan. It was published online on March 8, 2026, in Arthritis & Rheumatology.

LIMITATIONS:

The single-arm, real-world observational design of the study prevented establishment of causal relationship between b/tsDMARDs and BMD changes. Data on fragility fractures came from patient reports and physician records, likely missing asymptomatic fractures. Detailed information on dosage and adherence to antiosteoporosis medications was unavailable.

DISCLOSURES:

Financial support for this research was provided in part through the University of Occupational and Environmental Health and additional support through its Advanced Research program. Some authors reported receiving lecture fees, speaking fees, research funding, and/or honoraria from multiple companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.