ORIGINAL RESEARCH article
Front. Immunol.
Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders
Traditional Clinical Risk Factors Outperform Disease Activity and Hematologic Indices for FRAX Hip Fracture Risk in Rheumatoid Arthritis
Li-Na Zhang 1
Yuwei Wang 2
Xin Li 2
Sheng-Guang Li 3
Di Jin 2
1. International Hospital, Peking University, Beijing, China
2. Weifang People's Hospital, Weifang, China
3. Peking University International Hospital, Beijing, China
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Abstract
Background: Hip fractures are among the most devastating complications of osteoporosis, yet determinants of the Fracture Risk Assessment Tool (FRAX)– estimated 10-year hip fracture probability (FRAX-Hip) in rheumatoid arthritis (RA) remain incompletely defined. The incremental value of RA disease activity and complete blood count (CBC)–derived inflammatory indices beyond traditional FRAX clinical risk factors is uncertain. Objectives: To identify determinants of 10-year FRAX-Hip risk in RA and to compare the predictive performance and incremental value of RA disease activity indices and CBC-derived inflammatory markers. Methods: In a cross-sectional cohort of 248 RA patients undergoing dual-energy X-ray absorptiometry, we calculated femoral neck bone mineral density (BMD)–adjusted FRAX-Hip and defined high risk as FRAX-Hip ≥3%. Determinants were assessed using Firth penalized logistic regression and multivariable linear regression, and incremental value was evaluated using changes in area under the receiver operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results: High FRAX-Hip risk was mainly driven by older age, female sex, lower body mass index, glucocorticoid exposure, and lower femoral neck BMD. Among disease activity measures, the Simplified Disease Activity Index (SDAI) provided the largest— yet modest—incremental improvement over a base clinical model (ΔAUC = 0.013; NRI = 0.903; IDI = 0.075). In contrast, CBC-derived inflammatory indices showed poor discrimination (AUC 0.46–0.62) and negligible incremental value. The clinical model explained >93% of the variance in log-transformed FRAX-Hip. Conclusions: Traditional FRAX clinical factors dominate FRAX-Hip risk estimation in RA. SDAI adds only modest incremental value, whereas CBC-derived indices do not improve risk stratification. FRAX with BMD remains a robust tool for identifying high-risk patients, underscoring the importance of optimizing age-, glucocorticoid-, and bone density–related risk factors while maintaining tight RA disease control.
Summary
Keywords
disease activity, FRAX, Hip fracture, NLR, Osteoporosis, Rheumatoid arthritis, SDAI
Received
07 December 2025
Accepted
20 February 2026
Copyright
© 2026 Zhang, Wang, Li, Li and Jin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Sheng-Guang Li; Di Jin
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