Background Patients with rheumatoid arthritis (RA) have a higher risk of fractures at all skeletal sites than individuals without RA. Our observational cohort RA study in Japan (conducted by the Institute of Rheumatology Rheumatoid Arthritis [IORRA]) recently showed that fractures at different skeletal sites have different features, suggesting that the establishment of customized strategies for each fracture site may be important in preventing fractures in patients with RA . To the best of our knowledge, no study has focused on the risk factors for proximal humerus fractures in patients with RA.
Objectives To evaluate the association between potential risk factors and the occurrence of proximal humerus fractures in Japanese patients with RA using data from the IORRA cohort study.
Methods The IORRA was a prospective observational cohort study of 11,907 Japanese patients with RA (82.0% female; mean age, 56 years) conducted at the Tokyo Women's Medical University between 2000 and 2012. Self-reported proximal humerus fractures were verified using patient medical records. Cox proportional hazards models were used to analyse independent contributions of various risk factors to proximal humerus fracture occurrence.
Results During a mean follow-up of 5.7 years, 199 patients reported 210 fractures in the shoulder and arm. Among these patients, 92 proximal humerus fractures following minor trauma in 90 patients were verified with medical records. The multivariate Cox regression analyses estimated that the hazard ratios of sustaining a proximal humerus fracture increased by 4.7 for not taking oral bisphosphonates (p=0.01), 2.1 for history of fracture (p<0.01), 2.0 for high serum C-reactive protein levels (mg/100 mL; p<0.05), 1.4 for every 10 years of increased age (p<0.01), and 1.1 for a high daily prednisolone dose (per mg/day; p<0.01).
Conclusions Not taking oral bisphosphonates, history of fracture, high C-reactive protein, advanced age, and a high daily prednisolone dose appear to be associated with the occurrence of proximal humerus fractures, which were different from risk factors for clinical vertebral, hip, and distal radius fractures in the same cohort. Intake of oral bisphosphonates and a reduction in the daily prednisolone dose together with good management of the disease and prevention of falls in RA patients of advanced age or with a history of fracture may be important in preventing proximal humerus fractures.
Ochi K, Furuya T, Ikari K, Taniguchi A, Yamanaka H, Momohara S. Sites, frequencies, and causes of self-reported fractures in 9,720 rheumatoid arthritis patients: a large prospective observational cohort study in Japan. Arch Osteoporos. 2013;8:130.
Disclosure of Interest M. Ishibashi: None declared, M. Watanabe: None declared, K. Ochi: None declared, T. Furuya: None declared, E. Inoue: None declared, O. Ishida: None declared, K. Yano: None declared, Y. Sakuma: None declared, S. Yoshida: None declared, K. Ikari: None declared, A. Taniguchi: None declared, H. Yamanaka Grant/research support: Abbott, AbbVie, Asahikasei, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taishotoyama, Takeda, Teijin, Consultant for: Abbott, AbbVie, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, Mitsubishi Tanabe, Nippon Kayaku, Pfizer, Takeda, Teijin, Speakers bureau: Abbott, AbbVie, Astellas, Bristol-Myers Squib, Chugai, Eisai, Mitsubishi Tanabe, Pfizer, Takeda, Teijin, S. Momohara: None declared