Background Oral health is an important issue for patients with rheumatoid arthritis (RA), because many RA patients are treated with bisphosphonates. Bisphosphonate use appears to be associated with osteonecrosis of the jaw (ONJ) [1], and periodontitis is a potential risk factor for RA [2]. Limited data exist regarding dental treatment, tooth extraction, and ONJ in Japanese patients with RA.

Objectives This study aimed to evaluate the dental history and complications of patients in our Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort.

Methods The IORRA is a prospective observational study of Japanese RA patents. Patients with RA enrolled in the IORRA cohort completed self-administered questionnaires as part of the April IORRA surveys of 2014, which included their dental treatment, tooth extraction by a dentist during the past 6 months (from October 2013 to March 2014), and history of ONJ. ONJ histories were validated using the patients' medical records. Logistic regression was used to determine the variables associated with tooth extraction.

Results Among 5779 Japanese patients with RA (median age, 65 years; female, 85%), 2323 patients (40%) received dental treatment, and 378 (6.5%) underwent tooth extraction by a dentist during the past 6 months. Among 1257 patients treated with oral bisphosphonates and denosumab, 533 patients (42%) received dental treatment, and 83 (6.6%) underwent tooth extraction during the past 6 months. Among the patients who underwent tooth extraction and took bisphosphonates during the past 6 months (n=34), 22 (65%) were advised by physicians and dentists to stop bisphosphonate use before the tooth extraction. In a multivariate model, advanced age (P=0.0060) and current smoking (P=0.0072) were associated with tooth extraction.

Among the patients, 25 reported a history of ONJ. Of those, we confirmed ONJ with the medical records of 6 patients during the past 2 years. Among the 6 patients with ONJ, all were females over 65 years of age, 5 and 4 were treated with oral bisphosphonates and prednisolone, respectively, at the diagnosis of ONJ, and 1 had a history of oral bisphosphonate treatment. The incidence of ONJ was 0.5/1,000 person-years in all patents, and 1.4/1,000 person-years in female patients over 65 years of age.

Conclusions Many Japanese patients with RA receive dental treatment and undergo tooth extraction by dentists. Japanese physicians should consult dentists before prescribing bisphosphonates and denosumab, especially for elderly female RA patients taking prednisolone.

References

1. Khan AA, et al. Bisphosphonate-associated osteonecrosis of the jaw in Ontario: a survey of oral and maxillofacial surgeons. J Rheumatol. 2011: 38: 1396-402.

2. Routsias JG, et al. Autopathogenic correlation of periodontitis and rheumatoid arthritis. Rheumatology (Oxford). 2011: 50; 1189-93.

Acknowledgements We thank all of the members of the Institute of Rheumatology, Tokyo Women's Medical University for the successful management of the IORRA cohort.

Disclosure of Interest T. Furuya: None declared, S. Momohara Speakers bureau: Abbvie, Chugai, Eisai, Mitsubishi Tanabe, and Takeda, A. Taniguchi: None declared, H. Yamanaka Grant/research support from: Abbott, AbbVie, Asahikasei, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, GlaxoSmithKline, Janssen, Mitsubishi Tanabe, MSD, Nippon Kayaku, Pfizer, Santen, Taishotoyama, Takeda, and Teijin, Consultant for: Abbott, AbbVie, Astellas, AstraZeneca, Bristol-Myers Squib, Chugai, Daiichi Sankyo, Eisai, Mitsubishi Tanabe, Nippon Kayaku, Pfizer, Takeda, and Teijin, Speakers bureau: Abbott, AbbVie, Astellas, Bristol-Myers Squib, Chugai, Eisai, Mitsubishi Tanabe, Pfizer, Takeda, and Teijin. SM has participated in speakers bureaus for Abbvie, Chugai, Eisai, Mitsubishi Tanabe, and Takeda