Prevalence of Temporomandibular Disorders in Rheumatoid Arthritis and Associated Risk Factors: A Nationwide Study in Taiwan

Aims: To investigate the association between temporomandibular disorders (TMD) and rheumatoid arthritis (RA), as well as potential risk factors for TMD and the preventive effect of medications on TMD, by using the Taiwan National Health Insurance Research Database. Methods: In total, 17,317 patients newly diagnosed with RA and 17,317 matched controls without RA were followed up from 2000 to 2010. Cox regression was used to determine risk factors for developing TMD. Kaplan-Meier curve with log-rank test was used to determine the cumulative risk of TMD in RA patients and the effects of antirheumatic medications. Results: Cox regression showed a higher risk of developing TMD if patients had RA (adjusted hazard ratio [HR] 2.538, P .001) and a lower risk if patients were of male gender and elderly (≥ 40 years) in comparison to younger patients (20 to 29 years) (P .01). Patients with insomnia, stroke, and mental disorders had, respectively, 4.756, 6.929, and 9.671 times the number of events of TMD compared to those without diseases (P .001). No patients with RA treated with disease-modifying antirheumatic drugs (DMARDs) developed TMD after the 11-year follow-up. Conclusion: RA patients had 2.538 times the events of TMD compared with non-RA patients during this trial in Taiwan. The other risk factors for developing TMD included female gender, younger age, insomnia, stroke, and mental disorders. The DMARDs had a beneficial effect on prevention of TMD. Keywords: disease modifying anti-rheumatic drugs, methotrexate, National Health Insurance Research Database, rheumatoid arthritis, temporomandibular disorders