The frequency and associated factors of erosive osteoarthritis in patients with rheumatoid arthritis

Erosive osteoarthritis (EOA) is a deformative joint disease affecting small joints of hands that causes pain and disability, as does rheumatoid arthritis (RA). So, EOA may interfere with the assessment of RA disease activity. In this study, we aimed to determine the frequency and associated factors of EOA in patients with RA and pay attention to the overlap syndrome between RA and EOA. The electronic medical files of adult RA patients were reviewed retrospectively. Patients with another rheumatic diseases were excluded. Hand X-rays were read by two rheumatologists and one radiologist. Patients with RA were divided into two groups according to the presence of EOA. We totally analyzed 619 patients with a mean age of 54.2 years, and 82.8% of them were female. The 95.4% of patients had RA-type erosive changes according to the Modified Sharp Score. We found the frequency of EOA to be 6.3% in patients with RA. Erosive osteoarthritis was significantly higher in patients who had >50 years of age (p= 0.006), disease duration >10 years (p= 0.003), and anti-CCP negativity (p= 0.02) than in those without. In multivariable regression analysis, only age was the independent predictive factor for EOA (p