Distribution of erosions in hands and feet at the time for the diagnosis of RA and during 8-year follow-up

Background Joint destruction in rheumatoid arthritis (RA) is usually evaluated by radiographs of both hands and feet, while the inflammatory status mostly is evaluated by DAS28 which, however, does not include the feet. Objectives To investigate the distribution of erosions in hands and feet in early RA over 8 years and its potential clinical implications. Furthermore, the group of patients never showing erosions has been addressed. Methods This study comprises 1041 patients from the BARFOT study of patients with early RA. Radiographs of hands and feet were performed at baseline, 1, 2, 5, and 8 years and evaluated by the Sharp van der Heijde scoring (SHS) method (32 joints in the hands and 12 in the feet). Disease activity was measured by DAS28, SR, CRP, and function with HAQ. Results In the feet, there were significantly more eroded joints in percent of examined joints than in the hands at all time points. Patients with erosions only in the feet were younger, more often seropositive and smokers. They had significantly lower baseline DAS28, than the patients with erosions only in the hands. The patients without erosions over time were, at diagnosis, significantly younger and less frequently seropositive compared with patients having erosions. Conclusions This study highlights the importance of evaluating the feet in patients with RA, both with clinical examinations and with imaging and lends support to the notion that seropositivity and smoking are risk factors for erosive disease. Further studies of patients with nonerosive disease are needed. Key Points: • Foot problems are common in RA • This study emphasizes the limitations of DAS28 and Sharp van der Heijde score as regards evaluating disease activity and radiographic damage • This study highlights the importance of evaluating the feet in patients with RA with clinical examinations and imaging • This study also points out the need of further studies of patients with non-erosive RA.