Background Joint destruction in patients with rheumatoid arthritis (RA) is mostly evaluated by scoring radiographs of both hands and feet using the Sharp van der Heijde or Larsen scoring methods. In contrast, DAS28, the most commonly used composite measure of inflammation measure, does not include the feet.
Objectives To study the distribution of erosions in hand and wrist (hands) and feet in early RA and elucidate if the feet should be included also in composite measures of inflammation
Methods This study comprises 1 052 patients from the BARFOT study of patients with early RA, recruited 1992–2006. 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 at baseline was measured by the DAS28.
Results In the feet there were significantly more eroded joints in percent of examined joints at all time points (p<0.001), and higher erosion scores in percent of maximum erosion score at 5 and 8 years (0.037 and 0.021 respectively), compared with the hands.
There were no differences in mean joint space narrowing (JSN) between hands and feet at any time point. Patients with erosions only in the feet had significantly lower DAS28, mean 4.59, compared with the patients in the other groups, mean 5.03 in the no erosions group p=0.031, mean 5.17 in the group with erosions only in the hands, p=0.013, and mean 5.15 in the group with erosions in both hands and feet, p=0.031.
Conclusions Joint destruction over time was more pronounced in the feet than in the hands. Baseline erosions limited to the feet were associated with low disease activity, suggesting that inflammation localized to the feet may not be reflected by DAS28. These observations may have relevance to the evaluating of disease activity and progression in the individual patient. Possibly inclusion of the feet to DAS28 might improve the validity of this disease activity measure.
Disclosure of Interest None declared