Plantar foot pressures are not related to disease activity in rheumatoid arthritis

Background: foot pressures are elevated within the RA foot, particularly under the forefoot. Recent evidence has linked joint damage, as measured by radiological erosion scores, to increased plantar forefoot pressures. However, it is not clear whether plantar forefoot pressures in RA are also related to inflammatory disease activity. The objective of this study was to investigate relationships between forefoot pressures and disease activity (DAS28) in a sample of RA patients.Methods: a cross sectional study design was used in which patients with RA (ACR criteria) were investigated for plantar foot pressures. Foot pressure measurements were recorded by an FScan In-shoe system, (Tekscan Inc. USA) according to standard protocol. Average foot pressures were calculated for the entire plantar foot area, and the third step was selected for analysis. The outcome variables (identified in Table 1) for both left and right feet were recorded. The data was split into groups according to DAS28 scores(identified in table 1) to define RA disease activity.Results: 149 patients (119 female and 30 male) with RA (34 seronegative, 114 seropositive and 1 unidentified) completed the study: mean age 59.3 (SD 12.5) years, weight 73.3 (14.9) Kg, disease duration 12.28 (10.3) years. The mean ESR was 23.3 (19.2), CRP 12.5 (18.1), DAS28 scores 3.9 (1.3). Foot pressure and footstep time variables are reported in table 1. Using analysis of variance no significant differences between DAS28 groups were found for any of the foot pressure variables (Peak pressure L p¼0.410, R p¼0.412; Time of peak pressure L p¼0.094, R p¼0.075; Total footstep time L p¼0.165, R p¼0.459; Force-time integral L p¼0.441, R p¼0.961; Mean force L p¼0.867, R p¼0.452). However, a test for trend showed there was a borderline association between DAS28 group and time of peak pressure (left p¼0.014; right p¼0.058) and that this was independent of age (left ¼0.063 p¼0.01;, right ¼0.043, p¼0.058).Conclusions: data from this study suggest that patients with higher disease activity may have longer times of peak pressures. Since longer times of peak pressures in diabetes patients have been linked to secondary mechanical damage, it is recommended that further investigations into the importance of temporal and spatial foot pressures in RA patients with high disease activity is undertaken.Disclosures: A.G. received funding from Arthritis Research Campaign for a research intern for the duration of the study. C.B., L.H., C.J.E., D.C. and N.K.A. have declared no conflicts of interes