Rheumatoid arthritis (RA) is a chronic disease that affects mainly small joints from hands and feet. The aims of this study were to analyze the prevalence of foot involvement in a sample of Brazilian RA patients and to explore the influence of disease variables such as inflammatory activity, serological, and epidemiological profile in this type of involvement. One hundred RA patients and 100 healthy controls paired for gender, age, and body mass index answered the FFI-BR (Foot Functional Index-Brazilian version) that evaluates foot function. RA patients had epidemiological and clinical data collection upon direct questioning and chart review. C-reactive protein (CRP), ESR (erythrocyte sedimentation rate), and DAS28-ESR were used to measure disease activity. In the RA sample, 98% had foot pain versus 76% in the controls (p < 0.0001; OR = 15.4; 95% CI = 3.4-67.5); 96% had some difficulty in function versus 66% of controls (p < 0.0001; OR = 12.3; 95% CI = 4.1-36.5); and 73% had some incapacity versus 20% of controls (p < 0.0001; OR = 10.8; 95% CI = 5.5-20.9). Values of FFI-BR showed correlation with ESR (p = 0.006), CRP (p = 0.01), and DAS28-ESR (p < 0.0001). No association between FFI-BR total score and gender, ethnic background, positive rheumatoid factor, tobacco exposure, and any of used medications was found (all p = ns). The majority of RA patients suffers from foot problems and was associated with inflammatory biomarkers. The control of inflammatory activity may help in the treatment of this problem.

Rheumatoid arthritis (RA) is a chronic, progressive inflammatory disease that can cause limitations and difficulties in activities of daily living (ADLs), due to pain, gait impairment and difficulties with self-care. 1 Damage to the ankles and feet occurs in 85% to 100% of these patients and contributes greatly to their loss of quality of life. 2 Typically, foot involvement indicates more aggressive disease and requires more than just pharmacological care. 3 Studying functional disability of the feet is important because, in addition to causing the abovementioned limitations, this form of disability has been correlated with higher risk of falls due to stiffness, pain, muscle weakness and balance disorders, which increases mortality, health resource utilization and loss of patients' work capacity. 4,5 Although RA patients frequently complain about their feet, such complaints are often overlooked by healthcare professionals. Specific instruments for foot health assessment, including the Brazilian versions of the Foot Health Status Questionnaire (FHSQ-BR) and the Foot Function Index (FFI-BR), measure the day-today impact of involvement of the feet in RA. These instruments provide data that help in understanding the repercussions of this involvement and the respective therapeutic indications. This can improve the quality of life of the individuals affected. 3 OBJECTIVE The objectives of the present study were to assess the disability that originated through foot involvement among RA patients, as indicated using the FFI-BR and FHSQ-BR questionnaires, and to evaluate the influence of inflammatory activity on the dysfunction of foot joints.