Foot orthosis treatment improves physical activity but not muscle quantity in patients with concurrent rheumatoid arthritis and sarcopenia

Objectives Foot impairment in rheumatoid arthritis (RA) may exacerbate sarcopenia from physical inactivity because of foot pain while walking. The present study aimed to investigate the prevalence of sarcopenia in patients with RA-associated foot impairment, and whether treatment with a foot orthosis improved physical activity and muscle quantity. Methods Thirty-two patients with RA were diagnosed as sarcopenic or nonsarcopenic, and the prevalence of sarcopenia was determined. Eleven patients with sarcopenia were treated with a foot orthosis. The following parameters were compared between baseline and after 6 months of treatment: physical activity (walking, moderate-intensity activity, and vigorous-intensity activity), foot pain while walking, Health Assessment Questionnaire (HAQ) score, and body composition parameters, including muscle quantity. Results Sarcopenia was present in 25/32 patients (78.1%). The use of a foot orthosis improved walking activity (p = .02), foot pain while walking (p = .02), and HAQ score (p = .02). However, there were no significant changes in moderate- or vigorous-intensity activities or body composition parameters, including muscle quantity. Conclusion Patients with RA-associated foot impairment had a high rate of sarcopenia. Treatment with a foot orthosis increases light-intensity physical activity such as walking, but does not enhance moderate-to-vigorous-intensity activities or increase muscle quantity.