Factors associated with sarcopenia in Japanese patients with rheumatoid arthritis: results from the IORRA cohort study

To investigate the prevalence of and factors associated with sarcopenia in Japanese patients with rheumatoid arthritis (RA). We analyzed a cross-section of patients with RA participating in the Institute of Rheumatology Rheumatoid Arthritis cohort survey in 2021. Participants completed self-administered questionnaires, including a 5-item sarcopenia screening index (SARC-F). Patients with a SARC-F score of 4 or higher were categorized as having sarcopenia. Among 2416 Japanese patients with RA (2113 women and 303 men; mean age 63.9 years), 341 (14.1%) patients were categorized as having sarcopenia. In a multivariable analysis of patients of all ages, age, body mass index (BMI), disease duration, history of fracture, patient pain on a visual analog scale (VAS), patient or physician global assessments based on VAS, and use of nonsteroidal anti-inflammatory drugs (NSAIDs), biologic disease-modifying antirheumatic drugs (bDMARDs), and corticosteroids were significantly (P < 0.05) associated with sarcopenia. Disease duration, patient global assessments based on VAS, and use of NSAIDs and bDMARDs were significantly associated with sarcopenia among the patients aged < 65 years, whereas age, female sex, BMI, disease duration, history of fracture, patient pain VAS and global assessments based on VAS, and use of bDMARDs and corticosteroids were significantly associated with sarcopenia in patients aged = 65 years. In Japanese patients with RA, age, BMI, disease duration, history of fracture, patient pain VAS and global assessments based on VAS, and use of NSAIDs, bDMARDs, and corticosteroids were associated with sarcopenia. Among older patients with RA, female sex was additionally associated with sarcopenia.