Ultrasound evaluation of muscle quality in rheumatoid arthritis: a reliability study of the Spanish Ultrasound Muscle Assessment in Rheumatoid Arthritis (SpUMAR) score - Molina-Collada, Juan; Bellon, Jose Maria; Blanco-Caceres, Boris; Coronel, Luis; de Agustin, Juan Jose; Estrada, Paula; Garmendia Sanchez, Elena; Garcia Vivar, M Luz; Garcia Vivar, M Luz; Olivas-Vergara, Otto; Jimenez Nunez, Francisco Gabriel; Mayordomo, Lucia; et al. (ARTHRITIS RESEARCH & THERAPY, 2026)