Efficacy and safety of combined therapy with synthetic disease-modifying antirheumatic drugs in rheumatoid arthritis: Systematic literature review Jaime Calvo Alén; Trinidad Pérez; Susana Romero Yuste; Iván Ferraz-Amaro; Juan José Alegre Sancho; José Antonio Pinto Tasende; Francisco Maceiras Pan; Juan Carlos Quevedo; M. Vanesa Hernández-Hernández; Cristina Hidalgo Calleja; Alejandro San Martín Álvarez; María Isabel Tevar Sánchez; Raimon Sanmartí;