... the resulting scales and items an exploratory fac-tor analysis was made to determine grouping of theinformation obtained from patients self-reports. Finally,an evaluation was made of the usefulness ... patients in which fibro-myalgia is more severe due to a greater social andoccupational impact, and a greater variety in theTable 1 Exploratory factor analysis; factor loadings byinstruments ... (Hospital LaPaz, Madrid), C Hidalgo (Centro Reumatológico, Salamanca), J Mundo(Hospital Clinic, Barcelona), P Muñoz-Carreño (Hospital General, Guadalajara),R Queiró (Hospital General de Asturias,...