Abstract
Background: For multinational clinical trials in multiple sclerosis (MS), identifying cross-country differences on quality of life (QoL) is important for understanding patients’ response variability. No study has compared QoL between Spanish and American MS samples. This study aims to: 1) compare QoL and depressive symptomatology between Spanish and American patients, and against normative data; 2) compare the interrelationship between such constructs between countries; and 3) compare sociodemographic and clinical predictors on these outcomes. Method: 114 participants with MS were included and matched for gender, disability and education. The SF-36 Health Survey and BDI-FastScreen (BDI-FS) were the outcomes. ANCOVA, partial-correlations and multiple regression analyses were compared between countries. Results: Spaniards reported worse depressive symptomatology and QoL, and clinically significant impairment in all QoL dimensions, while Americans showed clinically significant impairment only in physical domains. Among Spaniards, more Bodily pain was more related to worse Social functioning and Vitality, and worse Vitality was more related to worse Social functioning than among Americans. From the regression models, Physical functioning predicted BDI-FS greater among Americans. Conversely, disability and Role-emotional predicted BDI-FS and Mental health, respectively, significantly stronger in Spain. Conclusions: Spaniards show worse QoL and depressive symptomatology and greater clinically significant impairment than the Americans.