About the Authors

Oscar Fernández

oscar.fernandez.sspa@juntadeandalucia.es

Affiliation Hospital Universitario Carlos Haya de Málaga, Málaga, Spain

Javier Agüera

Affiliation Hospital Universitario Reina Sofía Córdoba, Spain

Guillermo Izquierdo

Affiliation Hospital Virgen de la Macarena, Sevilla, Spain

Javier Millán-Pascual

Affiliation Hospital La Mancha Centro, Alcázar de San Juan, Spain

Lluis Ramió i Torrentà

Affiliation Hospital Josep Trueta, Girona, Spain

Pedro Oliva

Affiliation HUC de Asturias, Oviedo, Spain

Javier Argente

Affiliation Hospital Puerta del Mar, Càdiz, Spain

Yasmina Berdei

Affiliation Hospital de Salamanca, Salamanca, Spain

Jose Maria Soler

Affiliation Hospital de Sant Joan de Déu de Manresa, Manresa, Spain

Olga Carmona

Affiliation Hospital de Figueres, Figueres, Spain

Jose Maria Errea

Affiliation Hospital de Barbastro, Barbastro, Spain

Jordi Farrés

Affiliation Bayer Hispania, Barcelona, Spain

on behalf of the Group on Adherence to IFNb-1b in Spain

Competing Interests

This study was supported by Química Farmacéutica Bayer S.L.and RPS Research Ibérica. RPS Research Ibérica helped in the statistical analysis. The corresponding author (Oscar Fernández, MD, PhD) has received honoraria as consultant in advisory boards, and as chairmen or lecturer in meetings (Bayer-Schering; Biogen-Idec, Merck-Serono, TevA, Novartis and Sanofi-Aventis).He has also participated in clinical trials and other research projects sponsored by Bayer-Schering; Biogen-Idec, Merck-Serono, TevA, Novartis and Sanofi-Aventis. The author (Olga Carmona, MD, PhD) has received honoraria as consultant in advisory boards, and as a lecturer in meetings (Bayer-Schering; Biogen-Idec, Merck-Serono, TevA, Novartis and Sanofi-Aventis). She has also participated in clinical trials and other research projects sponsored by Bayer-Schering; Biogen-Idec, Merck-Serono, Teva, Novartis and Sanofi-Aventis. The remaining authors have declared that they have no conflict of interest. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: OF. Performed the experiments: OF J. Agüera GI JM LRIT PO J. Argente YB JMS OC JE. Analyzed the data: JF. Wrote the paper: OF. Group on Adherence to IFNb-1b in Spain: OF (18 patients); Hospital Carlos Haya J. Agüera (12 patients); Hospital Universitario Reina Sofía GI (12 patients); Hospital Virgen de la Macarena JM (12 patients); Hospital La Mancha Centro LR L (12 patients); Hospital Josep Trueta AT (10 patients); Hospital Universitario Central de Asturias J. Argente (7 patients); Hospital Puerta del Mar YB (7 patients); Hospital de Salamanca JMSa (7 patients); Hospital de Manresa OC (6 patients); Hospital de FigueresJME (6 patients); Hospital de Barbastro JM. Sanz (4 patients); Hospital Obispo Blanco AL (3 patients); Hospital Obispo Blanco CR (3 patients); Hospital de Barbastro NT (1 patient); Hospital Clínico de Valladolid.