1. Lluita contra la Sida Foundation; Germans Trias i Pujol University Hospital; Badalona Spain
2. Universitat Autònoma de Barcelona; Badalona Spain
3. Universitat de Vic-Universitat central de Catalunya; Spain
4. Statistics and Operations Research Department; Universitat Politècnica de Catalunya; Barcelona Spain
5. Department of Econometrics; University of Barcelona; Barcelona Spain
6. CETIR Centre Mèdic; Barcelona Spain
7. Irsicaixa Foundation; Germans Trias i Pujol University Hospital; Badalona Spain