[1] Univ Milano Bicocca, Res Ctr Publ Hlth, CESP, I-20052 Monza, Italy
[2] Univ Naples Federico 2, CIRFF, Ctr Pharmacoecon, Naples, Italy
[3] Reg Hlth Author Lombardia, Milan, Italy
[4] Univ Insubria, Dept Clin & Biol Sci, Varese, Italy
[5] Univ Milano Bicocca, Dept Stat, Milan, Italy