[1] Hosp Ramon & Cajal, Resp Dept, E-28034 Madrid, Spain
[2] Univ Alcala de Henares, IRYCIS, Madrid, Spain
[3] Univ Hosp Bern, Div Gen Internal Med, CH-3010 Bern, Switzerland
[4] Washington Univ, Sch Med, Div Pulm & Crit Care Med, St Louis, MO USA
[5] Washington Univ, Sch Med, Div Gen Med Sci, St Louis, MO USA
[6] Hosp Ramon & Cajal, Dept Med, E-28034 Madrid, Spain