1 2nd Respiratory Medicine Department, Attiko University Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece.
2 1st Respiratory Medicine Department, Sotiria Chest Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece.
3 5(th) Respiratory Medicine Department, Sotiria Chest Hospital, Athens, Greece.
4 Respiratory Medicine Department, University Hospital of Ioannina, University of Ioannina Medical School, Ioannina, Greece.
5 2nd Respiratory Medicine Department, Attiko University Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece. Electronic address: loukstel@med.uoa.gr.