National and Kapodistrian University of Athens - 4th Department of Internal Medicine, National and Kapodistrian University of Athens, National and Kapodistrian University of Athens, Evangelismos General Hospital of Athens, Thriasio General Hospital of Eleusis, National and Kapodistrian University of Athens, National and Kapodistrian University of Athens, University of Patras, Korgialeneion-Benakeion General Hospital, Thriasio General Hospital of Eleusis - 2 nd Department of Internal Medicine, G. Gennimatas General Hospital of Athens, National and Kapodistrian University of Athens, General Hospital of Larissa, Korgialeneion-Benakeion General Hospital, National and Kapodistrian University of Athens Medical School - 3rd Department of Internal Medicine, National and Kapodistrian University of Athens - 4th Department of Internal Medicine, National and Kapodistrian University of Athens, National and Kapodistrian University of Athens - 4th Department of Internal Medicine, Hellenic Institute for the Study of Sepsis, Tzaneio General Hospital of Piraeus, General Hospital of Kerkyra - Department of Pulmonary Medicine,, University of Ioannina - 1st Department of Internal Medicine, University of Patras, Larissa University General Hospital - Department of Internal Medicine, Korgialeneion-Benakeion General Hospital, University of Patras - Department of Internal Medicine, National and Kapodistrian University of Athens, Thriasio General Hospital of Eleusis, Evangelismos General Hospital of Athens - 5th Department of Internal Medicine, National and Kapodistrian University of Athens, National and Kapodistrian University of Athens and Cornell University - Weill Cornell Medicine