1 Respiratory Unit, San Paolo Hospital, Dept of Scienze della Salute, Università degli Studi di Milano, Milan, Italy.
2 Respiratory Unit, San Paolo Hospital, Dept of Scienze della Salute, Università degli Studi di Milano, Milan, Italy Casa di Cura del Policlinico, Dipartimento di Scienze Neuroriabilitative, Milan, Italy [email protected].
3 Clinical Epidemiology and Medical Statistics Unit, Dept of Biomedical Sciences, University of Sassari-Research, Medical Education and Professional Development Unit, AOU Sassari, Sassari, Italy.