1. Department of Hospital Medicine, Hospital Clínico San Carlos, Universidad Complutense, Madrid, Spain.
2. Department of Cardiac Surgery, Hospital Clínico San Carlos, Universidad Complutense, Madrid, Spain.
3. Department of Methodological and Preventive Health Medicine and IdISSC of Hospital Clínico San Carlos, Madrid, Spain.
4. Department of Cardiac Surgery, Hospital La Paz, Madrid, Spain.
5. Division of Hospital Medicine, The Johns Hopkins Bayview Medical Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.