1. Department of Epidemiology; Lazio Regional Health Service; Rome Italy
2. Department of Anesthesiology and Intensive Care; Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico; Milano Italy
3. Department of Surgical Sciences; University of Turin; Turin Italy
4. Department of Anaesthesia, Intensive Care and Emergency; ‘Città della salute e della Scienza’ Hospital; Turin Italy
5. Department of Laboratory Medicine; Ospedale Civile Sant’Agostino Estense; Modena Italy
6. Italian Cochrane Centre; University of Modena and Reggio Emilia; Modena Italy
7. Department of Medical and Surgical Sciences for Children and Adults; University of Modena and Reggio Emilia School of Medicine; Modena Italy
8. Unit of Methodological/Statistical Support to Clinical Research; Azienda-Ospedaliero Universitaria; Modena Italy