title: When should we change our clinical practice based on the results of a clinical study? The hierarchy of evidence.
authors: Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano, Milan, Italy.
authors: Giorgio
authors: G
authors: Costantino
authors: Nicola
authors: N
authors: Montano
authors: Giovanni
authors: G
authors: Casazza
mesh_terms: D019317:Evidence-Based Medicine / Q000592:standards*; D006801:Humans; D012106:Research / Q000592:standards*; D016896:Treatment Outcome