title: [What meta-analyses teach us: pros and cons].
abstract: The exponential increase in publications focusing on important clinical issues represents a major challenge for patients, physicians, and decision-makers, despite the braggadocio of many experts. Meta-analysis, when conducted within the context of a systematic review, offers an efficient and potent tool to summarize the clinical evidence accrued on a specific clinical question. Despite their many strengths, which include statistical precision, external validity, and the opportunity to analyze subgroups and moderators, meta-analyses also have many limitations. In addition, they are criticized because potentially an exercise in "mega-silliness", mixing "apples and oranges", unable to improve the quality of primary studies (in keeping with the say "garbage in-garbage out"), and focusing on an "average patient" who is only hypothetical. Yet, it is evident that meta-analyses will continue to play a key role in informing decision making whenever the best approach is not self-evident. Thus, it is mandatory to know their main features in order to use them critically and constructively, without being dominated nor scared.
authors.affiliation: Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Sapienza Università di Roma, Latina - Fondazione Eleonora Lorillard Spencer Cenci, Roma.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Biondi-Zoccai
authors.affiliation: Divisione di Cardiologia, Università degli Studi, Torino.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: D'Ascenzo
authors.affiliation: Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Sapienza Università di Roma, Latina - Dipartimento di Angiocardioneurologia, IRCCS Neuromed, Pozzilli (IS).
authors.forename: Giacomo
authors.initials: G
authors.lastname: Frati
authors.affiliation: VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Abbate
mesh_terms: D003657:Decision Making; D006801:Humans; D015201:Meta-Analysis as Topic; D012107:Research Design; D012196:Review Literature as Topic