title: [Basic concepts for network meta-analysis].
abstract: Systematic reviews and meta-analyses have long been fundamental tools for evidence-based clinical practice. Initially, meta-analyses were proposed as a technique that could improve the accuracy and the statistical power of previous research from individual studies with small sample size. However, one of its main limitations has been the fact of being able to compare no more than two treatments in an analysis, even when the clinical research question necessitates that we compare multiple interventions. Network meta-analysis (NMA) uses novel statistical methods that incorporate information from both direct and indirect treatment comparisons in a network of studies examining the effects of various competing treatments, estimating comparisons between many treatments in a single analysis. Despite its potential limitations, NMA applications in clinical epidemiology can be of great value in situations where there are several treatments that have been compared against a common comparator. Also, NMA can be relevant to a research or clinical question when many treatments must be considered or when there is a mix of both direct and indirect information in the body of evidence.
authors.affiliation: División de Farmacoepidemiología y Farmacovigilancia, Departamento de Medicamentos de Uso Humano, Agencia Española de Medicamentos y Productos Sanitarios (AEMPS), Madrid, España; Fundación Instituto de Investigación en Servicios de Salud, Valencia, España. Electronic address: ferran_catala@hotmail.com.
authors.forename: Ferrán
authors.initials: F
authors.lastname: Catalá-López
authors.affiliation: Instituto de Diagnóstico Ambiental y Estudios del Agua (IDAEA), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, España.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobías
authors.affiliation: Centro Cochrane Iberoamericano (CCIb), Hospital de la Santa Creu i Sant Pau, Barcelona, España.
authors.forename: Marta
authors.initials: M
authors.lastname: Roqué
mesh_terms: D000071076:Network Meta-Analysis as Topic; D000078202:Systematic Reviews as Topic
keywords: Comparaciones mixtas; Comparaciones múltiples; Evidence synthesis; Metaanálisis en red; Mixed-treatment comparisons; Multiple-treatment comparisons; Network meta-analysis; Revisión sistemática; Systematic review; Síntesis de evidencia