title: [Use of multiple regression models in observational studies (1970-2013) and requirements of the STROBE guidelines in Spanish scientific journals].
abstract: BACKGROUND
  In medicine and biomedical research, statistical techniques like logistic, linear, Cox and Poisson regression are widely known. The main objective is to describe the evolution of multivariate techniques used in observational studies indexed in PubMed (1970-2013), and to check the requirements of the STROBE guidelines in the author guidelines in Spanish journals indexed in PubMed.
  
  
  METHODS
  A targeted PubMed search was performed to identify papers that used logistic linear Cox and Poisson models. Furthermore, a review was also made of the author guidelines of journals published in Spain and indexed in PubMed and Web of Science.
  
  
  RESULTS
  Only 6.1% of the indexed manuscripts included a term related to multivariate analysis, increasing from 0.14% in 1980 to 12.3% in 2013. In 2013, 6.7, 2.5, 3.5, and 0.31% of the manuscripts contained terms related to logistic, linear, Cox and Poisson regression, respectively. On the other hand, 12.8% of journals author guidelines explicitly recommend to follow the STROBE guidelines, and 35.9% recommend the CONSORT guideline.
  
  
  CONCLUSIONS
  A low percentage of Spanish scientific journals indexed in PubMed include the STROBE statement requirement in the author guidelines. Multivariate regression models in published observational studies such as logistic regression, linear, Cox and Poisson are increasingly used both at international level, as well as in journals published in Spanish.
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, España; Facultat de Medicina i Ciències de la Salut, Universitat Intenacional de Catalunya, Sant Cugat, Barcelona, España.
authors.forename: J
authors.initials: J
authors.lastname: Real
authors.affiliation: Pla Director d'Oncologia de Catalunya, Institut Català d'Oncologia, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, España; Departament de Ciències Clíniques, Universitat de Barcelona, Campus de Bellvitge, L'Hospitalet de Llobregat, Barcelona, España.
authors.forename: R
authors.initials: R
authors.lastname: Cleries
authors.affiliation: Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, España; Oblikue Consulting, Barcelona, España.
authors.forename: C
authors.initials: C
authors.lastname: Forné
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, España; Universitat Autònoma de Barcelona, Bellaterra, Barcelona, España.
authors.forename: A
authors.initials: A
authors.lastname: Roso-Llorach
authors.affiliation: Facultat de Medicina i Ciències de la Salut, Universitat Intenacional de Catalunya, Sant Cugat, Barcelona, España; Unitat de Control del Tabaquisme, Programa de Prevenció i Control del Càncer, Institut Català d'Oncologia, L'Hospitalet de Llobregat, Barcelona, España; Grup de Prevenció i Control del Càncer, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, España. Electronic address: jmmartinez@iconcologia.net.
authors.forename: J M
authors.initials: JM
authors.lastname: Martínez-Sánchez
mesh_terms: D015706:Bibliometrics; D003627:Data Interpretation, Statistical; D035081:Editorial Policies; D017408:Guidelines as Topic; D015999:Multivariate Analysis; D064887:Observational Studies as Topic / Q000379:methods* / Q000592:standards; D010506:Periodicals as Topic / Q000592:standards*; D016012:Poisson Distribution; D039781:PubMed; D012044:Regression Analysis; D013030:Spain
keywords: Análisis de regresión; Análisis multivariante; Epidemiology; Epidemiología; Estudios observacionales; Linear models; Logistic models; Modelos de Poisson; Modelos de riesgos proporcionales; Modelos lineales; Modelos logísticos; Multivariate analysis; Observational studies; Poisson models; Proportional hazards models; Regression analysis