title: Systematic reviews and meta-analyses on psoriasis: role of funding sources, conflict of interest and bibliometric indices as predictors of methodological quality.
abstract: BACKGROUND
  The quality of systematic reviews and meta-analyses on psoriasis, a chronic inflammatory skin disease that severely impairs quality of life and is associated with high costs, remains unknown.
  
  
  OBJECTIVE
  To assess the methodological quality of systematic reviews published on psoriasis.
  
  
  METHODS
  After a comprehensive search in MEDLINE, Embase and the Cochrane Database (PROSPERO: CDR42016041611), the quality of studies was assessed by two raters using the Assessment of Multiple Systematic Reviews (AMSTAR) tool. Article metadata and journal-related bibliometric indices were also obtained. Systematic reviews were classified as low (0-4), moderate (5-8) or high (9-11) quality. A prediction model for methodological quality was fitted using principal component and multivariate ordinal logistic regression analyses.
  
  
  RESULTS
  We classified 220 studies as high (17·2%), moderate (55·0%) or low (27·8%) quality. Lower compliance rates were found for AMSTAR question (Q)5 (list of studies provided, 11·4%), Q10 (publication bias assessed, 27·7%), Q4 (status of publication included, 39·5%) and Q1 (a priori design provided, 40·9%). Factors such as meta-analysis inclusion [odds ratio (OR) 6·22; 95% confidence interval (CI) 2·78-14·86], funding by academic institutions (OR 2·90, 95% CI 1·11-7·89), Article Influence score (OR 2·14, 95% CI 1·05-6·67), 5-year impact factor (OR 1·34, 95% CI 1·02-1·40) and article page count (OR 1·08, 95% CI 1·02-1·15) significantly predicted higher quality. A high number of authors with a conflict of interest (OR 0·90, 95% CI 0·82-0·99) was significantly associated with lower quality.
  
  
  CONCLUSIONS
  The methodological quality of systematic reviews published about psoriasis remains suboptimal. The type of funding sources and author conflicts may compromise study quality, increasing the risk of bias.
authors.affiliation: Department of Dermatology, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.|Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Gómez-García
authors.affiliation: Department of Dermatology, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.|Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: J
authors.identifier: http://orcid.org/0000-0002-0286-4107
authors.initials: J
authors.lastname: Ruano
authors.affiliation: Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Aguilar-Luque
authors.affiliation: Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Gay-Mimbrera
authors.affiliation: Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.|School of Medicine, Universidad de Córdoba, Córdoba, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Maestre-Lopez
authors.affiliation: Department of Dermatology, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.|Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Sanz-Cabanillas
authors.affiliation: Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: P J
authors.initials: PJ
authors.lastname: Carmona-Fernández
authors.affiliation: Department of Dermatology, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.|Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: M
authors.initials: M
authors.lastname: González-Padilla
authors.affiliation: Department of Dermatology, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.|Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Vélez García-Nieto
authors.affiliation: Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC)/Hospital Universitario Reina Sofía/Universidad de Córdoba, Córdoba, Spain.|Department of Pharmacy, Hospital Universitario Reina Sofía, Menendez Pidal Ave, 14004 Córdoba, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Isla-Tejera
mesh_terms: D001319:Authorship; D016265:Conflict of Interest; D003880:Dermatology / Q000706:statistics & numerical data; D032984:Ethics, Research; D006801:Humans; D055811:Journal Impact Factor; D015201:Meta-Analysis as Topic; D010506:Periodicals as Topic / Q000941:ethics / Q000592:standards; D011565:Psoriasis; D017594:Publication Bias; D012109:Research Support as Topic; D012196:Review Literature as Topic