title: Quality of meta-analyses for randomized trials in the field of hypertension: a systematic review.
abstract: Doubling on average every 6 years, hypertension-related meta-analyses are now published twice weekly and are often considered the highest level of evidence for clinical practice. However, some hypertension specialists and guideline authors view meta-analyses with skepticism. This article evaluates the quality of hypertension-related meta-analyses of clinical trials.
  
  
  
  A systematic search was conducted for meta-analyses of clinical trials recently published over 3.3 years. Specific criteria reproducibly assessed 26 features in the four domains of meta-analysis quality, domains justified by fundamental analytics and extensive research: analyzing trial quality, analyzing heterogeneity, analyzing publication bias, and providing transparency.
  
  
  
  A total of 143 meta-analyses were identified. A total of 44% had 8+ deficient features with no relation to journal impact factor: odds ratio relating 8+ deficient features to the upper third versus lower third of impact factor = 1.3 (95% confidence limit 0.6-2.9). A total of 56% had all four domains deficient. Quality did not improve over time. Thirty articles (21%) reported statistically significant results (P < 0.05) from inappropriate DerSimonian-Laird models, whereas unreported, appropriate, Knapp-Hartung models gave statistical nonsignificance; 88% of these 30 articles reported the incorrect results in their abstracts. A total of 60% of all meta-analyses failed to conduct analyses in subgroups of quality when indicated, 63% failed to report Tau and Tau, 57% omitted testing for publication bias, none conducted a cumulative analysis for publication bias, and 71-77% omitted mentioning in their abstracts problems of trial quality, heterogeneity, and publication bias.
  
  
  
  Although widespread, deficiencies in hypertension-related meta-analyses are readily corrected and do not represent flaws inherent in the meta-analytic method.
authors.affiliation: aUCONN School of Medicine, Bridgeport, Connecticut bUniversity of Colorado Hospital, Aurora, Colorado cRutgers Robert Wood Johnson Medical School, Brunswick, New Jersey dPacific Northwest University of Health Sciences, Yakima, Washington eJohnson & Johnson, Titusville, New Jersey, USA.
authors.forename: George C
authors.initials: GC
authors.lastname: Roush
authors.forename: Brigani
authors.initials: B
authors.lastname: Amante
authors.forename: Tanveer
authors.initials: T
authors.lastname: Singh
authors.forename: Hiwot
authors.initials: H
authors.lastname: Ayele
authors.forename: Morakinyo
authors.initials: M
authors.lastname: Araoye
authors.forename: Danwen
authors.initials: D
authors.lastname: Yang
authors.forename: William J
authors.initials: WJ
authors.lastname: Kostis
authors.forename: William J
authors.initials: WJ
authors.lastname: Elliott
authors.forename: John B
authors.initials: JB
authors.lastname: Kostis
authors.forename: Jesse A
authors.initials: JA
authors.lastname: Berlin
mesh_terms: D006801:Humans; D006973:Hypertension / Q000628:therapy*; D055811:Journal Impact Factor; D015201:Meta-Analysis as Topic; D016032:Randomized Controlled Trials as Topic; D058028:Research Report / Q000592:standards*