title: Systematic reviews showed insufficient evidence for clinical practice in 2004: what about in 2011? The next appeal for the evidence-based medicine age.
abstract: OBJECTIVE
  The aims of the Cochrane systematic reviews are to make readily available and up-to-date information for clinical practice, offering consistent evidence and straightforward recommendations. In 2004, we evaluated the conclusions from Cochrane systematic reviews of randomized controlled trials in terms of their recommendations for clinical practice and found that 47.83% of them had insufficient evidence for use in clinical practice. We proposed to reanalyze the reviews to evaluate whether this percentage had significantly decreased.
  
  
  METHODS
  A cross-sectional study of systematic reviews published in the Cochrane Library (Issue 7, 2011) was conducted. We randomly selected reviews across all 52 Cochrane Collaborative Review Groups.
  
  
  RESULTS
  We analyzed 1128 completed systematic reviews. Of these, 45.30% concluded that the interventions studied were likely to be beneficial, of which only 2.04% recommended no further research. In total, 45.04% of the reviews reported that the evidence did not support either benefit or harm, of which 0.8% did not recommend further studies and 44.24% recommended additional studies; the latter has decreased from our previous study with a difference of 3.59%.
  
  
  CONCLUSIONS
  Only a small number of the Cochrane collaboration's systematic reviews support clinical interventions with no need for additional research. A larger number of high-quality randomized clinical trials are necessary to change the 'insufficient evidence' scenario for clinical practice illustrated by the Cochrane database. It is recommended that we should produce higher-quality primary studies in active collaboration and consultation with global scholars and societies so that this can represent a major component of methodological advance in this context.
authors: Botucatu Medical School (FMB), UNESP - Universidade Estadual Paulista, Botucatu, São Paulo, Brazil.
authors: Paulo José Fortes
authors: PJ
authors: Villas Boas
authors: Regina Stella
authors: RS
authors: Spagnuolo
authors: Amélia
authors: A
authors: Kamegasawa
authors: Leandro Gobbo
authors: LG
authors: Braz
authors: Adriana
authors: A
authors: Polachini do Valle
authors: Eliane Chaves
authors: EC
authors: Jorge
authors: Hugo Hyung Bok
authors: HH
authors: Yoo
authors: Antônio José Maria
authors: AJ
authors: Cataneo
authors: Ione
authors: I
authors: Corrêa
authors: Fernanda Bono
authors: FB
authors: Fukushima
authors: Paulo
authors: P
authors: do Nascimento
authors: Norma Sueli Pinheiro
authors: NS
authors: Módolo
authors: Marise Silva
authors: MS
authors: Teixeira
authors: Edison Iglesias
authors: EI
authors: de Oliveira Vidal
authors: Solange Ramires
authors: SR
authors: Daher
authors: Regina
authors: R
authors: El Dib
mesh_terms: D003430:Cross-Sectional Studies; D055317:Evidence-Based Practice / Q000592:standards*; D006801:Humans; D011897:Random Allocation; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D012196:Review Literature as Topic