title: Using systematic reviews to inform NIHR HTA trial planning and design: a retrospective cohort.
abstract: BACKGROUND
  Chalmers and Glasziou's paper published in 2014 recommends research funding bodies should mandate that proposals for additional primary research are built on systematic reviews of existing evidence showing what is already known. Jones et al. identified 11 (23%) of 48 trials funded during 2006-8 by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme did not reference a systematic review. This study did not explore the reasons for trials not referencing a systematic review or consider trials using any other evidence in the absence of a systematic review. Referencing a systematic review may not be possible in certain circumstances, for instance if the systematic review does not address the question being proposed in the trial. The current study extended Jones' study by exploring the reasons for why trials did not reference a systematic review and included a more recent cohort of trials funded in 2013 to determine if there were any changes in the referencing or use of systematic reviews.
  
  
  METHODS
  Two cohorts of NIHR HTA randomised controlled trials were included. Cohort I included the same trials as Jones et al. (with the exception of one trial which was discontinued). Cohort II included NIHR HTA trials funded in 2013. Data extraction was undertaken independently by two reviewers using full applications and trial protocols. Descriptive statistics was used and no formal statistical analyses were conducted.
  
  
  RESULTS
  Five (11%) trials of the 47 funded during 2006-2008 did not reference a systematic review. These 5 trials had warranted reasons for not referencing systematic reviews. All trials from Cohort II referenced a systematic review. A quarter of all those trials with a preceding systematic review used a different primary outcome than those stated in the reviews.
  
  
  CONCLUSIONS
  The NIHR requires that proposals for new primary research are justified by existing evidence and the findings of this study confirm the adherence to this requirement with a high rate of applications using systematic reviews.
authors.affiliation: Wessex Institute, University of Southampton Alpha House, University of Southampton Science Park, Southampton, SO16 7NS, UK. S.D.Bhurke@southampton.ac.uk.|National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. S.D.Bhurke@southampton.ac.uk.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Bhurke
authors.affiliation: National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. andrewc@southampton.ac.uk.|University of Southampton and University Hospital Southampton NHS Foundation Trusts, Southampton, UK. andrewc@southampton.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cook
authors.affiliation: National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. A.Tallant@southampton.ac.uk.
authors.forename: Anna
authors.initials: A
authors.lastname: Tallant
authors.affiliation: Wessex Institute, University of Southampton Alpha House, University of Southampton Science Park, Southampton, SO16 7NS, UK. A.J.Young@southampton.ac.uk.|National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. A.J.Young@southampton.ac.uk.
authors.forename: Amanda
authors.initials: A
authors.lastname: Young
authors.affiliation: National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. Elaine.Williams@southampton.ac.uk.
authors.forename: Elaine
authors.initials: E
authors.lastname: Williams
authors.affiliation: Wessex Institute, University of Southampton Alpha House, University of Southampton Science Park, Southampton, SO16 7NS, UK. J.P.Raftery@southampton.ac.uk.|National Institute for Health Research (NIHR), Evaluation, Trials and Studies Coordinating Centre (NETSCC), University of Southampton, Southampton, SO16 7NS, UK. J.P.Raftery@southampton.ac.uk.|University of Southampton and University Hospital Southampton NHS Foundation Trusts, Southampton, UK. J.P.Raftery@southampton.ac.uk.
authors.forename: James
authors.initials: J
authors.lastname: Raftery
mesh_terms: D006801:Humans; D009313:National Health Programs; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012189:Retrospective Studies; D012196:Review Literature as Topic