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. 2007 Apr;100(4):187-90.
doi: 10.1177/014107680710011415.

Reports of clinical trials should begin and end with up-to-date systematic reviews of other relevant evidence: a status report

Mike Clarke  1 , Sally Hopewell, Iain Chalmers
Affiliations

Reports of clinical trials should begin and end with up-to-date systematic reviews of other relevant evidence: a status report

Mike Clarke et al. J R Soc Med. 2007 Apr.

Abstract

Objective: Scientific and ethical justification for new clinical trials requires them to have been designed in the light of scientifically defensible assessments of relevant previous research. Reliable interpretation of the results of new clinical trials entails setting them in the context of updates of the reviews upon which they were deemed scientifically and ethically justifiable. We have shown previously that most reports of randomized trials published in five general medical journals in May 1997 and in May 2001 failed to set their results in the context of the findings from similar research. In the current study, we assess whether there had been progress in this respect in 2005 and also investigate the extent to which reports begin by referring to systematic reviews providing the justification for the new research reported.

Design: Assessment of the Introduction and Discussion sections in all reports of randomized trials published during May 2005 in five general medical journals.

Setting: Reports of randomized trials in five general medical journals.

Participants: Annals of Internal Medicine, BMJ, JAMA, Lancet and New England Journal of Medicine.

Interventions: None.

Main outcome measures: The inclusion or mention of one or more systematic reviews in the Introduction or Discussion section of each report assessed.

Results: We found 18 reports of randomized trials. The Introduction sections referred to systematic reviews in five (27%) of these reports. None of the discussion sections of the 15 reports of trials that were not the first published trials to address the question studied placed the results of the new trial in the context of an updated systematic review of other research. Although reference was made to relevant systematic reviews in five of these 15 reports, there was no integration - quantitative or qualitative - of the results of the new trials in an update of these reviews. In the remaining ten reports there was no evidence that any systematic attempt had been made to set the new results in the context of previous trials.

Conclusions: There is no evidence of progress between 1997 and 2005 in the proportion of reports of trials published in general medical journals which discussed new results within the context of up-to-date systematic reviews of relevant evidence from other controlled trials. Although the proportion of trials referring to systematic reviews in Discussion sections has increased, the majority of reports continued to fail even to do this. Similarly, most researchers appear not to have considered a systematic review when designing their trial. Researchers and journal editors do a disservice to the interests of the public and others involved in healthcare decision-making by acquiescing in this situation.

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References

    1. Clarke M. Doing new research? Don't forget the old. Nobody should do a trial without reviewing what is known. PLoS Medicine 2004;1: 100-2 - PMC - PubMed
    1. Chalmers I, Altman DG. How can medical journals help prevent poor medical research? Some opportunities presented by electronic publishing. Lancet 1999;353: 490-3 - PubMed
    1. Clarke M, Chalmers I. Discussion sections in reports of controlled trials published in general medical journals: islands in search of continents? JAMA 1998;280: 280-2 - PubMed
    1. Clarke M, Alderson P, Chalmers I. Discussion sections in reports of controlled trials published in general medical journals. JAMA 2002;287: 2799-801 - PubMed
    1. Dalziel SR, Walker NK, Parag V, et al. Cardiovascular risk factors after antenatal exposure to betamethasone: 30-year follow-up of a randomised controlled trial. Lancet 2005;365: 1856-62 - PubMed

APPENDIX 1: References to the 18 identified trials.

    1. Bill-Axelson A, Holmberg L, Ruutu M, et al. Scandinavian Prostate Cancer Group Study No. 4. Radical prostatectomy versus watchful waiting in early prostate cancer. N Engl J Med 2005;352: 1977-84 - PubMed
    1. Brain EG, Bachelot T, Serin D, et al. RAPP-01 Trial Investigators. Life-threatening sepsis associated with adjuvant doxorubicin plus docetaxel for intermediate-risk breast cancer. JAMA 2005;293: 2367-71 - PubMed
    1. Ciliberto H, Ciliberto M, Briend A, Ashorn P, Bier D, Manary M. Antioxidant supplementation for the prevention of kwashiorkor in Malawian children: randomised, double blind, placebo controlled trial. BMJ 2005;330: 1109-11 - PMC - PubMed
    1. Dalziel SR, Walker NK, Parag V, et al. Cardiovascular risk factors after antenatal exposure to betamethasone:30-year follow-up of a randomised controlled trial. Lancet 2005;365: 1856-62 - PubMed
    1. DuPont HL, Jiang ZD, Okhuysen PC, et al. A randomized, double-blind, placebo-controlled trial of rifaximin to prevent travelers' diarrhea. Ann Intern Med 2005;142: 805-12 - PubMed

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