Journal of Clinical Epidemiology
Volume 63, Issue 10 , Pages 1082-1090, October 2010

Reported effects in randomized controlled trials were compared with those of nonrandomized trials in cholecystectomy

  • Dirk Müeller

      Affiliations

    • Institute for Research in Operative Medicine (IFOM), University Witten/Herdecke, Cologne, Germany
    • Department of Business Administration and Health Care Management, University of Cologne, Cologne, Germany
    • Corresponding Author InformationCorresponding author. Institute for Research in Operative Medicine, University Witten/Herdecke, Ostmerheimer Street 200, 51109 Cologne, Germany. Tel.: +49-0-221/989-57-0; fax: +49-221-98957-30.
    • ,
  • Stefan Sauerland

      Affiliations

    • Institute for Research in Operative Medicine (IFOM), University Witten/Herdecke, Cologne, Germany
    • ,
  • Edmund A.M. Neugebauer

      Affiliations

    • Institute for Research in Operative Medicine (IFOM), University Witten/Herdecke, Cologne, Germany
    • ,
  • Marc Immenroth

      Affiliations

    • Ethicon Endo-Surgery (Europe) GmbH, Norderstedt, Germany

Accepted 14 December 2009. published online 26 March 2010.

Abstract 

Objectives

Because external validity of randomized controlled trials (RCTs) may be insufficient, the performance of nonrandomized controlled trials (nRCTs) is increasingly debated. RCTs and nRCTs were compared using the example of laparoscopic vs. open cholecystectomy (LC vs. OC).

Study Design and Setting

RCTs and nRCTs comparing LC and OC were identified by searching PubMed. To assess internal and external validity of the studies, patient characteristics, relative risks, and mean differences of RCTs and nRCTs were compared by meta-analytic techniques.

Results

In total, 162 studies were analyzed (136 nRCTs and 26 RCTs). Significant discrepancies between RCT- and nRCT-based results were revealed for 3 of 15 variables: overall complications (P<0.021), wound infections (P<0.014), and length of hospital stay (P<0.005). In RCTs and in nRCTs, length of hospital stay and return to work were significantly reduced when using LC compared with OC. The results of nRCTs were more often heterogeneous among themselves (11 of 15) as compared with RCTs (4 of 15).

Conclusion

The results of RCTs and nRCTs differ significantly in at least 20% of the variables. External validities of RCTs and nRCTs in LC vs. OC appear to be similar. Between-study heterogeneity was larger in nRCTs than in RCTs of cholecystectomy.

Keywords: Observational studies, External validity, Internal validity, Epidemiological research, Laparoscopic cholecystectomy, Heterogeneity

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PII: S0895-4356(10)00020-X

doi:10.1016/j.jclinepi.2009.12.009

Refers to erratum:

  • Erratum to “Reported effects in randomized controlled trials were compared with those of nonrandomized trials in cholecystectomy” [J Clin Epidemiol 2010;63:1082–90]

    Dirk Müller, Stefan Sauerland, Edmund A.M. Neugebauer, Marc Immenroth
    Journal of Clinical Epidemiology September 2011 (Vol. 64, Issue 9, Page 1049)

Journal of Clinical Epidemiology
Volume 63, Issue 10 , Pages 1082-1090, October 2010

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