Methods of blinding in reports of randomized controlled trials assessing pharmacologic treatments: A systematic review
2006

Methods of Blinding in Randomized Controlled Trials

Sample size: 819 publication Evidence: moderate

Author Information

Author(s): Boutron Isabelle, Estellat Candice, Guittet Lydia, Dechartres Agnes, Sackett David L, Hróbjartsson Asbjørn, Ravaud Philippe

Primary Institution: INSERM U738, Paris, France

Hypothesis

What methods can be used to establish and maintain blinding in randomized controlled trials of pharmacologic treatments?

Conclusion

The study classifies and describes various methods of blinding that can help improve the quality of clinical trials.

Supporting Evidence

  • Blinding is essential to avoid bias in clinical trials.
  • About 60% of the reviewed trials described their blinding methods.
  • Methods to establish blinding included using identical treatments and active placebos.
  • Only 58% of reports provided details on blinding methods.
  • Blinding outcome assessors is crucial for reliable trial results.
  • Creative blinding methods can help overcome barriers in clinical trials.
  • Improved reporting of blinding methods is needed in scientific literature.
  • Blinding helps prevent conscious and unconscious biases in trial outcomes.

Takeaway

This study looks at how to keep patients and doctors from knowing which treatment is being given in drug trials, which helps make the results more reliable.

Methodology

A systematic review of randomized controlled trials published in 2004 in high impact-factor journals, focusing on blinding methods.

Potential Biases

Lack of detailed reporting on blinding methods may lead to biases in interpreting trial results.

Limitations

The study only included trials published in high impact-factor journals and may not capture all blinding methods used in other studies.

Digital Object Identifier (DOI)

10.1371/journal.pmed.0030425

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