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Biopharmaceutical studies constitute a vital field aiming to enhance drug delivery methods and refine therapeutic approaches, drawing upon diverse interdisciplinary knowledge. In research methodologies, the choice between controlled and non-controlled studies significantly influences the study's reliability and accuracy.
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[Risk of bias in controlled clinical trials].

C Schmucker1, J J Meerpohl2, A Blümle2

  • 1Institut für Evidenz in der Medizin (für Cochrane Deutschland Stiftung), Medizinische Fakultät, vertreten durch das Universitätsklinikum Freiburg, Albert-Ludwigs-Universität, Breisacher Str. 153, 79110, Freiburg, Deutschland. schmucker@ifem.uni-freiburg.de.

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Critical appraisal of clinical studies helps avoid bias, which is a systematic error. This review explains bias types, avoidance strategies, and Cochrane tools for assessing bias risk in studies.

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Area of Science:

  • Clinical research methodology
  • Evidence-based healthcare

Background:

  • Clinical study results face risk of bias, leading to systematic errors.
  • Bias can result in incorrect healthcare decisions, including overtreatment or undertreatment.

Purpose of the Study:

  • To explain common types of bias in clinical studies.
  • To differentiate between various bias types and provide avoidance strategies.
  • To introduce Cochrane tools for assessing bias risk in randomized and non-randomized studies.

Main Methods:

  • Explanation of frequently encountered bias types.
  • Differentiation and strategies for avoiding systematic errors.
  • Presentation of Cochrane risk of bias assessment tools.

Main Results:

  • Key components of bias assessment tools are highlighted with examples.
  • Examples include randomization, confounding, blinding, data completeness, and selective reporting.
  • Distinction is made between bias and other study limitations like external validity and imprecision.

Conclusions:

  • Critical appraisal is essential for evidence-based healthcare.
  • Understanding and mitigating bias improves the reliability of clinical study findings.
  • Cochrane tools offer a structured approach to assess bias risk.