[Risk of bias in controlled clinical trials].

Area of Science:

• Clinical research methodology
• Evidence-based healthcare

Background:

• Clinical study results are vulnerable to bias, defined as systematic error deviating from the truth.
• Bias can lead to 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 offer strategies for their avoidance.
• To introduce Cochrane tools for assessing bias risk in randomized and non-randomized studies.

Main Methods:

• Explanation of frequently encountered bias types and differentiation strategies.
• Presentation of Cochrane risk of bias assessment tools for different study designs.
• Illustrative examples of key bias assessment components: randomization, confounding, blinding, data completeness, and selective reporting.

Main Results:

• Understanding bias is crucial for critical appraisal in evidence-based healthcare.
• Cochrane tools provide a structured approach to assess bias risk.
• Distinguishing bias from other study limitations like external validity and imprecision is important.

Conclusions:

• Effective bias assessment safeguards against erroneous clinical decisions.
• Implementation of bias avoidance strategies and utilization of assessment tools enhance research integrity.
• Critical appraisal, including bias assessment, is fundamental to evidence-based healthcare practice.