Rationale for unequal randomization in clinical trials is rarely reported: a systematic review

Area of Science:

• Clinical Trials Methodology
• Biostatistics
• Medical Research Reporting

Background:

• Unequal randomization (non-equal allocation ratios) is a trial design strategy.
• Assessing the quality of reporting for such trials is crucial for evidence appraisal.

Purpose of the Study:

• To evaluate the reporting standards of unequal randomization in clinical trials.
• To identify the reported justifications for employing unequal randomization.

Main Methods:

• Systematic review of 106 reports of two parallel-group randomized controlled trials with unequal randomization (2009-2010).
• Data collection included abstract/full-text review and author surveys.

Main Results:

• The randomization ratio was omitted in 8.5% of reports and 51.9% of abstracts.
• Sample size calculations failed to account for unequal randomization in 25.7% of reported trials.
• Justification for unequal randomization was absent in 77.4% of reports; safety was the primary reason in 41 trials.

Conclusions:

• Improved reporting of randomization ratios, sample size calculations, and justifications is needed.
• Enhanced transparency aids readers in evaluating trial quality and risk of bias.