A new analysis presented at the 10th Peer Review Congress suggests that when researchers designate a specific outcome as "primary" in a randomized clinical trial (RCT), the estimated effect size for that outcome may be inflated compared to the same outcome when labeled "secondary."
The study compared RCTs that identified a particular outcome as primary against those that designated it as secondary. The hypothesis was that primary outcomes would show larger effect estimates due to potential biases introduced by trial design and conduct aimed at achieving positive results.
Findings indicate that the distinction between primary and secondary outcomes can influence how results are reported, raising concerns about overestimation in primary outcomes. This has implications for evidence-based medicine, as primary outcomes often drive conclusions and treatment recommendations.
The research calls for greater transparency and methodological rigor to minimize bias in clinical trial reporting.