From the Guidelines
The peer review process is only moderately effective at minimizing bias in industry-sponsored (IS) trials, with significant limitations that compromise its reliability. Journal peer review often fails to detect important methodological flaws, selective outcome reporting, and publication bias in IS research, as highlighted in a study published in the British Journal of Pharmacology 1. Studies have shown that IS trials are more likely to report favorable outcomes for sponsor products compared to independently funded research, despite undergoing the same peer review process, with a systematic review published in the International Journal of Surgery finding that research funded by the pharmaceutical industry had four times the odds of having outcomes favoring the sponsor than research funded by other sources 1. Common biases that persist include selective publication of positive results, inappropriate comparators, selective endpoint reporting, and post-hoc subgroup analyses that highlight favorable findings. Peer reviewers typically lack access to raw data, complete study protocols, or statistical analysis plans, making it difficult to identify manipulation of results. Additionally, time constraints, limited expertise in specialized methodologies, and potential conflicts of interest among reviewers further compromise the process. More effective approaches include requiring pre-registration of trials, data sharing, independent statistical analysis, and greater transparency in funding relationships, as emphasized in the PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions 1. While peer review provides some quality control, it should be viewed as just one component in a broader system needed to ensure research integrity in industry-sponsored clinical trials. Key considerations for improving the peer review process include:
- Increasing transparency in funding relationships and potential conflicts of interest
- Providing access to raw data and complete study protocols for peer reviewers
- Implementing independent statistical analysis and data sharing
- Requiring pre-registration of trials to reduce selective publication and outcome reporting biases.
From the Research
Effectiveness of Journal Peer Review Process
The journal peer review process has been found to be prone to various types of bias, which can affect the quality and validity of published research, including industry-sponsored trials.
- The peer review process can introduce bias, and a double-blind peer review system is supported on equipoise and fair-play principles to mitigate this bias 2.
- The current single-blind peer review process used by most scientific journals is not bulletproof and is prone to reviewer and editorial bias, which can lead to manuscripts being judged based on interests irrelevant to the content itself and not on merit alone 3.
- To minimize bias in industry-sponsored trials, measures such as mandatory registration of interests by those involved in research, support for the 'registered reports' publication format, and making comprehensive study documentation available on a World Health Organization research repository can be implemented 4.
Sources of Bias
The chief sources of bias in peer review include the clinical outcome and the reviewer, but there are ways to mitigate any bias 5.
- Bias can be introduced into research studies through various factors, including factors related to the exposure of patients to treatments, factors that influence inclusion of patients in the study, and factors related to assessment and measurement 6.
- Methods to address bias in both design and analysis stages of a study include restriction, matching, multivariate analysis, instrumental variable estimation, and the prevention of misclassification of information 6.
Mitigating Bias
Improving the peer review process is necessary to minimize bias in industry-sponsored trials, and this can be achieved by implementing measures such as double-blind peer review, open peer review, and increasing transparency and accountability 2, 3.
- A critical overview of the problems, progress, and suggested next steps in reducing bias and improving transparency in medical research highlights the need for a broad-based campaign to mobilize public opinion and implement changes 4.