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Meta-analyses of adverse effects data derived from randomised controlled trials as compared to observational studies:
Su Golder1, Yoon K Loke, Martin Bland
1Centre for Reviews and Dissemination, University of York, York, United Kingdom. su.golder@york.ac.uk
Plos Medicine
|May 12, 2011
Summary
Systematic reviews of adverse effects show no difference in risk estimates between randomized controlled trials (RCTs) and observational studies. This meta-analysis of meta-analyses suggests reviews should include both study types for comprehensive adverse effect evaluation.
Area of Science:
- Medical research methodology
- Evidence-based medicine
- Pharmacovigilance
Background:
- Debate exists regarding the use of randomized controlled trial (RCT) data versus observational data in systematic reviews of adverse effects.
- Assessing the relative merits of different study designs for adverse effect reviews is crucial for evidence-based decision-making.
Purpose of the Study:
- To compare risk estimates of adverse effects derived from meta-analyses of RCTs with those from meta-analyses of observational studies.
- To evaluate the level of agreement and disagreement between these two data sources in systematic reviews.
Main Methods:
- A meta-analysis of meta-analyses was conducted, including studies where pooled estimates from RCTs and observational studies on the same adverse effect could be directly compared.
- Searches were performed across ten databases, supplemented by reference checking, expert consultation, citation searches, and hand-searching key journals and proceedings.
- Nineteen studies, encompassing 58 meta-analyses, were included in the final analysis.
Main Results:
- The pooled ratio of odds ratios (RCTs vs. observational studies) was 1.03 (95% CI 0.93-1.15), indicating no significant average difference in risk estimates.
- Confidence intervals for harm estimates overlapped in 93% of meta-analyses, and statistical significance agreed in 64% of cases.
- Discrepancy between study types decreased with larger study sizes, and a symmetric funnel plot suggested no consistent difference in risk estimates.
Conclusions:
- Empirical evidence indicates no average difference in adverse effect risk estimates between meta-analyses of RCTs and observational studies.
- Systematic reviews of adverse effects should not be limited to specific study types, advocating for the inclusion of both RCTs and observational data.
- Findings support the integration of diverse study designs in systematic reviews to provide a more comprehensive understanding of intervention-related harms.
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