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Is OR "portable" in meta-analysis? Time to consider bivariate generalized linear mixed model
Medrxiv : the Preprint Server for Health Sciences
|November 11, 2020
Summary
Odds ratios (OR) should not replace relative risks (RR) in clinical trials. Study-specific ORs correlate negatively with baseline risks, challenging the assumption of portability in meta-analyses.
Area of Science:
- Biostatistics
- Clinical Epidemiology
Background:
- A recent proposal suggested replacing relative risk (RR) with odds ratio (OR) for reporting treatment effects in clinical trials and meta-analyses.
- This recommendation was based on the assumption that ORs are 'portable' across studies with varying baseline risks, an assumption that requires careful justification.
Approach:
- Analyzed Spearman's rank correlation between study-specific ORs and baseline disease risk across 40,243 meta-analyses from the Cochrane Database of Systematic Reviews (CDSR).
- Utilized a meta-analysis example (oral sumatriptan vs. placebo) to illustrate the relationship between OR, RR, risk difference (RD), and baseline risk.
Key Points:
- A significant negative correlation was observed between study-specific ORs and baseline disease risk in most CDSR meta-analyses.
- This indicates that higher ORs are typically found in studies with lower baseline risks, contradicting the portability assumption.
Conclusions:
- Replacing RR or RD with OR is currently inadvisable for clinical trials and meta-analyses due to the observed correlation with baseline risk.
- The concept of a 'portable' effect measure in meta-analysis may not hold universally.
- Recommended using bivariate generalized linear mixed models to report conditional effects based on baseline risk, accounting for the correlation between effect measures and baseline risks.
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