In the Interim... The Fallacy of Ordinal Endpoints
In this episode of "In the Interim…", Dr. Scott Berry and Dr. Lindsay Berry investigate the statistical foundations and clinical implications of analyzing ordinal endpoints, drawing on experience from major stroke and COVID-19 trials. Discussion centers on the Modified Rankin Scale, DAWN, MR CLEAN, and REMAP-CAP, demonstrating that methods such as proportional odds, dichotomization, and utility weighting all impose explicit or implicit clinical weights on the outcome categories. The episode presents direct mathematical derivations, exposes the equivalence between proportional odds models and value-weighted analysis, and uses real trial data to explore how statistical and clinical perspectives on endpoint weighting may diverge. Emphasis remains on transparency and the need for clinically relevant weight assignment in trial endpoints.
Key Highlights
- Structural overview and clinical significance of the Modified Rankin Scale scores.
- Illustration that proportional odds models and dichotomized analyses apply hidden, prevalence-driven or threshold-based weights.
- Utility weighting in DAWN, formulated from EQ-5D patient utilities and economic studies, with observed alignment.
- MR CLEAN investigators' critique of utility weighting; empirical data demonstrated relative consistency and challenged the claim that statistical approaches resolve variation across patients.
- REMAP-CAP platform trial: Organ Support Free Days endpoint analyzed with proportional odds imposed weights on the scale from death to free of organ support .
- Extension of these arguments to win ratio/rank-based approaches, with caution that all methods encode clinical assumptions.
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