FIG. 3.

Power curves for adjusted analyses using regression-based methods (sample n=400 per treatment group). Analyses were adjusted for the baseline probability of unfavorable outcome (i.e., GOSE categories: 1–4), as calculated using the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) core prognostic model. Power curve for sliding dichotomy method (10 prognostic groups) is shown for comparison (red curve). For average percentile method, only results from Wilcoxon rank sum test are displayed in the figure (similar results were noted with t-test). For GEE, we only show the results under the assumption of exchangeable correlation structure (similar results were noted under the assumption of unstructured correlation). GOSE, Extended Glasgow Outcome Scale; GEE, generalized estimating equations.