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Table 2 Statistical power when subgroup analysis is done for each risk factor one-at-a-time

From: Multivariable risk prediction can greatly enhance the statistical power of clinical trial subgroup analysis

  

Risk Factor Prevalence *

  

10%

25%

50%

  

Statistical Power of Subgroup Comparison †

Risk Factor Effect Size (Odds Ratio)

1.5

.08

.12

.13

 

2.0

.13

.21

.22

 

3.0

.26

.41

.44

  1. * Risk Factor is one of six independent risk factors, with the other five risk factors having a prevalence of 25% and an odds ratio of 2 when the 5-year CER for those without any risk factors is .75% (see Table 1 and Figure).
  2. † Statistical subgroup comparisons tests the power to detect whether those with the risk factor had a greater relative benefit from treatment than those without the risk factor.