non-inferiority sample size rare events

Reply
Occasional Learner jsb
Occasional Learner
Posts: 1

non-inferiority sample size rare events

Hello

I need to calculate the sample size in person-years for a single group prospective cohort study (surveillence study) aiming to demonstrate non-inferiority.  I have some information based on population A from a previous study.  I want to obtain the sample size needed to show that the events of interest in population B is non-inferior to population A by some margin or error.  In SAS, there is a one-sample one-sided method for analyzing proportions.  However, my event is extremely rare.  Through quite a bit of searching it seems that the normal approximation is being used to calculate sample sizes such as in my case.  At this point, I have decided to use PROC POWER’s non-inferiority test for a proportion. Does anyone know if it is acceptable by the FDA (or the standard) to use the normal approximation assumption to calculate sample size for non-inferiority trials even when the event is rare?  If it is not acceptable, does someone have advice on which method/procedure you might use or have used?  Or to the software that may help?

 

Post a Question
Discussion Stats
  • 0 replies
  • 117 views
  • 0 likes
  • 1 in conversation