"Fot the guesstimated placebo group, what would 15% be equal to in per 100 patient years,... about 8%,...? What formula do I use to caluclate the median to the 100 patient years,...?"
I believe one divides the percentile event rate at the median follow up period by the number years in the median follow up period. So in the hypothetical example of 15% event rate at 24 months, this would equate to 7.5 events per 100 patient years.
BearDownAZ