Biostats question help! Thanks.

#1
As I am very new to Biostats and research papers, I have a few questions in regards to a paper that I just read (noninferority of medicine A over D ), please explained the bolded and underscored sections:

#1. noninferiority margin of 2.00 for the upper limit of the two-sided 95% confidence interval of the hazard ratio
#2. We determined that the enrollment of 1000 patients would provide a power of 80% to show the noninferiority of A at a one-sided alpha level of 0.025, assuming an estimated 1-month incidence of the primary efficacy outcome of 7% with D.
#3 Proportional-hazards assumptions were tested with the use of a generalized Wald test for a joint hypothesis on all interaction terms specified in the statistical models

Thank you so much, please explain in layman terms, thanks!!
 

hlsmith

Less is more. Stay pure. Stay poor.
#2
1.) the comparator treatment would have to be greater than 2 units worse than the reference drug for it to be inferior. In particular, the top bound of its 95% confidence interval on the hazard would have to be below greater than the 2 unit threshold.

2.) I don't want to just give you all the answers, so I will let you look up power, since it is pretty straightforward. However, I will note it is calculated based on the investigator's presumed treatment effectiveness. One-sided alpha 0.05 would be the same thing as the 0.05 two-sided version. It just focuses on one of the tails.