Question regarding sample in EBP project

#1
Hi,

I was hoping someone could provide me with some insight for an evidence based practice project I am working on. I'm currently appraising clinical trials in which patients are randomized to receive the experimental drug or the standard currently used drug. I know this is probably simple, but I'm confusing myself about what the actual sample population is, whether it is the intention-to-treat (ITT) group or the all-subjects-treated (AST) group.

For example:
182 participants were randomized, n=88 to the arm of the study I am looking at.
n=48 were assigned to the experimental drug group and n=40 the the control group.

-Within the experimental group, 11 participants were discontinued for various reasons, so the AST and ITT was n=37.
-Within the control group, 2 participants were discontinued for various reasons, and 1 participant received the drug prematurely--this makes the AST n=38 and the ITT n=37. Then another participant was discontinued due to a serious adverse event, making the total who completed the study n=37

My question is, what is the SAMPLE? Is it the original number randomized (n=88), the the AST or ITT groups, or those who completed the study (experimental n=37 + control n=37)?

Thank you!
 

hlsmith

Omega Contributor
#2
So you are looking at a published RCT? Did the publication have a Figure patient inclusion chart, if not make one. I always recommend that one of these are made to truly visualize the study design, application of inclusion/exclusion criteria, and actual sample. It all depends on why you are looking for a sample number? Otherwise the sample size can vary depending on what qualifiers you use in your description. Think about loss to follow up, your sample was 100, but the analytics can only be run on those followed to the end of the study. So now you have multiple sample sizes depending on qualifiers.